Livestock Feed Resources and Feed Evaluation in Europe Present Situation and Future Prospects

LIVESTOCK PRODUCTION SCIENCE Official Journal of the European Association for Animal Production (E.A.A.P) Revue Officielle de la F&d&ration Europ~enne de Zootechnie (F.E.Z.) Offizielle Zeitschrift der Europ~ische Vereinigung for Tierzucht (E. V. T.) Odt3HLIHa/IBHBll;I )KypHa.a EBponeficKofi ACCO[IHauHH NO )K~BOTHOBOACTBy(E.A.)K.)

Editors R D. Politiek (Wageningen, The Netherlands): Editor-in-chief H. de Boer (Zeist, The Netherlands) Honorary Editor-in-Chief J. Boyazoglu (Roma, Italy): E.A.A.P. Secretary General E. Wagner (Luxembourg): Newsletter G. Brem (Munich, Federal Republic of Germany) Ch. Gall (Hohenheim, Federal Republic of Germany) Y Henry (Rennes, France) W.G. Hill (Edinburgh, Gt. Britain) H. Karg (Munich, Federal of Republic of Germany) A. Figueiredo Nunes (Santar~m, Portugal) V. ~stergaard (Foulum, Denmark) J.P. Signoret (Nouzilly, France) M. Soller (Jerusalem, Israel) J D. Wood (Langford, Gt. Britain) Editorial Advisory Board T C. Cartwright (College Station, TX, U.S.A.) M. Cicogna (Milano, Italy) E.P. Cunningham (Castleknock, Ireland) C). Dannell (Uppsala, Sweden) J.C. Flamant (Castanet-Tolosan, France) J.F. O'Grady (Dunsany, Ireland) J. Hodges (Roma, Italy) A. Horn (Budapest, Hungary) R. Jarrige (Theix, France)

L. Ollivier (Jouy-en-Josas, France) K. Rohr (Braunschweig, Federal Republic of Germany) G. Sch5nmuth (Berlin, German Democratic Republic) H. Staun (KeJbenhavn, Denmark) F. Torres (Cali, Colombia) J. Unshelm (Menchen, Federal Republic of Germany)

VOLUME 19 (1988)

ELSEVIER, A m s t e r d a m

- Oxford - New York - Tokyo

XXV

Procedure of the Study GENERAL The working group for this study was set up by the commission on Animal Nutrition of the E.A.A.P. in autumn 1984. It concentrated on compiling technical data, because economic and structural development information is treated exhaustively in the E.A.A.P. issue of 1982. The study includes the updating of information on the availability of forage crops, cereals and other seeds and of by-products of agro-industrial origin. In addition, the nutritional value of these feeds has to be defined. New results of research into the metabolism of nutrients suggested a move onto new evaluation systems. This entailed a shift in the ranking of the economic value of the feeds, and thus in the feed and feeding policy, not only for the farmer but also on the level of international trade. This study deals largely with this topic. While progressing in the study, the group decided that neither problems of import and export of feedstuffs nor a production budget for Europe should be tackled. The reader is referred in this respect to current studies under the auspices of the Organization of Economic Cooperation and Development ( O.E.C.D. ) and the European Economic Community (E.E.C.). WORKING GROUP MEMBERS AND OTHER AUTHORS Members of the working group were experts, invited from various countries/regions in Europe. They were encouraged to contact colleagues elsewhere in Europe to support them. Thus the working group could be kept small and efficient. The group held four plenary sessions-two in Ziirich and two in Brussels-to discuss the work's progress and the drafted chapters. In addition part of the group convened during the E.A.A.P. study meetings in Greece, Hungary and Portugal. The members of the working group were F. de Boer, Institute for Livestock Feeding and Nutrition Research ( I.V.V.O ), Lelystad, The Netherlands (Chairman) J.L. Tisserand, Ecole Nationale Supdrieure des Sciences Agronomiques Appliqu~es, Dijon, France (Secretary) G. Alderman, University of Reading, United Kingdom H. Bickel, Institute of Animal Sciences, Swiss Federal Institute of Technology, ETH-Zentrum, Ziirich, Switzerland Ch. V. Boucqu~, Rijksstation voor Veevoeding, Melle-Gontrode, Belgium 0301-6226/88/$03.50

© 1988ElsevierSciencePublishersB.V.

xxvi Y. Henry, Institut National de Recherches Agronomiques (I.N.R.A.), Centre de Rennes, Saint-Gilles, France Y. van der Honing, Institute for Livestock Feeding and Nutrition Research (I.V.V.O.), Lelystad, The Netherlands J. Lee, Agricultural Institute, Wexford, Ireland A.P. Namur, F~d~ration Europ~enhe des Fabricants d'Aliments Compos~s, Brussels, Belgium F. Sundst~l, Agricultural University of Norway, As, Norway S. Szentmihalyi, Institute for Animal Nutrition, Herceghalom, Hungary (died in 1985 and succeeded by N. Todorov ) N. Todorov, Institute of Zootechnics and Veterinary Medicine, Stara Zagora, Bulgaria H. Vogt, Institut fiir Kleintierzucht der F.A.L., Celle, Federal Republic of Germany H. Zlatic, Institute for Animal Husbandry and Dairy Science, Zagreb, Yugoslavia (left the working group prematurely for health reasons and was succeeded by P.E. Zoiopoulos ) P.E. Zoiopoulos, Feedingstuffs Control Laboratory, Lykovrisi Attikis, Greece. In addition the following authors contributed to the study: E. Austreng, B. Grisdale-Helland, S.J. Helland and T. Storebakken, Institute for Aquaculture Research, As, Norway L.O. Fiems, Rijksstation voor Veevoeding, Melle-Gontrode, Belgium F. Lebas, Institut National de Recherches Agronomiques (I.N.R.A.), Centre de Toulouse, Castanet-Tolosan, France E.L. Miller, University of Cambridge, Cambridge, England J. Morel, Swiss Federal Research Station for Animal Production, Grangeneuve, Switzerland K.P. Parris, Organization for Economic Cooperation and Development ( O.E.C.D. ), Paris, France A.H. Tauson, Swedish University of Agricultural Sciences, Uppsala, Sweden. F. Malossini, Faculty of Agriculture, University of Udine, Italy provided valuable help in checking various chapters for particular aspects involving Mediterranean countries. SUPPORTINGORGANIZATIONS The study has been stimulated considerably by a series of organizations, who have sponsored the work financially or materially. This highly-appreciated support was provided by - Commission of the European Communities, Brussels

xxvii - F~d~ration Europ~enne des Fabricants d'Aliments Compos~s (F.E.F.A.C.), Brussels - Merck, Sharp and Dohme, Brussels - Monsanto Europe, Brussels

Federal Republic of Germany H. Wilhelm Schaumann Stiftung zur FSrderung der Agrarwissenschaften, Hamburg

-

France - Compagnie Franqaise de Nutrition Animale (C.O.F.N.A.), Tours - Guyomarc'H, Vannes - Lilly France, Saint Cloud Organisation Nationale Interprofessionnelle des Ol~agineux, Paris Pioneer France Mais, Toulouse Roussel-U.C.L.A.F., Paris Unigrains, Paris Union Nationale Interprofessionnelle des Proteagineux, Paris -

-

-

-

-

Greece Hellenic Society of Animal Production, Athens Elviz, S.A., Hellenic Feedstuffs Industries, Plati Imathias

-

-

Ireland Irish Corn and Feed Association, Dublin

-

Italy Associazione Italiana di Allevatori, Rome

-

The Netherlands -

Produktschap voor Veevoeder, Den Haag

Norway -

-

-

-

-

Kraftforimport~renes Landsforening, Oslo Norkorn, Oslo Norsk M~lleforening, Oslo Norske Felleskj~p, Oslo Statens Kornforretning, Oslo

Sweden AB Cardo, Malm5 - Sollebolagen AB, Uddevalla Svenska L a n t m a n n e n s Riksforbund, Stockholm -

-

oo, XXVlll

- Svensk Oljeextraktion, Karlshamn Switzerland

Hoffman-La Roche, Basel Migros Genossenschaftsbund, Ztirich - V e r e i n i g u n g der Landwirtschaftlichen Genossenschaftsverbande Schweiz, Winterthur Vereinigung Schweizerischer Futtermittelfabrikanten, Zellikofen -

-

der

United Kingdom

British Society of Animal Production, Penicuik - Eli Lilly Co., London Paul's Agriculture, Ipswich -

Highly-appreciated support was also received from the Institute for Livestock Feeding and Nutrition Research ( I.V.V.O. ) in Lelystad, as well as from the Institute of Animal Sciences, Swiss Federal Institute of Technology, ETH Zentrum, Ztirich, which provided mailing, typing and other facilities. We thank all group members and other authors for their great efforts to complete the task in the time scheduled, in spite of the daily obligations in their professional positions. The editors pay special tribute to G. Alderman, University of Reading (U.K.) for the linguistic revision of various texts. PROF. DR. H. BICKEL President (1980-1986) E.A.A.P. Commission on Animal Nutrition

IR. F .

DE

BOER

Chairman E.A.A.P. working group

Livestock Production Science, 19(1988)1

1

Elsevier SciencePublishersB.V., Amsterdam-- Printed in The Netherlands

Foreword

It is generally recognized that feed is the most important single item in livestock production costs. Thus awareness of the feed resources, and knowledge of the nutritional value of feedstuffs in order to feed the animal adequately to its requirement, are as essential as the knowledge of the genetic potential of the animals and of the management of production. In 1982 Politiek and Bakker edited the E.A.A.P. long range study "Livestock Production in Europe, Perspectives and Prospects". It provides a wealth of qualitative and quantitative information on European livestock production. Livestock feeding is touched on in various chapters of that study but in a rather general way. The Commission on Animal Nutrition of the European Association for Animal Production, therefore, decided to set up a working group to collect information about animal feeds in the European context. This book, published as a double issue of the E.A.A.P. journal "Livestock Production Science", is the report of the working group. Some 25 specialists generously contributed their time and knowledge to the study. The best thanks are due to all those who contributed to this important study. Credit is specially paid to Ir. F. de Boer, Chairman of the Working Group, and Prof. Dr. H. Bickel, President of the E.A.A.P. Commission on Animal Nutrition during the relevant period, for their efficient leadership of the work. A number of international and national organisations within the agricultural industry have kindly sponsored the study. Many thanks are due to them for this valuable support. ARNE ROOS President European Association for Animal Production

Livestock Production Science, 19 (1988) 3-10 Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands

3

I. I M P A C T OF F E E D IN L I V E S T O C K PRODUCTION F. DE BOER and H. BICKEL INTRODUCTION

The economic production of livestock products as human food is achieved by combining a number of factors, which are under the control of the livestock farmer. He has to combine the effects arising from the genotype and health of the animal with optimal nutrition and environmental conditions. Livestock research, education and extension have been concerned with these factors for a long time. The magnitude of effort in the different sectors in the past has not been equal, nor closely co-ordinated. The breeding of animals was the first area to receive a great deal of attention, resulting in remarkable progress in increasing the productive potential of the various types of livestock: cattle were bred specifically for their ability to produce milk or meat, or even to be dual purpose; pigs were bred to produce varying proportions of lean-to-fat ratios in the carcase, whilst poultry were bred either primarily for egg production or for meat production. Many different types of sheep breeds have been evolved with the production of wool as an additional parameter. At first, breeding goals were more concerned with typical shape and colour traits, with the presumption that these were related to production characteristics, often leading to exaggerated emphasis on these characteristics, as can still be seen in the livestock show rings today. Nevertheless, supported by the results of modern genetic research activity, the end result has been the breeding of highly-productive livestock for many different purposes. Animal health, or freedom from animal disease, has also been a major sector of research, development and application in livestock production. In contrast to livestock breeding, its effects on livestock productivity is often striking, particularly the ability to cure or prevent a particular disease. The establishment of the nutrient requirements of animals and reliable systems for feed evaluation has taken a great deal of time, but farmers can alter the way they feed their livestock quite rapidly, and affect livestock production considerably in this way. The striking effects of feeding upon livestock production are probably responsible for the farmers saying "First feeding, then breeding". This statement does not imply that priority should be given to feeding above breeding, or the reverse, but rather that animal breeding cannot be done successfully in the absence of good feeding. Nowadays, because of the very high genetic potential of European livestock, 0301-6226/88/$03.50

© 1988 Elsevier Science Publishers B.V.

and the sophisticated and still-developing animal feeds and nutritional science, concerted action by both disciplines, together with animal-health programmes, is essential for further progress in livestock production. The goal of sustaining high levels of yield for long periods will only be reached, however, if optimal environmental conditions such as housing, climatic conditions and farm management, are provided. Such factors have been less important when animal production levels were at a more moderate level, but in the current sophisticated systems, with high levels of individual production by animals, their influence is becoming increasingly important. The pursuit of high individual production levels in livestock is economically feasible, because the fixed costs of the livestock-production system, involving housing, capital investment, equipment and so on, are spread over a greater quantity of output and their effects are reduced in the overall costs of production. FEED COSTS AND EFFICIENCYIN LIVESTOCKPRODUCTION At the physiological level, the amount of feed used per unit of livestock product depends mainly on the ratio of food energy output by livestock, related to the animal feed-energy input. Other criteria such as protein in both food and feed can also be considered. However, the efficiency of feed energy utilisation is by far the most important and comprehensive measure by which to judge the efficiency of animal-feed usage. Two levels of efficiency of feed energy utilisation can be defined: (1) the animal level, i.e. the efficiency of energy utilisation by the individual animal; (2) the production-system level, i.e. the efficiency of energy utilisation by the whole production system. The efficiency of energy utilisation at the animal level improves as the ratio of production energy increases, in relation to the animal's maintenance requirement, i.e. increasing the animal's level of production. The amount of feed used per unit of livestock product decreases accordingly. However, the law of diminishing returns will also apply beyond a certain point, depending on the type of livestock production involved, which may result in lower profitability of higher production levels. The energy value of the animal feed itself, the livestock products, and the partial efficiency of feed energy utilisation for the particular livestock product, all influence total efficiency, and thus overall feed costs (Bickel, 1977). However, judging feed efficiency merely on the level of the individual animal production, may give a biased picture. Blaxter (1969) stressed that the efficiency of the complete production system has to be taken into account. This means that the number of offspring of the parent generation, the production costs of rearing these, and their replacement rate, should be considered when making a final judgement of the complete system. The output of food produced by the system, has to be compared to the total feed input to the system. Ex-

TABLE 1 Efficiencyof foodproductionby livestock-productionsystems Calculationbasedon

Dairy cattle Beefcattle Pigs Hens Broilers

Gross Energy

Gross Protein

H a

Bb

H

B

0.12 0.11 0.17 0.11 0.10

0.12-0.19 0.06 0.21 0.15 0.16

0.23 0.06 0.12 0.18 0.20

0.21-0.28 0.11 0.16 0.31 0.26

aH= Holmes (1970). bB = Bickel (1977). amples of the efficiency of feed utilisation, considering all these factors, are given in Table I, as calculated by Holmes (1970) and Bickel (1977): It is evident that the efficiencies of various total-production systems vary according to the energetic efficiency of the individual animal, its prolificacy, longevity and replacement rate. Irrespective of differences in these parameters, pig-production systems show the highest levels of efficiency, and beef production, when not combined with milk production, the least efficient use of feed energy. Of all the costs involved in the various animal-production systems, feed costs are the most important single item. This is illustrated in Table II for some countries, although the method of calculation differs for each country. It is obvious that feed costs as a percentage of total production costs vary with the livestock-production system. If the fixed costs, such as calf rearing, housing and capital investments are high, the farmer will try to reduce these costs per unit of product by increasing the production level. If the financial income from the livestock product is smaller than the total cost of production required to maintain and manage the livestock unit, the farmer or the unit will lose money, and probably ultimately stop production. Thus, controlling production costs of the system is a very important aspect of management of livestock-husbandry systems. Farmers can affect many of these factors themselves, whereas affecting the selling price of the product is far more difficult. Increasing individual animal productivity is not without its risks to the longevity and health of the animals involved. Overcoming such problems requires careful integration of the disciplines involved in livestock husbandry, environment, breeding, feeding and health care. If these important areas are given careful attention, very high individual production levels can be achieved without adverse effects (de Boer, 1986).

6 TABLE II Feed costs as percentage of total costs of livestock farming, costs of family labour on farm excluded, in some countries Country

Veal Beef Milk Pigs

Poultry

Source

Breeding Fattening Hens Broilers Belgium

65

55

42

46 44

Denmark France

18 34 69 43 14 65

F.R.G. Greece Ireland Italy Luxemburg Netherlands

28 28 46 33 64 44 60 49 44

82

82

85

70

63

66

70 75 74

63

83 58

69

82

86

69

64 83 84

64 83 59

64

76 62

64

68

Norway

59

55 60

Switzerland

48

46

45

51

54

58

U.K. Yugoslavia

20

23 14

44 34

42

74 40

52

Buyle (1984) Goffinet (1984) Buyle (1986a, b) F.A.D.N. (1986) F.A.D.N. (1986) Teffene and Vanderhaegen (1986) Stevens (1987) F.A.D.N. (1986) F.A.D.N. (1986) F.A.D.N. (1986) Lee (1987) a F.A.D.N. (1986) F.A.D.N. (1986) F.A.D.N. (1986) Wisselink (1984) b F.A.D.N. (1986) Sundstol, Homb and Herstadt (1987) c Bickel (1987) d S.B.V. (1986) F.A.D.N. (1986) Zlatic (1987) e

aj. Lee, personal communication, 1987. bG.j. Wisselink (1984), personal communication based on Landbouwcijfers. LEI, s'Gravenhage. CF. Sundstol, Th. Homb and O. Herstad, personal communication, 1987. dH. Bickel, personal communication, 1987. Based on "Schweizerischer Bauernverband" Brugg and on "Verband Schweizerischer GefRigelhalter". Zollikofen. ell. Zlatic, personal communication, 1987. Figures are an average of regions with very different production conditions. The purchase price of animals is relatively high, thus causing relatively low figures for feed costs. FEEDSANDFOODS

Although physiological efficiency calculations concerning feed energy utilisation are essential for the understanding of the differences in feed-conversion ratios between animal species, they do not explain why production systems with low efficiencies of energy utilisation are not only maintained but even promoted in some areas. This is a consequence of the competition between mankind and animals for food resources. The proportion of animal feed which

T A B L E III Area utilizable for agriculture (106ha) (F.A.O., 1973, 1985; S.B.V., 1986) World

Arable land Pastures Ratio of pastures to arable land

Netherlands

Switzerland

1973

1984 a

1973

1984 ~

1972

1985 a

1985 b

1460 2990

1476 3151

0.8 1.3

0.9 1.1

0.3 1.7

0.3 1.7

0.3 0.8

1.6

1.2

6.2

6.2

2.7

2.0

2.1

aAdded to original table. bWithout Alpine pastures.

is readily acceptable as food for human nutrition has to be taken into account in this matter. A number of animal feeds are suitable for human food as well, cereals being a classic example, but there are others such as skimmed milk powder, peas, potatoes and some byproducts such as wheat bran. The use of such products as feed for livestock is criticised by some people who are concerned about human societies suffering from shortages of food. Some go so far as to suggest that livestock husbandry should be discontinued or reduced in scale. They suggest that all land occupied by feed suitable for livestock should be used instead for the production of human food. These criticisms are backed up by citing the efficiency rations of food production by animals and food production by arable crops. Invariably these comparisons come out in favour of primary food production by plants. There is no argument about that fact, but the picture is an over-simplification. This questioning of the continuance of any form of livestock husbandry overlooks the fact that large areas of the world (and Europe) are unsuited for the production of food crops, as shown in Table III, (de Boer, 1975). Table III shows that there is twice as much pasture as arable land in the world. Even in areas with a high percentage of "utilised agricultural area" (UAA), as in The Netherlands, the area of pasture exceeds the area of arable land. This is particularly the case in Alpine regions such as Switzerland. Vegetation from pastures can only be utilised efficiently by ruminant livestock, cattle, sheep and goats. This is also true for the large amounts of byproducts now produced by the food-processing industries. Such vegetation and by-products generally cannot even be utilised by human beings at all. The use of ruminant livestock therefore, is a necessity, in order to produce food from these sources, and so act as a two-stage primary-food producer (de Boer, 1980 ). Schtirch (1975) stresses this fact, stating that maximally, only 25% of the total animal feed used for ruminant production can be used directly for human nutrition. This p h e n o m e n o n of a two-stage primary-food production system requires a different approach in calculating feed-utilisation efficiency ratios.

8 TABLE IV Yield of food energy and protein of animal origin in relation to energy and protein input, which would be directly acceptable to human nutrition Energy E" Milk from dairy cattle Beef Milk and beef (double-purpose breeds) Pork Eggs Poultry meat

Protein Bb

2.30 1.30 (0.41) ~ 0.40 0.23 0.29

E 3.0 2.7 (0.94) ~

1.2 0.4 0.2 0.3

0.34 0.40 0.43

aE = van Es (1978). bB = Bickel et al. (1979). CCereal-based intensive feedlot system.

Although the calculations of efficiency of feed-energy utilisation are correct when comparing individual animals or production systems, they do not deal satisfactorily with the problem if man and animals compete for the same food resource. Differences in the proportion of feed acceptable to both human and animal nutrition vary with animal species and production systems. Van Es (1978) and Bickel et al. (1979) have calculated the ratio of animal-product energy related to the food energy utilised by these animals which would have been directly acceptable for h u m a n nutrition (Table IV). Table IV shows clearly, for example, that cows produce 2.3 times more humanly-acceptable food energy by converting roughage to food than that which would be directly available from arable land. It is also clear from the data that feeding concentrates to non-ruminants, pigs and poultry, does utilise food suitable as human food. Just as in the case of the ruminants however, some of these concentrates can be partly replaced by by-products. However, transport costs, the lack of an adequate infrastructure and purchasing power in many parts of the world, prevent farmers responding rapidly to economic trends, so that we may not see much change in the near future in this area. LIVESTOCK FEEDING, CONSUMERHEALTH AND ENVIRONMENTAL POLLUTION

Increased concern is being expressed these days about possible health risks to the population from the consumption of food being produced by modern agriculture. There is also increasing concern about pollution of the environment arising from aspects of livestock production. Such concerns deserve appropriate and adequate attention. In the case of livestock husbandry, animal

feeds are used as carriers for a wide range of additives, which are very beneficial to the livestock concerned. Consumers, however, need to be reassured that no trace of these additives is present in the food that they purchase for eating. Sometimes animal feeds also contain other agents, such as moulds or bacteria, which may be harmful to consumers. Whilst animals possess, as do humans, a sophisticated physiological purification system (the liver and kidneys ), which often but not always prevents the passage of such contamination, a continuous awareness of these risks is needed. The increasing pollution problem arising from livestock production is due to the fact that roughly 40% (Bickel et al., 1979) of the feed energy ingested is excreted as waste: faeces and urine. Apart from causing complaints in denselypopulated areas about serious and offensive odours, the accumulation of various mineral elements in soil and in surface water may also cause problems. The quality of drinking water may be impaired in the long run, and natural vegetation may also suffer from the mineral imbalances. Appropriate alterations in feeding technology and quality may alleviate these problems. For example, it has been shown that the excessive pollution by phosphorus on pig farms can be successfully restricted by lowering the level of phosphorus addition to feeds, and by utilising the intrinsic phosphorus in feeds, particularly that associated with phytate, more efficiently, {Jongbloed, 1987 ). It is possible that the pollution by other elements, particularly heavy metals, could be curtailed substantially in a similar manner. It is evident that livestock farmers, in accepting new developments in animal nutrition, must ensure that any risk to consumer health and environmental pollution is excluded when adopting such new techniques.

REFERENCES Bickel, H., 1977. Der Futteraufwand in der Rindviehproduktion unter Beriicksichtigung des Wirkungsgrades der Energieverwertung. Schweiz. Landwirtsch. Forsch., 16: 175-214. Bickel, H., Schiirch, A., Zihlmann, F., Studer, R. and Fiissler, P., 1979. Energieaufwand und Energieertrag in der Tierproduktion. Ber. Landwirtsch. Sonderh., 195: 31-39. Blaxter, K., 1969. Efficiency of Farm Animals in Using Crops and Byproducts in Production of Foods. Proc. 2nd World Conf. Anim. Prod., Bruce Publ. Co., St. Paul, MN, pp. 31-40. Buyle, A., 1984. La rentabilit~ de l'engraissement de taurillons. Rev. Agric. (Brussels), 37: 672-683. Buyle, A., 1986a. La rentabilit~ des productions avicoles dans les exploitations sp$cialisSes. (Exercice 1985-1986); Inst. Econ. Agric. Publication no. 473. Buyle, A., 1986b. La rentabilit~ des productions porcines dans les exploitations sp~cialisSes. {Exercice 1985-1986), Inst. Econ. Agric., Bruxelles. Publication no. 474. De Boer, F., 1975. Van wat de mens niet lust of smaakt wordt door het vee iets goeds gemaakt. Bedrijfsontwikkeling, 6: 131-135. De Boer, F., 1980. Bij- en afvalprodukten als veevoer. Diergeneeskd. Mere., 27: 203-211. De Boer, F., 1986. Perspectives of bovine production. From cow to supercow? In: DSA (Bureau Europden d'Information pour le D~veloppement de la Sant~ Animale), Symposium proceed-

10 ings: Future Production and Productivity in Livestock Farming: Science versus Politics, Elsevier, Amsterdam, pp. 21-36. F.A.D.N. (Farm Accountancy Data Network), 1986. Document 1982/1983-1983/1984; Office for official publications of the European communities; Luxembourg. Data provided by K.J. Poppe, LEI,'s Gravenhage. F.A.O., 1973. Production Yearbook, Vol. 27, F.A.O., Rome. F.A.O., 1985. Production Yearbook, Vol. 39, F.A.O., Rome. Goffinet, R., 1984. Structure du prix de revient du lait pour un ~chantillon d'exploitations avec 40 60 vaches et un rendement laitier compris entre 4000 et 5000 litres. Communication interne, Inst. Econ. Agric., Bruxelles. Holmes, W., 1970. Animals for food. Proceedings of the Nutrition Society. 29: 237-244. Jongbloed, A.W., 1987. Phosphorus in the feeding of pigs. I.V.V.O., Lelystad. Thesis, 343 pp. S.B.V., 1986. Statistische Erhebungen und Schiitzungen: 63. Schweizerischer Bauernverband, Brugg. Sch~irch, A., 1975. Kongressband 1974; Die Bedeutung der Tierproduktion fiir die Sicherung der zukiinftigen Ern~ihrung. Landwirtsch. Forsch., Vol. 31. Erstes Sonderheft, pp. 21-35. Teffene, O. and Vanderhaegen, J., 1986. Economie des productions porcines. In: J.M. Perez, A. Rerat and P. Mornst (Editors), Le porc et son ~levage. Bases scientifiques et techniques. Maloine, Paris, pp. 503-565. Van Es, A.J.H., 1978. Losses and gains of energy during production of food for human consumption in animal husbandry. Agric. (Leuven), 23: 359-374.

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II. F E E D S T U F F S II. 1. I n t r o d u c t i o n F. DE BOER

Any product of vegetable or animal origin may be classified as a feedstuff, provided animals are capable (without risk to their health) of utilizing its organic and inorganic components. This implies that there is a large variety of feedstuffs and, therefore, classifying feedstuffs is a necessity. Roughages (or forages) and concentrates are generally accepted as classes of feedstuffs. Trying to define in an appropriate and simple way a set of criteria for them is fairly difficult, but it is nevertheless very useful for statistical purposes. Crude-fiber content is often a criterion for characterizing both groups of feedstuffs; in general roughages contain more and concentrates contain less than 18% crude fiber (Crampton, 1956). Even so, feedstuffs in each group show considerable variety. Fresh feed, such as grass, would belong to the group of concentrates. It is nevertheless classified as a roughage because of its high moisture content, which means a low level of nutrients per unit of weight. This also applies to other feedstuffs when their moisture content is more than 40% (O.E.C.D., 1985). Roughages and concentrates may therefore be characterized along three criteria as shown below

Roughages Concentrates

Dry-matter content in feed

Level of nutrients per unit weight of feed

Crude-fiber content in feed

< 60 > 60

Low High

> 18 < 18

The statistical Office of the European Economic Community (Eurostat) splits feedstuffs in groups that are marketable and not marketable, broadly covering concentrates and roughages respectively. However, when considering single feedstuffs from both groups individually it is easy to find exceptions to these rules. Some roughages, such as first-class wilted silage, may approach or even enter the class of concentrates, while a feedstuff such as artificially-dried grass - clearly a marketable f e e d - belongs, according to its crude-fiber content, 0301-6226/88/$03.50

© 1988 Elsevier Science Publishers B.V.

12 to the group of roughages. In general, however, the criteria quoted above permit feedstuffs to be classified in a very acceptable way. In the class of concentrates cereals traditionally play a predominant role. In some regions, however, this picture has changed considerably and cereals have been partly replaced by cereal substitutes such as manioc, while simultaneously by-products from food industries have gained more and more importance as well. By-products, of vegetable as well as of animal origin, form a "floating" class of feeds. Technology of feed processing into food produces a continuous and ever changing flow of by-products. Some of these (oilmeals) have a long and reputable history, others became available more recently, and yet new ones will come into the picture in future. Compound-feed industries have combined these various concentrates into compound feeds, and these have made a very big impact on livestock production today. Based on this pragmatic approach, the following chapters will illustrate in more detail the impact of forages, cereals and other seeds, by-products of vegetable and animal origin and compound feeds for livestock feeding in Europe.

REFERENCES Crampton, E.W., 1956. AppliedAnimal Nutrition. W.H. Freeman and Co., San Francisco, CA, pp. 3-11. O.E.C.D., 1985. The O.E.C.D. Feed Supply Utilization Account (F.S.U.A.): A methodologyto completeF.S.U.A.sat a national level.O.E.C.D., Paris (Mimeograph).

Livestock Production Science, 19 (1988) 13-46

13

Elsevier SciencePublishers B.V., Amsterdam-- Printed in The Netherlands

II. 2. Forages JOHN LEE INTRODUCTION General

In the broadest sense, forage refers to the vegetative portions of plants that are consumed by animals and for the purpose of this review embraces natural and artificial or sown grassland, annual and perennial green fodder from arable land and certain crop residues. It includes pasture, rough grazing, hay, silage, root crops, forage maize, straw and certain root tops. Rough grazing land denotes communities of natural plants that are grazed or browsed. Forages have a bulky nature in comparison to concentrates. Thus, bearing in mind the capacity of the rumen and the filling effect of forages in the gut, supplementary feeding with concentrates is frequently practised to satisfy nutritional needs. As increasing amounts of supplementary concentrates are fed, the ruminant animal eats less forage. In many cases supplementary concentrates partly replace rather than supplement the forages with which they are fed. Feeding very high concentrate levels may even decrease intake of forage, and result in a change in composition of volatile fatty acids in the rumen to an extent which brings about ruminant disorders. The large variability in feed composition is illustrated in Table I, which presents some examples of major forages from various regions in Europe. Grass, which is the major component of the forages, has the advantage of being, to a large degree, a complete diet for ruminants in most circumstances. However, it is not balanced for all possible animal production purposes and has a variable composition, in contrast to cereals which have a high and consistent energy value, and therefore compared with grass are more predictable and easier to feed. Young leafy grass has, for example, an excess of protein combined sometimes with a high soluble-carbohydrate content. The forages may be conveniently categorised under the headings grassland, root crops and green fodder from arable land, the latter two comprising annual fodder crops. Table II shows the extent of the major forages. Permanent grassland is the most significant, in terms of areal extent, with temporary grassland being particularly significant in Denmark. Temporary grassland also has a major significance in Fennoscandia (Finland, Sweden and Norway), where the grassland balance comprises 2.0 Mha under leys and 0.7 Mha under permanent 0301-6226/88/$03.50

© 1988ElsevierSciencePublishersB.V.

14 TABLE I Examples of forage composition in Europe Forage

Dry matter (gkg -1 forage)

Fresh grass N 140-305 M 183-280 E 168-340 Grass hay N 882-951 M 859-936 E 840-883 Oat and vetch hay M 790-862 Grass silage N 177-585 E 154-265 Maize silage N 240-350 M 233-397 E 143-350 Maize stover M 291-916 E 334-421 Potatoes N 219-221 E 231-257 Sugarbeetleaves andtops, ensiled N 180-230 M 178 E 133 Fodderbeets N 127-214 E 133

Organic matter (g kg -~ DM)

Crude protein (g kg -1DM)

Crude fibre (gkg -1 DM)

Metabolisable energy (MJ kg -1DM)

810-937 860-930 880-945

63-259 80-174 65-195

167-359 174-320 201-370

7.0-13.2 7.1-12.0 6.4-11.4

844-942 851-940 879-950

52-199 75-196 76-175

172-397 244-389 235-371

5.9-12.9 7.7-9.7 5.1-9.8

870-929

74-158

268-333

8.3-9.6

861-953 863-927

90-260 102-203

185-360 229-348

6.7-12.1 7.3-11.9

961-967 929-951 905-944

78-106 81-94 68-109

165-275 206-273 214-353

7.5-11.7 9.7-9.9 8.3-9.9

889-940 883

44-54 81-84

292-362 346-370

6.3-8.0 7.8-7.9

926-949 953-954

90-113 73-83

22-33 27-28

11.8-13.4 10.9-11.0

670-678 652 917

104 90 110

907-948 917

55-76 110

135-148 107 73 43-128 73

7.9 7.7 10.3 11.6-12.5 10.3

N = North and Western Europe; M = Mediterranean area; E = Eastern Europe. References for N: I.N.R.A., 1978; D.L.G., 1982; LTK, 1982; M.A.F.F., 1986; Centraal Veevoederbureau, NL, 1983. References for M: I.A.M.Z., 1981, 11. References for E: Berlacu, 1983; N. Todorov, personal communication, 1970.

p a s t u r e . R o o t c r o p s a r e s i g n i f i c a n t in P o l a n d , a n d a r a b l e g r e e n f o d d e r ( l a r g e l y f o r a g e m a i z e ) h a s a m a j o r s i g n i f i c a n c e in F r a n c e , I t a l y a n d D e n m a r k in particular. F o r a g e s f r o m t h e a b o v e s o u r c e s a r e f e d to r u m i n a n t a n i m a l s b e c a u s e t h e y

15 TABLE II Extent of major forages ( 103 ha) Permanent grassland

Austria Belgium Bulgaria Czechoslovakia Denmark France Finland F.R.G. G.D.R. Greece Hungary Iceland Ireland Italy Luxemburg The Netherlands Norway Poland Portugal Romania Spain Sweden Switzerland U.K. Yugoslavia U.S.S.R.

2100 656 (77) 2216 (85) 2458 (77) 243 (22) 12 734 (61) 153 4675 (78) 1673 (74) 5271 1888 (80) 2300 4562 5121 (62) 70 (74) 1143 (84) 155 5466 (80) 3.0 5231 (90) 11 000 367 1600 11 754 (75) 6400 320 000 (89)

Temporary annual grass

Feed root crops

35 9 171 326 2665 735 107 106 300 82 587 300 8 35 376 288

-

(4) (0.3) (5) (30) (13)

18 16 18 132 305

(2) (5)

134 (2) 63 (3)

(3)

20 (1)

(4) (9) (3)

24 31 (0.4) 0.1 (0.1) 2 (0.1)

(4)

.

. 218 (4)

(2) (0.6) (1) (12) (2)

257 (4) . 88 (1)

899 1844 (12) 17 774 (5)

Green fodder from arable land (maize, clover, lucerne, etc.)

119 (1) 1714 {0.5)

143 366 555 397 5045

Total

(17) (14) (17) (36) (24)

852 2607 3202 1098 20 749

1086 (18) 406 (18) 371 (16)

6002 2248

2755 16 185 864 . 277 1891

{33.5) (17) (13) (12) (5)

(12)

21 752 (6)

2361 5173 8207 94 1365 6875 5814 15608 361 240

Percent area in parentheses. Sources: Eurostat, 1983; C.M.E.A., 1979; A. Kornher, personal communication, 1983.

can convert forage cellulose into utilisable nutrients through microbial fermentation, whereas simple-stomached animals are of course largely dependent on cereals/concentrates. Melville (1960) argued that the output of human food energy and protein from a hectare of land utilised by ruminants is only a fraction of the output which can be obtained in the form of direct-use crops such as cereals, and that, in view of the poor nutritional status of much of the world's population, land devoted to producing "luxury" feeds should be diverted to direct-use crops. Against this background it is relevant to investigate the extent to which forage areas could, if necessary, be diverted to direct-use food

16 crops. Areas devoted to feed grain are excluded since it is a plausible assumption that they are also suited to direct-use food crops.

E.E.C. region The Utilised Agricultural Area (UAA) of EEC-10 extends over 101.9 Mha, and comprises 49.3 Mha of arable land, 46.2 Mha permanent grassland and 6.0 Mha temporary grassland. In the arable category annual forage crops occupy 4.5 Mha with lucerne occupying 2.0 Mha. Since the land-use types, temporary grassland, annual forages and lucerne, have similar soil requirements to food crops, it may be inferred that 12.5 Mha could, if necessary, be diverted to direct-use food-crop production. It is notable that France alone accounts for 40% of the total area with this land-use option. A study of the land resource base of the EEC-10 (Lee, 1986) concluded that 30.6 Mha were well suited to cultivation, 26.7 Mha were suited, 48.5 Mha were moderately/poorly suited and 48.4 Mha were unsuited. While cultivation is feasible on the moderately/poorly suited category it must in practice be largely excluded from consideration for mechanised arable systems, and it was concluded that the land pool having viable arable land use options was limited to 57.0 Mha, classified as being well suited or suited to cultivation. It must, nevertheless, be concluded from the above figures that the permanent grassland areas in the main correspond with the lower arable suitability classes and would not therefore, have an alternative food-crop option.

East and South East Europe Eastern European diets are basically cereal-based, while Western European diets contain a large share of grassland products. In Eastern Europe grassland does not play an important role in ruminant production, the percentage UAA under grass is small, and relatively low yields suggest natural grassland farming and a general restriction of grassland to areas of poor suitability for arable use. The major grassland areas include the valleys and flood plains of rivers and hill/mountain zones such as the Carpathians, the Stara Planina and Rhodope foothills and the Transylvanian Alps. Grains form the most significant part of the feed resources, ranging from 30-40% of the forages and feed resources in Romania and Poland to 60-70% in Hungary and Bulgaria. Areas devoted to feed grains would also be adapted for direct-use food-crop production as would the non-grain fodder-crop area (fodder roots, forage/green maize and grass crops). The latter category extends over 9.2 Mha in the Centrally Planned Economy (CPE) zone (Yugoslavia included).

17 GRASS

General The best index of the impact of grassland utilisation in a country is the extent of the agricultural area that is devoted to grassland (Table III). As stated earlier, there are pronounced geographic differences in that parameter. Another important factor is pasture composition. For example, the EEC-10 grassland area of 53.0 Mha (50% UAA) includes 6.0 Mha of temporary grassland, with France and the U.K. accounting for the major component, and it is notable that a high proportion of temporary pastures also occur in Denmark. These pastures are most responsive to management inputs and their yield performance is superior to that of permanent grassland.

Agro-ecologic variation Because of considerable variation in agro-ecological conditions, grassland productivity may show considerable spatial variation in Europe. It is appropriate, therefore, to examine these variations. For this purpose, Europe may be divided into five major geographic/climatic regions ( Papadakis, 1966) ( Fig. 1 and Table III) which are described below. (i) North West and West Europe: France (North West); Benelux; Denmark; U.K.; Ireland. Cool marine-cool temperate climate dominant. ( ii ) Central Europe: Federal Republic of Germany ( F.R.G. ) ; German Democratic Republic (G.D.R.); Poland; Czechoslovakia; Hungary; Switzerland; Austria. Cool temperate climate dominant in the north, warm continental-steppe dominant in the south and Taiga in the high alps. ( iii ) South East Europe: Bulgaria; Romania; Yugoslavia. Steppe climate dominant in lowlands and semi-warm continental-cool temperate dominant in mountain zones. (iv) Mediterranean Europe: Portugal; Spain; Italy; France (South); Greece; Yugoslavia (coastal). Mediterranean climate dominant. (v) Northern Europe and European U.S.S.R.: Fennoscandia; Iceland; U.S.S.R. Cool/cold temperate climate dominant in Fennoscandia and the Baltic Republics and cold continental dominant in the U.S.S.R.

Actual production in Europe Management inputs are highly significant in grassland production; these include the level of fertilizer input, the grazing system and the application of irrigation. Owing to possible intra-country variation in ecological factors it is difficult to apply reliable national pasture output figures. Nevertheless, based on a comprehensive examination (Lee, 1983 ) Table IV sets out such acom-

18

10.2

10.1

__

6%,

,p

~s

II 0

7.7

7-2 ( ~ )

7.6

7"6

9"2

7.5

6'2

~

6.8

%1

Fig. 1. C l i m a t i c R e g i o n s . 6 = M e d i t e r r a n e a n : 6.1 = s u b t r o p i c a l m e d i t e r r a n e a n ; 6.2 = m a r i n e m e d i t e r r a n e a n ; 6.5 = t e m p e r a t e m e d i t e r r a n e a n ; 6.6 = cold m e d i t e r r a n e a n ; 6.7 = c o n t i n e n t a l m e d i t e r r a nean; 6.8=semi-arid subtropical mediterranean; 6.9=continental semi-arid mediterranean. 7 = M a r i n e : 7.1 = w a r m m a r i n e ; 7.2 = cool m a r i n e ; 7.3 = cold m a r i n e ; 7.5 = w a r m t e m p e r a t e ; 7.6 = cool t e m p e r a t e ; 7.7 = cold t e m p e r a t e . 8 = C o n t i n e n t a l : 8.2 = s e m i - w a r m c o n t i n e n t a l ; 8.3 = cold c o n t i n e n t a l . 9 = Steppe: 9.1 -- w a r m s t e p p e ; 9.2 = s e m i - w a r m s t e p p e ; 9.4 = t e m p e r a t e s t e p p e . 10 = Polar: 10.1 = taiga; 10.2 = t u n d r a ; 1 0 . 4 - - i c e cap; 10.5 = a l p i n e . Source: P a p a d a k i s , 1966.

19 TABLE III Extent of grassland by the major regions and share of grassland in UAA Region

Grassland (106 ha)

Percentage of UAA

North West and West Europe France The Netherlands Belgium Luxemburg Denmark U.K. Ireland Total

15.4 1.2 0.7 0.1 0.6 13.6 5.1 36.7

49 59 49 60 21 73 90 59

Central Europe F.R.G. G.D.R. Poland Czechoslovakia Hungary Switzerland Austria Total

4.8 1.8 5.7 2.6 2.0 1.6 2.1 20.6

40 22 33 25 20 80 56 34

South East Europe Bulgaria Romania Yugoslavia Total

2.2 5.4 6.4 14.0

30 30 44 36

Mediterranean Portugal Spain Italy Greece Total

3.0 11.0 5.4 5.6 25.0

50 35 30 60 39

1.3 0.5 0.9 2.3 5.0

36 52 35 99 53

101.3 337.8

44 61

439.1

54

Northern Europe Sweden Norway Finland Ireland Total Europe U.S.S.R. Europe and U.S.S.R., total

For some countries outside the E.E.C. temporary grassland may be excluded. Sources: Eurostat, 1981; F.A.O., 1979; A. Kornher, personal communication, 1983.

20 TABLE IV Estimated production from grassland and level of N application (1981) Average pasture/hay yield ( D M kg h a - ' ) North West and West Europe France 4500 The Netherlands 12 000 Belgium 1 6000-12 000 Denmark 10 000 U.K. 5000-6000 Ireland 6000-7000 Central Europe F.R.G. G.D.R. Poland Czechoslovakia Hungary Switzerland Austria

South East Europe Bulgaria Romania Yugoslavia Mediterranean Portugal Spain Italy Greece Northern Europe Sweden Norway Finland Iceland

Average N application ( kg ha - ~) 30 265 50-300 150-250 39-167 50

5870 3270 3000 2180-3000 1600 2000-9000 (Hill) 2400-4500 (Hill)

100 -

500-2500 (Pasture) 1500-6000 (Hay) 2000 + 2700-5400

300-2000 1000 (South) 1000 (Pasture) 2200-7360 (Hay) 2000

1500-3000 5000 1500-3000 3830 4000

20 20 20 20

(North) (South) (North) (Hay) (Hay)

'C.V. Boucqu~, personal communication, 1986. Source: Lee, 1983.

parison of pasture yields. There is a lack of comparative data for the level of input of nitrogen, which is the major grass growth-promoting nutrient. Clearly, highest yields occur in the north-west and west, and the lowest yields in the Mediterranean, Northern Fennoscandia and in the south-east, with the central region recording intermediate levels of yields. However, there may be pronounced intra-country variation e.g. Southern Fennoscandia and lowland

21 areas of Switzerland/Austria compared with the Alpine zone. Although there is only scant information and a lack of comparative data, it may be concluded that the level of nitrogen application is highest in North Western and Western Europe. In Eastern European countries, such as Poland and Czechoslovakia, much of the grassland area comprises natural meadows and haylands receiving comparatively low levels of fertilizer application.

North West and West Europe Grassland output at farm level in the U.K., France, the F.R.G. and Ireland is 4500-8000 kg DM ha -1, whereas in Benelux and Denmark it is 8000-12 000 kg ha-1, which reflects intensive pasture use at farm level. Rainfall and the available water capacity of the soil are major yield determinants, with output in the U.K., for example, ranging from 6000-14 000 kg DM ha -1 under intensive fertilisation. Milk outputs of 9000 1 h a - 1 and beef outputs of 950 kg h a are attainable from the better grasslands of the region. Central Europe In the Central European zone of Poland and the German Democratic Republic, grasslands are concentrated along the valleys and flood plains of rivers as well as in the Ore-Sudeten-Carpathian hill and mountain zones of the south. In the North German Plain and the Vistula Valley, intensively fertilised grassland has a yield potential of 7000-9000 kg DM ha-1 in the sandy areas, and up to 11 000 kg ha -1 in high-fertility areas. Under farm conditions in Poland grassland output ranges from 1700-6500 kg DM ha -1 in the river valleys, depending on available moisture. In the montane/submontane zones of Switzerland, Austria, Poland, the F.R.G. and Czechoslovakia output declines from 9500 kg DM ha -1 at 400-600 m to 1500-2000 kg DM ha -1 at 1500-2200 m. In lowland Czechoslovakia productive capacity of natural grassland is about 9500 kg DM h a - 1, whereas in the arable lowland of Switzerland clover leys are capable of outputs as high as 14 000 kg DM h a - 1. Under the steppe conditions of the Hungarian Plain moisture stress is a major limitation, with seeded legume/grass swards showing a 100% response to irrigation compared with 35% in the North German Plain. South East Europe Grassland occurs largely in the montane and submontane zones, such as the Carpathians and Transylvanian Alps in Romania, the Stara Planina and the Rhodope in Bulgaria and the extensive mountain and hill regions of Yugoslavia. In Romania, unfertilised permanent pastures yield about 2000 kg DM h a - 1. Yields of 3000-4500 kg DM h a - 1 are attainable from fertilised Bromus inermis and Festuca/Agrostis swards, compared with seeded pasture yields of 9500 kg DM ha -1. In Bulgaria, meadow yields range from 1500-6000 kg DM h a - 1, depending on meadow type and altitude. In the better areas ( < 500 m)

22

of Croatia in Yugoslavia, rainfed yields in excess of 10 000 kg DM ha-1 have been achieved from natural meadows. Mediterranean The permanent grazings of the Mediterranean zone are subject to severe moisture stress with annual production being limited to about 1000 kg DM ha-1 and with stocking rates ranging from the equivalent of 0.25 livestock units (LU) ha-1 in Portugal to as little as 0.05 LU ha-1 in the poorer forest ranges of Greece. However, improved technology is capable of raising production levels to about 3500 kg DM h a - 1. In this ecological zone, irrigated legume and legume/grass swards are capable of outputs of 20 000 kg DM h a - 1. Similarly in the steppe regions of Hungary, Romania, Bulgaria and South U.S.S.R., irrigated swards yield 13 000-17 000 kg DM h a - 1. Northern Europe Temporary pastures are an important component of Southern Fennoscandian grassland where the average yield of good grass/clover leys is 8000 kg DM ha-1. Despite the brevity of the growing season, photoperiodically long-day grasses are capable of outputs of 5000-7000 kg DM h a - 1, even within the Arctic Circle. High nitrogen exacerbates winter damage to swards with a depressing effect on yields. In Western Scandinavia, the disadvantages of a northern latitude are modified by the favourable Gulf Stream influence. In the Baltic and forest zones of the U.S.S.R., intensively fertilised (200 kg N h a - 1) pastures have a yield capacity of 6000-9000 kg DM ha-1. In the Ukraine yields range from 6000 kg (Carpathians) to 2000 kg DM h a - 1 (steppe zone). Importance of grass as an animal feed

The estimated share of grassland in animal feed consumption in E.E.C. and Eastern European countries is compared in Table V. For EEC-9, grassland is taken to be synonymous with perennial fodder crops comprising meadows, pastures, clover, lucerne and other perennial fodder crops. Clearly the reliance of Eastern European countries on grassland is substantially less than in E.E.C. countries. When the data from Table V are compared with Table III (share of grassland in UAA) a general correlation exists: a higher share of grass in animal diets coincides with a higher share of grassland in the UAA. There are notable exceptions such as Benelux, which although characterised by the highest pasture yields in Europe, has a comparatively low share in animal feed. This is attributed to high levels of concentrate feeding to ruminants and, notably, to the high yielding dairy herd in that region. Obviously the composition of feed resources differs from country to country in accordance with environmental conditions, farming systems and production technology. Lowland countries such as Poland, the G.D.R. and Hungary have,

23 TABLE V Estimated share of grassland in total ruminant feed composition in E.E.C. countries and in Eastern European countries Pasture

Hay

Silage

Total

EEC-9 Countries (French feed units ( % ) ) 1 Belgium/Luxemburg 8.4 Denmark 32.3 F.R.G. 26.0 France 30.9 Ireland 62.6 Italy 8.4 The Netherlands 26.7 U.K. 59.3

20.2 3.9 15.8 23.4 10.2 27.3 6.6 13.2

22.4 10.8 18.2 16.7 24.1 17.3 20.7 10.5

51 47 60 71 97 53 54 83

Eastern Europe (grain units ( % ) ) Bulgaria Czechoslovakia G.D.R. Hungary Poland Romania Yugoslavia U.S.S.R.

20.2 50.9 39.6 36.1 41.1 38.7 42.2 22.4

13.8 8.1 10.4 8.9 9.9 14.3 23.8 36.6

34 59 50 45 51 53 66 59

Sources: Lee, 1983; Eurostat, 1980; F.A.O., 1979; van Dijk and Hoogervorst, 1984. 1Feed unit system based on Leroy's system of feed equivalents is the system still in use by Eurostat (Statistical Office of the European Communities).

in general, a smaller percentage of pastures than countries with a more varied relief such as Bulgaria and Yugoslavia.

Contribution to human food supply The value of grassland is determined by its contribution to food supply. Local and foreign demand for foodstuffs and aspects of farm management determine the extent to which grassland potential is exploited (van Dijk and Hoogervorst, 1984). By examining the role of milk, beef, veal, mutton, lamb and goat meat in the domestic food supply in various countries, the relative importance of consumer demand for future grassland developments can be illustrated (Table VI ). The data in Table VI show that grassland products are more significant in diets in E.E.C. countries than in Eastern European countries. In the latter, cereal consumption is relatively high and beef consumption is fairly low. Other kinds of meat (or meat products) seem to compensate for this. In general, it can be concluded that Eastern European (C.P.E.) diets are basi-

24 TABLE VI Per capita annual energyintake from various food categoriesproducedby ruminants in 1978 (kJ) Food category All meat and meat products Beef Sheep and goat Milk and milk products Cereals Milk {products)/ cereals ( %) Beef/cereals (%)

Bulgaria C.S.S.R. G.D.R. Hungary

Poland

Romania

EC-9

588 104 54

796 221 8

825 187 8

667 121 4

675 175 4

525 96 21

775 475 25

450 2184

488 1474

838 1292

325 1634

283 1663

442 2189

776 1130

21 5

33 15

65 15

20 7

17 11

20 4

69 42

Source: van Dijk and Hoogervorst, 1984. cally cereal based, while Western European diets contain a larger share of grassland products. Since virtually all countries are now self-sufficient in these products it can also be concluded t h a t grassland production plays a more important role in the domestic food supply in Western European countries. In addition to domestic demands for grassland products, countries may also be faced with foreign sources of demand. In centrally planned economies exports may also be the result of political efforts aimed at pursuing a favourable balance of payment position with western countries. Self-sufficiency ratios (SSRs) for milk show t h a t Mediterranean countries and the U.K. are importers of milk and dairy products. These imports range from 10 to 27% of domestic utilisation. European C.P.E. countries have self-sufficiency ratios ranging from 99 to 109; in all other European countries milk production by far exceeds domestic h u m a n consumption (E.A.A.P., 1982). For beef and veal the differences in Europe are much bigger. Some countries are large exporters (Ireland's SSR was 613% in 1978), while others have to import large quantities ( Greece 52%; Italy 39% ) of domestic consumption (E.A.A.P., 1982 ). The Eastern European countries as a group are self-sufficient, with the C.S.S.R. and the G.D.R. as net importing countries, and Hungary as an important net exporter. Bulgaria and Romania are important exporters of m u t t o n (O.E.C.D., 1981-1982). Thus in various European countries, and most notably in Denmark, Ireland, The Netherlands, Hungary, Poland and Romania, grassland production has important implications for the national economy via its contribution to foreign trade. (van Dijk and Hoogervorst, 1984). Grassland products can potentially be based on grass only, but in practice there is a wide variety of diets for ruminants. Therefore, the techniques and economies of production determine whether, how and to what extent grassland is used to produce grassland products (van Dijk and Hoogervorst, 1984).

25

Production potential Lee (1978) constructed a land-capability map for forage production for the continent of Europe, and more recently Lee (1984) compiled a draft soil-suitability map (1:1 million) for grassland for the EEC-10 countries. Ecological factors such as precipitation deficits, temperature regimes and soil/land conditions were taken into account in the assessment. In general, land north of the 60th parallel (Scandinavia) and south of the 44th parallel (Mediterranean countries) are ill-suited for grassland production. The most favourable conditions are present in North Western and Western Europe, Ireland, the U.K., Benelux, North West France and Bavaria. In the predominantly hilly areas, where a high proportion of the UAA is devoted to grassland, such as the Central European highlands, Alpine Foreland and Massif Central, grassland production/utilisation is restricted by soil conditions such as stoniness, rockiness and accessibility. Throughout much of the remainder of Europe moisture deficit is a major factor restricting yields, e.g. in the lowland Balkans and the North G e r m a n and Polish plains. From an economic standpoint, it is important to determine the extent to which different countries exploit their grassland resources. Table VII is an inter-country comparison of suitability for grassland with the proportion of grassland in the UAA. In general, those countries which are well suited ( Class A) have a relatively high proportion of their UAA under grassland, and TABLE VII Suitability for grassland, Classes A-E 1. Yieldpotential (103kg DM ha -1 ) in parentheses Grassland (% of UAA)

Class A (10-12)

65-100

Ireland U.K. (W)

35-65

The Netherlands Belgium France (NW)

<35

Class B (8-10)

Class C (5-8)

Class D (3-6)

Class E (1-5)

Switzerland

Iceland

France U.K. (E) F.R.G.

Austria Czechoslovakia Yugoslavia Norway (S) Poland

Greece Portugal Norway (N)

G.D.R. Denmark

Sweden (S) Finland ( S )

Romania Sweden(N) Bulgaria Finland (N) Hungary Spain Italy

1Ranking scale from A to E: A= well suited for grassland; E = very poorly suited for grassland. Sources: Lee, 1983; Lee, 1984.

26 vice versa for these countries which are listed as very poorly suited (Class E ). Iceland is exceptional, and the position here is explained by the fact that the country is also poorly adapted to arable farming and has a higher relative suitability for grassland. Because of lack of adequate data, it is difficult to compare actual and potential yields by country. However, some observations are possible, for instance, in countries such as The Netherlands and Denmark, the land area devoted to grassland is well exploited; this is reflected by the high level of yields achieved in practice relative to yield potential. Although Denmark is suited to grassland its relative suitability for arable purposes is higher than for grassland. Countries such as Ireland and France achieve low yields relative to their potential. ANNUALFODDERCROPS General Table II shows the crop extent by country. Root crops are of minor significance in comparison with the green-fodder category. A notable exception is Denmark and also Poland to a lesser extent. Green fodder is largely synonymous with the green or forage maize crop. Production E.E. C. countries Profound changes are taking place in the balance of annual fodder crops. Fodder beet and other root crops are showing a substantial decline, with green maize showing a remarkable expansion. Tables VIII and IX show the trends in the E.E.C. area. It is evident that the maize crop is systematically expanding in all countries. In 1983 2.9% of the EEC-10 UAA was under green maize, with the highest concentration occurring in The Netherlands (7.8% UAA), Belgium (6.9% UAA), the F.R.G. (6.7% UAA) and France ( 4.4% UAA). France and the F.R.G. account for about 80% of the total EEC-9 green-maize area. TABLE VIII Changesin area of fodderbeet, other fodderroot crops and greenmaize (EEC-9) (10a ha) Category

1970-1972

1980-1982

Fodderbeet Other fodderroots

953.3 523.1 1103.6

470.7 324.1 2791.3 (1983)

Green maize Source: Lee, 1986.

27 TABLE IX Change in green maize area by country (103 ha)

1973 1983

F.R.G.

France

Italy

The Netherlands

Belgium/ Luxemburg

U.K.

Ireland

Denmark

346.1 807.9

634.4 1391.3

102.2 300.0

49.9 156.7

43.7 107.5

6.7 15.3

0.7

0.5 16.9

Source: Lee, 1986.

C.M.E.A. 1 countries

Non-grain fodder crops comprising fodder roots, silage and fodder maize, and grass crops took up 28% of the arable area in 1978 ( O.E.C.D., 1981-1982 ). Fodder-crop balance is changing, with fodder maize and green fodder area increasing, and a corresponding decline is taking place in root crops. A trend is also emerging with regard to sugar beet; with more of it being allocated for feed at the expense of sugar exports. In Romania the forage area is to a certain extent residual insofar as it is used in practice as a reserve, from which land is taken for the expansion of the nonfodder crop area, and is projected to decline. Green-fodder production in Romania has been criticised for yielding too few "nutritive units" per hectare, and a switch of land to better quality forages, especially maize, would help the position ( O.E.C.D., 1981-1982). Increasing livestock numbers on low-productivity grassland, and an inadequate forage crop yield over the period 1970-1980, led to an increase in grain consumption for feed purposes of about 33% in Bulgaria. Natural meadows are of low productivity, and yields per hectare have not increased for decades. Because of the low productivity of natural pastures, cattle and sheep depend to a large extent on field forage crops, which in 1978 accounted for about 21% of the sown area (O.E.C.D., 1981-1982). Maize and lucerne account for 85% of the area cropped for cattle feed, with green maize yielding 11 500-19 260 kg DM h a - 1, and lucerne hay yielding 5440 kg DM h a - 1. Fodder beet on socialised farms yields 50-60 t ha-1. An inadequate production of coarse and succulent feeds and meadow hay means that other feed sources have to be tapped in order to balance the energy and protein components in the feed ration. Measures here include the crushing and pelletisation of straw, the use of grain maize byproducts, the production of green meal and the use of sunflower by-products ( O.E.C.D., 1981-1982). Production of fodder crops in Poland has been a relatively dynamic branch of the feed economy, with the area under these crops expanding by 50% over the period 1960-1979 and with perennial grass and fodder maize showing an increase of 100%. However, while crop areas increased they were not accom1Councilfor Mutual EconomicAssistance.

28 panied by corresponding productivity increases ( O.E.C.D., 1981-1982 ). Feed grain is growing in importance as the prime source of animal feed, with pastures and perennial grasses being second in importance, hay and straw being the third most important and with potatoes also being an important contributor. Root crops have shown a substantial decline in the G.D.R. dropping from 222 000 ha in 1957-1961 to 57 000 ha in 1975-1978, and grassland area is also declining. Between 1957-1961 and 1978 the arable area showed an annual average decline of 3000 ha, while the comparable grassland figure was 7300 ha. It is estimated (O.E.C.D., 1981-1982) that over the period 1970-1978, a total of 158 000 ha of grassland were diverted to arable use. In Hungary, alfalfa and silage maize are showing an increasing contribution whereas root crops are declining. Meadow and pasture yields at 1500-1600 kg ha -1 (hay) have been virtually at the same level as prior to the Second World War; however, it is technically possible to increase these yields substantially through fertilisation and irrigation. Table X lists the yields for the major annual fodder crops. Within the E.E.C. zone Italy recorded the highest green-maize yields with Greek yields being exceptionally low. For fodder beet the highest yields were recorded in Belgium TABLE X Yields from major annual fodder crops, 1980-1983 (103kg ha- 1) Country E.E.C. F.R.G. France Italy The Netherlands Belgium Luxemburg U.K. Ireland Denmark Greece C.M.E.A. Bulgaria Hungary G.D.R. Poland Romania Czechoslovakia U.S.S.R.

Green maize Fodder beet 45.7 40.5 52.0 46.3 47.3 45.8 37.5

97 58 37 85 99 70 63

40.0 13.3

52

14.9 19.9 23.5 32.4 14.0 27.9 15.3

46 33 43 38 43 43 24

Yields within C.M.E.A. countries refer to all feed root crops (1979). Sources: Eurostat, 1983; C.M.E.A., 1979.

29

and Germany and the lowest yields in Italy. In contrast, within the C.M.E.A. zone green maize yields are low, particularly in Hungary, Bulgaria and Romania. Similarly, root-crop yields within the C.M.E.A. zone are poor by E.E.C. standards, although a comparison between all feed-root crops in the former zone with fodder beet in the latter may be somewhat misleading.

Importance of annual fodder crops to animal feed supply E.E. C. countries Feed balance-sheet statistics compiled by the E.E.C. (Eurostat, 1980) provide a convenient source of information on annual crops (Table XI). Annual fodder crops comprise root crops, green maize and other crops. The latter category includes green cereals, green pulses, green oil seeds and green mixtures. Table XI indicates that annual fodder crops are particularly significant in Italy, Germany and France. On a feed-unit basis, green maize makes the greatest contribution for most countries, with the notable exceptions of the U.K., TABLE XI Contribution of annual fodder crops to livestock feeding Annual fodder crops (AFC) ( % total) EEC-9 Countries (French feed units {% ) ) F.R.G. 13.2 France 14.6 Italy 17.6 The Netherlands 4.5 Belgium/Luxemburg 10.6 U.K. 2.7 Ireland 1.4 Denmark 8.0 Eastern Europe {Grain units Bulgaria Czechoslovakia G.D.R. Hungary Poland Romania Yugoslavia U.S.S.R.

(%)) 7.0 13.6 22.2 6.4 22.4 6.6 2.5 13.3

Root crops (% AFC)

Maize silage (% AFC)

Others (% AFC)

32 23 4 9 35 74 93 100

52 60 49 90 62 15

16 17 47 1 3 11 7 -

20 34 62 30 84 44 68 38

80 66 38 70 16 56 32 62

1Feed unit system based on Leroy's system of feed equivalents is the system still in use by Eurostat ( Statistical Office of the European Communities). Source: Eurostat, 1980; F.A.O., 1979.

30

Ireland and Denmark. In The Netherlands, green maize is an outstanding contributor in this respect, and to a lesser extent in Belgium and Luxemburg. In the U.K., Ireland and Denmark root crops comprise the greater part of the annual fodder category, whereas in Italy other green-fodder crops make a significant contribution, with root crops assuming a negligible role. C.M.E.A. Countries It is evident that grains form the major part of the feed resources for all countries, but their significance varies from country to country. In Poland and Romania grains form less than 40% of the forage and feed resources of those countries, while in Hungary they form almost 70%. Hay produced on arable land occupies first place in the forage resources of Czechoslovakia and Romania, while in Poland, Yugoslavia and the G.D.R. first place is taken by meadow hay. Maize for green forage and silage is important mainly in CzechTABLE XII Contribution of some crop by-products to livestock feeding Straw I ( % total feed)

Sugar beet leaves and tops (% total feed)

Other ( % total feed)

EEC-9 Countries (French feed units ( % ) )2 F.R.G. 0.8 France 0.2 Italy 1.7 The Netherlands 0.2 Belgium/Luxemburg 0.4 U.K. O.8 Ireland 0.5 Denmark 3.7

2.0 0.1 0.4 3.0 0.1 0.1 1.9

0.1 0.7 0.2 -

Eastern Europe (Grain units ( % ) ) Bulgaria 4.3 Czechoslovakia 3.1 G.D.R. 2.9 Hungary 4.5 Poland 3.1 Romania 4.4 Yugoslavia 4.3 U.S.S.R. 2.8

2.0 4.4 3.5 2.4 3.5 2.8 2.1 2.3

1Expressed in modern feed evaluation systems (see Chapter III.2) the contribution of straw is larger. Source: Eurostat, 1980; F.A.O., 1979. 2Feed unit system based on Leroy's system of feed equivalents is the system still in use by Eurostat (Statistical Office of the European Communities).

31 oslovakia and the G.D.R. and roots in the G.D.R. Potatoes are particularly important in Poland and to a lesser extent in the G.D.R.

Crop by-products The contribution of crop by-products to feed resources is given in Table XII. Crop by-products comprise largely cereal straw and leaves/tops of root crops. Their contribution to feed supply is marginal. However, in Denmark, crop byproducts account for 5.6% of total feed units. Crop by-products are more significant in Eastern and South East Europe than in the E.E.C. zone. Sizeable quantities of by-products from crop farming, in addition to field crops and feed from pasture land, are available for Hungarian animal farming, but so far have been inadequately used. Such reserves are approximately 9.0 Mt of maize stalks, 0.5 Mt of straw fit for feeding without processing (straw from oats and barley, pea haulms etc.) and 0.6 Mt of sugar-beet pulp. Full utilisation of this potential feed would be equivalent to an added arable and pasture-land feed-production area of 250 000-300 000 ha. It has to be assumed, however, that the investment required for mobilising this reserve, as well as hectare yield increases in feed production, is lacking, and that, therefore, both can be put to use only to a limited degree for the foreseeable future ( O.E.C.D., 1981-1982). CONSERVED FORAGE

Production The feeding of conserved forage is an integral part of European ruminant systems, and the significance of forage utilisation (grass) in the conserved state may be gauged from Table XIII. Recently Wilkinson (1987) conducted a survey of silage making in 17 countries of Western Europe. He showed that about 10% of the grassland area was mown for silage. A significant proportion of Western European grassland is not mown at all owing to inaccessibility, but the area mown for hay is estimated to be at least similar to the silage area ( Wilkinson, 1987; Table XIV). Maize is the most important forage crop cut for silage, accounting for 30% of the total land area used for silage in 1985. In terms of yield of DM ha-1 maize is highly significant, possibly accounting for 50% of the total DM conserved as silage in Western Europe (Wilkinson, 1987). Recent trends in silage and hay production are depicted in Table XV. The E.E.C. countries accounted for 93% of the total silage DM and 78% of the total hay conserved in Western Europe in 1985. Within the E.E.C., France, F.R.G. and the U.K. accounted for 69% of the total silage and 67% of the total hay produced in 1985. Silage making increased by 60% in Western Europe.

32 TABLE XIII Significance of conserved forage in Europe

Finland Sweden Norway Denmark

Total production (106 t DM)

Conserved forages ( % )

Forage

Hay

Silage

1.5

65 85 30 25

35 15 70 75

0.1 0.5 0.1 1.1 6

30 50 25 35 55

70 50 75 65 45

2

70 60

30 40

Maize silage

2.6 5.6 1.8 1.5

Ireland1 U.K. The Netherlands Belgium/Luxemburg F.R.G.

5.7 12.4 5.4 4.0 19.6

France Italy

40 15.2

0.2 1.4 1 7 11

3.5

Roots ( + tops)

0.3

1Data for Ireland refer to 1986. Source: Data on the amount of conserved forages in Europe compiled by Wilkinson, 1979. The data are based either on: (a) amounts of hay and silage dry matter in ruminant diets and the total ruminant population, or on (b) yield of conserved forage and the area of grassland and forage crops. TABLE XIV Estimated area of crops cut for silage in Western Europe (1985) (EEC-12, Austria, Switzerland, Scandinavia) Crop

Area (106 ha)

Grass Maize Legumes (mainly lucerne) Other crops (mainly beet tops and leaves)

6.6 3.3 0.3 0.9

Source: Wilkinson, 1987.

About half of this increase was at the expense of hay. The overall rate of increase in silage production was 6% per annum. The increase was somewhat higher in the Alpine and Scandinavian countries than in the E.E.C. countries. Grass may be conserved by: (a) natural drying (haymaking); (b) artificial drying to a stage at which chemical breakdown and microbial action cease (dried grass) ;

33 TABLE XV Estimatedproductionof silageand hay in WesternEurope, 1975-1985 (106t DM total production) 1975

EEC-12 Austria and Switzerland Scandinavia Total

1985

Silage

Hay

Total

Silage

Hay

Total

44.6 1.7 1.0 47.3

58.3 5.8 7.3 71.4

102.9 7.5 8.3 118.7

70.9 3.2 1.9 76.0

45.8 4.7 7.6 58.1

116.7 7.9 9.5 134.1

Source:Wilkinson, 1987. (c) ensiling in anaerobic conditions (silage). With haymaking the aim is to reduce the moisture content as rapidly as possible to a safe storage level, with a minimum loss of dry matter and nutrients. The prevailing weather, crop maturity and yield, and the mechanical treatment of the crop will all affect rate of drying. Reduction in feeding value of hay may occur because of field losses and storage losses. Some of these losses are referred to later. Moisture content must be reduced to 15-20% for satisfactory storage. Hay making remains the dominant method of forage conservation in many areas, particularly in mountainous regions. In 1980, in Sweden, 85% of conserved forage was in the form of hay, and corresponding figures for France and Finland were 70% and 65%, respectively. In Denmark and The Netherlands 75% of conserved forages were in the form of silage. However, use of silage is not allowed in some European areas such as Switzerland, where milk is intended for manufacture of cheeses such as Gruyere and Emmenthal.

Losses in conservation of hay Lingvall and Nilsson (1979) reported that 95% of the hay preserved in Northern Europe is of poor quality, with a low content of both protein and metabolizable energy (ME), with many farmers regarding hay as a roughage feed to meet the maintenance requirements of cattle. Efficient hay systems need to produce material of 10.5-11.0 MJ ME and 110-130 g DXP kg -1 DM, and this can be achieved by cutting herbage for hay early. Later cutting, which is a common practice, involves additional concentrate supplementation owing to lower digestibility and protein levels in the late-cut material. Hay is very sensitive to weather, with bad weather not only increasing field losses but also decreasing nutritive values. Losses in the field occur during the wilting period, as a result of plant and micro-organism activity, leaching by rain and losses due to the mechanical treatment of the crop. The magnitude of these losses is summarised in Fig. 2. It can be seen that losses increase strongly with increas-

34

50 o Conventional mower 40

z~ F l a i l m o w e r

: ::::::::

30 = ~

o

2 20 "2

.....

~-:?:)0:i :

o-"Y 0

,o

_ .L'L'~

oo 0

TO--=

80

--

60

,

I 40

I" 9°°°

,

,

20

Dry matter losses %

Fig. 2. D r y - m a t t e r losses in field curing of hay (Wieneke, 1972).

ing degree of wilting, and that this increase is highly dependent on the weather (Wieneke, 1972 ). Rain is the major cause of losses during wilting. In Swedish experiments, the average difference between losses in plots with rain and those without was 630-850 kg DM ha-1 depending on mower type. As mentioned above, in addition to causing DM losses, rain also causes a severe decrease in feeding value. Furthermore, prolonged bad weather may lead to serious decreases in the hygienic quality of the hay, often resulting in the crop becoming unsuitable as feed. In districts where sufficiently many 5-6-day periods of fine weather normally do not occur, field curing cannot be recommended. This applies at least to the entire part of North Western Europe that is influenced by the Atlantic low pressures. In such areas it is important that the time in the field is reduced. Conditioning gives a rapid wilt but is often not enough, therefore haymaking also implies that the hay must be removed from the field before it has reached a moisture content permitting storage. A final drying or some kind of preservation must then be done elsewhere. In Sweden it has been found that a system permitting the hay to be removed from the field after a maximum of two wilting days with good weather, gave a reasonable balance between risks and costs. Effective wilting techniques result in moisture contents around 30-40%, which is a suitable level for subsequent barn drying. In other districts the maximum wilting period may be different (Lingvall and Nilsson, 1979). The use of organic acids and their salts (propionic acid and liquid anhydrous ammonia) in the preservation of moist hay has been investigated (Klinner and Holden, 1977). While results are positive, there are many problems to be overcome

35 before their use can be recommended. Until reliable methods of chemical preservation of hay are developed haymaking in most of Europe must include some form of final indoor drying.

Losses in conservation of silage Zimmer (1979) concludes that the potential of silage systems is high, and that even the requirements of highly-producing animals can be met. A system of early-cut, pre-wilted silage shows the most advantages if the system is well managed and technology ensures a good type of fermentation, while Flynn and O'Kiely (1983), concluded that similar livestock-production targets are achievable from good silage and grazed grass. In the silage-making process the original herbage is preserved either directly after cutting or in a wilted state. Moisture contents vary from 85-75% for grasses and legumes to 75-50% for whole-crop cereals. Preservation is achieved by lowering the pH. Temperature, pH, moisture content, air/oxygen ratio, chemical composition of the crop and technology are factors which influence the nutrient recovery of the crop ensiled. Some of these factors are discussed later. Because ensiling is less dependent on weather it is a more efficient conservation method than hay, particularly under the more humid conditions in Western Europe. Sometimes grass material is artificially dried as a method of forage conservation ( dried grass). The material is dried to a stage at which chemical breakdown and microbial action have ceased. Herbage destined for this method of conservation is usually at a less advanced growth stage than is field-dried herbage (hay).

Effects of forage conservation on nutrient losses and feed intake Energy and protein values and intake of conserved forages are determined primarily by those of the fresh forage conserved. During conservation these values are decreased in the field and during storage. Field losses owing to respiration, leaf-shatter and leaching by rain, and losses during storage owing to oxidation, fermentation and effluent contribute towards a decrease in nutrient value in the conserved material. These factors adversely affect the most digestible components of the forage, especially the water-soluble carbohydrates and proteins, resulting in an increase in fibre content, a reduction in organic matter and nitrogen digestibility, and a reduced dry-matter intake. Reduction in energy value and protein value during conservation is greater in hays than in silages. Artificial dehydration keeps these losses to a minimum. It reduces to a small extent the digestibility of legumes, but has no effect on grasses dried at high or low temperatures (Henke and Laube, 1968; Demar-

36 q u i l l y , 1970; P r y m a n d W e i s s b a c h , 1 9 7 7 ) . T h e m a g n i t u d e a n d r e d u c t i o n i n t h e o r g a n i c - m a t t e r d i g e s t i b i l i t y o f h a y s o v e r f r e s h h e r b a g e is c l o s e l y r e l a t e d t o t h e d r y - m a t t e r l o s s e s d u r i n g d r y i n g ( S h e p p e r s o n , 1960; D e m a r q u i l l y a n d J a r r i g e , 1969 ). I t is a t a m i n i m u m f o r b a r n - d r i e d h a y s a n d g r a s s h a y s d r i e d r a p i d l y i n the field, and increases sharply with the length of the drying period and the a m o u n t o f r a i n . T h e o r g a n i c - m a t t e r d i g e s t i b i l i t y o f f o r a g e s e n s i l e d c o r r e c t l y is g e n e r a l l y v e r y s i m i l a r t o t h a t o f t h e f r e s h f o r a g e ( H a r r i s a n d R a y m o n d , 1963; D e m a r q u i l l y , 1973 ). T a b l e s X V I a n d X V I I i l l u s t r a t e s o m e o f t h e s e e f f e c t s . TABLE XVI Differences in the chemical composition and nutritive value to sheep of conserved forages compared with fresh herbage Number of Change in samples content (% DM)

Dried Grasses Legumes Hay Barn dried2 grass Field dried, good weather Field dried, + rain < 10 days Field dried, + rain > 10 days Barn dried2 lucerne Field dried, good weather Silage Direct cut grass Direct cut + F A Direct c u t + F A + F Wilted (30-35% DM) Direct cut lucerne Direct cut + F A

Change in nutritive value ( % change from fresh value)

Crude fibre

Crude 0 M Net energy Voluntary DM protein digestibility content 1 intake

17 4

- 0.7 -1.8

0 +0.5

- 1.6 -8.3

0 0

- 3 -12

36

+ 2.7

- 0.6

- 6.1

- 7.7

- 12

32

+ 1.6

- 0.6

- 6.1

- 7.9

- 20

14

+3.9

-1.0

-8.4

-11.7

-24

10 16

+5.3 + 3.3

-1.5 - 1.6

-13.1 -5.6

-16.7 - 10.7

-30 - 15

10

+9.1

-4.2

-12.2

-18.7

-26

64 96 24 10 11 19

+3.2 +2.4 +2.5 +0.9 + 3.1 +1.9

+0.4 +0.2 +0.3 -0.3 - 0.6 -0.7

-1.1 +0.4 -2.2 -3.1 - 1.4 -1.5

-4.4 -1.1 -4.3 -5.6 - 3.6 -3.5

-21 -17 -23 -30 - 13 -14

1Calculated in feed units for milk production (I.N.R.A., 1978) assuming that conservation does not modify the gross energy content. 2Low temperature drier (125-150 ° ). FA = Formic acid; F = formaldehyde. Source: Jarrige et al., 1984.

37 TABLE XVII Losses in haymaking in the Mediterranean area ( % ) Experiment and type of forage

DM

DXP

NE

Experiment (A), different forages ( n = 17) Experiment (B), forages including lucerne first cut Level of lucerne Low (av. 21.6%) n= 8 Medium (av. 43.8%) n = 18 High (av. 60.1% ) n-- 18

17.6

31.6

24.8

14.4 23.7 32.7

Source: Maymone, 1959.

At farm level moderate quality and low productivity, in all countries, result from delayed cutting, low D-value (percentage digestible organic matter in the dry matter), and sub-optimal ensiling technique. Regarding the short period when D-values of herbages are adequate, harvesting and filling capacity need careful planning. Air is the most negative factor, creating avoidable loss and reduction in nutritive value and intake. The combination of equipment and storage units therefore becomes important and needs attention (Zimmer, 1979). Technical microbiology needs to standardise substrate conditions by a better control of agronomic measures and harvesting, and needs to control and improve environmental conditions of anaerobic fermentation and storage. Research should concentrate on protein degradation, influence of air, heating, complex chopping/crop characteristics/density interactions, cheap sealing methods and additives with low residues (Zimmer, 1979 ). The present situation of silage making is characterised by a steady increase in the amount of forage conserved as silage in all countries, owing to its wellknown advantages (Gartner, 1976; de Boer et al., 1977; McIlmoyle, 1977; McIlmoyle and Steen, 1979 ), but it is also characterised by a standstill in quality, at an only moderate level. This is a result of a combined effect of late cutting and suboptimal conservation, and is illustrated by mean crude-fibre contents of silage or hay of 30-32% of dry matter (DM). Further, unsatisfactory intake, caused mainly by this low quality, results in low productivity from roughage, normally little more than maintenance (Zimmer, 1979). Reductions of 40% in the feed value of silage when compared with the corresponding standing crop have been reported for Hungary (Hancock, 1971 ). Conservation losses may be avoidable or unavoidable, and they are summarised in Table XVIII. Unavoidable changes in nutrient status and digestibility of the forage crop during ensiling are rather low in contrast to avoidable losses. At a comparable stage of maturity, the intake of silage is significantly increased either by pre-wilting (Marsh, 1979) or to a lesser extent by using additives, mainly formic acid (Waldo, 1978). This can be explained as a combined

38 TABLE XVIII Energy losses and causative factors Process

Classified as

Residual respiration

Unavoidable 1-2

Plant enzymes

Fermentation

Unavoidable

2-4

Micro-organisms

Effluent

Both

5- > 7

DM content

Field losses by w i l t i n g

Unavoidable 2- > 5

Weather, technique, management, crops

Secondary fermentation

Avoidable

0->5

Crop suitability, environment in silo, DM content

Aerobic deterioration during storage

Avoidable

0-> 10

Filling time, density, silo sealing, crop suitability

Aerobic deterioration after unloading (heating)

Avoidable

0- > 15

As above, DM content of silage, unloading technique, season

Total

Approx.losses Causativefactors (%)

7- > 40

Source: Zimmer, 1979. effect of a stabilised and restricted fermentation and saved digestible nutrients. Zimmer (1979) concluded that productivity of wilted silage (range 3 5 - 5 0 % D M ) is superior to direct-cut silage and barn-dried hay as a result of better recovery and higher intake. However, wilted silage in this respect should be defined as a silage without perceptible reduction in digestible energy and increase in protein degradability. Furthermore, early-cut is superior to late-cut material despite a higher gross yield of D M in the more mature material. Two aspects of increasing interest are the necessary capacity and the right combination of equipment. N u m b e r and size of livestock, rate of change of D-values of the crops and weather risk in the region give the basic information needed to organise harvest. Over 10 days, during heading, digestibility will be reduced by 4-8 units, with higher figures in the more continental regions (Demarquilly and Jarrige, 1971; Green et al., 1971). Systems are available with harvesting rates of 5-15 t wilted material ha-1 with maize up to 25 t ha-1. Labour does not differ very much in the range of 4-7 man hours h a - 1 for grass, or 10-14 man hours ha -1 for maize (Pirkelmann and Schurig, 1975; Howe, 1977; Chambers, 1978).

39

Intake of conserved forages, especially grass silage Silage made from grass cut at the leafy stage, and properly preserved, has a feeding value for cattle similar to that of the fresh material (Flynn, 1981) (Table X I X ) . Carcase gain rather t h a n liveweight gain is the important parameter, and liveweight gain (Table X I X ) is a poor index of carcase gain owing to gut fill differences. The small difference in dry-matter intake is due to the methodology used - oven drying, leading to the underestimation of DM silage compared with grass owing to loss of volatiles. (P. O'Kiely, personal communication, 1987.) Badly-preserved silage is likely to have a lower nutritive value than wellpreserved silage made from similar material, because of considerable gaseous production from breakdown of soluble digestible nutrients and from the deamination of amino acids. Digestible-organic-matter intake fundamentally determines the potential of forages for animal production. Both voluntary dry-matter intake and digestibility are depressed by the increase in crude fibre resulting from increasing plant maturity, or as a consequence of loss of cell content during field drying. The high potential of early-cut hays for milk production has been confirmed in numerous experiments (Bertilsson et al., 1980). However, the voluntary dry-matter intake of direct-cut silages appears variable, unpredictable, frequently low and less than that of hay made from the same crop ( Moore et al., 1960; Merrill and Slack, 1965 ). However, research indicates (O'Kiely, 1984) that increasing forage dry-matter content to the hay level is associated with a further increase in intake, which is not reflected in production with cattle, as is shown in Table XX. Silage and hay made from the same herbage have also been compared in feeding trials on dairy cows (Merrill and Slack, 1965). These trials indicate TABLE XIX Effect of ensiling on forage feedvalue Grass Silage1 DM ( %) DMD ( %) DM intake ( % of liveweight) g kg-1 WO.75 Daily liveweightgain ( kg day- 1) Daily carcase gain ( kg day- 1)

22.9 71 2.00 92.6 0.81 0.42

23.3 71 1.9 87.1 0.66 0.43

1Silage had a mean NH-N of 6% of total N. W = mean liveweight. Source: Flynn, 1981; P. O'Kiely,personal communication, 1987.

40 TABLE XX Liveweightand carcase gains by cattle fed on hay or silagewith differentcutting dates Cut 27 May

Daily liveweightgain (kg day- 1 ) Daily carcase gain (kg day- 1) Intake of dry matter (kg day- 1) Carcase gain t- ~DM intake

Cut 10 June

Silage

Hay

Silage

Hay

0.61 0.45 6.32 71.2

0.73 0.38 7.60 50.0

0.32 0.19 5.58 34.1

0.50 0.20 7.24 27.6

Source: O'Kiely, 1984. that although the silage was consumed in smaller quantities than the hay, differences in milk yield were generally small and rather conflicting. Direct-cut or slightly-wilted silages, therefore, appear to have a greater efficiency per kg dry matter than has good hay made from the same herbage, both for milk production and liveweight gain in growing cattle; low-moisture silages show an intermediate value. Decreasing chop length (i.e. flail harvesters versus precision chop harvesters) increases intake in sheep (Dulphy and Demarquilly, 1972, 1973) and cattle (Dulphy and Michalet, 1975). Fine chopping increases production in animals fed silage with concentrates. Experiments show increases in voluntary intake, milk production and daily gain in dairy cows ( Castle et al., 1979; Weiss et al., 1979). The use of additives in silage results in increased intake and production in cattle, sheep and dairy cows. The positive effect of formic acid on the intake and growth rate of cattle has been established (Waldo, 1977). Similarly, with dairy cows fed concentrates, responses in terms of intake, milk yield and weight gain have been obtained with the addition of formic acid to direct-cut silages. The observed increase in production response to the increased intake implies that the nutritive value of the ensiled herbage is slightly improved by the formic acid treatment. Efficient treatment with additives appears to increase silage intake, by reducing the production of fermentation acids and the breakdown of amino acids by proteolytic micro-organisms. Many studies have shown that increasing the dry-matter content of silage by wilting improved fermentation, quality and dry-matter intake (Merrill and Slack, 1965; Marsh, 1979). However, production response both with growing-fattening cattle and dairy cows is generally low. Production response to the increased intake is generally low, because of a reduced efficiency of utilisation of wilted silage (O'Kiely, 1984 ). In a comprehensive review Zimmer and Wilkins (1984) compared wilted and unwilted silages on a European scale. They concluded that differences in feeding value between unwilted additivetreated and wilted non-additive-treated silages were small, although DM in-

41 take was increased by wilting by 4.0, 9.0 and 6.0% for cows, growing cattle and sheep, respectively. This tendency towards increased intake was not translated into improved performance. Silage-related diseases Various health disorders have been attributed to silage, particularly badlypreserved silage. The end products of clostridial fermentation may cause health problems in animals. High butyric-acid content in silage may be a predisposing factor in the occurrence of ketosis in early-lactation cows ( Roffler et al., 1967 ). High concentrations of ammonia and rapidly-degradable nitrogenous compounds lead to an excessive absorption of ammonia from the rumen, and may lead to disturbances in the acid-base status of subclinical disorders. Other health disorders are associated with fungal and bacterial contamination of silage (Vetter and von Glan, 1978). Also, highly-digestible silages made from young herbage may give rise to soft faeces, which has sometimes been claimed to favour the development of mastitis, endometritis and lameness in dairy cows. Kalac and Woolford (1982) concluded that the majority of the potential hazards to health associated with silage can be curbed by the production of goodquality silage. The use of an acid additive and/or pre-wilting, and the provision of an effective seal, will greatly assist in achieving this goal. However, improvement in silo management is not necessarily a panacea for oestrogenic disorders, which are likely to arise from legume silages, or, similarly, in respect to pesticide residues. The oestrogen question can only be resolved by the plant breeder. (Kalac and Woolford, 1982. ) CONCLUDINGREMARKS Development in feed resource utilisation in E.E.C. countries O.E.C.D. (1986) examined developments in feed use in the EEC-9 area over the 1973-1974 to 1981-1982 period. The principal trends and changes are shown below. (1) Roughage feeds continue to provide the major share of both energy and protein in total feed resource utilisation, although the percentage share and absolute quantity of roughage utilised for feed is on a downward trend. (2) An increasing use of concentrate feeds in the Community reveals a higher growth rate for protein-rich, compared with energy-rich, concentrates. Between 1973-1974 and 1981-1982 the expansion in total concentrate feed utilisation, measured in terms of product weight, energy and protein, rose by, respectively, 12.3%, 14.7% and 28.0%. (3) The utilisation of most concentrate feeds grew over the review period, although the quantities of maize, oats, other grains and processed green fodder

42 utilised for feed declined. The energy-rich concentrate feeds registering the largest expansion in utilisation were: manioc; animal and vegetable oils and fats; other concentrate feeds (which include for example citrus and fruit pulps, vegetable industry by-product waste). Among the protein-rich concentrates growth in utilisation was especially rapid in the case of vegetable oilmeals, byproducts of the brewery, distillery and starch industry, and milk by-products ( such as skim-milk powder). (4) While the total feed use of cereals over the review period declined, the utilisation of feed barley and wheat expanded, accounting for 11.8% of total feed resources expressed in energy terms during 1973-1974 and 1975-1976, rising to 12.8% by 1979-1980 and 1981-1982. (5) Much of the declining use of roughage feeds in the Community is explained by the decrease in utilisation of forage for feed, and to a lesser extent hay and root crops. These three feed sub-groups together contributed 51.3% of total feed resource utilisation expressed in energy terms, and 58.0% in protein terms, in the early 1970s, by the end of the decade the respective percentages were down to 44.1 and 49.1%. (6) To some extent the downward trend in utilisation of forage, hay and root crops has been offset within the roughage feed group by the increasing utilisation of forage/silage maize, other cultivated fodder crops (for example forage oilseed and cereal crops) and straw, but also to a more limited extent milk and other roughage feeds (such as food waste). In the E.E.C., forage crops are the most basic resource for animal production. While the grass component has been decreasing with an increasing reliance on concentrate feed, this trend is likely to be reduced, owing to livestock-production surpluses. Serious surpluses will take pressure off production per unit area, with future emphasis being placed on efficiency of animal production.

Prospects of forageproduction in Europe Forages play a considerably lesser role in Eastern European countries where diets contain a smaller proportion of grassland products. Land area (UAA) under grass is low, and low yields point to natural grassland production. It seems that considerable improvement in productivity is possible. In order to utilise to the maximum grass and forages in highly-efficient animal systems some factors have to be improved. Low-cost grass growth can be achieved in well-managed permanent pastures with ley pastures as a complement, by better adjustment of N fertiliser and by use of selected species including legumes. Harvesting at an optimum stage, good inexpensive preservation methods, correct adjustment of stocking rate and grazing management could lead to maximum utilisation of forage by animals. It is also necessary to use efficient animals which have sufficient feed-intake capacity and high production potential.

43 As f a r as c o n s e r v e d f o r a g e s are c o n c e r n e d , t h e r e are m a n y failures in cons e r v a t i o n . F o r hay, field losses f r o m r e s p i r a t i o n , m e c h a n i c a l t r e a t m e n t , leaching a n d s t o r a g e losses c a n e x c e e d 50% of t h e crop. H a y m a k i n g m u s t b e c o m e less d e p e n d e n t on w e a t h e r t h r o u g h i n c r e a s i n g d r y i n g r a t e w i t h c h e m i c a l s or b y i m p r o v i n g t h e efficiency of m e c h a n i c a l t r e a t m e n t . P r e s e r v a t i v e s could also m i n i m i s e w e a t h e r r i s k s b y allowing h a y to be b a l e d a t a h i g h e r m o i s t u r e cont e n t . T h e p e r c e n t a g e of forage c o n s e r v e d as silage is increasing. S u c c e s s will d e p e n d on c r o p s u i t a b i l i t y a n d on t h e t e c h n o l o g y used. A c h i e v i n g a n a e r o b i c c o n d i t i o n s quickly in t h e silo is e s s e n t i a l if in-silo losses are to be m i n i m i s e d . T h e use of c h e m i c a l a d d i t i v e s c a n reduce p o o r f e r m e n t a t i o n risks.

REFERENCES Berlacu, G., 1983. Valoarea Nutritiva a Nutreturilor Normele de Hrana si Intocmirea Ratilo. Vol. II. Editura Ceres, Bucharest. Bertilsson, J., Burstedt, E. and Knuttson, R.G., 1980. The voluntary intake of hay and silage fed to dairy cows with different levels of concentrate. In: C. Thomas (Editor), Forage conservation in the '80s. Occasional Symposium No. 11, British Grassland Society, Brighton. B.G.S., Hurley, Maidenhead, U.K., pp. 372-374. Castle, M.E., Retter, W.C. and Watson, J.N., 1979. Silage and milk production: comparisons between grass silage of three different chop lengths. Grass Forage Sci., 34: 293-301. Chambers, J.T., 1978. Agriculture in Northern Ireland. 53 No. 2, pp. 44-50. C.M.E.A., 1979. Council for Mutual Economic Assistance. Statistical Yearbook, pp. 231-236. C.V.B., 1983. Veevoedertabel. Centraal Veevoederbureau in Nederland, Lelystad. De Boer, P.B., van Dijk, H. and Oostendorp, D., 1977. Statistisches fiber Rindvieh und Schafhaltung in den Niederlanden. Proefstation voor de Rundveehouderij, Lelystad. Cited by Zimmer, 1979. Demarquilly, C., 1970. Influence de la d~shydration h basse temperature sur la valeur alimentaire des fourrages. Ann. Zootech., 19: 45-51. Demarquilly, C., 1973. Composition chimique, caract~ristiques fermentaires, digestibilit~ et quantit~ ing~r~e des ensilages de fourrages verts: modifications par rapport au fourrage vert initial. Ann. Zootech., 22: 1-35. Demarquilly, C. and Jarrige, R., 1969. The effect of method of forage conservation on digestibility and voluntary intake. Proc. l l t h International Grassland Congress, Surfers Paradise, Australia. St. Lucia, University of Queensland Press, pp. 733-737. Demarquilly, C. and Jarrige, R., 1971. The digestibility and intake of forages from artificial and natural grassland. Proc. 4th Gen. Meet. European Grassland Federation, Lausanne, 1971. Association pour le developpement de la culture fourrage, Domaine de Changins, 1260 Nyon, Switzerland, pp. 91-106. D.L.G., 1982. DLG-Futterwerttabellen ffir Wiederkauer. d. Dokumentations-steUe d. Univ. Hohenheim. DLG-Verlag, Frankfurt am Main. Dulphy, J.P. and Demarquilly, C., 1972. Influence de la finesse de hachage des ensilages de gramince sur le comportement alimentaire des moutons. Ann. Zootech., 21: 443-451. Dulphy, J.P. and Demarquilly, C., 1973. Influence de la machine de r~colte et de la finesse de hachage sur la valeur alimentaire des ensilages. Ann. Zootech., 22: 199-217. Dulphy, J.P. and Michalet, B., 1975. Influence compar~e de la machine de r$colte sur les quantit~s d'ensilage ingSrees par des gSnisses et des moutons. Ann. Zootech., 24: 757-763.

44 E.A.A.P., 1982. Projections for the utilisation, production and self-sufficiency in European countries for milk and veal, pork, mutton and lamb, eggs and poultry. In: R.D. Politiek and J.J. Bakker (Editors), Livestock Production in Europe. E.A.A.P. Publication No. 28. Elsevier Scientific Publishers, Amsterdam, pp. 308-335. Eurostat, 1980. Feed balance sheet - resources. Statistical Office of the European Communities, Luxembourg, pp. 72-103. Eurostat, 1981. Crop Production 2. Statistical Office of the European Communities, p. 25. Eurostat, 1983. Crop Production 4. Statistical Office of the European Communities, pp. 22-29. F.A.O. Production Yearbook 1979, p. 33. Flynn, A.V., 1981. Factors affecting the feeding value of silage. In: W. Haresign and D. Lewis ( Editors ), Advances in Animal Nutrition. Butterworth, London, pp. 81-89. Flynn, A.V. and O'Kiely, P., 1983. Grass Conservation. Paper II. Grass Production Seminar. Johnstown Castle Research Centre, Wexford. An Foras Taluntais, Dublin. Gartner, K., 1976. Agrartechnik, 26: 608-610. Green, J.O., Corrall, A.J. and Terry, R.A., 1971. Technical Report No. 8. Grassland Research Institute, Hurley, 81 pp. Hancock, J., 1971. Development and prospects of the cattle industry in Hungary. F.A.O. Mimeograph Report, Rome. Harris, C.E. and Raymond, W.F., 1963. The effect of silage on crop digestibility. J. Br. Grass. Soc., 18: 204-212. Henke, G. and Laube, W., 1968. Untersuchungen zur Heisslufttrockung von Grfinfutter. 2. Mitteilung Verluste an verdaulichen N~ihrstoffen. Arch. Tierernaehr., 18: 437-446. Howe, S., 1977. Power Farming, 56: 4, 8-11. I.A.M.Z., 1981. Options mediterrandenes. Serie Etudes. Tableaux de la valeur alimentaire pour les ruminants des fourrages et sous-produits d'origine mediterranSenne. International Centre for Advanced Mediterranean Agronomic Studies, 11, rue Newton, Paris. I.N.R.A., 1978. Tables de l'Alimentation des Ruminants. I.N.R.A. Publications, Versailles, pp. 89-128. Jarrige, R., Demarquilly, C. and Dulphy, J.P., 1984. In: J.B. Hacker (Editor), Forage conservation. Nutritional limits to animal production from pastures. C.A.B., Farnham Royal, U.K., pp. 363-387. Kalac, P. and Woolford, M.K., 1982. A review of some aspects of possible associations between the feeding of silage and animal health. Br. Vet. J., 138: 305-320. Klinner, W.E. and Holden, M.R., 1977. Advances with chemical preservatives for hay. ASAE/CIGR International Grain and Forage Harvesting Conference. Ames, IA. Am. Soc. Agric. Eng., P.O. Box 410, St. Josephs, MI 49085, pp. 303-307. Lee, J., 1978. Land use/beef production relations in the E.E.C. with special reference to land capability. In: J.C. Bowman and P. Susmel (Editors), Proc. E.E.C. Seminar on the Future of Beef Production in the European Community. Martinus Nijhoff, 1979, pp. 19-50. Lee, J., 1983. The spatial pattern of grassland production in Europe. In: A.J. Corrall (Editor), Proc. 9th General Meeting European Grassland Federation. Occ. Symposium No. 14. British Grassland Society, pp. 11-20. Lee, J., 1984. Suitability and productivity of land resources of EEC-10 for grassland use. A study carried out on behalf of the European Community. Johnstown Castle, Wexford, pp. 101-131. Lee, J., 1986. The impact of technology on the alternative uses for land. F.A.S.T. Occasional Paper 85, E.E.C., Brussels. Lingvall, P. and Nilsson, E., 1979. Efficient hay systems. In: C. Thomas (Editor), Proc. European Grassland Federation. Forage Conservation in the '80s. British Grassland Society, Occ. Symposium No. 11, pp. 175-185. L.T.K., 1982. Fodermedelstabeller och Utfodringsnormer. Eriksson, S., Sanne, S. and Thomke, S. (Editors), LTs Forlag, LTK.

45 M.A.F.F., 1986. Feed Composition - - U.K. Tables of Feed Composition and Nutritive Value for Ruminants. Chalcombe Publications, Marlow. Marsh, R., 1979. The effects of wilting on fermentation in the silo and on the nutritive value of silage. Grass Forage Sci., 34: 1-10. Maymone, B., 1959. Aspetti particolari della conservazione dei foraggi. Ann. Inst. Sperimentale Zootech. Roma, 6: 447-473. McIlmoyle, W.A., 1977. Animal production from different systems of conservation. Proc. Int. Meeting on Animal Production from Temperate Grassland. An Foras Taluntais, Dublin, pp. 62-66. McIlmoyle, W.A. and Steen, R.W.J., 1979. The potential of conserved forage for beef production. In: C. Thomas (Editor), Forage Conservation in the '80s. Proc. European Grassland Federation Symposium. B.G.S., Hurley, Maidenhead, U.K., pp. 144-153. Melville, J., 1960. Animal products and their competitors. Proc. 8th International Grassland Congress, Reading. B.G.S., Hurley, Maidenhead, U.K., pp. 35-40. Merrill, W.G. and Slack, S.T., 1965. Feeding value of perennial forages for dairy cows. A review. Animal Science Mimeo. Series No. 3, Cornell University. Moore, L.A., Thomas, J.W. and Sykes, J.F., 1960. The acceptability of grass/legume silage by dairy cattle. Proc. 8th International Grassland Congress, Reading. B.G.S., Hurley, Maidenhead, U.K., pp. 701-704. O.E.C.D., 1981-1982. Prospects for agricultural production and trade in Eastern Europe. Paris, Vol. 1, 1981, Vol. 2, 1982, O.E.C.D., Paris. O.E.C.D., 1986. The O.E.C.D. feed supply utilisation account (FSUA). Results for the European Economic Community-9 1973-1981. Paris (mimeo). O'Kiely, P., 1984. Silage in Ireland. Seminar on Impact of Agriculture on Groundwater in Ireland. A contribution to the UNESCO International Hydrological Programme. Published by Irish National Committee of the International Hydrological Programme, pp. 87-122. Papadakis, J., 1966. Climates of the World and their Agricultural Potentialities. Printed in Argentina, copyright by J. Papadakis, Cordoba 4564, Buenos Aires, Argentina. Pirkelmann, H. and Schurig, M., 1975. Der Einfluss technischer Verfahren auf die Kosten der Silierung im Hoch - und Flachsilo. Der Tierzuechter, 12: 524-529. Prym, R. and Weissbach, F., 1977. Changes in feeding value of preserved grass and legumes by the action of high temperatures. Proc. 13th International Grassland Congress, Leipzig. Akademia Verlag, Berlin, pp. 1387-1389. Roffler, R.E., Niedermeier, R.P. and Baumgardt, B.R., 1967. Evaluation of alfalfa-brome forage stored as wilted silage, low moisture silage and hay. J. Dairy Sci., 50: 1850-1813. Shepperson, G., 1960. Effect of time of cutting and method of making on the feed value of hay. Proc. 8th International Grassland Congress, Reading, pp. 704-708. Van Dijk, G. and Hoogervorst, N., 1984. Prospects for grassland utilisation in Eastern Europe. Neth. J. Agric. Sci., 32: 175-191. Vetter, R.L. and Von Glan, K.N., 1978. Abnormal silages and silage related disease problems. In: M.E. McCullough (Editor), Fermentation of Silage. A Review. National Feed Ingredients Association, West Des Moines, IA, pp. 281-332. Waldo, D.R., 1977. Potential of chemical preservation and improvement of forages. J. Dairy Sci., 60: 306-326. Waldo, D.R., 1978. The use of direct acidification in silage production. In: M.E. McCullough (Editor), Fermentation of Silage. A Review. Natural Feed Ingredients Association, West Des Moines, IA, pp. 117-182. Weiss, P.H., Girard, P. and Lemaitre, G., 1979. Effect of Italian ryegrass conservation methods on quality of silages, dry matter conservation and milk production. In: C. Thomas (Editor), Forage Conservation in the '80s. Proc. European Grassland Federation, Occ. Symposium No. 11, British Grassland Society. B.G.S., Hurley, Maidenhead, U.K., pp. 403-407.

46 Wieneke, F., 1972. Verfahrenstechnik der Halmfutterproduktion, Gottingen, pp. 304-373. Cited by Lingvall and Nilsson, 1979. Wilkinson, J.M., 1979. Production of hay and silage in Europe. In: C. Thomas (Editor), Forage Conservation in the '80s. Proc. European Grassland Federation, Occ. Symposium No. 11, British Grassland Society. B.G.S., Hurley, Maidenhead, U.K., p. 457. Wilkinson, J.M., 1987. Silage in Western Europe: A survey of 17 countries. Chalcombe Publications, Marlow Bottom, Bucks., U.K., pp. 1-5. Zimmer, E., 1979. Efficient silage systems. In: C. Thomas (Editor), Forage Conservation in the '80s. Proc. European Grassland Federation, Occ. Symposium No. 11. British Grassland Society. B.G.S., Hurley, Maidenhead, U.K., pp. 186-197. Zimmer, E. and Wilkins, R.J. (Editors), 1984. Efficiency of silage systems - a comparison between wilted and unwilted silages (Eurowilt). Landbauforschung VSlkenrode, Sonderheft 69, p. 72.

Livestock Production Science, 19 (1988) 47-95 Elsevier SciencePublishers B.V., Amsterdam-- Printed in The Netherlands

47

II. 3. Cereals, Pulses and Oilseeds N.A. TODOROV

INTRODUCTION

General

In this chapter the term 'cereals' is used to describe all starchy vegetable seeds, regardless of their botanical family. Therefore wheat, barley, oats and rye belong to this group as well as maize, rice, sorghum and some others. Also, the word grain is sometimes used here to indicate this group of feedstuffs. Cereals, pulses and oilseeds contribute approximately 30% of the total energy supplied to farm animals in Europe with a predominant share coming from cereals. There is considerable variation, in this respect, between different countries owing to the structure of animal husbandry, production conditions and levels of production. The proportion of cereals is usually between 60 and 85% of the energy in rations for poultry, 40-85% for pigs, 10-40% for dairy cattle and 5-25% for sheep. In some countries a significant quantity of cereals is replaced by other feeds which have a high energy concentration in the dry matter such as maize-gluten feed, cassava, potatoes, sugar beet and other roots, and the proportion of grain is lower than mentioned above. These replacers of cereals can be used in the fresh or dried form. Inclusion in compound feeds is possible only after drying. In The Netherlands, the replacement of cereals with cassava and maize-gluten feed has been extensive in compound feeds for dairy cattle and pigs. The replacement of grain is limited by the production of those replacers, by the high cost of dehydration and other factors. In spite of the possibilities for replacement, grain is the main concentrate and has a key position in animal husbandry. It determines, to a large extent, the level of production and as a consequence determines the efficiency of animal production. In livestock husbandry, recently, a tremendous increase in productivity, growth in specialization, mechanization and rapid increase of size of production units, have increased the need for grain. In this way, animal production in much of Europe is becoming more dependent on grain. This is because of the unique characteristics of grain as a high-energy, highly-palatable feed. 0301-6226/88/$03.50

© 1988Elsevier SciencePublishersB.V.

48

Advantages and constraints of cereals, pulses and oilseeds as animal feed During vegetative growth, reserve energy is accumulated in seeds in the form of starch (in cereals), oil (in oilseeds) and partly protein in legumes. These nutrients are necessary for a good start to new plant development from seed. They are utilized by the action of the enzymes of the germinating seeds. The enzymes of the alimentary tract of animals also digest seed-reserve nutrients very easily. The true digestibility of starch, oil and protein in cell contents is about 98% (Goering and Van Soest, 1970). On the contrary, there are no enzymes in the animal organism for the digestion of cellulose and hemicellulose, which comprise a large proportion of forage. Their digestibility depends on bacterial activity in the rumen and large intestines. Generally, roughages, being high in fibre content, are less digestible than grains and other seeds, even in ruminant animals. The net energy of dry matter of grain is 1.2-5 times higher than roughages of different quality. High-producing animals should receive a ration with a high-energy density. When low-energy rations are used, for example a diet high in roughage, the animal cannot physically ingest sufficient feed to meet its energy needs for production. Hence, there is a suppression of production potential. A high-energy ration allows the animal to meet its energy requirements with less feed, which the animal is able to ingest. For high production from good dairy cows it is generally necessary to feed a liberal amount of grain, in addition to plenty of high-quality roughage. In spite of the advantages of grain as a high-energy feed for all classes of animals, it is impossible to feed an extremely large quantity to ruminants because of digestive problems, such as acidosis or bloat. Roughages are necessary to keep the level of crude fibre above 8-12% of ration dry matter (DM) for fattening ruminants and above 16-18% of DM for dairy cattle and other lactating ruminants. A very high level of starch in the ration causes unfavourable changes in rumen fermentation, especially for lactating animals and causes the "low milk-fat syndrome". According to present-day knowledge, the upper limit for starch in the ration of dairy cows is 30-35% of DM. This means that cereals should not make up more than 50-60% of ration DM for dairy cows. The upper limit for cereals is even lower for rations based on maize silage containing a significant quantity of grain. Under favourable conditions, cereals can comprise 75-80% of rations DM at the end of the fattening period for ruminants. The level of grain feeding is important both for a high rate of growth and for production of high-quality meat desired by the consumer. Fattening cattle and lambs must receive considerable quantities of grain to produce good-quality meat. Pigs and poultry must be fed mainly on concentrates, because their digestive systems can make only limited use of forage. The proportion of grains fed to these animals is high. When grain is in an unfavourable position because of high prices and/or taxes, there is a trend towards replacement of grain by cas-

49

sava, maize-gluten feed, potatoes and other concentrates. The proportion of grain in compound feeds for swine in such a situation may fall as low as 10%. CEREALS

Nutrient characteristics Cereals are concentrates rich in carbohydrates and are therefore used as energy sources. Their low protein level and deficiencies in some minerals and vitamins can be relatively easily overcome by protein, mineral and vitamin supplements. They are concentrated stores of highly-digestible material in a dehydrated, prepacked form, which makes handling, transportation and storage easy. This makes them very attractive for the farmers and agricultural merchants. In addition, the variation in composition of grains and their feeding value are much smaller compared to forages. This ensures uniformity of the rations and as a result animal production is constant and high. Starch The starch content of cereals ranges from about 45% of DM in oats to 73% in sorghum (Table I). The starch is highly digestible (90-98%). The crudefibre content is generally inversely related to starch content and to overall feeding value. The nude grains such as maize and wheat are higher in feeding TABLE I

Chemical composition and energy value of cereals ( data compiled by author) Item

Barley Barley Maize Wheat Triticale Rye 6-row

Chemical composition ( g k g - 1 DM) Crude protein 110 120 Crude fat 18 23 Crude fibre 64 52 Nitrogen-free extract 782 779 starch 580 590 sugar 20 21 Ash 26 26 Calcium 1.2 1.2 Phosphorus 3.9 3.9 Energy value ( MJ k g - 1 DM) ME, ruminants DE, pigs AMEA~, poultry

13.7 14.8 13.0

Oats

Sorghum Millet

120 35 29 796 700 15 20 0.4 3.3

2-row

13.7 14.9 13.6

~For high-tannin sorghum 13.7. bAME = Apparent Metabolizable Energy.

106 47 24 808 700 20 15 0.4 3.1

130 23 27 802 680 31 18 0.8 4.0

140 22 27 791 620 55 20 0.9 3.6

116 22 27 813 640 5O 22 0.9 3.2

120 55 112 680 440 18 33 1.2 3.8

14.2 16.4 15.9

14.0 16.0 14.8

14.0 15.8 14.5

13.9 15.7 12.0

11.5 13.2 12.3

13.8 15.8 15.3 a

128 38 95 696 590 10 43 0.5 3.4 12.7 13.6 14.0

50 value than hulled grains like oats and barley. Maize has the highest net energy value followed by grain sorghum, wheat, triticale, barley and rye. Oats with their thick hulls are higher in crude fibre and therefore lower in net energy. Sugars comprise 1.2-2.5% of cereal DM, 0.9-1.2% being sucrose, 0.03-0.06% maltose, 0.1-0.6% glucodifructose, 0.12-0.29% raffinose and others. Only rye and triticale of all cereals contain 5.5-6.5% sugar.

Protein. Protein levels in cereals are only moderate and therefore generally below the animal's requirements. Crude-protein levels vary from 10 to~13% of DM. Some varieties of wheat may have considerably more protein than this. In very dry years, the protein content of cereals is higher than normal. About 85-95% of the nitrogenous components are in the form of protein. Although cereals are not used as protein feeds, the fact that they are incorporated in livestock diets in large amounts, especially for non-ruminants, means that a large proportion of the protein in the diet is provided from cereal. Cereal proteins are deficient in certain essential amino acids, particularly lysine and methionine. Glutamic acid is the most abundant amino acid in cereals, followed by leucine and proline. Scientists are trying to improve grain proteins by genetic manipulation. The most effective way of altering the amino-acid composition of seeds, with high concentration of alcohol-soluble proteins (prolamine), is through mutations which reduce synthesis of other protein fractions, preferably albumins and globulins. The embryo and aleurone layers of cereal seeds are rich in protein, which has a good amino-acid balance. Selection for a larger aleurone layer and larger embryo will improve nutritive value. Pulses and oilseeds are used to some extent for animal feed and are relatively rich in protein. The quality of protein they contain varies widely. Oil. The oil content of cereals varies with the species. Oats and maize contain 4-6% oil which is 2-3 times higher than wheat and barley. The embryo contains much more oil (10-20%) compared with the endosperm (1-2%). Pulses, generally, are low in oil, whereas oilseeds contain between 18-50% oil, with sunflower seeds ranking the highest. The oils in grain are unsaturated, the main fatty acids being linoleic and oleic. Maize, oats and oil-bearing seeds are a good source of essential fatty acids for animals. Calcium and phosphorus. All seeds are deficient in calcium, usually containing less than 0.15%. They contain 0.3-0.4% phosphorus. Roughages however, are relatively rich in calcium and deficient in phosphorus. Substantial proportions (70%) of the phosphorus in grain are bound in the form of phytate, a form of phosphorus that is of little value to poultry. Vitamins. Cereals are deficient in Vitamin D and, except for fresh yellow maize,

51 also deficient in Provitamin A, carotene. All of the grains supply Vitamin E in fair amounts. All of the various grain-processing techniques result in losses of Vitamin E and carotene. Grains are fairly rich in thiamine, but are low in riboflavin. Wheat, barley and grain sorghum contain considerable quantities of niacin. Maize, oats and rye have a much lower content of this vitamin. Anti- nutritive substances These are found in some cereals and may retard growth, to some extent, in young chicks, if used in large quantities in rations. Adult poultry and other species are less sensitive. These substances are beta-glucan in barley and to some extent in oats and rye; soluble pentosans and polyphenols in rye; antienzymes in oats and barley; tannins in sorghum and sometimes in barley. The high level of crude fibre in oats and barley also restricts their use in diets for young chicks and small pigs. Problems created by beta-glucan and soluble pentosans can be reduced or eliminated by the addition of the enzymes beta-glucanase and pentosanases in diets for poultry and swine. The maximum levels of inclusion of different cereals in rations are specified later. Most legume seeds contain some bitter substances, alkaloids, glucosides and other toxic materials, which must be taken into account when they are included in compound feeds or in rations for various classes of animals. Utilization The author estimates that in Europe (including the U.S.S.R. ) about 240-260 million metric tons of cereals were used annually for animal feeding during the period 1975-1985. In the U.S.S.R. only, feed cereals were 72-103 million tons for 1980-1984 (U.N., E.C.E., 1984). The major proportion of cereals fed to animals are coarse grains (barley, maize, oats, rye, sorghum and others). About 80% of the total utilization of the coarse grain (Table II) is for animal feed (85-95% oats, 80-90% maize, 80-85% barley and 40-60% rye). A large quantity of wheat is also used for animal feed. After 1950, the quantity of wheat used for feeding animals in Europe rose significantly. For the period 1973-1982 about 10-15 million tons of wheat were used for feeding animals in the EEC-10 (Eurostat, 1985) and 42-43 million tons in the U.S.S.R. (U.S.D.A., 1985). Further increases in the quantity of wheat used for animal feed have taken place in 1984-1986, 22 million tons for EEC-10 (Eurostat, 1985). There is a significant variation in the proportion of wheat fed to animals between countries and years. There has been a continuous increase in the quantity of wheat and coarse grain utilized in Europe during the last 35-40 years (Table II) because of an increase in the grain used for animal feed. The contribution of cereal grains in livestock feeding can be measured by calculation of the proportion of energy in animal rations supplied by cereals. In E.E.C. countries this is still done by

52 TABLE II Production and utilization a of grain in Europe (Mt year- 1) Period

1934-1938 1946-1950 1951-1955 1956-1960 1961-1965 1966-1970 1971-1975 1976-1980 1981-1985

Wheat

Coarse grain

Production

Utilization

Production

Utilization

80(42) b 66(35) 93(46) 117(49) 120{56) 159(69) 173(83) 188(89) 189(108)

89(52) 80(50) 102(56) 128(64) 133(69) 165(79) 184(91) 196(90) 208(108)

135(77) 104(58) 125(72) 135(81) 149(93) 179(113) 216(135) 240(146) 256(166)

144(87) 109(64) 131(78) 145(92) 166(112) 199(134) 240(156) 277(172) 279(177)

~Data for utilization are calculated by addition of import and subtraction of export from production. Therefore, they include all purposes utilization (food, feed, seeds, industrial processingetc. ). bValues in parentheses are values excluding U.S.S.R. data. Sources: F.A.O. Production Yearbook (various years ); F .A.0. Trade Yearbook (various years ) ; C.M.E.A. Statistical Yearbook (various years). using the (Leroy) net energy unit (French Feed Unit). In 1977/1978 (Eurostat, 1983 ) the contribution of cereals was 30% in EEC-9. Per country it varies considerably: Ireland 11%; France 22%; The Netherlands 26%; the U.K. 27%; Belgium and Luxemburg 29%; F.R.G. 30%; Italy 34%; Denmark 41%. The proportion of cereals fell to 23% of net energy in animal feed in 1982/83 for the EEC-10 (Eurostat, 1985). For some Eastern European countries this proportion on the base of net energy (oat-feed units) for 1971-1975 is: Romania 32%; Poland 38%; G.D.R. 42%; Czechoslovakia 46%; Yugoslavia 54%; Bulgaria 62%; Hungary 69% (F.A.O., 1979). Of course, the number of different species of animals, production conditions and many other factors influence the pattern of the data.

Production The production of cereals in Europe and the percentage contribution of the different crops are shown on Table III. The production of barley, maize and wheat has increased recently, whereas oats, rye and other cereals have remained constant or diminished (Fig. 1 ). There has been abig increase in cereal production, about 50% during the last 10 years (1975-1985), in Western and Central Europe.

Variation in yield The variation in yield of cereals in Europe is considerable. The highest yield is achieved in North-West and Western Europe, followed by Central Europe.

53 TABLE III Production of cereals in Europe, thousand tons per year (average for 1981-1985) Region and country

Barley

Maize

Wheat

Oats

Rye

Total

North-West andWest France The Netherlands Belgium and Luxemburg Denmark U.K. Ireland

29012(34) ~ 10495(12) 42448(49) 10 403(21) 10439{21) 26 990(53) 212(16) 2(0.1) 975(75) 794(37) 53{2) 1 118(52) 5 630(72) -1 606(21) 10426(47) 1(--) 11313(51) 1 547{73) -446(21)

2759(3) 1723(3) 86{7) 141{7) 147{2) 551(2) 111(5)

789(0.9) 321(0.6) 25(2) 31(1) 385(5) 26(0.1) 1(--)

86422 50 711 1 301 2 169 7 782 22354 2 105

Central F.R.G. G.D.R. Poland Czechoslovakia Hungary Switzerland Austria

23 267{26) 9413{38) 3 990{38) 3 618(16) 3 507(32) 1 053(7) 257(26) 1 429(28)

6895(8) 2634(11) 685(7) 2611(12) 469(4) 142(1) 55{6) 299{6)

13 197(15) 1744(7) 2 204(21) 8089(36) 642(6) 146{1) 25{3) 347{7)

88 540 24575 10 368 22 235 10 900 14 413 974 5 075

Northern Sweden Norway Finland South-East andEast Bulgaria Romania Yugoslavia U.S.S.R. Mediterranean Portugal Spain Italy Greece Albania

4 637(44) 2 398(40) 637(52) 1 602{47) 49597{23) 1 204{14) 2 493(12) 700(4) 45200(26) 9 771(23) 75(6) 7 613(47) 1 296(7) 757(15) 30(3)

10612(12) 31 145(35) 1010(4) 9206(37) 2(--) 3 388(33) 65(0.3) 5 263(24) 885(8) 5 389(49) 6 973(48) 6 065(42) 147(15) 486(50) 1 530(30) 1 348(27) -----

2 033(19) 1 486{25) 113{9) 434{13)

3 382(32) 1 666(28) 461{38) 1 255(37)

284{3) 206{4) 2(0.1) 76(2)

10 560 5 941 1 216 3 403

38391(18) 96524(44) 15651(7) 12101(6) 218305 2 906(34) 4 260(50) 39(0.5) 36(0.4) 8 546 12 714{59) 6271(29) 85(0.4) 45(0.2) 21 703 10 571{63) 5 093(30) 267(2) 80(0.5) 16 771 12200(7) 80900(47) 15260(9) 11940{7) 171285 11 739(28) 17 084(41) 488(37) 388{29) 2 425(15) 4 693{29) 6 774(37) 9 003{49) 1 688(33) 2 459{48) 364(36) 541 (53)

1 172(3) 119(9) 572(4) 382(2) 69(1) 30(3)

401(0.9) 90(7) 264(2) 27(0.1) 11 (0.2) 9(0.8)

42 050 1 319 16 065 18 569 5 077 1 020

aValues in parentheses are the percentage of total region or country production. Source: F.A.O. Production Yearbook, 1983 and 1985.

The yield of cereals is much lower in Northern, South-East and Eastern Europe and in the Mediterranean region (Table IV). The main factors limiting yield in northern regions are sunshine and temperature, while in Southern Europe and the Mediterranean region it is water supply to crops. There is a considerable similarity of soil and climate requirements amongst the cereals. Most of the soils that are good for wheat are also suitable for barley,

54

"50 L2C

"20

39(

390

36(

360

33(

330

MAIZE

300

30C

OIHER

270

c o 21.[

2/,0

21C

~10

c 0 18(

BARLEY

180

~15~

co c o

150

12(

120

90

90

60

60

WHEAT

30

3C /

19 /.1938

19/,61950

i

19511955

i

19S61960

i

t9611965

i

19661970

i

19711975

i

19761980

i

1981 198~'

Fig. 1. Cereal production in Europe including U.S.S.R. (cumulative data; the top line shows total cereal production).

oats or rye, but it is not always possible to grow wheat and barley on soils which are suitable for rye. The areas of soil suitable for cereal production in Europe are shown in Fig. 2. At the same time, there are some differences among cereal crops. The northern latitude limit for maize is 52-54 ° N, winter wheat 60-62 ° N, spring wheat 62-64 ° N, rye 64-66 ° N, oats 65-66 °N and barley 67-69 ° N. Rye and oats are hardier crops t h a n wheat and barley. Buckwheat, rye, oats and wheat are tolerant of acid soils. Barley does not suffer from salinity but is sensitive to acid soils. Rye and buckwheat may be grown on poor and acid soils not suitable for growing o t h e r grains.

Efficiency of cerealproduction The efficiency of cereal production differs considerably as shown in Table V (Delorit et al., 1984). Cultivation of only the most energy-efficient crops would obviously provide an advantage for overall energy utilization. However yield per hectare, cultivation or harvesting costs and selling price of grain are important factors. On the other hand, it is necessary to provide the nutritional components for a balanced diet for farm animals. With recent advances in animal nutrition science, balancing rations for the different classes of animals is not bound up with specific feeds as in the past.

55 TABLE IV Yield of cereals in Europe a {kg h a - 1) average for 1981-1985 Region and country North-West and West France The Netherlands Belgium and Luxemburg Denmark U.K. Ireland Central F.R.G. G.D.R. Poland Czechoslovakia Hungary Switzerland Austria Northern Sweden Norway Finland South-East and East Bulgaria Romania Yugoslavia U.S.S.R. Mediterranean Portugal Spain Italy Greece Albania

Barley

Maize

Wheat

Oats

Rye

Total

4561 5161 5312 4274 4918 4921

6152 8000 6721 -1000 --

5526 7116 5896 6345 6466 6820

3707 5150 4274 4038 4433 4826

3096 4071 4212 4430 4192 3696

5252 6474 5496 4568 5576 5235

4658 4363 3063 4090 3686 5074 4205

6173 2810 4135 4840 6132 7719 7576

5667 4836 3270 4663 4620 5250 4439

4200 3780 2516 3360 2956 4849 3590

3972 3211 2465 3469 1913 4915 3657

4895 4123 2745 4316 5019 5429 4807

3691 3606 2796

----

5156 4511 2957

3691 3823 2889

3769 2782 2124

3954 3738 2820

3579 3195 2493 1480

5145 4137 4586 2940

4023 2804 3461 1510

1143 1278 1590 1231

1429 1346 1604 1269

4168 3479 3899 1484

853 1976 3246 2330 2372

1370 5581 6980 8855 3906

1146 1968 2774 2518 2829

680 1240 1880 1501 1507

637 1129 2422 1800 821

1133 2154 3694 3255 2850

aSource: F.A.O. Production Yearbook, 1983 and 1985.

Trends in cereal production In Europe, trends show an increase in the production of maize, wheat and barley at the expense of the area used for fodder roots, oats, beans, chick peas, lentils and rye. The combined share of the European grain total from maize, wheat and barley has risen from 58.8% in 1934-1938 to 86.7% in 1981-1984. The expansion in the production of maize, wheat and barley has largely reflected the development of new varieties of seeds, capable of responding to heavier application of fertilizers and improved cultivation and harvesting methods. The continuing development of new high-yielding varieties, or varieties with

56

Fig. 2. Soil suitable for cerealproduction {adapted fromBroekhuizen,1969). improved nutritive value, changes in the technology of growing and harvesting crops will cause further changes in the proportion of the various cereals used in animal feeding. The expansion of maize production in Europe is expected to continue. The area sown with rye will probably decrease. To some extent this may happen to oats and maslin (mixed cereals). The area suitable for cereal production in Europe is larger than the area actually used for the cultivation of cereals. This means that there is some room for expansion of cereal growing. Thus, based on soil conditions solely, cereals could replace some fodder roots, maize grown for silage, lucerne and other seeded legume and grass.

57 TABLE V Water and energyutilization in cerealand in soyabean production Crop

Litres waterper kg DM produced

Energyoutput per unit of energyinput

Barley Maize Wheat Oats Millet Sorghum Soyabean

464 368 500 597 271 ---

-4.4 3.2 2.6 -5.3 2.7

But fodder roots and seeded perennial fodder crops in North and North-West Europe are high-yielding crops. For some regions of Central and Southern Europe, ensiling whole plant maize yields more net energy per hectare with less cost than grain production. In many regions in Europe there are marginal soils for cereal production. Expanding grain cultivation to sloping land, however, will increase the cost of grains. Early-maturing hybrids are used in successful maize cultivation in the Northern areas of Europe. Cold-tolerant cultivars of wheat and other small grains have also been selected which enable cropping to move further north and to higher altitudes.

Future prospects In general, there are several potential ways of expanding cereal production in Europe, if this should be necessary. On the other hand, relatively low-price grains are available on the market outside Europe, which make European exports inefficient. In the near future, therefore, a significant increase in the area planted with cereals in Europe as a whole is not expected. The total production of cereals, however, will rise, owing solely to increases in yields per hectare, the result of genetic and technical progress. The increase will be bigger in the U.S.S.R. and some Eastern and Southern regions of Europe, because of the level of yield attained already elsewhere in Europe and a concomitant degree of exhaustion of the available yield potential. This will permit the production of enough cereals for self-sufficiency in Europe as a whole, including the U.S.S.R., and even to provide some surplus, in spite of the growing demand for grain. In many countries in Europe, the utilization of grain and human consumption of almost all animal products has reached saturation level. However, in the Mediterranean countries, U.S.S.R., some Eastern and other countries, grain output has not kept pace with the increasing demand for food of animal origin, which

58 requires an expansion of livestock production. The introduction of grain-saving systems for feeding ruminants is important for these countries. An increase in the production of maize silage with high DM content and its utilization by dairy cattle, beef cattle and sheep may provide the possibility of achieving that goal. An increase in roughage quality is an alternative technique for achieving the same objectives. Barley Nutrient characteristics The energy value of barley is high, 13.3 MJ ME kg -1 DM (according to I.N.R.A., 1978) or 12.8 MJ ME kg- 1DM for ruminants (according to M.A.F.F., 1976). It has about 93% of the metabolizable energy of maize and 94% of that of wheat. Light-weight barley (40-50 kg hl -~) is worth considerably less than heavy, plump barley ( 60-65 kg hl- ~) as it contains a larger proportion of hull. The hulls form about 15% of the weight, and because of them barley averages 55 g kg- ~DM in crude fibre content. Hulless varieties of barley exist but they yield considerably less than the ordinary varieties, which discourages their cultivation. Hulless varieties are higher in protein and starch content compared with normal barley. Energy digestibility is approximately 73% in ordinary and 77% in hulless barley. Barley contains 100-140 g crude protein (XP) kg -~ DM. For malting, barley medium to low in protein is preferred, but for animal feeding, high-protein barley needs less protein supplementation. With increasing XP in grain there is a decrease in lysine in XP and biological value as well as a decrease in crude fibre. Protein quality is not high, lysine being the first limiting amino acid and threonine second. Investigators in Sweden after screening 2500 barley varieties have found a barley type, 'Hiproly', with a high protein and high lysine content. Much breeding effort has been expanded to introduce this simplyinherited characteristic into an adopted genetic background (Doll, 1981 ). 'Hyproly' crosses (Mutant 7 and 1508) have 4.1-5.22 g lysine per 100 g XP, mainly because of an increase in glutelin. The biological value is 85.4-89.8 compared to 67.8-74.4 for commercial cultivars (Tallberg and Eggum, 1981 ). Unfortunately, strains selected for high lysine seem invariably to produce small and shrivelled grains, owing to impaired starch accumulation and consequently have yielded poorly. At present, the considerable effort required to breed highyielding, high-lysine barley cannot be economically justified, but extensive research is being conducted on the synthesis of storage protein in barley and this may eventually point the way to breeding success. High-lysine barley is used successfully in pig and poultry feeding.

59

Utilization Barley should form a large proportion of the concentrates for beef cattle, ewes, growing and fattening lambs, pigs and poultry (except broilers). There are some data showing that barley can be included in large quantities in rations for dairy cows, but not above 6-8 kg daily. Rolled or bruised barley supplemented with protein, minerals and vitamins A and D can be sole feed for intensive fattening of bulls according to the "barley-beef system". Barley has too high an energy density for horses and mixing with bulky feeds such as bran or oats is advisable. Barley is less palatable for poultry than maize or wheat. Because of the hulls and beta-glucan content the growth rate of chicks is decreased if more than 20% of barley is used in rations for broilers. The presence of beta-glucan in barley limits the growth of chickens by increasing the viscosity of the intestinal contents, which interferes with nutrient assimilation (White et al., 1981 ). It can cause an increase in water intake and the moisture content of droppings. There is a secondary effect attributable to higher levels of microbial activity. The level of beta-glucan in barley can vary from 1.5 to 8% depending on the variety of barley and environmental conditions under which barley was grown. In areas with low rainfall, barley has higher levels of beta-glucan than in areas with adequate water supply. Addition of enzymes (beta-glucanases) has been shown to improve the nutritive value of barley for poultry. Barley with enzymes can be used in broiler rations as successfully as wheat. For laying hens, barley is a good feed and may form a large part of the diet (up to 70% ). Barley should be ground, crushed or rolled, but sheep can be fed whole barley. It should be ground to medium fineness for dairy and beef cattle. Fine to medium grinding is preferred for pigs and poultry. Too fine a degree of grinding is undesirable, as finely-ground barley may become pasty in the mouth and consequently unpalatable. Because of the hard nature of the kernel, barley should be ground more thoroughly than maize. High-moisture barley is stored and fed to animals in some countries (see pp. 64-67).

Production Barley is the most widely-cultivated animal-feed cereal throughout Europe. Three species of barley are cultivated: six-row (Hordeum vulgare), two-row (H. distichum) and irregular barley (H. irregulare). There is a tendency to shift from spring to winter barley. It is a very important crop, being grown on a large scale in the U.K., Denmark, France, F.R.G. and Spain. The U.S.S.R. has by far the largest area planted to barley and is the biggest single producer (Fig. 3 ). Barley is especially suited to Northern Europe because of its short growing season and to Southern Europe and the Mediterranean because barley is not strongly affected by the scanty summer rainfall. As winter barley matures before the midsummer heat, it does well south of the areas where spring barley

60 7.:~

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.:.

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Fig. 3. Barley growing in Europe, 1984 (one dot is equal to 5000 ha) (compiled by the author on the basis of national data).

thrives. Winter barley is not as hardy as winter wheat and rye. It is possible to grow winter barley where the average winter temperature is above - 4 ° C. Some cultivars are considerably resistant to frost and drought• Barley is best adapted to a cool, moist climate, but may withstand high temperatures under low humidity. It grows well on well-drained loamy soils with a pH of 7-8 which supplies enough phosphorus and potassium. Barley is tolerant to salinity but not to acid soils.

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62 The production of barley has increased 4-5 times above its level in the early post-war years (Fig. 4). The rise in production is even higher in the U.S.S.R. (Fig. 5 ). Part of the additional output resulted from an expansion in the area planted to barley and the remainder came from improvement in yields, which have reflected the development and use of better seeds, the heavier application of fertilizers and improved harvesting methods. A large increase in barley production has been achieved in the U.K. From the early 1950s to 1968 the area under barley in the U.K. was nearly trebled and the production was nearly quadrupled. Recently, there has been a tendency for a slight decrease of the area planted with barley in Europe. In spite of the large production of barley, Europe as a whole is a net importer of this cereal, but barley production is in surplus in France, Denmark, the U.K., Sweden and Ireland. Maize General

Maize is an extremely variable plant consisting of many types, some even having flowers and kernels on the tassel. There are 6 types based on kernel characteristics, namely: dent ( Z e a m a y s indentata ) , flint { Z. m. indurata ) , pop ( Z. m. everta ) , flour or soft ( Z. m. amilacea ) andpod maize ( Z. m. tunicata). The most important type is dent maize followed by flint maize. Other types are not as important as feed maize in Europe. Flint maize comprises mainly hard starch, and its kernels are very hard. Many hybrids of flint maize ripen very early and their seeds germinate better in cold, wet soil in the spring. For these reasons, they are grown further north in Europe than dent types. The colour of both dent and flint maize grains differs widely, usually being yellow, white, red or blue. Considerable variations from 80 to 190 days, occur in the length of the growing period required for grain maturation, but most maize hybrids have a growing season of 100-150 days. Early-maturing hybrids produce shorter stalks, smaller ears and kernels and lower yields than the later-maturing varieties of Southern Europe. Since 1950, only hybrid maize has been planted in Europe. N u t r i e n t characteristics General. Maize ranks high amongst the grains in digestible and metabolisable

energy content. This is because maize is very rich in starch, high in oil (3-6%) and very low in fibre (about 2% ) and is therefore highly digestible. The digestibility of organic matter in maize is 84% for cattle and 86% for pigs, compared with 81 and 81%, respectively, for barley and 68 and 67% for oats.

63 Another advantage of maize is that it is the most palatable of the cereals for livestock. A possible explanation of this is the high fat content and the physical properties of maize. It breaks down on chewing to produce particles which are more palatable than meal from wheat and other grains. Maize is low in protein, the average content being about 10% of DM. To satisfy the protein needs of poultry, pigs and other livestock, high quantities of protein supplements are necessary. Protein content increases with increasing levels of nitrogenous fertilizers of both normal and 'Opaque-2' maize. The protein of ordinary maize is of poor quality for non-ruminants because it is low in two of the essential amino acids: lysine and tryptophan. In addition, the low tryptophan (which is a precursor of niacin) and the low availability of niacin will lead, eventually to a niacin deficiency and "pellagra" in those monogastric animals which depend on maize as a major dietary constituent. Yellow maize has considerable Vitamin A value, because it contains the pigments cryptoxanthin and carotene, precursors of Vitamin A. There is a correlation, to some extent, between its fat and pigment content. Part of the yellow colour of maize is due to xanthophyl, which has no Vitamin A value, but enhances colour in egg yolks and broiler skin. On storage, the Vitamin A value of maize may decrease considerably, without any great changes in colour. In most European countries, broilers with coloured skin are desired. In the U.K. white broilers are preferred, thus white maize varieties are often fed to these broilers. When care is taken to provide sufficient Vitamin A in the ration, yellow and white maize are equal in nutritive value.

High-lysine maize. In 1963 a team of researchers from Purdue University discovered that an old strain of maize known as 'Opaque-2', a chalky-kernelled type, was twice as high in the amino acids lysine and tryptophan as ordinary maize. The difference is primarily attributed to the zein:glutelin ratio. The biological value of high-lysine maize is 72-78% versus 63 % for normal varieties (Eggum et al., 1979). Later, another high-lysine and high-methionine strain was found and named 'Floury-2'. But the millenium that seemed near with the discovery of high-lysine maize has remained frustratingly out of reach. Highlysine hybrids yield less than ordinary dent hybrids. The m u t a n t gene is linked with a soft kernel, which is both light in weight and vulnerable to pest attacks. High-lysine hybrids are less resistant to some diseases, contain a higher percentage of moisture early in the harvesting season and suffer greater kernel damage in harvesting. This type of maize has never been widely grown commercially in Europe. There is controversy as to whether it is more economically feasible to correct the protein quality of ordinary maize in diets, with supplements of high-quality protein or synthetic amino acids, instead of cultivating low-yielding, high-lysine hybrids. From the long-term point of view breeding of high-lysine maize holds sufficient promise to merit continuance of breeding programmes.

64

High-protein maize. A type of maize has been developed with a protein content of up to 20% or even 30%. The increase is mainly caused by a high level of zein which has very little lysine and tryptophan. The yield of the present highprotein hybrids is generally so much lower than the best ordinary hybrids that their use has not become common. Breeders have also developed a high-oil maize with a 6-9% oil content which is 1.5-2 times the oil content of ordinary maize. These hybrids produce good yields and are attractive as feed grains because of their energy concentration. Another potentially-attractive type of maize is the multi-eared (prolific) hybrids. They produce 2 or 3 ears on the main stalk, and hold potential for further increases in the yield of maize. Utilization Maize is one of the best feeds for all classes of livestock, when it is fed so as to take advantage of its great merits and to correct its deficiencies. Since maize has a very high energy density it is usually mixed with wheat bran or other bulkier feeds when a large quantity of grain is given to horses, dairy cows and other ruminants. When fed in a properly-balanced ration, maize can be used successfully as the only grain for breeding ewes, fattening lambs, working horses and even for fattening cattle and dairy cows. For various classes of non-ruminant animals, maize is an unexcelled feed when combined with high-quality protein supplement and minerals and the potential vitamin deficiencies are corrected. Maize can comprise a substantial proportion, up to being the only grain, of a concentrate mixture. Because of its high energy value, maize is excellent for feeding to broilers, fattening pigs, lambs and young calves. High-fat maize tends to promote deposition of soft fat in pigs, but this is not a problem with very fast growing strains nowadays. Production Maize ranks second in volume of production amongst the feed cereals in Europe. It is the most valuable cereal, often referred to as "king grain" because its energy value exceeds that of other grains. Maize is produced mainly in Southern and Central Europe. A large proportion of the arable area is planted to maize in southern France, Italy, Portugal, Hungary and the Balkan peninsula (Fig. 6 ). Early-maturing hybrid cultivars have been developed which have moved the boundary for successful and safe maize production further north in Europe. Good harvests can be produced on many types of well-drained soil with good water-holding capacity. It is important to have generous, well-distributed rainfall or irrigation for the best growth of maize. The growing period should be frost-free with an abundance of warm weather and sunshine. The area under maize in Europe as a whole has not changed significantly from 1934 to 1984. There has been an expansion in the area planted to maize in France and some other countries, but a decrease in Italy and others. For the

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same period, yield and total production have increased more than three times. The improvement in yield is a result of the advances in the biological and technological factors of maize production. In spite of the increased production, importation of maize into Europe has increased continuously and significantly up to 1980 (Figs. 7 and 8). Significant quantities of feed maize are imported into all European countries except France and Hungary. The largest importers are now Spain, Italy, the U.S.S.R., Benelux, the F.R.G., Poland, the G.D.R. and Czechoslovakia.

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Fig. 8. Maize area, yield, production and utilization data for U.S.S.R. (compiled by the author).

67

Conservation and processing o[ maize grain Recently, in Europe, less maize has been stored in the ear form and less maize and cob meal is used. More power is needed to grind ear maize than shelled maize. However, it may cost less to grind the ear form than to shell the maize and then grind it. High-moisture maize is now becoming more popular in Europe. Grain with 20-30% moisture is stored in a silo of some type rather than dried to a moisture content below 15%, which is required for storage without spoilage. If 1-1.5% propionic or a mixture of acetic and propionic acids is added, safe storage is possible in any type of store. In areas where the winter precipitation is low, acid-treated grain can be stored out of doors for several months with little if any spoilage. High-moisture grains are usually rolled or coarsely ground when fed. Storing ground maize or maize and cob meal in trench silos is practiced successfully in many countries. High-moisture grain and maize and cob meal are used with good results in pig and ruminant feeding. Feed conversion in fattening cattle is sometimes improved compared to dried maize. High-moisture grain storage permits earlier harvesting, which results in lower losses. Savings in the cost of drying grain may be substantial. Furthermore, high-moisture grain requires considerably less power for rolling. In Europe, maize is usually ground for feeding. There is no advantage in grinding shelled maize for sheep. Exceptions are: (1) for sheep with poor teeth; (2) for young lambs up to 6 weeks of age; (3) when it is necessary to prepare a mixture. Coarse or medium-fine grinding is sufficient for cattle and horses, but medium grinding is preferred for swine and poultry. Popping, micronizing, roasting, flaking, exploding and reconstitution (raising the moisture content to 25-30% and storing in an oxygen-limiting silo for 2-3 weeks) of grains intended for fattening cattle and sheep is not popular in Europe because of the high costs of such processes. These methods of processing are sometimes used in the U.S.A. and are effective when cattle are fed highconcentrate rations. A method of impregnating the whole maize grain to meet the nitrogen and mineral requirements of growing-finishing lambs has been developed (Koeln et al., 1985a,b ). About 80 % of the added nitrogen, 70 % of the calcium and 60 % of the potassium are associated unwashably with the kernels. The final product may contain 12-18% crude protein. Ammonia release in the rumen is lower for impregnated grain compared with other methods of supplementing non-protein nitrogen ( N P N ) in the ruminant ration. The digestibility of dry matter, organic matter and nitrogen-free extract tends to be greater for impregnated maize than for ordinary maize. Fattening lambs fed with impregnated maize perform as well as those fed with compound feed with oil meal ( Paliev, 1986 ). It is possible to add urea and minerals to high-moisture grain before ensiling or storing it.

68

Wheat General Twelve species of wheat are cultivated in Europe; common wheat ( Triticum vulgare) being the most widely grown. This comprises: hard red spring, hard red winter, soft red winter and white. Winter wheat varieties usually outyield spring wheat. A semi-dwarf wheat introduced recently is high yielding and is frequently referred to as "miracle wheat". The best known is that developed by Dr. Norman Borlang at the International Maize and Wheat Development Centre in Mexico. A great deal of effort has been expended in the development of hybrid wheat, but so far its use is very limited. The increase in yields have not justified the high cost of the hybrid seed. One advantage of wheat is its better adaptation to direct combining than any other small grains. Nutrient characteristics According to its digestible and metabolizable energy values, wheat ranks second after maize among cereals. Wheat has only 2% fibre and is as digestible as maize. It contains less fat than maize (2 versus 5% ) which is the reason for its slightly lower energy value. Wheat surpasses all cereals in its protein content. As a consequence, less protein supplement is needed to balance a ration for livestock when wheat is the principal grain. However, the protein content of wheat varies widely, depending on the type of wheat, variety, climate and soil fertility. Hard spring wheat may have 15-16% protein, hard winter wheat 13-14% and soft wheat is lower in protein, at 10-14%. In the warm, moderately-dry Mediterranean and central zones, the kernels are hard, dark coloured, vitreous, high in protein and low in starch content. The same variety grown under the cool, moist conditions of Northern Europe, results in a grain that is soft and starchy, with a low protein content. Wheat well supplied with available nitrogen is hard and high in protein, whereas wheat grown in soil low in nitrogen is soft and starchy. The protein in wheat grain is of relatively poor quality, like other cereals. The first three limiting amino acids are lysine, threonine and valine. There is a tendency for an inverse relationship between protein and lysine. When protein content increases by fertilization the lysine content in the crude protein decreases. Glutenin contains about three times as much lysine as that present in gliadin. Glutenin and gliadin possess the property of elasticity, which is considered to be the main reason why finely-ground wheat forms a pasty mass in the mouth and is unpalatable when given to animals. Wheat is very low in calcium, containing only 0.08% and relatively rich in

69 phosphorus, with an average content of 0.40%. It is deficient in Vitamins A and D. Wheat is a good source of thiamine but has a low riboflavin content. Utilization Wheat is usually well liked by farm animals. However, because wheat is a high-energy grain and has a rather pasty nature, the best results are secured when wheat comprises not more than 35-50% of the concentrated mixture for dairy cows, beef cattle, ewes, fattening lambs, horses and pigs. In many experiments, it has been shown that it is possible to use wheat as the only grain for beef cattle, fattening lambs, sows, growing and fattening pigs and even for dairy cows. Despite this, animals like a mixture with barley and other grains more than wheat alone, and the tendency to go "off feed" is less of a problem when wheat is not the only grain in the rations for ruminants, fed large quantities of concentrate, or included in the compound feed for pigs. For horses, wheat should be mixed with a bulky feed to prevent colic. Wheat is preferred to all other grains when given as whole grain to poultry. Depending on the price, wheat can be used satisfactorily as a complete substitute for maize, barley and other grains. It is not advisable to feed wheat soon after harvesting, since wheat is more prone to produce digestive disturbances in unadapted animals if this is done. Wheat grain should be ground to a medium degree of fineness for feeding to cattle, horses and pigs. Wheat ground to a fine, floury meal is less palatable and more apt to form a pasty mass in the mouth. It is not necessary for wheat to be ground for sheep or poultry, except when mixtures are prepared. Highmoisture wheat can be stored and used as described for conservation and processing of maize grain. Production Wheat is grown in the largest amount of any grain produced in Europe and in the world. It is not usually grown intentionally for animal feed and all commonly-grown varieties were developed with flour-milling qualities in mind rather than animal-feeding value. In spite of that, wheat is extensively used for livestock feeding in Europe. For the period of 1973-1982 in Western Europe ( E.E.C. countries) 10-15 Mt and for 1984-1986 about 22 Mt of wheat per year were used as animal feed. In the U.S.S.R., this quantity is much more variable from about 30 to 50 Mt, which comprised more than 1/3 of the total grain fed to livestock (U.S.D.A., 1985). Low-grade wheat, not suitable for milling, is commonly fed to animals. The quantity of wheat which is used for feed is larger when the price is unusually low, or when there is a shortage of feed grains and a surplus of wheat. Wheat ranks third among cereal feed grains in Europe (comprising 20-30% of total grain). Recently, there has been some shift from barley to wheat. It is grown in all countries (Fig. 9).

70

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The share of the arable area planted with wheat is large in the Ukraine, France, the U.K., the F.R.G., Romania, Spain and Italy. Vast areas of land are planted with wheat in the U.S.S.R., the leading world producer of this grain. The area under wheat in Europe as a whole has shown little change over a long period, with a decrease in the war years and recovery with a tendency to decline after the 1950s and 1960s (Fig. 10). Wheat production is concentrated in the temperate zone (Central Europe, the Mediterranean and Ukraine), but can be produced successfully in northern regions which can offer about 90 days of

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temperate weather per year. Hardy strains have been developed to grow as far north as the Arctic circle in Finland, Sweden and Norway. Cold-tolerant varieties have the ability to harden before the advent of cold weather. There is a gradual increase in the dry matter, sugars, amide nitrogen and amino acids in the tissues of wheat. As a result the plant develops a greater tolerance to freezing and precipitation of proteins. Under snow cover, winter wheat can withstand a temperature of - 40 ° C for a short period of time. Winter killing results when the crowns of the plants are subject to temperatures below - 1 5 - 1 6 ° C, especially in windy weather. Wheat can withstand the cold of northern areas quite well, yet it grows successfully in the hot continental and mediterranean climate if the humidity is not too high. The shortness of the growing season is compensated for by longer days. Wheat generally grows better in places with long days. Wheat can be grown successfully under a wide range of soil conditions. The best are fertile, well-drained silt and clay loam soils. Wheat does not tolerate acid soils very well, optimum pH being between 7 and 8.5. Wheat can grow well in areas where the annual rainfall varies from 250 to 1700 mm. Advances in breeding, cultivation and harvesting of wheat have permitted significant increases in yield ha-1 (Figs. 10 and 11 ). The rise in wheat production is solely caused by an increase in yield. Nevertheless, there is still a net importation of wheat into Europe. In North-West Europe, mainly high-quality durum wheat

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Oats

Nutrient characteristics Most oats are used as feed for livestock and only a very small portion is used for the preparation of human food products. Oats have the lowest energy value of grains, about 12.0 MJ ME per kg DM for ruminants (M.A.F.F., 1976). When the hulls are removed from the oats the resultant groats contain only about 2 % crude fibre and 7% lipids and have a metabolisable energy value equal to or even higher than maize. There is a great variation in the proportion of hulls in oats and consequently in their digestibility and feeding value. Low-weight oats (30-35 kg hl-1) may have almost 50% hulls while the very heavy plump oats may have only 20% hulls ( 55-58 kg hl- 1). On average, oats contain about 26% hulls, 11% crude fibre and weigh about 41 kg hl-1. Hull-less oat varieties, in which the hulls are removed from the kernels in the threshing process, are available. They are not grown widely, because the ordinary type with hulls

73 yield much more. Naked oats have a metabolisable energy value equal to maize, and have high protein and fat contents which makes them good, even for broilers. Oats contain about 12% crude protein varying from 6 to 17%. The protein is not of good quality, though superior to that in maize. The first limiting amino acid is lysine, and the second methionine. Some hybrids obtained by crossing of wild and cultivated types have 20-25% crude protein. Such crossing is difficult and the transfer of the desirable trait is a slow and tedious procedure. Nevertheless, the prospect for development of high-yielding, high-protein and more disease-resistant varieties of oats by breeding is good. Oats contain about 5% oil, the highest of the cereals. Varieties with higher oil content are available. Oats are low in calcium and only fair in phosphorus content. They also lack carotene and Vitamin D and have low riboflavin and niacin contents. Utilization Oats are the favoured cereal for horses and ruminants. They are less popular for pigs and poultry feeding because of their comparatively high crude fibre content and lower metabolisable energy value. Because of the bulky hulls, oats form a loose mass in the stomach that can be easily digested and do not cause colic in horses. Oats may be the only concentrate fed to horses. Some dairymen include oats in the concentrate mixture for cows if the price is not very high, because they feel that oats have higher feeding value for dairy cows than could be expected from the content of metabolizable energy shown in the tables for feeding value of feedstuffs. This is not proved experimentally but is possibly caused by the high fat content of oats. Oats may be used to give bulk to an energy-dense concentrated mixture. Oats are well liked by sheep and may be used extensively for breeding flocks, for young lambs and for starting fattening lambs on feed. The proportion of oats is generally reduced gradually as fattening progresses. For pregnant sows, oats can form 50% of the ration without reducing its efficiency. The increased fibre content of the ration is beneficial. For growing and fattening pigs, oats should form not more than 25% of the ration. When forming a large part of the ration for pigs, oats tend to produce fat which is softer than that produced by maize or especially barley. Because of their relatively low metabolizable energy value, oats are not suitable for inclusion in broiler starter mashes, but oats are good feed for replacement pullets. They improve feather development and prevent feather picking and cannibalism. For laying hens, oats can make up to 25% of the total weight of the mixture. If the oats are heavy and plump, as much as 40% in mashes for laying hens will

74 give satisfactory results. The lower ME content is the only restriction for the use of oats. Oats are ground to coarse to medium fineness for feeding to animals. Sheep and horses can receive whole oats. For horses with poor teeth and for foals up to 7-8 months of age, grinding or crushing is advisable. Production Oats rank fourth as a cereal crop in Europe, exceeded by barley, wheat and maize, by area sown and amount produced. It is grown everywhere but is a more important crop in the northern part of Europe and the mountainous regions (Fig. 12 ). Oats grow best in a cool, moist climate. Hot weather during blossoming causes failure of the flowers to produce kernels (blasting). Some varieties, however, are adapted to warm climates. Winter oats are not as hardy as winter wheat and barley, but recently hardier varieties have been developed and winter oats production has been extended northward to areas where the average minimum temperature is - 2 0 ° C. Oats are not very sensitive to soil conditions and acidity. However, good yields are produced on well-drained, fertile soils which hold moisture well. It is better not to grow oats continuously on one field. There are many different varieties with compact or spread panicals, with hull or naked, with white, yellow, gray, red or black colour of kernels, sown in the spring or in the autumn, with varying length of time needed by them to mature. Nevertheless, the advance in breeding of oat varieties with desirable traits is not comparable to the advances in wheat or maize breeding. This is one of the reasons for the reduction in the cultivation of oats in Europe (Figs. 13 and 14). Although oats have declined in importance as a cereal crop they are still cultivated fairly widely. Germany, France, Poland and the U.S.S.R. are the most important producers of oats. The total production of oats has changed only slightly because of the increased yield per hectare. It is expected that the tendency to reduce the area sown with oats will continue, but at a reduced rate. Some renewal of interest in oats by the end of the century is expected.

Rye Nutrient characteristics Rye is nearly as heavy a grain as wheat, with a weight of 70-73 kg h i - 1. It is very similar to wheat in composition but contains more lysine than wheat. In spite of that, lysine is the first limiting amino acid in rye, followed by tryptophan and arginine.

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Utilization Rye is the only one of the common grains that is sometimes unpalatable to livestock. Rye is apparently liked better by sheep than by most other animals. Feeding rye as the only grain, after gradual adaptation, gives similar results to feeding a mixture of different grains to fattening lambs. When fed as the only concentrate in excessive amounts to other animals, rye is apt to cause digestive

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77

disturbances. Rye should be fed with due care and only as a part of the concentrate mixture. Good results are obtained when rye comprises not more than 30% of the concentrate mixture for horses and up to 40% for dairy and beef cattle, for fattening pigs and lactating sows. Rye produces poor results with young pigs when it forms more than 30-35% of the ration. When feeding pregnant sows, rye should be avoided, because of the risk of ergot poisoning. Rye should not be used for chicks during their first week of life. The content of pentosans (2-6% of DM) in rye depresses the growth of chicks because of their extremely viscous, sticky properties, and their ability to retain a large volume of water and to interfere with nutrient utilization and probably intake (Antoniou and Marquarot, 1981). If a large quantity of rye is fed to chicks, their droppings become so sticky that they ball up the toes. Rye is not usually fed in large quantities to broilers because of growth depression attributed to nutrient malabsorption, especially fat. This may be eliminated, to a considerable extent, by gamma irradiation of rye, a germ-free environment and supplementation with an enzyme (pentosanase), which is a most promising technique. It may be used with success for growing replacement pullets and laying hens if it forms not more than 50% of the ration. When significantly contaminated with ergot, rye is unpalatable to animals, and may even be dangerous if it contains too much of this poisonous substance. The ergot fungus (Claviceps purpurea) contains a mixture of alkaloids which, if consumed by pregnant animals, may cause abortion. Before feeding to livestock, rye should be stored for several weeks to be conditioned and to avoid digestive disturbances. If the change to rye is made abruptly, digestive problems are possible, especially when a large amount of rye is included in the mixture. The preparation and processing of rye for feeding animals is similar to that for wheat.

Production The proportion of rye amongst the cereal feeds is not large in Europe. However, rye has an important place in agriculture because of its hardiness and its ability to grow on soils that are not suited for growing other grains. Rye can be grown where such soils exist (Fig. 15). Production of rye is significant in the U.S.S.R., Poland, the F.R.G. and the G.D.R. Most of the areas sown with rye are not good enough for wheat and barley or are in mountainous zones at high altitude or in far northern cereal-cultivation regions. The northern limit of rye extends beyond that of winter wheat. Rye is attacked less by insects and diseases than the other cereals. It germinates rapidly, grows at low temperature and matures early. Most rye is grown on poor sandy soils. High yields may be obtained on fertile soils and with good cultivation. It grows better on well-drained light loams than on heavy clay, wet and poorly-drained soils.

78

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2ooo

Fig. 17. Rye area, yield, production and utilization data for U.S.S.R. (compiled by the author).

80 than the supply. As animal feed, rye is inferior to barley, wheat and maize. Therefore, it is not realistic to anticipate an increase in rye production in the near future. There are few possibilities to increase the yield of rye at the same rate as other cereals, because relatively little breeding work is being done with rye and the available number of varieties is considerably smaller than of wheat, barley and maize. The winter varieties are more productive than the spring ones under similar conditions. Some replacement of spring rye for winter rye is expected. Triticale General Triticale is a man-made crop since it is a cross between wheat and rye. The aim has been to combine the high yields of wheat and the winter hardiness, the disease resistance and to some extent the higher lysine content of rye. The name "triticale" is derived from the genus of wheat 'TRITIcum' and the genus of rye, 'seCALE'. The first crosses between bread-wheat and rye date from 1896. In 1930 a cross between durum wheat and rye was obtained. Many different types of crosses and backcrosses have been reported recently. Triticale has been a constant subject of controversy, but it appears that it is finding a place of some importance in cropping systems in Europe. It does have a place on droughty and poor soils and in areas where the production of other cereals is marginal. Recent breeding efforts have been directed towards eliminating the problems associated with triticale: late maturity, excessive head breaking and seed shattering, deficient tillering, shriveled seed and overly tall stem. Some of the varieties have improved their resistance to ergot, stem and strip rust, septoria and mildew. Nutrient characteristics Many feeding experiments on triticale have been carried out recently, using different classes of animals. These studies show that the feeding value of triticale is approximately the average of wheat and rye. It is low in crude-fibre content (2%) and high in metabolisable energy value, 13.8 MJ k g - 1DM. Crudeprotein content is 12-16% and its quality is slightly higher than that of wheat. Triticale has more lysine than has wheat. Utilization The palatability of triticale is better than that of rye. It can replace at least half if not all of the cereal grains, if it is gradually introduced in feed to replace an equal weight of maize or wheat for both ruminants and non-ruminants. Triticale is much more suitable as poultry feed than rye and may comprise up to 60% of compound feeds. Grinding and other processing before the feeding of triticale to animals is the same as for wheat.

81

Production It is expected, that in Europe, the area planted with triticale and its production will increase in future. It will replace mainly rye and oats and partly barley and wheat in arable-crop programmes. Sorghum Nutrient characteristics Sorghum grain contains more crude protein (11-13%) and ash (about 2% ) but less lipids (about 3.8% ) than maize. It has a metabolisable energy value of 13.2 MJ kg -1 DM (M.A.F.F., 1976), above that of barley, but less than maize and wheat. Like other grain, it is deficient in protein and calcium and lacks Vitamin D. Even the yellow sorghum seeds are deficient in carotene. Quality of protein is low. Limiting amino acids are lysine, threonine and tryptophan. Some varieties have less lysine than maize. The palatability of the grain from different varieties is not the same and depends on the content of tannin and other bitter substances. The white and yellow seeds contain less tannin (0.2-0.4%) than the brown seed (0.6-3.6%). Sorghum grain is well liked by all classes of animals in spite of the general belief that it is less palatable than maize. Utilization The grain of sorghum is close to maize grain in feeding value. It is a very good feed for cattle, horses and sheep and can comprise a large part of their ration. For these species of animals, sorghum may replace barley or maize completely. The tannin content reduces protein degradability in the rumen and promotes better utilization of protein by ruminant animals. With pigs and poultry, the feeding value of sorghum depends to a certain extent on its tannin content. Palatability and digestibility decrease with an increase in tannin content. Both energy and protein ( amino acid) digestibility are influenced by tannin. Treatment of sorghum grain with a solution of 0.8 N HC1 or 0.8 N NaOH, or 3.75% Magadi soda (Na2CQ.NaHCO32H20), about 25% by weight, and storing for 2 days, decreases tannin content considerably and improves digestibility of protein and dry matter. Micronization of sorghum or adding polyethyleneglycol improves the nutritive value of high-tannin sorghum. Low-tannin grain sorghum is excellent for breeding sows and fattening pigs. It produces as rapid a live-weight gain as maize and has a feeding value about 95% of that of maize. Hybrids which have high-tannin content are less palatable and are of less value. The suitability of sorghum for poultry rations depends on its tannin content. Low-tannin sorghum is a good feed and can replace other cereals by up to

82 50-60%, without any significant effect on productivity and growth, feed-conversion efficiency and mortality. A large proportion of grain sorghum in a broiler ration will produce whiteskinned birds, unless enough alfalfa meal or other source of pigments is included to give yellow colour where it is desirable. It is advisable to introduce sorghum gradually into rations and to make few changes, especially when large amounts of sorghum are fed. The processing of grain sorghum for feeding is similar to that for maize. Production Sorghum is grown on small areas in the southern part of Europe, as it is more drought resistant than maize. It is sometimes referred to as the "camel crop" among cultivated plants. The leaves and stems of sorghum are covered with waxy material that reduces water losses and permits growth under conditions of limited rainfall and high summer temperature. Transpiration losses of water are also reduced because of the relatively small leaf surface. The plants may remain dormant during a dry period and then grow again when conditions are favourable. In areas where rainfall is scanty, sorghum outyields maize, but it is the opposite in areas with higher rainfall or under irrigation. The area planted with sorghum is very small nowadays compared with that which can grow the crop. Growing sorghum is a good alternative for regions in Southern and Central Europe often suffering drought. Lack of experience does not permit this crop to take the place it merits. In addition, there are some harvesting and bird problems. Birds may cause serious damage to the crop. Hybrids are available that are distasteful to birds. Special adjustments to the combine are necessary. Harvesting should be delayed until the grain is thoroughly dry and contains less than 13% moisture at the time of combining. This is difficult to achieve sometimes in the autumn. Because of the hard coat; seeds when apparently dry may contain much moisture and may heat in the bin. Another reason for not cultivating sorghum is the farmer's feeling that when winter grains are sown immediately after the removal of the sorghum, their yields are often reduced by as much as 15%. This may be caused by the moisture content and nutrient depletion of dry and relatively poor soils. There are a great number of hybrids from which to choose and some give good yields of seed. A large grain sorghum head may contain up to 2000 seeds. Most of the newer varieties are shorter, dwarf types that are easier to harvest with a combine. Other cereals

Several other cereals are grown on small areas in different regions of Europe. Their share of the concentrate part of livestock feeds is very small both in Europe as a whole and the regions were they are cultivated.

83

Millet In Southern Europe, several species are grown which produce small grain: pearl or bulrush millet (Pennisetum typhoideum), foxtail millet (Setaria italica), proso-millet (Panicum miliaceum), finger millet (Eleusine coracana) and Japanese barnyard millet (Echinochloe frumentacea). The crude-protein content varies from 10 to 18%, the oil content is 2-5% and the crude fibre 5-10%. Millet has a nutritive value similar to that of oats. Lysine is the limiting amino acid, followed by tryptophan and methionine plus cystine. It may be included in animal rations as for barley and oats. Low-fibre millet is good feed for chicks and broilers. Millet should always be ground for all classes of animals (except possibly for poultry).

Buckwheat Buckwheat (Fagopyrum esculentum) is not really a cereal but it has much the same general nutritive characteristics as the cereal grains. It is grown mainly for the manufacture of flour for human food and only a small quantity is available for animal feed. Buckwheat has a short growing season and does better than other grains on poor or acid soils. The biggest producer is the U.S.S.R. The grain contains 11-17% fibre, because the woody hulls of buckwheat form 18-22% of the seed. Protein content varies (8-16%) and consists mainly of albumin and globulin instead of that typical for cereal: prolamine and glutelin. Lysine content in buckwheat is higher than in other cereals and the quality of protein is rather high. Fat content is low, between 1.8 and 3.7%. Buckwheat is not very palatable for livestock and should not form more than 35 % of the mixture for cattle, sheep and horses. It contains too much fibre and is not a good feed for small pigs and poultry. Emmer

Emmer ( Triticum dicoccum) is a close relative of wheat but its hulls are usually not removed from the kernels during threshing. It resembles oats in composition and feeding value and may be used in the same manner as oats in feeding different classes of animals. When a large proportion of the hulls are removed in threshing, emmer resembles barley in feeding value.

Spelt Spelt ( Triticum spelta) is very similar to emmer.

Rice Usually only off-grade rice is available for feeding farm animals. Rice ( Oryza sativa) is grown in the southern and some central regions of Europe. Rough rice (paddy) contains about 20% of hulls which are rich in silica. The hull is easily removed to leave a product known as brown rice. Rough rice is nearly as high as oats in fibre content and is even poorer than maize in protein. Rice has

84 the common merits of cereals as a feed and also the same deficiencies. Rough rice can be included in concentrate mixtures for cattle, sheep and horses in the same proportions as oats. Brown rice and polished rice are preferable for pigs and poultry. In well-balanced rations, brown rice can replace maize or barley completely. PULSES

Nutrient characteristics Pulses belong to the family Leguminosae, cultivated for their seeds. The principal species belong to the genera Phaseolus, Pisum, Cicer, Vicia, Lupinus, Lens and others. Compared to cereals, pulses are relatively rich in protein, in the range 20-38%. The quality of protein in pulses differs among species and varieties. Generally, it is only fair, because they are deficient in the sulfur-containing amino acids, methionine and cystine. All species (soya-bean, field pea, beans, vetch, lupines etc. ) are rich in lysine and are a good supplement to cereals. Almost all of the pulses contain components which possess anti-nutritional properties. Among the chemical factors that can create problems in feeding pulses are protease inhibitors, phenolic compounds (tannins, isoflavonols, etc. ), goitrogens, anti-vitamins, cyanogens, metal-binding factors, lathyrogens and lectins (phytohaemagglutinins). Cooking (treating with moisture and temperature), germination, fermentation, infrared cooking, microwave processing and dielectric heating can destroy most of these substances and can reduce the risks of feeding pulses to animals. Excessive cooking on the other hand can reduce the biological value of the protein. The rivals of pulses as protein sources, the oil meals, are usually well processed and without anti-nutritional and toxic substances. Like cereals, pulses are a good source of energy and a fair source of phosphorus but a poor source of calcium. They have little or no carotene but they may contain a significant amount of thiamine, niacin or riboflavin.

Utilization Most of the pulses are used primarily for h u m a n consumption, but they can be fed to livestock effectively. Some species, lupins, vetch, dried field peas and cowpeas are cultivated primarily for livestock feed. Soya beans and peanuts are pulses, which are used almost entirely for oil production. The oilseeds (soya bean, rape, sunflower, peanut and others ) are discussed later in this chapter. Annually (1983) 2.5 million tons of pulses are used for animal feeding in Europe, which is about 1% of the amount of cereals fed to animals.

85

Production

Pulse production in Europe has decreased in recent years. The main reason is intensification of grain production. Pulses do not respond as well as cereals to heavy fertilization, they suffer from many weeds, diseases and pests, and they are not as suitable as the principal cereals for intensive agricultural production. There is not sufficient progress in the selection of high-yielding and disease-resistant varieties of different pulses compared to cereals. For the present-day situation of pulses, an important factor is the availability of relatively inexpensive imported oil meals which compete with pulses as a source of protein for animal feeding. In spite of the decrease of the total area sown with pulses, some species like field pea and horse beans, have been expanding recently in West and Central Europe. E.E.C. subsidies for pulses are strongly stimulating the increase in production. Protein yields of pulses per ha are relatively low. This is shown in Table VI, which compares the average yields of pulses and cereals in 1984 and 1985. It is evident that maize and wheat yield more protein per hectare than chick peas, common beans, lentils and horse beans. Soya beans and peas outyield wheat in protein by 18 and 90%. Cereals, however, yield much more energy. Recently, the yields of soya beans, horse beans and peas have increased in many parts of Europe. Pulses are grown throughout Europe but nowhere do they occupy a large proportion of the arable area. The total area sown with pulses in Europe is gradually decreasing. From 1969/70 to 1984 it diminished from 4 to 2.6 Mha. Total production of pulses diminished for the same period from 3.3 to 2.8 Mt (F.A.O., 1984). This tendency will probably continue for the next 10-20 years, but at a slower rate. It is expected that at the beginning TABLE VI Grain and crude-protein yield of some cereals and pulses Crop

Wheat Maize Barley Peas, dry Soya beans Horse beans Lentils Beans, dry Chick peas

Yield ( kg h a - 1) Grain"

Crude protein

4539 5303 4088 3729 1576 1714 883 598 675

510 490 430 970 600 450 230 160 140

aSource for grain yield: F.A.O. Production Yearbook (1984-1985).

86 TABLE VII A r e a p l a n t e d w i t h pulses a n d oilseeds in E u r o p e a n d U S S R in 1000 ha" Crops

Pulses Peas Beans Horse beans Chick peas Lentils T o t a l pulses Oilseeds Sunflowerseed Rapeseed Soya beans Seed c o t t o n Linseed Groundnuts Sesame seed

1934-1938

1951-1955

1971-1975

1976-1980

1981-1985

Europe

Europe

Europe

U,S.S.R.

Europe

U.S.S.R.

Europe

U.S.S.R.

U.S.S.R.

U.S.S.R.

540 3440

---

474 3202

---

324 2558

3712 38

274 1653

3870 50

448 1273

4953 51

1090 400 110 5580

---13 900

910 510 128 5250

---15 650

553 222 87 3743

12 2 57 3821

416 170 92 3015

40 -19 5086

325 139 96 2785

--21 6075

545 210 35 135 270

3276 110 180 2027 2611

-544 -444 500

---2024 --

1670 1215 208 320 294

4485 10 832 2810 1441

1906 1352 393 272 286

4516 13 815 3037 1249

2678 2061 547 263 225

4153 107 823 3239 1107

-38

-.

10

1

12 7

1

10 3

12 45

-.

.

.

--

1 --

"Source: F.A,O. P r o d u c t i o n Y e a r b o o k ( v a r i o u s y e a r s ) .

TABLE VIII Yield o f p u l s e s a n d oilseeds c r o p s ( k g h a - 1), Crops

Pulses Peas Beans Horse beans Chick peas Lentils T o t a l pulses Oilseeds Sunflowerseed R a p e seed Soya beans Seed cotton Linseed Groundnuts Sesame seed

1934-1938

1951-1955

1971-1975

1976-1980

1981-1985

Europe

U.S.S.R.

Europe

U.S.S.R.

Europe

U.S.S.R.

Europe

U.S.S.R.

Europe

U.S.S.R,

1210 290 1060 470 620 --

-----460

1324 326 984 480 636 --

-----470

1709 298 1417 606 791 --

1360 1851 1896 1099 123 --

1962 413 1379 628 832 823

1434 1857 2750 -618 1358

2968 571 1518 612 733 1232

1119 1613 --566 1166

640 1000 770 420 b 480 2000 270

590 800 540

-1214 --

-------

1295 2000 1407 1894 619 2011 .

1324 890 567 2727 272 645

1381 2123 1324 1960 597 2100 260

1008 949 638 2939 223 1164 278

1479 2338 1408 2340 531 2229 459

1190 551 619 2815 201 1832 690

700 b

--

320 -340

508 -.

.

.

"Source: F.A.O. P r o d u c t i o n Y e a r b o o k ( v a r i o u s y e a r s ) . b D a t a are for c o t t o n seed.

87 TABLEIX

Productionofpulsesandoilseedsinl000tons a Crops

1934-1938

1951-1955

1971-1975

1976-1980

1981-1985

Europe

Europe

Europe

Europe

U.S.S.R.

Europe

U.S.S.R.

U.S.S.R.

U.S.S.R.

U.S.S.R.

Pulses 650

--

628

--

551

5036

538

5526

1381

5520

Beans Horse beans Chick peas

Peas

1010

--

1046

--

753

71

671

93

735

83

1170

--

896

--

783

23

574

110

493

--

180

--

244

135

2

107

--

85

--

Lentils Total pulses

70

--

84

---

69

72

76

9

70

10

2461

5815

3468

7070 4943

Oilseeds Sunflower seed Rapeseed Soya beans Cottonseed Linseed Groundnuts Sesame seed

( 3 0 8 0 ) b 6400

{2898)

(7350)

(2298)

(5204)

347

1949

--

--

2145

5965

2696

5048

3977

210

88

664

--

2431

8

2886

13

4865

59

29

97

--

--

288

471

516

518

772

508

57

1424

184

1290

392

4975

334

5811

369

5642

129

845

254

--

183

393

170

278

119

223

24

--

--

--

--

--

24

1

23

2

12

9

--

"Source: F.A.O. Production Yearbook (various years). bother pulses such as cow peas and vetch are not included in the total in parentheses.

of the new century, as a result of the advance in the development of highyielding varieties, adapted to highly-mechanized production, the interest in pulses as animal feed will increase again. Data for the main pulses produced in Europe are given in Tables VII, VIII and IX. Field pea

Nutrient characteristics and utilization Peas (Pisum sp. ) are an excellent, highly-palatable feed for livestock. They contain about 25% crude protein, 1.2% fat and 13.8 MJ ME kg- 1DM (M.A.F.F., 1976). The protein is high in lysine and relatively low in methionine. Thus, they balance cereal proteins very well. In Eastern Europe where large amounts of sunflower-oil meal, rich in methionine, is used, peas can be used to balance the amino acids in rations for pigs and poultry. Field peas can be included as much as necessary to balance the protein in rations for different classes of ruminant animals. Experiments with pigs show that field peas can replace a large proportion (50-75%) of soya bean oil meal without adverse effects on rate of gain, feed-conversion efficiency and carcass quality. If rations are well balanced for amino acids, especially methionine and tryptophan, peas can be the sole source of protein for growing pigs with liveweight above 60 kg, corresponding to a level of 30% of peas in the ration. The supply of sulphur-con-

88 taining amino acids by cereals compensates to some extent for their low content in peas. The level of tryptophan is critical in diets containing a high level of peas in combination with maize, which is also deficient in this amino acid. Even in young pigs after weaning, when peas are combined with high-quality protein sources, such as fish meal or skim milk, satisfactory growth rates can be obtained with up to 20% of peas. In rations for reproductive sows, field peas may be included up to 20-25% and almost completely replace soya bean meal. For highly-prolific sows it is advisable to combine peas (up to 20% ) with other protein sources to ensure maximal litter size and weight at birth and weaning. In rations for broilers, replacement pullets and laying hens, field peas may comprise up to 20-25% of the diet and replace 50-75% of oil meals. Production The pea is a long-day plant, requiring a minimum of 13 h of light before it will flower. It prefers loams, especially clay loams. It requires an adequate supply of moisture, especially during blossoming. The field pea is a cool-weather crop, and is therefore grown mainly as a winter crop in Southern Europe and as a summer crop in northern and mountainous regions. In Europe (excluding the U.S.S.R. ) for the last 10 years the area sown with field peas has increased from about 250 000 ha (1974-1976) to about 470 000 ha (1984) (F.A.O., 1984). Development of new, high-yielding varieties with reduced leaves, lodge resistance and with better disease and pest resistance and improvements in the technology of production have increased yield per hectare from 1940 to 3406 kg and total production of dried peas from 487 to 1598 thousand tons for the same 10-year period. The effect of the E.E.C. subsidy on field pea cultivation may be partly responsible for the increase. Expansion of pea production will probably continue in future in Europe and the U.S.S.R. Field peas are a very promising crop for protein production in Europe when seeking self sufficiency in protein. Horse bean

Horse ( field or broad) beans (Viciafaba) grow on clay-loam soils with enough moisture. There are a large number of varieties which fall into two main classes, winter and spring. The winter varieties outyield ( by 3-4 tons ha - 1) the spring varieties (about 3 tons h a - 1). Spring varieties have a higher protein content (about 27% ) compared to winter varieties (23%). Crude-fibre content is about 7-8%, oil content is 1-1.5%. Digestibility and protein retention are greater for the tannin-free varieties compared with the tannin-containing ones. Horse beans can serve as a satisfactory source of protein in animal feeding. Methionine and cystine are the main limiting amino acids, with a combined value of 2-2.3% in the protein. The second limiting amino acid is tryptophan.

89 Lysine content is relatively high at 6.3-6.8% of proteins. Because of the very low level of sulphur-containing amino acids, the biological value is significantly lower compared to soya bean oil meal. Horse beans can be used successfully in rations for all classes of animals. In rations for dairy and beef cattle and sheep, horse beans may be included in large quantities and even be the sole source of supplemental protein. For non-ruminants it is important to take into account the deficiency of methionine and the level of tannin. Moisture and temperature treatment of horse beans affect their utilization by the destruction of condensed tannins and other anti-nutritional substances. The elimination of condensed tannins from horse beans by genetic selection would significantly improve their nutritional value for non-ruminants and especially for chickens. Tannin-free horse beans can comprise up to 30% of the mixture for broilers, sows and pigs, but tannin-rich varieties may only be used up to 10% of the mixture for broilers and 20% for pigs. More than 15% horse beans in rations for hens reduced performance and egg weight, regardless of tannin content. It is important to balance rations well for methionine plus cystine and tryptophan and to ensure enough niacin in rations with a high level of horse beans for non-ruminant animals.

Other legume seeds The share of other pulses (except horse beans and field peas) in animal feeding in Europe is very small; less than 0.1% of the total grain feed. There are no countries or even small regions in Europe where they are an important feed resource.

Lupin seed The seeds of most varieties of lupins (Lupinus spp. )contain poisonous alkaloids and alpha-galactosides. However, varieties of yellow, white and blue sweet lupins have been developed which contain little or no alkaloids. Sweet lupins are a fairly good substitute for other protein supplements in rations for cattle and sheep. In rations for chicks they may form 20%, for laying hens 10% and for growing and fattening pigs 10%. It is not advisable to include lupins in diets of sows and very small piglets. It should be kept in mind that the aminoacid composition of lupins is not well balanced, methionine being the first limiting amino acid. Lysine content (4.8-5.8% of protein) is also insufficient. In the white varieties of lupins the content of sulphur-containing amino acids and lysine are about 20-25% more than in the yellow varieties of lupins. Lupin seed contains no heat-labile factors that inhibit lysine availability specifically for pigs. The low lysine availability is not due to impaired digestibility.

90

Chick pea Chick pea ( Cicer arietinum) is extremely drought resistant. It is grown only in the Mediterranean zone of Europe on a small area. Chick peas resemble field peas in composition, but they are slightly lower in protein (about 20% ) and somewhat higher in fat. They are a good source of lysine, but deficient in tryptophan, methionine and cystine. They may be included in relatively high proportions in concentrate mixtures for cattle, sheep, horses, pigs and poultry. They can be used uncooked in pig rations. Cooking appears to improve their utilization by poultry.

Cow pea Very small amounts of cow peas ( Vigna sinensis) are produced in Europe. They have a similar composition to field peas, protein content being 18-29% and the quality is fair. Cow peas can be used with success as a protein supplement in feeding cattle, sheep and horses. For pigs and poultry they can be used satisfactorily after cooking and balancing the amino acids. Technologically, cow-peas have disadvantages because most of the varieties ripen unevenly, which makes combining difficult.

Vetch Vetch ( Vicia sativa) is grown in limited areas in Southern Europe and has a similar composition to the field pea. Vetch is sometimes poisonous to livestock because of the presence of glucosides from which prussic acid may be formed. The danger of poisoning can be avoided by soaking the seed for 24 h or by steaming it. Some samples contained compounds which are known to produce neurotoxic effects (Liener, 1975). Vetch can be fed to cattle, horses and sheep at a moderate rate. Pigs and poultry, and to some extent horses, are more sensitive to the unfavourable substances.

Chickling vetch Chickling vetch (Lathyrus sativus) is cultivated in small areas in Mediterranean countries. It is similar in composition and feeding value to vetch. Chickling vetch is very rich in lysine ( 7.4% of crude protein) and may be potentially useful as a lysine supplement. Sometimes chickling vetch may be toxic and cause skeletal lesions, retardations of sexual development and various degrees of paralysis. Horses are most sensitive to these neurotoxins and lathyrism. Chickling vetch can be included at up to 15-20% of the concentrate mixture for different classes of animals. It is not advisable to use it for pregnant animals.

Pigeon pea Pigeon pea (Cajanus cajan) is grown in very limited areas in the Mediterranean area and is extremely drought resistant. They contain 20-23% protein,

91

which is very deficient in tryptophan, methionine and lysine. They must be cooked before feeding.

Velvet beans Velvet beans (Stizolobium spp.) are grown in a very restricted area in Europe. They are generally fed whole in the pod to livestock. Velvet beans in the pod contain about 18% protein and 13% fibre. They are satisfactory for dairy cows, beef cattle or sheep when forming not more than 35 % of the concentrated mixture. In large quantities they are a laxative. Velvet beans contain substances poisonous to pigs, causing severe vomiting and diarrhoea.

Beans and lentils Beans (Phaseolus spp.) and lentils (Lens esculenta) are grown mainly in the Mediterranean region and primarily for human consumption. For animal feeding the cull beans and lentils are used, which are sorted out from the firstquality dried beans and lentils. They include discoloured, shrunken, damaged beans and lentils and also some waste such as broken bits of stem, small stones and dirt. There are many kinds of beans: common bean, dried beans, kidney bean, navy bean, mung bean and others. To some extent they all contain trypsin inhibitors, alphagalactosides and tannin. Raw kidney beans are believed to contain an antagonist of Vitamin E because of the low levels of plasma tocopherol observed in chicks fed kidney beans (Desai, 1966). Lima beans contain large quantities of cyanogens. The haematoglutinins present in dried beans are known to exhibit different degrees of specificity towards blood cells from different species of animals. All these anti-nutritional substances can be partially eliminated by heat treatment. All beans, except mung beans, respond to cooking. Beans and lentils can make a significant contribution to the protein and energy in rations of all classes of farm animals, if measures are taken to compensate for deficiencies and to utilize their merits. Beans and lentils contain 20-28% protein which is rich in lysine (6-6.3% of protein). Although not very palatable for livestock, beans and lentils can comprise up to 20% of the concentrate mixture for cattle, sheep and horses. In rations for growing pigs they may comprise 15% and for sows 10%. For poultry, they may be included up to 30% and for laying hens up to 15%. It is preferable to cook the beans for poultry and pig feeding. Cooked beans can be fed in large amounts to all classes of animals, but cooking involves considerable expense. Mung beans may form 30% of mixtures for all classes of animals without cooking. Newlyharvested beans should be allowed to mature for several weeks before being fed to animals.

92 OILSEEDS

Nutrient characteristics Oilseeds are rich in protein (approximately 38% for soya bean, 28% for groundnut, 23% for linseed, 20% for cottonseed, 15% for sunflower seed) and oil (35-50% for sunflower seed, 40-50% for groundnut, 48-55% for sesame seed, 35-45% for rapeseed, 32-44% for linseed, 20-37% for safflower, 17-22% for soya beans ). They have a fair phosphorus content and are low in calcium.

Utilization Oilseeds are used mainly for processing into vegetable oil and oil meals (for oil meals see Chapter II.4 by Boucqu~ and Fiems (Boucqu~ and Fiems, 1988) ). As a rule it is economically and biologically advantageous to feed animals with oil meal which is processed properly to make nutrients highly available and to destroy the anti-nutritional factors present in most oilseeds. Sometimes certain amounts of whole soya beans, unprocessed cottonseed and other oilseeds (but not very toxic castor beans) are fed to animals. There is always a proportion of small, broken or shrunken oilseeds (screenings). Those products usually end up as animal feed. There are several specific situations when the feeding of unprocessed oilseeds is justified. Recently, it has been shown that giving about 2 kg whole cottonseed per animal increased the fat content in dairy cows milk by 0.3-0.35 %. The same quantity of ground whole cottonseed does not influence or even slightly decrease the fat content of milk (Todorov et al., 1985). The physical form of seeds is a decisive factor for the effect of whole cottonseed. Whole seeds do not permit extensive biohydrogenation of the unsaturated fatty acids in the rumen as in the case of formaldehyde-protein protected oils. At the same time, digestibility of whole seeds is good, and losses of whole seeds in the faeces of cows are less than 2% of the intake. There is a tendency to improve the energy utilization of rations containing whole cottonseed. Experiments with whole sunflower seed, sunflower seed screenings and whole, raw or roasted, soya beans show similar responses as are obtained with cotton seed, but the effect is much smaller. The percentage of fat in milk can be increased by 0.1-0.15% with the inclusion into the ration of 2 kg whole sunflower seeds or sunflower seed screenings or soya beans. It seems reasonable to include about 2 kg whole cottonseed and even whole soya beans and whole sunflower seeds in the rations of dairy cows when a high fat content in milk is desirable and the prices of oilseed are favourable. Furthermore, in some countries (Bulgaria etc. ) cottonseed is not processed for oil production. Some oilseeds may be used as feeds which impart a bloom or gloss to the hair

93 of animals for shows or competitions. It is common practice to give about 100 g soaked linseed to horses to make them attractive with sleek shiny coats. Linseed is also a laxative, hence it may be used to regulate the bowels. Sometimes pigs are used to clean up the fields after groundnuts have been dug. Whole nuts are well utilized by pigs, but excessive quantities may cause soft pork. It is not advisable to feed cottonseed and raw soya beans to non-ruminant animals, because of the toxic substance known as gossypol in cottonseed and various anti-nutritional substances in soya beans. Once properly heated, whole soya beans are a valuable source of energy and protein for pigs. To avoid soft fat it is necessary to limit the quantity for fattening pigs to 10% of the mixture. Raw or even farm-cooked soya beans have definite limitations for poultry feeding. They are much less satisfactory than soya bean oil meal. Small quantities, not exceeding 5% of the concentrate mixture, of ground linseed and rapeseed may be used for ruminant feeding. Linseed and rapeseed contain glucosides from which prussic acid (linseed) and mustard oils ( rape seed) may be formed in the digestive tract of animals under certain conditions. Production Data for the production of the principal oilbearing seeds in Europe and in the U.S.S.R. are given in Tables VII, VIII and IX. Sunflower seeds and cottonseeds are produced mainly in the U.S.S.R., Southern Europe and the Mediterranean countries. Rape is cultivated almost everywhere, but the most important production regions are Central and Northern Europe, mainly France, Poland, the G.D.R., the U.K., Sweden, Denmark, Finland, the F.R.G., Czechoslovakia and Hungary. Groundnut and sesame are grown mainly in the Mediterranean countries and small areas in the U.S.S.R. Soya beans are cultivated in the U.S.S.R., Romania, Yugoslavia, Bulgaria, Hungary, Italy, France, Spain and others. Linseed production is well spread over Europe, but on a small area. Main producers are the U.S.S.R., Poland, Romania, France, Czechoslovakia and Hungary. Castor beans are produced in the U.S.S.R. and Romania, and safflower in the Iberian peninsula. Two oil-yielding crops have expanded recently in Europe: rape in Northern Europe and sunflower in Southern Europe and the Mediterranean countries. In the E.E.C.-10 rapeseed production in 1985 was about 70% more and sunflower seed production over 30% more than in 1981. France is the biggest producer of rape. The area planted with these crops may continue to increase in the future, depending on the E.E.C. subsidy. Recently, new varieties of rape have been developed which are low in erucic acid and glucosinolates. These varieties are named "double zero" (00), to distinguish them from common "simple zero", (0), varieties (low in erucic acid only). The nutritive value of properly processed "double zero" rape seed is

94 higher than the classical "0" type. When included in well-balanced diets rapeseed oil meal "00" type may replace up to 2/3 of soya bean oil meal in rations for growing-finishing pigs (to comprise up to 15% of feed mixture ). Rapeseed oil meal may comprise not more than 10% of rations for chicks. It is not advisable to use rapeseed oil meal for sows and laying hens. Russian high-oil containing varieties of sunflower, yield much more oil compared to other oil crops. Sunflower is well suited to the climate in Southern Europe and the Mediterranean countries. A restriction to the use of sunflower oil meal is its high crude-fibre content (about 18% ). OTHER SEEDS

Acorn In some regions of Europe, acorns (the nut of the oak), beechmast, known also as beechnut, and chestnut are used for animal feeding. Usually the pigs are allowed to pannage the scattered nuts. Those nuts, picked up and processed, may be included at up to 10-15% in concentrate mixtures for cattle, sheep, pigs, horses and in laying hen rations. Acorn contains considerable amounts of tannin and other anti-nutritional substances. Given in large amounts they may be toxic (poisoning of cattle has been recorded). Rations with above 25% acorn meal produced eggs with coloured yolks and low hatchability.

Screenings and weed seeds When cereals and pulses come from the combine harvester they contain various amounts of screenings, which must be removed, as completely as possible, before grain is milled for human food or issued for sowing. The screenings consist of small, broken or shrunken kernels of grain or pulses, smaller weed seeds, some quantity of chaff, broken pieces of stems and sometimes sand and dirt. The best screenings consist chiefly of broken and shrunken kernels of grain with oats and other palatable weed seeds. They have a chemical composition and feeding value similar to oats. Light, chaffy screenings are much higher in fibre and lower in feeding value. If screenings contain a large proportion of mustard seed and pig weed they are unpalatable. Screenings containing poisonous seed may cause bad effects in the livestock when fed. Screenings should be finely ground, even for sheep, to avoid the passage of weed seeds through livestock and into the field in the manure. Screenings are often fed to fattening lambs, ewes, dairy and beef cattle. Ground good-quality screenings can be used satisfactorily up to 25% in con-

95 c e n t r a t e m i x t u r e s . I f t h e y do n o t c o n t a i n p o i s o n o u s w e e d seeds it is possible for t h e m to be i n c l u d e d in pigs a n d p o u l t r y rations, at a b o u t 1 0 - 1 5 % .

REFERENCES Antoniou, T. and Marquarot, R.R., 1981. Influence of rye pentosans on the growth of chicks. Poult. Sci., 60: 1898-1904. Boucqu~, Ch.V. and Fiems, L.O., 1988. Feedstuffs. 4. Vegetable by-products of agro-industrial origin. Livest. Prod. Sci., 19: 97-135. Broekhuizen, S. (Editor), 1969. Atlas of Cereal-Growing Areas in Europe. PUDOC, Elsevier, Amsterdam, London, New York. C.M.E.A. (various years). Statistical Yearbook of C.M.E.A. Countries. Statistika, Moscow (in Russian). Delorit, R.J., Greub, L.J. and Ahlgren, H.L., 1984. Crop Production. 5th edn., Prentice-Hall Inc., Englewood Cliffs, NJ. Desai, I.D., 1966. Effect of kidney beans (Phaseolus vulgaris) on plasma tocopherol-level and its relation to nutritional muscular dystrophy in the chick. Nature (London), 209: 810. Doll, H., 1981. Barley genetics. Proc. 5th Int. Barley Genetics Symp., Edinburgh, U.K. Eggum, B.O., Nillegas, E.M. and Vasal, S.K., 1979. Progress in protein quality of maize. J. Sci. Food Agric., 30: 1148-1153. Eurostat, 1983. Crop production. Statistical Office of the European Communities. Eurostat, 1985. Commission of the European Communities. The Agricultural Situation in the Community, 1985 Report. Brussels, Luxemburg. F.A.O., 1979. Beef production in Eastern and South-Eastern Europe. A joint study by F.A.O. and the Agricultural University of Warsaw, Rome, Italy. F.A.O., 1984 (and other years). Agricultural Production Yearbook, F.A.O., Rome. F.A.O. (various years). Trade Yearbook, F.A.O., Rome. Goering, H.K. and Van Soest, P.J., 1970. Forage Fibre Analyses, Agriculture Handbook No. 379, A.R.S., U.S.D.A., Washington, DC. I.N.R.A., 1978. Alimentation des Ruminants. I.N.R.A. Publications, Versailles. Koeln, L.L., Webb, K.E. Jr. and Fontenot, J.P., 1985 (a). Urea, calcium, potassium and sulphur impregnation of whole corn-development and in vitro evaluation. J. Anita. Sci., 61: 487-494. Koeln, L.L., Webb, K.E. Jr. and Fontenot, J.P., 1985 (b). Utilization by sheep of whole shelled corn impregnated with urea, calcium, potassium and sulphur. J. Anim. Sci., 61: 495-503. Liener, I.E., 1975. In: M. Friedman (Editor), Protein Nutritional Quality of Foods and Feeds, Part 2. Marcel Dekker Inc., New York. M.A.F.F., 1976. Energy Allowances and Feeding Systems for Ruminants. H.M.S.O., London. Paliev, H., 1986. Utilization of whole corn grain treated with urea and water solution as component of concentrate mixture for early weaned lambs for fattening. Zhivotnovud. Nauki, 23:51-56 (in Bulgarian with English summary). Tallberg, A. and Eggum, B.O., 1981. The nutritional value of high-lysine barley genotypes. Qual. Plant., Plant Foods Hum. Nutr., 31: 151-161. Todorov, N., Tashev, T., Peichevski, I. and Palaveeva, Z., 1985. Effect of whole and ground cottonseed and whole sunflower on milk performance of cows and milk composition. Zhivotnovud. Nauki, 22: 3-12 (in Bulgarian with English summary). U.N., E.C.E., 1984. Review of Agricultural Situation in Europe. United Nations, New York. U.S.D.A., 1985. Foreign Agriculture Circular. Grains, World Grain Situation and Outlook. U.S.D.A., Washington, DC. White, W.B., Bird, H.R., Sunde, M.L., Prentice, N., Burger, W.C. and Marlett, J.A., 1981. The viscosity interaction of barley beta-glucan with Trichoderma viride cellulase in the chick intestine. Poult. Sci., 60: 1043-1048.

Livestock Production Science, 19 (1988) 97-135

97

Elsevier SciencePublishersB.V., Amsterdam-- Printed in The Netherlands

II. 4. Vegetable By-Products of Agro-Industrial Origin CH. V. BOUCQUl~and L.O. FIEMS

INTRODUCTION During the last ten years there has been an increased consciousness of environmental protection. Dumping or burning wastes or agro-industrial byproducts present potential air and water pollution problems. High-moisture wastes are also difficult to burn. Many by-products have a substantial potential value as animal feedstuffs. Ruminants, especially, have the unique capacity to utilize fibre, because of their rumen microbes. This means that cereals can be largely replaced by these by-products (de Boer, 1985). Consequently the competition between human and animal nutrition can be decreased. Nevertheless, there is an increased cereal supply owing to genetic and management improvement. The utilization of agro-industrial by-products may be economically worthwhile, since conventional feedstuffs are often expensive. However, livestock have historically utilized large amounts of well-known and widely-available traditional by-products such as oil meals, bran, middlings, brewers' grains, distillers' grains, beet pulp and molasses. But less conventional by-products have become available, such as vegetable- and fruit-processing residues, whey and culinary wastes. Of course, by-product utilization for animal production is only one possibility. Other alternatives are their use as fuel or fertilizer, or as a carbohydrate source for microbial fermentation processes. The extent of by-product utilization as a feed ingredient depends on the costs of the conventional feedstuffs, the safety for animal health, and the attractiveness of alternative uses. As some raw materials can be used for different production processes, the available amount of the various by-products is difficult to estimate, and it is even more difficult to assess the quantity used as animal feed. This chapter gives an estimate of the amount of by-products obtained from the processing of raw materials. Various classifications of by-products are possible. Preston (1981b) divided by-products into two major groups according to the content of moisture and fermentable organic matter. Within each class of by-products with a high or low fermentable carbohydrate content, those with high or low moisture con0301-6226/88/$03.50

© 1988ElsevierSciencePublishersB.V.

98

tent can be identified. The first group requires further processing to store them for future use. By-products can also be divided according to their origin: from the food industry; from the non-food industry; crop residues; animal wastes. This chapter deals only with the by-products of vegetable origin, except straw and other fibrous by-products. They are divided according to their origin: milling; starch production; fermentation industry; sugar industry; fruit and vegetable processing; oil industry; wood and paper industry. ORIGIN OF VEGETABLE BY-PRODUCTS AND PROCESSING

Milling by-products of cereal grains Wheat In the case of wheat milling, by-products account for about 28% of the intact kernel. Wheat millfeeds can be classified on the basis of a decreasing fibre content. Some typical specifications are given in Table I (Church, 1984). About 50% of the total wheat millfeed consists of bran. Middlings amount to about 45% of total millfeed. Mill run or pollards ( _+95% ) is a blend of bran and middlings. Shorts and red dog account for about 1 and 4%, respectively. The wheat by-product can also be sold complete as straight run wheat feed or as two separate products: fine wheat feed and bran (Barber and Lonsdale, 1980).

Maize Dry milling of maize grain results in the following by-products: grits, bran and germ meal. Hominy is a mixture of bran, germs and a part of the starch portion. The approximate amounts of by-products obtained after dry milling 100 kg of wheat and maize is presented in Table II. TABLEI Characteristics of wheat millfeeds ( % ) Wheat millfeeds

Minimum protein

Minimum fat

Maximum fibre

Bran Middlings Mill run Shorts Red dog

13.5-15 10-14 14-16 14-16 13.5-15

2.5 3.0 2.0 3.5 2.0

12.0 9.5 9.5 7.0 4.0

99 T A B L E II Relative a m o u n t s ( % ) of by-products from 100 kg wheat or maize Source a n d byproducts Wheat Flour Bran a Middlings a Shorts Red dog Maize Flour Bran Grits Germ meal Maize oil

By-product (%)1

72 14 12.6 0.3 1.1 60 20-22 8-10 8.5 1.5

aBran + middlings = mill run or pollards.

Rice Rice milling primarily results in the removal of the hulls from the kernel. Rice bran comprises the pericarp, the aleurone layer, the germ and some of the endosperm. This product is comparatively high in fat. Solvent-extracted rice bran is also produced. Rice polishings are obtained after brushing the grain to polish the kernel, 100 kg brown rice grains gives about 27 kg hulls, 9 kg polishings and 64 kg polished kernels. By-products of the starch industry The main raw materials for starch production in Europe are maize and potatoes, although milo and manioc can also be used.

Maize With maize, starch is produced by wet milling. Starting from 100 kg of maize grain: 62-68 kg starch, 3 kg oil, 3.2 kg germ meal, 20 kg gluten feed, 4.5 kg gluten meal and steepwater are obtained. These by-products can be marketed as individual feed ingredients, or mixed into the maize-gluten feed, resulting in + 27 kg maize-gluten feed besides + 3 kg maize germ oil. Consequently, the chemical composition of the maize-gluten feed can vary quite a bit. The production of maize starch after wet milling is shown in Fig. 1.

100 MAIZE GRAIN (100 kg) steeping

steepwater

x \ \

degermination

maize

germ

"

=

maize oil

~ m a i z e \ \

milling washing

hulls (bran) . . . . . . . . .

(3kg)

germ meal (3.2kg)

I I

~ m a i z e gluten feed (20kg)

maize gluten meal (4.5 kg)

STARCH (62--68 kg) corn syrup

1

DEXTROSE

"

Fig. 1. By-products from the wet milling of maize grain.

Wheat

As maize is imported and liable to taxes, and the EEC has a grain (wheat) surplus, the industry is looking to wheat as an alternative source for starch production. The grain is first milled, leaving a dry by-product. The flour is further moistened, sieved and centrifugated to provide starch, gluten and a wet by-product. Both by-products are mixed and dried, providing wheat-gluten feed. In comparison with maize-gluten feed, crude-protein content is lower: about 17% in the dry matter. Wheat gluten can also be produced from wheat flour with a slurry of 20-30% DM as residue. Potatoes

Using potatoes as a primary source, potato pulp is the by-product remaining after extraction of starch with cold water. Per 100 kg potatoes, 16-20 kg starch is produced and 3-3.5 kg dried potato pulp. Other by-products are: potato filter cake (the residue recovered from the waste water by vacuum filter); potato protein water (the solubles recovered 100 kg potatoes p/~~

potato waste (-+0.9 kg DM ) starch (-+17.5 kg DM )

potato pulp

(l.6kg DM)

(

potato protein (+-1.2kg DM )

potato juice " , ~

(4 kg DM)

potato starchmilk slurry

(-+2.8 kg DM )

Fig. 2. By-products from potato-starch production.

101

by rewetting and regrinding the cake and centrifuging again). A production process for potato starch in The Netherlands is given by Davids (1985) (Fig. 2).

By-products of alcoholproduction and~orfermentation industry Distilling Considerable amounts of grain are used in the brewing and distillery industry. A large number of distilled spirits are produced throughout the world. They differ according to: the area of origin (bourbon whisky, U.S.A., cognac, France, schnaps, Germany, Scotch whisky, Scotland, tequila, Mexico, vodka, U.S.S.R., grappa, Italy); the type of raw material used (maize, wheat, rye, barley, oats, milo, buckwheat, potatoes, fruits, grape marc) ; preparation of the raw materials; proportion of raw materials (a mash for manufacturing bourbon whisky must contain a minimum of 51% maize, but more typical ingredients are 75% maize, 12% rye and 13% barley); fermentation conditions; distillation processes; maturation processes; mixture techniques. A flow diagram of a commercial distillery based on maize grain is given in Fig. 3. The main by-products are distillers' grains and distillers' solubles. Distillers' solubles are often dried back into the grains, giving distillers' grains with solubles. Approximately 33% of the original dry matter can be recovered in the by-products, 20% in the distillers' grains and 13% in the solubles. This means that 100 kg of grains provides + 33 kg distillers' dried grains with solubles or _+20 kg distillers' dried grains and + 32.5 kg condensed distillers' solubles with + 35% DM. Different production processes can be applied. For instance in Britain the extracted grains and wort are separated after malting while in the U.S.A. the entire mixture is fermented and distilled. Alcohol can also be produced from potatoes as shown in Fig. 4. This proMAIZE GRAINS (100 kg ) + malt gelatinization

+ saccharification

WORT + yeast fermentation distillation

solubles ( 3 2 . 5 k g - - 35°/o D M ) w h o i e stillage

FINE A L C O H O L ( + 3 7 . 5 t )

Fig. 3. Flowdiagramof maize grain distillation.

d i s t i l l e r s ' grains ( 2 0 kg -- 90 °/o DM )

102

100 kg POTATOES starch extraction POTATO STARCH

÷ malt + yeast fermentation

~

distillation

L

LI

--

-

stillage 1 3 2 1 - - 6 " 1 , DM

ALCOHOl- (4"-8.5 I )

Fig. 4. Alcohol production from potatoes.

cessing method results in the production of 132 1 solubles with 6% DM per 100 kg of potatoes. Another source for alcohol production is molasses. A typical alcoholic distillate from the fermentation of cane molasses is rum. Distillation of 100 kg beet molasses yields 40 kg condensed molasses solubles with 65% DM. For cane

T A B L E III Chemical composition a of some condensed molasses residues using different production processes Beet molasses Citric acid b Dry matter (%) Crude protein (%) N-free extract ( % ) Ash ( % ) Calcium ( % ) Phosphorus (%) Magnesium ( % ) Potassium ( % ) Sodium ( % ) Iron (ppm) Copper (ppm) Zinc (ppm) Manganese (ppm)

66.4 27.6 44.1 27.7 3.02 0.02 0.76 0.18 1.36 468 9 11 18

Ephedrine b 72.5 29.2 43.9 26.4 1.29 0.20 0.36 7.92 5.42 2703 10 92 53

aExpressed on a dry matter basis. bWeigand, 1985. cPotter et al., 1985. dChen et al., 1981.

Cane molasses Desugarized molasses b 67.1 41.2 44.8 14.0 7.40 0.06 0.06 0.78 1.14 1036 10 139 22

Ethanol

Citrus molasses Citric acid b

Ac

S c

53.3 10.2 23.8 2.19 0.09 1.20 7.96 0.79 1394 41 24 187

52.6 8.7 32.6 2.06 0.16 1.07 11.59 0.84 1865 116 57 72

62.6 18.5 53.8

Ethanol d 45.0 10.6 74.6 14.6 2.48 0.18 0.26 3.80 1.33 2762 18 43 25

103

molasses, only 35 kg condensed solubles are left after distillation. Molasses can also be used as the basic material for other fermentation processes yielding citric acid, yeast, monosodium glutamate, acetic acid, acetone, butanol, lactic acid, glycerol, dextran, aconitic acid and itaconic acid (Paturau, 1969). Table III shows that the composition of condensed molasses solubles is largely dependent on the origin and the fermentation process. In Italy, carob is also one of the sources for alcohol production ( Manfredini and Cavani, 1983).

Brewing In the brewing process the initial step involves the malting of barley. Upon germination, the enzymes convert starch to malt sugar. The partially-germinated barley is barley malt. The sprouted barley is dried by heating to stop enzymatic activity. Malt sprouts and malt hulls are then separated. Barley malt is mixed with other grains, generally corn or rice, and a flavouring agent, hops, to form a mash. This mash is pressed to give the wort as end-product and brewers' grains as residue. Hops are now joined to the wort. After boiling, the hopped wort is filtered, leaving spent hops as residue. After this step, pure culture yeast is added to the wort and fermentation takes place. The excess yeast then produced is withdrawn, to be known as brewers' yeast. The fermented wort becomes beer. The brewery flow diagram is shown in Fig. 5. During malting about 10% DM losses occur. Starting with 100 kg barley malt about 3-5% malt sprouts and 110-130 kg wet brewers' grains ( + 20% DM) are produced. Depending on the economic conditions, brewers' yeast may be sold separately or dried and sold with the grains to yield a mixture of 95% dried brewers' grains and 5% dried brewers' yeast. Dried brewers' grains may also contain 3% dried spent hops. Also the dreg, which amounts to 0.25-0.8% of the malt DM, is often mixed into the brewers' grains. Consequently, this means that the brewers' grains vary in their nutritive value. BARLEY malting

i.

m a l t s p r o u t s and hulls ( 3 - - S k g )

BARLEY MALT (100 k g ) mashing filtration

b r e w e r s ' g r a i n s ( 110 -- 130 kg -- 20 "/o DM )

WORT ÷ hops + yeast fermentation

b r e w e r s ' y e a s t (4"1.5 kg -- d r i e d ) spent hops (-~0.9 kg - - d r i e d ) dregs

BEER

Fig. 5. Brewery flow diagram.

104

By-products of the sugar industry The main raw materials for sugar production are sugar beet and cane.

Sugar beet In the case of sugar beet, soil contamination averages 12.5%, but is largely dependent on the harvesting conditions. During washing, broken beets and beet roots are obtained. T h e y account for 2.5-5% of the beets and are either sold directly to the farmer for animal feeding or mixed with either the cleaned beets or the beet pulp. After extraction of the sugar, pulp is left; it is a valuable feedstuff for ruminants ( B h a t t a c h a r y a and Sleiman, 1971; Castle, 1972; Fairbairn, 1974; Boucqu~ et al., 1976). The pulp can be used as such, with a DM content of 10-12%, or pressed to 20-25% or dried to 88-90% DM. About 5 kg beet pulp DM is obtained per 100 kg sugar beets (Fig. 6). The extracted juice is then purified and crystallized, leaving scums and molasses. Scums are used as soil fertilizer, while molasses are used in animal nutrition, either as such or Sugar beets (lOOkg with 16"/. sugar) washing cleaning cutting Beet roots ( 2 . 5 - 5 k g ) Dried pulp (5.Skg) Beet slices hydration t diffusion Beet pulp (Skg DM) "x~ressing Juice carbonatat ion filtration crystallization

Pressed pulp (22,5kg) Scums (6.5 kg with 50%DM) l Molasses (4 kg) J-~dehydration !

White sugar (14 kg)

Dried molassed pulp (variable amounts)

Fig. 6. By-productsfrom the processingof sugar beets. TABLE IV Composition of normal and exchanged (Quentin) molasses Normal Exchanged Dry matter (%) Brix degrees Total sugar ( %) Crude protein ( %) Ash (%) Phosphorus (g kg- 1) Calcium (g kg-1) Potassium (g kg- 1) Magnesium (g kg- 1 ) Sodium (g kg- 1)

73 77 47 8 9.5 0.2 2.7 30-50

73 77 43 13 9.0 2.5 4.9 10.0

2.0

7.5

7.8

3.5

105

after mixing with pulp before drying. In some European countries (F.R.G., U.K. ) high amounts of molasses are mixed with pressed beet pulp before dehydration; in the U.K. dried molassed beet pulp contains up to 20% sugar. More sugar can be extracted from the molasses by the Quentin process. Before the third crystallization, some of the potassium and sodium ions are replaced by magnesium. As a result, this exchanged molasses contains less sugar, potassium and sodium and more magnesium (see Table IV) (Bernard et al., 1984). The amount of Quentin molasses varies from 0 to 30% of the total amount of molasses, following the state of trade. Molasses is also a fermentation substrate for the production of alcohol, yeast, citric acid, etc. About 4 kg molasses are produced from the processing of 100 kg sugar beet, and 6.5 kg scums with 50% DM. Sugar refining from cane is not discussed here, because cane is not produced in Europe. Cane molasses however, which is the residue of the home refining of imported crude cane sugar, is an important feed resource for European feed manufacturing.

Chicory This can also be used for sugar production as it contains glucose and fructose, and inulin which can be converted. The processing of chicory for sugar yields approximately 33 kg chicory pulp ( + 27% DM) per 100 kg chicory roots.

By-products from fruits and vegetables Citrus fruits The extraction of the juice from citrus fruits provides citrus pulp as residue. Citrus pulp consists of 60-65% peels, 30-35% segment pulp and 0-10% seeds. On average citrus pulp represents 60% of the fresh weight with a mean DM of 19.7%, but the residue can range between 49 and 69% (Martinez Pascual and Fernandez Carmona, 1980) of the initial weight. Pressing reduces the moisture to 65-75%. Molasses is then produced from the press liquor. Approximately 3.8 kg molasses may be obtained from 100 kg fresh grapefruit. Afterwards the pulp is dried, but it may also be dried without removing the press liquor. Dehydration of small particles of peel, pulp and seed, which were obtained by sieving the wet residue, provides dried citrus meal. Molasses is sometimes added back to the pulp during the drying process, but can also serve as a fermentation substrate in the beverage-alcohol industry, leaving condensed citrus molasses solubles as residue. There has also been some interest in the separation of the seeds. Citrus seed meal is left after the oil has been extracted from the citrus seeds. A review of the different citrus by-products is presented in Fig. 7. The differences in processing, in source and variety of fruit and in type of canning may produce a variation in the physical characteristics and nutritive value of citrus pulp.

106

CITRUS FRUITS (lOOkg) pressing

CITRUS RESIDUE l

-

f ~ Seeds ( (0--10 kg)"

pressing

juice Citrus oil

Fruit

Citrus seed meal D Press liquor

~ Molasses (3.8 kg)

CITRUS PULP (10--12kg DM)

Fig. 7. Schematic presentation of citrusby-products.

Apples Apple pomace is the by-product of the production of cider and juice. It accounts for about 18.5 kg wet or 4.2 kg dried apple pomace per 100 kg apples. Dried apple pomace is a source of pectin. Pectin-extracted apple pomace amounts to 80% of the original dried apple pomace.

Grapes Grape marc is the residue of the wine industry after the juice has been pressed out. The dried marc consists of 40% seeds and 60% pulp. After separating the pulp, the seeds are dried and cleaned. Oil is extracted with hexane, leaving about 85% grape-seed oil meal.

Tomatoes The manufacture of tomato juice and puree provides peels and seeds as residue. They account for about 4.5% of the fresh weight: 3% peels and 1.5% seeds. In some countries, seeds are used for oil production. Following seed pressing or extraction for oil production 73-82% tomato-seed oil meal is left as residue. The production of peeled tomatoes provides only peels as residue.

Coffee Coffee beans are the seeds of coffee fruits. The processing of 100 kg of coffee fruits gives approximately 43 kg coffee pulp, 6 kg shells, 12 kg slime and 39 kg beans. In practice, two by-products are obtained: the pulp and the shells. The production of instant coffee results in coffee grounds or coffee meal as residue. Coffee grounds can be used for the extraction of coffee-bean oil, leaving about 85% spent coffee cake. Coffee molasses is obtained by drying the sugars from the mucilage and pulp of coffee beans (Buitrago et al., 1974).

Almonds About 50% of the world production of almonds is concentrated in Mediterranean countries, such as Spain, Italy and Greece. World almond production

107 TABLE V By-products of different vegetables Crop

By-product

Estimated yield ( t h a -1)

DM-content (%)

Reference a

Asparagus Beans Belgian endive

stalks + leaves stalks + leaves leaves roots stalks+leaves stalks leaves stalks leaves washed roots stalks + leaves leaves stalks leaves green haulms leaves

5.0 15.0 25.0 29.0 45.0 16.8 7.2 40.0 30.0 10.0 25.0 5.0 30.0 4.0 9.0 30.0

17 30 10 14 15 22 11 15 15 11 10 12 10 10 25 15

2 1 2 3 2 1 1 2 2 1 2 1 1 2 1 2

Brussels sprouts

Cabbages Carrots Cauliflower Cauliflower {winter) Gherkins Leeks Peas Turnip rooted celery

1 = Francis (1980 ) ; 2 = Rijkens and Timmers (1983 ); 3 = Cappelle ( 1986 ).

amounted to 813 000 t in 1977-1979. The hulls are a by-product of the almond crop and the ratio of hulls to grains can be estimated at 1.7 ( Alibes et al., 1983 ). The chemical composition and nutritive value is largely dependent on the processing method. If hulls and shells are separated all at once from the grain, crude fibre can increase to more than 15% (Bath, 1981). However, newer varieties are characterized by softer shells. Besides the processing residues a lot of vegetable wastage stays on the field. Amounts of different vegetable by'products are given in Table V, based on the data of Francis (1980), Rijkens and Timmers (1983) and Cappelle (1986).

By-products of the vegetable oil industry General The most important raw materials for oil production are oil seeds. From the preceding text it is clear that oil can also be obtained from maize germs, citrus seeds, grape seeds and tomato seeds. Oilseed meals are extensively dealt with by Aherne and Kennelly (1982) and Kling and Wohlbier (1983). Concerning oil meals as a group of highly valuable by-products however, recent changes in the oil prices and of the protein/energy price ratio, leads to the situation that oil seeds are a priori no

108

longer to be considered as a primary source for oil extraction, resulting in a protein-rich by-product for animal feed. Consequently, the oil meals as well as the oil seeds, are primarily used as feed ingredients, while the oil becomes of minor importance. The potential use of full-fat oil seeds by livestock is described in the chapter on cereals and other seeds (Todorov, 1988) and elsewhere (Fenwick and Curtis, 1980; Thomke, 1981; Clandinin and Robblee, 1981; Anderson et al., 1983). The most important oil seeds that can be grown in Europe are rapeseed, sunflower, cottonseed, linseed and groundnut. Oil production from oil seeds is obtained either by pressing or extraction, with cakes or meals as residue. However, seeds with an oil content between 35 and 70% are currently pre-pressed followed by solvent extraction. This is the case for copra (coconut), linseed, peanuts, rapeseed and sunflower seed. A compilation of literature data concerning the amount of oil meal obtained from 100 kg seeds, beans or nuts is presented in Table VI. Besides the husks, groundnut kernels contain 4.1% skins. Dehulling or decortication is not always complete. Partially dehulled oil meal is obtained by sieving. Linseed production is associated with linseed chaff (flax husks) amounting to about 200 kg per 100 kg linseed. Cotton plants are ginned after harvest, resulting in cotton gin trash or cotton (plant) by-product. It consists of bars, stems, leaf fragments, a small amount of lint and dirt. The quantity of gin trash can be estimated at 0.5 t t - 1 cotton seed. Consequently, the chemical composition of the protein concentrates is largely TABLE VI Approximate oil a n d oil-meal production from 100 kg extracted seeds or nuts

Coconut Cottonseed Groundnut Linseed Palm kernel Rapeseed Safflower Sesame Soya bean Sunflower

Oil meal from undehuUed seeds

Dehulled seeds Oil meal

Hulls

38 85 64 a

13 41 38 70 a 51 49 20 30 75 62

25 44 30 16 45 18 7 8

65 65 48 82 70

aAdditional information in text.

Oil

62 15 36 30 49 35 35 52 18 30

109 dependent on the processing. Sometimes, depending on the surplus of oils and fats on the world market, the oil industry has no benefit in extracting maxim u m amounts of oil from the seeds. In these circumstances, the fat content in the oil meals exceeds considerably the mean tabular figures. Therefore, a chemical analysis is essential for each batch to estimate its feeding value. A short review of the main properties and some constraints of the oil meals follows.

Soya bean oil meal Soya bean oil meal (SBM) is generally referred to as the standard protein source, because it is the most widely used and the amino-acid pattern is suitable for pigs and poultry receiving diets of cereal grain ( Smith, 1977). In comparison with other meals, the availability of amino acids for monogastrics is high. Energy values of SBM are mostly higher than those of other meals, as a consequence of the low fibre content. SBM is not an important source of vitamins and minerals. Coconut meal Coconut meal is a relatively good source of protein and also of energy, which is more acceptable for ruminants. High levels of coconut meal can increase butterfat in the milk of dairy cows. Protein digestibility in pigs is not very high and lysine and methionine are lacking for monogastrics ( Hutagalung, 1981 ). Cottonseed meal Cottonseed meal has a somewhat lower protein content than SBM, depending on the amount of hulls removed. It has a higher fibre content, resulting in a lower energy value than SBM. Many essential amino acids are lower than in SBM and the availability for monogastrics may also be lower. For these reasons, and also because of the presence of gossypol, this meal is not very appropriate for monogastrics, especially laying hens. As a mineral source, cottonseed is poorer than SBM, but it compares favourably with SBM for most B-vitamins, except for biotin, pyridoxine and pantothenic acid. Groundnut meal Groundnut meal can contain less than 40% crude protein, but it can reach 50% when the nuts are decorticated. It is one of the oil meals with the highest fibre levels. Lysine, methionine, threonine and tryptophan are lower than in SBM, but arginine content is higher. Groundnut meal has a higher level of magnesium, manganese and selenium than SBM. However, it contains small amounts of oxalic acid ( +0.16% kg -1 DM).

110

Linseed meal Linseed meal is unique among oilmeals because of the presence of 3-10% of mucilage. The water-dispersible carbohydrate of mucilage is almost completely indigestible by non-ruminant animals. Moreover, the deficiency of essential amino acids requires the combination with a complementary protein source in rations for monogastrics. The mucilage is able to absorb large amounts of water, so that rumen retention time is increased and the gut wall is protected against mechanical damage, while constipation is prevented. In fattening cattle it gives a very good sleek appearance to the coat. Palm-kernel meal and safflower meal Palm-kernel and safflower meal both have a high crude-fibre content. The amino-acid availability in palm-kernel meal is relatively low. For these reasons, and also because both meals tend to be unpalatable, they are not widely used in diets for monogastrics. Rapeseed meal Rapeseed meal has a crude protein content between 35 and 39%. Newer varieties of rapeseed ( double zero) are called "canola meal" in Canada. These cultivars have less than 3% erucic acid in the oil and the glucosinolate content in the meal is lower than 5 mg g-1. Lysine and methionine content compare favourably with that in SBM, but amino-acid availabilities are lower than for SBM. The energy content of canola meal is lower than in SBM, owing to the fibre content. Newer (triple zero) cultivars were selected, with a yellow seed coat and a lower fibre content. In general canola meal is a rich source of minerals, but availability is negatively affected by the presence of phytic acid and fibre. However, despite the lower availability, canola meal is a better source of available calcium, phosphorus, magnesium, manganese, iron and selenium than is SBM. Sesame seed meal Sesame seed meal contains high levels of phytic and oxalic acid in the hulls, making minerals unavailable and provoking a bitter taste. Consequently, dehulling can improve dietary properties, as is also true for other oilseeds. However, dehulling is not always complete. Partially-dehulled meal is obtained by sieving. Dehulled sesame meal contains 42-46% crude protein. Its amino-acid profile (high in methionine, low in lysine) complements most other oilseed proteins. Sunflower seed meal Sunflower seed meal has a protein content vary}ng between 26% for undehulled and 44% for dehulled material. Dehulled sunflower seed meal is comparable with cottonseed meal, but protein quality is lower than in SBM. Lysine

111 OLIVES ( 100 kg ) ( 51.4 ~/~ DiM )

OLIVES (100 kg)

Olive oil (20kg) Oil mills

~

Grinding

f Vegetation (1001) waters ( 20 °/o DM )

OLIVE CAKE (33 kg )(75.7 % DM)

Ref iner

<

Heating OLIVE

PASTE

÷ H20

Olive oil ( 2 0 k g ) ( Soap

Centrifugation

Olive cake OLIVE CAKE (40kg)

( 130 kg ) Virgin olive oil (20 kg)

\ Vegetation waters (70 kg)

EXHAUSTED OLIVE CAKE (25.4 kg)(83°/o DM) Fuel

Furfural

Fig. 8. Diagram of the olive processing in Tunisia (left) and Italy (right) (Sansoucy, 1985).

content is remarkably lower, but methionine and arginine concentrations are higher than in SBM. Sunflower seed meal is richer in calcium, phosphorus and magnesium than SBM. B-vitamins and carotene are also significantly higher in sunflower seed meal.

Olives Oil can also be pressed or centrifuged out of olives leaving 33-40 kg olive cake per 100 kg of olives. Mostly the cake is subjected to an extraction with hexane to produce olive-kernel oil and a solvent-extracted olive cake as residue, which approximates 25 kg per 100 kg of olives. A diagram of olive processing is shown in Fig. 8. Exhausted or solvent-extracted olive cake contains approximately 15% water, 4% oil, 55% shells and 26% pulp. Olive pulp is obtained when the stones are separated before oil extraction. Other oils are produced from grape seeds, tomato seeds, citrus seeds, etc. These amounts are less important as they are obtained as by-products from other processing industries. By-products of the wood and paper industries Fibre residues It is estimated that about 3.6 kg of fibre residues are generated for 100 kg of wood pulp that is produced and processed into finished products. Hemicellulose extract is a by-product of the manufacture of pressed wood.

112 TABLE VII Analysesof lignin-sulfonate products

Solids ( %) Reducing sugars (%) Crude protein (%) Ash ( % ) pH

Modified ammonia base acid-sulfite

Calcium base acid-sulfite

Ammonia b a s e semichemical

Standard ammonia base acid-sulfite

53.3 3.8 23.6 0.7 5.3

56.0 12.3 1.5 6.0 3.6

52.6 3.8 23.6 1.0 5.8

50.7 14.9 12.1 0.5 5.1

It is the concentrated soluble material obtained from the t r e a t m e n t of wood at elevated temperature and pressure without use of acids, alkalis or salts. It contains pentose and hexose sugars and must have a total carbohydrate content of not less t h a n 55%. The t r e a t m e n t of wood with sulphuric acid removes the lignin. In this process, lignin-sulfite liquor is formed as a by-product. Depending on the method used, water-soluble salts of calcium, sodium, magnesium or a m m o n i u m may be present. In other pulping systems increased ratios of sulfur dioxide and bisulfite are used to dissolve the wood at a pH approaching neutrality. According to Meitner (1975), the analytical data from various lignin-sulfonate mixtures may vary from pulp mill to pulp mill (see Table VII). The properties of lignosulfonates make t h e m useful as binders in pelleted animal feeds. Woodworking provides large quantities of sawdust and shavings. The low feeding value of sawdust can be upgraded by using chemicals (Jelks method: nitric acid) so that to some extent the treated sawdust can be used in complete diets for beef cattle (Tisserand, 1985).

Miscellaneous Potato processing Beside starch production from potatoes large quantities of potatoes are also processed for h u m a n food such as flakes, French fries, chips etc. In consequence, quite a variable series of by-products are produced: steamed potato peelings (slurry), a high-moisture product with 12-15% DM, amounting to about 10% of raw potatoes; raw peelings, + 3% (15% DM) of the raw material; potato pomace as a remainder on rollers after potato flake production, 6-10% ( _+25 % D M ) of raw potatoes; pre-fried French fries, + 10% offals of fries, with about 30% D M and an oil content of + 6% (sometimes this offal is incorporated into the pomace ) ; crude starch, obtained by cutting potatoes into fries with water, this has a D M content of + 50% and amounts to 0.8% of raw po-

113

tatoes; potato by-product meal, or tater meal, is the residue from processing white potatoes and potato products for human consumption, and contains whole potatoes, peelings, potato pulp, chips and off-colour French fries (Dickey et al., 1971). It is estimated that about 35% of the pre-processed potato is discarded during processing (Church, 1984).

Fermentation processes A by-product of the fermentation industry, although not directly from food processing, is spent mycelium slurry. Antibiotics are produced by the growth of fungi on highly-digestible substrates, mainly sugars. After the fermentation, the mycelium is separated, together with some residue of the substrate, from the liquid phase, in which the antibiotic is mainly secreted. Until recently, a lot of mycelium slurry was dumped into the North Sea. Major fermentation antibiotics are penicillin, cephalosporin, tetracycline, erythromycin and aminoglycosides. The amount of waste per kg antibiotic production is estimated at 2.5 kg.

Vegetableprotein production After fat extraction, oil seeds are also used for the production of protein concentrates and isolates by aqueous extraction. The production scheme is presented in Fig. 9. In the case of soya-protein concentrates, the yield is about 60-70% of the defatted soya flour. Although under-utilized at present, rapeseed-protein concentrates and isolates have excellent functional properties, so they can be used at much higher concentrations than soya bean-protein products (Yehya and Jelen, 1985). DEFATTED SOYFLOUR OR FLAKES : lOOkg l i

÷ w a t e r , + Ca ++ ~

t°

precipitation of polysaccharides : 20 kg (85--90"/. DM)

protein extract l

clarificat ion , acidification to pH = 4.5

protein curd washing soy whey : 100 kg ( 8 - 1 0 %

DM)

neutralization (pH = 7.0) protein isolates : 3 0 - 4 0 kg

Fig. 9. Production scheme of protein isolates and by-products from defattecl soya flour.

114 CHEMICAL COMPOSITION, DIGESTIBILITY AND ENERGY VALUE OF BY-PRODUCTS

From the previous section it becomes clear that the chemical characteristics of some by-products are very variable, owing to different modes of processing and/or the mixing of different fractions of by-products. Maize-gluten feed can be cited as a typical example. Based on 15 samples of different origin Cottyn (B.G. Cottyn, unpublished data) found a wide range in chemical composition: 21.7-25.1% crude protein, 3.6-5.9% ether extract, 7.0-10.1% crude fibre and 9.4-23.2% starch in the dry matter. Cellulase organic-matter digestibility varied between 78.0 and 91.1%, resulting in an estimated net energy value of 6.25-7.73 MJ per kg DM. Some by-products are commonly used in animal feeding, such as the series of oil meals and cakes; for these classic by-products we may refer to the various feed tables. In Table VIII, we present the mean chemical composition of by-products and the extreme values (DM basis ). Table IX shows the apparent digestibility coefficients and the energy value for ruminants, as well as for pigs and poultry. The data for pigs and poultry are very limited, because fibrous materials, such as peanut skins and sunflower hulls, are not well utilized by pigs (Hale and McCormick, 1981; Gargallo and Zimmerman, 1981). Even with less fibrous materials, e.g. dried brewers' grains, 17.2% crude fibre (Table VIII), pig performances are depressed by higher incorporation levels (Qu~m~rd et al., 1983). For pigs and poultry more cereals are incorporated in the diet ( see Chapter II.3, (Todorov, 1988) ). CONSTRAINTS ON THE USE OF BY-PRODUCTS

Anti-nutritive factors Several by-products are characterized by the presence of anti-nutritive factors, such as trypsin inhibitors and lectins in soya bean meal and other pulses, gossypol in cottonseed meal, glucosinolates in rapeseed meal, linamarin, a cyanogenetic glycoside, in linseed meal, cassava and lima beans, other cyanogen substances in beans, peas, cassava (lotaustralin) and germinated sorghum (dhurrin), aflatoxins in peanut meal (from moulded peanuts), saponins in pulses, rapeseed and groundnuts, and alkaloids e.g. solanin in tomato leaves and green-coloured potatoes and shoots. The concentration of those compounds can mostly be reduced by appropriate processing and selection. Potato-protein water possesses a high trypsin-inhibitor activity, if not treated appropriately, which is similar to that in raw soya beans ( Gerry, 1977 ). Citrus-seed meal contains limonene, a monocyclic terpene (CloH16). It has a bitter taste and causes toxicity to pigs and poultry (Hutagalung, 1981 ).

115 T A B L E VIII Chemical composition of by-products (mean and extreme values; % on DM) Feedstuff

Values a

DM ( % )

Almond hulls

A m M

90.5 90.0 91.0

5.1 3.0 6.7

A m M A m M A m M A m M A m M

20.1 14.4 23.0 18.5 14.7 21.5 89.0

Apple pomace Fresh

Ensiled

Dried

Beet molasses

Beet molasses solubles

Beet pulp Wet

Pressed

Dried

Dried, molassed

Brewers' grains Fresh

Ensiled

Dried

Brewers' yeast Liquid

XP

XL

XF

XX

Ash

References b

3.2 2.4 4.0

13.0 11.0 17.0

74.3

9.7 6.6 11.1

1, 2, 3,4

4.2 2.2 2.7

16.9 14.2 20.6 19.8 19.5 20.1 18.1 17.0 20.0 0.

66.8 64.5 67.8

0.2 0 0.6

0

69.7 68.7 70.8 76.8 72.5 79.8 38.8 34.6 44.1

3.4 2.3 4.9 3.5 2.9 4.5 2.9 2.2 3.5 12.3 11.0 13.5 25.5 20.5 30.1

2, 3, 4, 5,6

76.4 75.0 78.0 64.3 62.1 66.4

5.8 4.4 7.8 6.8 6.7 6.8 4.7 4.0 5.1 10.5 7.7 14.0 35.5 27.6 38.6

A m M A m M A m M A m M

11.9 11.0 13.5 20.3 16.5 25.3 89.2 86.7 91.0 90.2 86.0 92.0

11.2 10.0 13.5 10.7 9.7 11.2 9.9 8.0 10.9 10.9 9.5 12.9

2.0 1.8 2.2 1.4 0.8 2.5 0.7 0.5 0.8 0.5 0.4 0.7

25.1 17.8 31.9 21.7 27.0 19.3 20.4 14.9 24.0 14.9 12.4 17.0

50.1 43.0 57.6 57.8 51.7 61.7 64.3 62.0 65.7 64.1 59.6 66.3

6.6 4.0 12.8 7.4 6.6 8.1 5.7 3.9 7.9 7.3 6.1 9.0

2, 3, 4, 10

A m M A m M A m M

23.6 22.0 26.0 27.0 25.0 28.1 93.1 91.0 97.5

24.4 19.3 29.6 24.0 19.3 30.4 27.0 22.2 29.8

7.1 6.5 7.9 9.2 7.9 8.9 7.1 5.3 9.0

15.9 13.3 17.7 17.3 16.0 18.1 17.2 12.6 20.4

47.6 45.5 50.7 45.1 38.4 50.7 44.9 40.4 48.3

4.4 4.0 5.0 4.4

2, 3, 4, 6, 17, 18, 19

4.0 3.7 4.2

2,3,4,20, 21, 22, 23

A m M

12.4 10.8 13.4

46.0 43.2 51.4

4.6 3.4 5.2 0

5 2, 3,4

2,3,4, 7

7, 8, 9

6, 10, 11, 12

2, 3,4,10, 13, 14, 15 2, 3,4,6, 16

6, 18, 19

24

116 T A B L E VIII (continued)

Feedstuff

Values a

D M (%)

XP

93.3 93.0 94.0 83.1 91.1 89.7 57.9 94.0 88.3 66.6 64.0 71.0 45.0

48.1 48.0 48.3 8.8 5.0 18.0 13.1 7.6 6.5 7.9 6.1 10.9 10.6

1.0 0.8 1.1 0.5 0.5 2.4 0.8 2.8 2.9 0.3

0.2

6.9 6.6 7.4 7.0 6.3 8.9 13.6 12.4 10.9 13.0 4.9

A A m M A m M

18.7 16.4 23.1 90.0 87.7 91.8 89.2 90.4 88.0 92.0 69.4 88.0 90.1 90.0 90.3 91.3 89.5 95.7

A m M A m M A m M A m M

92.1 91.0 93.0 6.7 6.4 7.0 92.5 90.0 95.5 91.5 91.0 92.0

Brewers' yeast (continued) Dried A m M Carobbeans (whole) Carob beans without seeds Carob seed meal Carob stillage Citrus meal Citrus-seed meal Citrus molasses A m M Citrus molasses solubles Citrus pulp Wet

Dried

Coffee cake Coffee grounds

Coffee molasses Coffee pulp, dried Cotton gin trash

Cotton-seed hulls

Distillers' grains Dried

Whole distillers' stillage Dried distillers' solubles Grains + solubles, dried

A m M A m M A m M

XL

XF

XX

Ash

References b

3.0 2.9 3.0 8.9 8.5 8.5

40.5 40.2 41.0 78.8 81.5

7.3 7.0 7.7 3.0 4.5

15.2 12.4 0

67.2

28.1 7.1

0

82.7 81.7 84.3 74.6

7.3 6.6 9.0 14.6

3.8 1.8 8.2 3.9 2.1 5.0 1.0 22.7 15.0 28.3 0.4

13.4 12.6 14.7 13.5 9.5 18.2 35.1 45.5 41.0 47.8 0

70.2 64.9 74.9 70.1 64.1 75.5 37.8 18.2 12.2 29.0 59.9

5.7 3.6 7.7 5.5 3.6 7.0 12.4 1.3 0.8 2.0 4.4

7.4 7.0 7.9 4.9 3.1 6.8

1.7 1.7 1.8 1.5 0.4 2.8

36.7 35.0 38.2 46.9 41.1 50.3

46.3 45.3 48.3 42.8 37.5 46.3

8.4 5.9 9.3 4.3 2.9 9.4

2,3,4,43,44

29.6 29.2 30.0 31.3 29.0 33.5 30.0 28.9 31.3 29.3 29.0 29.6

8.5 8.0 9.9 7.6 7.1 8.0 8.6 5.7 9.6 9.4 8.8 10.0

13.5 12.8 14.0 11.6 8.0 13.1 4.0 3.7 4.2 9.7 9.3 10.0

46.1 44.9 47.0 45.7 40.3 51.0 50.2 48.5 54.2 51.7 47.4 56.0

2.1 1.6 2.7 5.0 4.0 6.0 7.3 6.7 8.0 5.0 4.9 5.0

2,3,4,52,53

2,3,4

25 25 26 27 28 26 2, 3, 4, 28

29

2, 3, 28, 30

2, 3, 4, 28, 30, 31,32,33 34 4,35,36,37

26

2, 3, 4,45,46, 47, 48,49,50,51

4, 54

2,3, 4, 52,53

4,52

117 T A B L E VIII ( c o n t i n u e d )

Feedstuff

Values a

DM (%)

Flax husks

A m M

89.1 87.2 91.0

7.5 6.4 8.5

A m M A m M A m M

90.0 87.2 91.0 32.8 86.2 85.5 86.8 91.7 89.0 93.0

A m M A m M A m M

44.0 43.9 44.0 44.2 42.2 46.2 89.4 86.8 90.4

A m M A m M

Grape marc Dried

Silage Grape seed meal

Hop spent

Maize-gluten feed Wet, fresh

Wet, ensiled

Dried

Maize steep liquor Malt sprouts

Mycelium slurry

Olive cake, solv. extr.

Partly destoned

Expeller

Partly destoned

Olive pulp Solv. extr.

XP

XL

XF

XX

Ash

References b

2.2 1.5 2.9

36.5 31.5 41.5

43.3 38.5 48.1

10.6 10.4 10.7

2, 55

12.7 11.7 14.3 13.1 11.0

8.1 7.0 9.9 8.3 0.7

2, 3, 4, 5, 56, 57, 58

4.7 4.0 5.1

42.0 37.7 48.7 47.6 33.6 31.8 35.3 39.6 39.0 39.9

7.7 4.6 12.6 6.8 3.3

23.9 22.0 24.8

28.0 20.4 35.4 24.2 51.5 49.6 53.3 25.5 24.3 28.0

4.9

90.3 91.5 95.8 12.3 9.5 15.0

20.9 19.2 22.5 21.1 20.2 21.9 24.7 21.5 27.5 33.2 28.1 25.0 31.1 39.7 20.0 50.0

A m M A m M A m M A m M

88.8 87.5 90.0 87.5 85.0 90.0 80.4 76.1 88.6 87.5 80.0 95.0

A m M

87.3 82.5 91.9

59 55

6.3 6.0 7.0

2, 3 , 4

8.1 7.2 8.9 7.2 4.8 9.5 7.2 5.5 8.6

60, 61

3.1

9.4

62.5

3.4 2.3 4.6 1.3 1.7 1.5 1.8 2.0

8.8 8.0 9.7 5.5 13.9 9.7 15.7 6.5

56.1 53.1 58.9 49.3 45.9 55.5 34.1

7.1 6.6 8.0 16.1 8.4 30.0

11.2 9.0 13.3 11.5 9.0 14.0 8.3 6.4 10.4 10.5 9.0 12.0

4.1 3.1 5.0 5.0 4.0 6.0 18.9 11.5 30.8 22.5 15.0 30.0

36.1 34.6 37.5 25.0 15.0 35.0 26.8 15.5 42.5 25.0 20.0 30.0

41.3 40.0 42.6 51.5

7.5 6.4 8.5 7.0 6.0 8.0 5.2 3.4 8.2 6.5 6.0 7.0

70,71

13.3 10.2 15.8

5.5 3.9 8.8

21.9 17.6 26.9

50.3 46.5 57.7

6.8 5.9 8.5

2,73, 74

39.7 31.5 48.6 35.5

62, 63

2, 3, 4, 6, 60, 63, 64 65 2, 3, 66, 67

68,69

70

70,72,73

70

118 TABLE VIII (continued)

Feedstuff Olive pulp (continued) Expeller

Peanut hulls

Peanut skins

Potato peelings

Potato by-product meal Potato pulp Wet

Dried Rapeseed hulls

Safflower hulls Soya bean hulls

Sunflower hulls

Tomato pulp Dried

Wet Silage Wheat-gluten feed Wood molasses

Wood pulp

Valuesa

DM (%)

XP

XL

XF

XX

Ash

Referencesb

A m M A m M A m M A m M

80.8 63.0 95.0 90.2 88.2 92.0 92.5 91.7 94.0 20.5 11.1 25.0 91.4

13.4 9.2 17.9 7.3 6.6 8.4 17.5 17.4 17.6 10.0 6.9 14.1 8.1

26.4 21.5 47.7 1.4 1.1 1.8 23.6 22.7 25.5 0.3 0.1 0.5 5.4

21.1 19.6 26.2 61.7 58.6 63.5 12.8 12.6 13.1 3.8 2.5 6.1 5.1

33.5 29.0 38.9 24.5 20.8 29.0 43.2 41.5 44.2 79.6 68.2 87.4 63.9

5.5 3.6 13.0 4.4 3.6 5.0 2.8 2.7 3.0 6.3 3.1 11.1 17.5

2, 72, 73

14.7 13.1 17.0 88.1 85.7 90.0 89.0

5.8 4.7 7.9 6.7 4.4 8.7 16.9 13.8 20.9 3.6 13.2 9.7 15.8 9.3 4.1 20.0

3.0 0.3 7.7 0.3 0.1 0.5 13.3 7.0 20.7 3.7 3.2 1.5 5.0 4.4 1.6 6.8

10.2 2.3 15.9 6.1 3.7 7.8 29.1 20.3 39.7 58.2 35.0 27.7 40.9 44.8 32.1 56.7

78.4 75.9 82.1 83.9 79.2 90.0 31.4 27.4 36.1 32.7 41.9 36.8 44.5 38.0 29.9 46.9

2.6 1.9 3.1 3.0 1.7 4.7 4.7 3.8 5.5 1.8 4.4 3.5 5.0 3.5 2.3 4.9

23.6 23.0 24.0 21.7 19.2 17.2 0.9 0.8 1.0 1.6

8.9 4.2 10.6 12.3 14.6 5.2 0.7 0.5 0.8

24.1 17.8 26.3 27.3 44.9 7.5 0.9 0 1.7

36.5 6.9 32.4 3.5 43.4 10.6 34.3 4.3 16.8 4.5 62.1 8.0 89.8 7.8 86.7 5.3 93.3 10.0 2.3

A m M A m M A m M A m M A m M A m M

A m M

91.3 89.5 85.7 92.0 90.8 89.9 92.0 91.3 89.1 92.0 13.0 29.5 87.0 61.0 60.0 62.0

3,4, 75,76

2, 77, 78

3, 79,80

81 19, 80, 86

8O

83, 84, 85, 86

2, 3 2, 3, 4, 83, 86, 87, 88 3, 83, 85, 89, 90, 91, 92

2, 3, 4, 93

3 2 94 2,3,4

95

X P - - Crude protein; XL-- crude fat; XF = crude fibre; XX = nitrogen-free extracts. aA = Mean values; m-- minimum values; M = maximum values. bNumber of references, details in footnote c overleaf.

119 w e e d s e e d s , s u c h a s Datura stramonium, Lolium remotum a n d Lolium temulentum a r e p r e s e n t i n r a w m a t e r i a l s . I m p r o p e r c l e a n i n g o f p r e s s e s a f t e r e x t r a c t i n g c a s t o r oil o u t o f Ricinus communis c a n c a u s e c o n t a m i n a t i o n o f oil c a k e s . Sometimes,

Aberrant components and residues Some by-products possess typical inconveniences when fed in larger amounts. R i c e s t r a w is r i c h i n s i l i c a . T h i r t y p e r c e n t o f s i l i c a is d i s s o l v e d i n t h e d i g e s t i v e tract, absorbed as silicic acid and excreted in the urine. The concentration of silicic acid in the urine far exceeds its solubility limit, and thus it polymerizes into large insoluble molecular aggregates (Jackson, 1977). Rice hulls are also rich in silica. They have sharp edges which may irritate the intestine. The oil i n r i c e b r a n is p a r t i c u l a r l y u n s a t u r a t e d a n d m a y o x i d i z e e a s i l y u n l e s s i t h a s been stabilized.

TABLE VIII (continued) CReferences for Tables VIII and IX: 1 --- Alibes et al., 1983; 2 = Bath et al., 1983; 3 = Ensminger and Olentine, 1978; 4 = Preston, 1981; 5 = Alibes et al., 1984; 6 = Barber, 1985; 7 = Weigand, 1985; 8 = Manfredini et al., 1985; 9 -- Fiems et al., 1985; 10 = Boucqu~ et al., 1985; 11 = Cadot and Morel d'Arleux, 1985; 12 -- ThSwis et al., 1985; 13 -- Bhattacharya and Sleiman, 1971; 14 = Castle, 1972; 15 = Focant et al., 1983; 16 = Fairbairn, 1974; 17 = Barber and Lonsdale, 1980; 18 = Cottyn et al., 1975a; 19 = Cottyn et al., 1975b; 20 = Brooks, 1971; 21 = Chase, 1977; 22 = Kornegay, 1973; 23 -- Oster et al., 1977; 24 = Grieve, 1979; 25 = Frederella et al., 1983; 26 --Hutagalung, 1981; 27 = Manfredini and Cavani, 1983; 28 = Chapman et al., 1972; 29 = Chen et al., 1981; 30 = Lanza, 1985; 31 = Boucqu~ et al., 1969; 32 -- Cottyn and Boucqu~, 1969; 33 = Martinez Pascal and Fernandez Carmona, 1980; 34 = Prasad et al., 1980; 35 -- Campbell et al., 1976; 36 = McNiven et al., 1977; 37 = Wenk, 1979; 39 = Cabezas et al., 1976; 41 = Jarquin and Bressani, 1976; 42 = Arndt et al., 1980; 44 = Arndt and Richardson, 1982; 45 -- Brown et al., 1977; 46 = Hale et al., 1969; 47 = Holzer et al., 1978; 48 = Levy et al., 1977; 49 = Oltjen et al., 1977; 50 = Rao et al., 1984; 51 = Vijchulata et al., 1980; 52 = Berger, 1981; 53 -- Klopfenstein, 1981; 54 -- Steg et al., 1984; 55 = Cottyn et al., 1981; 56 = Dumont et al., 1985; 57 -- Economides and Hadjidemetriou, 1974; 58 = Matray and van Quackebeke, 1979; 59 = Reyne and Garambois, 1985; 60 = Droppo et al., 1985; 61 = Staples et al., 1984; 62 -- Jaster et al., 1984; 63 = Smits and Oostendorp, 1984; 64 = Fiems et al., 1986; 65 = Waldroup et al., 1970; 66 = Hegazi et al., 1975; 67 = B.G. Cottyn, unpublished data; 68 = Steg and Oostendorp, 1985; 69 = N.R.C., 1983; 70 = Sansoucy, 1985; 71 = Zoiopoulos et al., 1985; Razzaque et al., 1980; 73 = Th~riSz and Boule, 1970; 74 = Belibasakis, 1984; 75 = Utley and McCormick, 1972; 76 = Utley et al., 1973; 77 = Hale and McCormick, 1981; 78 --- McBrayer et al., 1983; 79 = Edwards et al., 1986; 80 -- N.A.S., 1972; 81 -- Dickey et al., 1971; 82 = Stanhope et al., 1980; 83 --- Aufr~re and Michalet-Doreau, 1985; 84 = Bell and Shires, 1982; 85 = Michalet-Doreau and Demarquilly, 1980; 86 = Sarwar et al., 1981; 86 = Cottyn, 1971; 87 = Garrigus et al., 1967; 88 --- Quicke et al., 1959; 89 = Cancalon, 1971; 90 -- Jordan and Hanke, 1969; 91 = Jordan and Hanke, 1970; 92 = Nikolic, 1982; 93 -Ammerman et al., 1963; 94 -- A. de Laporte, personal communication 1985; 95 = Dinius and Bond, 1975; 96 = I.N.R.A., 1984; 97 = W.P.S.A., 1987; 98 = Firkins et al., 1985; 99 = Oostendorp and Smits, 1985; 100 = Steg et al., 1984; 101 -~ Jones and Sibbald, 1979.

Almond hulls Apple pomace Wet (fresh) Dried Ensiled Beet molasses Beet pulp Wet (ensiled) Pressed (ensiled) Dried Dried, molassed Brewers' grains Wet (fresh) Dried Ensiled Brewers' yeast, dried Carob stillage Citrus molasses Citrus pulp Wet (fresh) Dried Coffee grounds Coffee pulp (dried) Cotton gin trash Cotton-seed hulls Distillers' grains Dried Whole stillage Dried dist. sol. Grains + sol., dried

By -products

49.4 60.4 60.4 61.2 81.6 80.3 43.0

53.0 27.0 0 68.5

64.4

62.7

67.1

86.1

54.8 47.5 38.6

83.1

0.0

XP

82.6 84.8 84.8 89.4

77.9

64.2

OM

8.02 9.04 8.52 8.94

4.06 3.48

7.94 7.63 3.23

7.18

6.53 6.36 6.10 7.56

6.81 7.50 7.16 7.50

7.40

35.0 10.0

88.0

74.7

40.6

85.0

14.40 4.63

14.33

11.66

12.09

14.12

88.5 87.7

85.0

76.0

84.0

34.0

11.09

12.43 11.33

10.60

10.84

10.27

2, 3, 4, 97 4, 54 2, 3, 4, 97 4,9,7

2, 3 2, 3, 4, 32, 33, 96 4, 96 39 2, 3, 4, 43, 44 2, 3, 4, 46, 50

2, 3, 4, 6, 17, 18, 19 2, 3, 4, 20, 22, 96, 97 6, 18, 19 2, 3, 4, 92, 96 27 2, 3, 4

2,3,4,10 6, 10, 11, 12 2,3,4,10 2,3,4,6

2,3,4 2, 3, 4, 96 5 2, 3, 4, 96, 97

13.00 9.90

7.10 6.48

XP

MEn (MJ kg -~ DM)

1,2,3,4

OM

(%)

Digestibility

References a

14.16

XP

DE (MJ k g - l D M )

Poultry

5.28

OM

Digestibility (%)

Digestibility (%)

NEI (MJ kg-~ DM)

Pigs

Ruminants

Digestibility and energy value of different by-products

TABLE IX

83.1 28.0 25.2 14.7 22.5

62.7 74.1 80.0

76.6

43.2 33.8 36.2

74.1 21.7 84.0

54.3

79.6 72.6 75.6

45.7 25.0 26.6

56.5

80.0

73.4

0

66.0

29.8 12.9 8.0 57.7

6.29 5.86 6.08 7.52 7.99

5.32 1.00 6.37 2.91

3.22 7.46 2.46 5.90 5.14 7.61

6.57

7.86

1.82

3.41 2.85 2.74

72.0

50.1

80.0 75.0 79.3

11.37 15.21

7.00

13.49

15.48

7.98

3.79

8.32 12.12 8.97

2, 3, 4 3 3 94 3

2 2 3,4, 76 2 81 3 96 83, 84, 85, 101 2,3 2, 3, 4, 83, 85, 86, 87, 88 3, 83, 85 68, 100

70 70 70 70

61, 63 62, 63, 98 2,3,4,96,97,98,99 65 2, 3, 67, 92

2 2, 3 2,3,4 59 55

OM -- organic matter; X P = crude protein; NGI = net energy lactation; DE -- digestible energy; M E , = metabolizable energy, corrected to zero nitrogen retention. ~Number of references, details in footnote to Table VIII.

Flax husks Hop spent Grape marc, dried Grape-marc silage Grape-seed meal Maize-gluten feed Wet, fresh Wet, ensiled Dried Maize steep liquor Malt sprouts Olive cake Solv. extr. Solv., partly destoned Expeller Exp., partly destoned Olive pulp Solv. extr. Expeller Peanut hulls Peanut skins Potato by-product meal Potato peelings Potato pulp, dried Rapeseed hulls Safflower hulls Soya bean hulls Sunflower hulls Spent-mycelium slurry Tomato pulp Dried Wet Ensiled Wheat-gluten feed Wood molasses

122

Before feeding rice bran to poultry it must be autoclaved or steamed to destroy a growth-depressing factor (Kratzer et al., 1974). Wood pulp fines are characterized by a high level of copper (40 ppm), which is potentially toxic for sheep (Millett et al., 1973 ). A major problem with the use of mycelia from antibiotics manufacturing, is the presence of residual antibiotics. It is necessary to remove traces of antibiotics from the mycelia before they can be fed to animals. Another potential problem can be the presence of heavy metals. Belyea et al. (1979) reported that lead and arsenic occurred in toxic concentrations in municipal solid waste, while mercury, cadmium and chromium were marginal. The level of polychlorinated biphenyls was dangerous. Feed use of tomato waste may be limited because insecticide levels are often higher than residue standards set for feeds. Removal of the tomato skin would increase the value of the pomace ( N.R.C., 1983). Constituents which cause metabolic disorders

By feeding high levels of molasses to ruminants, the fermentation pattern is characterized by high levels of butyric acid; in this situation, the animal is physiologically unable to metabolise the ketone bodies produced, leading to ketosis (Karalazos and Swan, 1976). For apple pomace the major problem is its high alcohol content (Alibes et al., 1984). Fontenot et al. (1977) reported that a combined feeding of apple pomace and non-protein nitrogen to beef cows resulted in the birth of small, deformed, dead or weak calves. When dried sugar beet pulp was fed near ad libitum as the sole feed (Wolter et al., 1979) or made up 60% of a diet fed to appetite (Drogoul et al., 1987) no digestive upsets in horses were reported. However, Kelly (1983) warned about the use of dried molassed beet pulp. It can cause colic, since horses have a small stomach and the pulp swells in water. Therefore, dried pulp must be soaked before feeding to horses. Feeding dairy cows with excessive amounts of sugar beet by-products containing large amounts of betaine, such as molasses and its fermentation residue, condensed molasses solubles, can give a fishy taint to milk. This is due to the transformation of betaine to trimethylamine. For the same reason, the use of fish meal should be restricted. Wet brewers' grains become rancid rather quickly. Therefore exposure to air must be limited. Malt sprouts can pose palatability problems if fed at high levels. Large amounts in dairy feeds can impart off flavours to the milk (Ensminger and Olentine, 1978). Coffee grounds had a strong diuretic effect on cattle. When 15% of the ration was coffee grounds, renal, urethral and bladder irritation was caused (Campbell et al., 1976). Furthermore, with rats receiving 30 or 45% coffee grounds in

123 the diet, 75 and 100% died, respectively. They became highly irritable and developed muscular weakness and uncoordination before dying. Death was caused by starvation because of feed refusal, although toxicity with central nervous system manifestation may have contributed. Coffee oil meal also has some negative drawbacks. It is unpalatable to livestock and at an incorporation of 20% of the diet it depresses weight gain and increases mortality in cattle and chicks (Mather and Apgar, 1956; Carew et al., 1967). Coffee pulp is also characterized by adverse effects on animal performance. Caffeine and tannins are the most suspected anti-nutritive factors. Cabezas et al. (1976) reported that caffeine should not exceed 0.12% of the total diet. Caffeine content in coffee pulp averages between 0.4 and 0.5%.

Limitations owing to the fibrousness of the by-product Many by-products contain a large amount of crude fibre. This makes these resources less valuable, especially for pigs, owing to a low digestibility and energy value. Fibrous by-products with a high lignin content are also poorly utilized by ruminants. Besides the low digestibility, lignocellulosic materials are often characterized by a low palatability and intake capacity. The previous tables demonstrate that the feeding value for pigs has only been investigated for a few by-products. Concerning feed intake by cattle, Oltjen et al. (1977) found that cottonseed hulls were consumed at 3.1% of body weight by steers in comparison with 2.0% for chopped straw and 1.4% for corn stover. Levy et al. (1977) reported that dry-matter intake relative to body weight was 5% higher on a cottonseed-hulls diet than on wheat-straw diets. The possibilities as well as the constraints of the utilization of fibrous by-products are comprehensively discussed by Sundstol (1988) in Chapter II.5. Fibrous by-products, e.g. hulls, are often bulky. Therefore, they are difficult to handle and transportation costs are high. Grinding and/or pelleting would provide a more convenient form for handling, storage and transportation. Pelleting increased bulk density from 236 to 609 kg m -3 for cottonseed hulls (Brown et al., 1977) and from 218 to 692 kg for peanut hulls (Utley et al., 1973).

Estimation of the feeding value In relation to the energy value of by-products for ruminants, Sauvant et al. (1985) demonstrated that the digestibility of by-products depends on the composition of the basic diet. A variable protein digestibility was also established by Stanhope et al. (1980), where it ranged from 5.3 to 31.1% for potato-processing residue incorporated in barley diets. A lot of by-products are characterized by wide variations in nutrient content.

124 For instance the crude-protein content on a dry-matter basis varied between 19 and 30% for fresh and ensiled brewers' grains, between 21.5 and 27.5% for dried maize-gluten and feed, between 4 and 20% for sunflower hulls (compare Table VIII). This makes tabular data less reliable and analysis of the by-product is highly desirable before it is used. Only a few data are available concerning the protein quality of the by-products. Dried brewers' grains and beet pulp contain relatively less soluble protein. The crude-protein fraction in condensed molasses solubles and in maize steep liquor is rich in non-protein nitrogen ( Lusby et al., 1982; Wagner et al., 1983 ). Condensed molasses solubles is a striking example of the problems that are encountered by feed evaluation. As most of the nitrogen is non-protein nitrogen ( N P N ) , C.V.B. (1977) assumed a utilization coefficient of 70%. Since 1982, C.V.B. calculated digestible crude protein based on the sum of the amino acids + 75 g per kg DM. It is assumed that the N P N above 12 g per kg DM ( × 6.25 = 75) has no energy or protein value. According to Weigand (1985), the betaine-N is almost completely excreted in the urine and only acetate as the metabolizable compound yields energy. The metabolizable energy amounts to about 7.5 kJ g-1 betaine, which is about 27% of its gross energy. As condensed molasses solubles contain about 16 MJ ME per kg digestible organic matter, Weigand (1985) proposed to subtract 8.5 kJ ME per g betaine (16-7.5). In the framework of the newer protein-evaluation systems more details about protein quality are necessary. It is important for the feed-manufacturing industry that the supply of sufficient quantities of by-products can be guaranteed for a relatively long term. If not, storage possibilities are to be investigated. By-products are used as feed ingredients in the dehydrated form. However, owing to the increased drying costs other preservation methods may be used, mainly for ruminant feeding. Ensiling offers a good alternative for beet pulp, maize-gluten feed, brewers' grains and potato pulp. If the wet material is ensiled, moisture and nutrient losses must be measured. Wet beet pulp ( + 10% DM) has dry-matter losses at ensiling of more than 25%. However, if the pulp is pressed at the factory to 20-25% DM, losses were decreased to about 10%. Processing may also affect the energy value. A comparison of energy values from apple pomace, beet pulp, brewers' grains, citrus pulp, etc. (Table IX) indicated a higher energy content for the fresh or ensiled pressed by-products than in the dehydrated form. UTILIZATIONOF BY-PRODUCTSFOR LIVESTOCKPRODUCTION The potential value of by-products in animal feeding depends on their nutritive characteristics, as, the fibrousness, the protein content, organic-matter digestibility and energy value. Palatability is also an important feature. The utilization may not be detrimental for the animal. The maximum inclusion

125 TABLE X Maximum inclusion rates of some by-products in livestock diets for optimal animal performances ( % ) By-product

Inclusion rate ( % ) Beef cattle

Dairy cattle

Almond hulls

30

25

Apple pomace Beet molasses

15-20 20-30

Beet pulp

95

Brewers' grains

15-20

Brewers' yeast Cassava

40

Citrus pulp

Pigs

Poultry

(2-8) a 5

(0-5) 2-5

10

(0-3)

(20)

10

15-20

(30)

(5) 20-40

(6) 10-30

25-40

40

5-10

3-5

Citrus molasses Coffee pulp

10-20 10-20

10-20 10-20

5-10 8-16

5-10

Coffee grounds

10-20

10-20

5

2

Coffee cake Condensed molasses solubles

(5) 10-15

5 (5)

5

(0-2)

Cottonseed hulls

10

25-30

Cottonseed meal Distillers grains with solubles Flax-seed hulls Grape pulp Grape-seed oil meal Linseed meal Maize-gluten feed Wet Dried

50-60

(15) (30)

(15) (40)

(8) (5)

8-10 20

(20) 15-20 10 free

(20) (15-20) (10) 10

(0-10) (0-6) (0-3) (5-10)

(0-8)

70 50

Maize-steep liquor Malt sprouts Peanut hulls

30 (10)

References

20 25-30

25 (10)

(15) 20

(15) (10)

(0-5) 3-12

5-10

25 (8-15)

Bath, 1981 Aguilar et al., 1984 Bath, 1981 Ensminger and Olentine, 1978 I.N.R.A., 1984 Karalazos et al., 1985 Andries et al., 1984 Boucqu~ et al., 1980 I.N.R.A., 1984 Bath, 1981 Qudmdr$ et al., 1983 Sullivan et al., 1978 I.N.R.A., 1984 Kling and Wohlbier, 1983 Montilla, 1976 Boucqud et al., 1969 Hutagalung, 1981 Kling and Wohlbier, 1983 Hutagalung, 1981 Hutagalung, 1981 Jarquin and Bressani, 1976 Carew et al., 1967 Hutagalung, 1981; Wenk, 1979 Prasad et al., 1980 Fiems et al., 1985 Gonry, 1975; I.N.R.A., 1984 Potter et al., 1985 Brown et al., 1977 Kling and Wohlbier, 1983 Peary et al., 1980 I.N.R.A., 1984 Matterson et al., 1966

Bath, 1981 Cottyn et al., 1981 Kling and Wohlbier, 1983 Vogt et al., 1979 Staples et al., 1984 MacLeod et al., 1985 Portsmouth and Marengos, 1986 Smits and Oostendorp, 1984 Waldroup and Rutherford, 1971

(8) Utley and McCormick, 1972

126 TABLE X (continued} By-product

Inclusion rate (%)

References

Beef cattle

Dairy cattle

Peanut meal Potato peels, steamed Rapeseed meal (ordinary or OO ) Rice bran

free (20 kg) 15

free ( 15 kg) 15

10 25 5-10

15

(15)

(0-10)

2.5-5

Sawdust (aspen} Spent newspaper

(20) 12

30 10

Sunflower meal

free

free

5

5-7

20

{35)

5-10

Wheat bran

Pigs

Poultry (0-5)

(3-7)

I.N.R.A., 1984 Edwards et al., 1986 Fiems and Buysse, 1985, 1986 I.N.R.A., 1984; Vogt, 1981 Bath, 1981 Portsmouth and Marengos, 1986 Satter et al., 1970, 1973 Daniels et al., 1970 Mertens et al., 1971 I.N.R.A., 1984 Portsmouth and Marengos, 1986 Bath, 1981; I.N.R.A., 1984

aValues in parentheses not referenced, based on feed industry experience.

rate in livestock diets is a result of these factors. Some figures are given in Table X. Apart from the presence of anti-nutritive factors, there are beneficial properties in some by-products. For instance, brewers' grains and distillers' grains are effective in controlling liver lipid accumulation in caged layers fed equicaloric, equifat and isonitrogenous corn-soya diets ( Maurice and Jensen, 1978). Other by-products, mainly fibrous or less-palatable materials such as hulls, can be used in larger amounts for slowly growing wintering cattle, or replacement heifers. However, rice hulls have no place in a normal feeding program. Only in extreme feed shortages can they replace a small part of the roughages in cattle rations (Bath, 1981). Intake of non-palatable by-products can be improved by the addition of molasses. For olive cake, 8-10% of molasses, and sometimes 30% is included (Sansoucy, 1985). CONCLUSIONS AND FUTURE TRENDS

From this overview, we can conclude that there is an extensive list of byproducts. A lot of them, as crop residues, are under-utilized. Environmental problems necessitate the investigation of alternative uses. These can be: animal feed resource, soil fertilizer or fuel. A typical example of different utilizations seems to be grape marc. Future research, mainly via a multi-disciplinary approach, is needed to look for the best use, mainly in terms of economy. However it is not sufficient that a by-product is better suited as an animal feedstuff than for other purposes, but it must also be cheaper than conventional feed ingredients.

127 It also became clear that the chemical composition of by-products can vary largely as a result of different processing methods and materials. The feedmanufacturing industry wants raw materials with a constant composition and a regular supply. Therefore simple analytical methods need to be developed for rapid and accurate feedstuff evaluation. Usually, analytical data does not give sufficient information ~bout protein quality, such as true protein and N P N fraction, the protein degradability, the amino-acid composition and organicmatter digestibility ( OMD ). This is another point for investigation. During the last decade there has been a shift from dried to wet by-products as a result of the increased cost of fossil energy. This is the case for beet pulp, citrus pulp, apple pomace, brewers' grains, grape marc, maize-gluten feed, liquid yeast and liquid whey. Maybe other by-products will follow these examples. More information about conservation, storage and nutrient losses is needed. Sometimes by-products are marketed as individual feed ingredients, or as a mixture of two or more feedstuffs. This can be illustrated by maize-gluten feed which is a mixture of steepwater, bran, gluten and germ meal. Brewers' grains can be used as such, or after incorporation of brewers' yeast and/or spent hops. Distillers' grains and solubles are dried separately, or the whole stillage is dried. In some countries e.g. the U.K. and the F.R.G. beet molasses are generally mixed into the beet pulp. In Italy (Sina et al., 1986) large quantities of condensed beet-molasses stillage (65% DM) are mixed into beet pulp or molasses. Wheat bran and middlings are gathered as mill run or pollards. Sometimes rice hulls or similar materials are incorporated into apple pomace during the squeezing operation, resulting in a reduced feeding value (Batch, 1981 ). This also explains the variability of analytical data. Safety for animal and human health must be guaranteed. Therefore an atmosphere of permanent alertness or even anxiety about residues must be created. Some by-products have a low nutritive value for animals. If they are still less interesting for other uses, improved utilization can be obtained by heating, steaming, grinding, chemical treatment, radiation, etc. This topic needs further research. Analytical data, nutritive value and residue studies offer a lot of information. However animal trials are indispensable to assess for feedstuffs palatability, animal efficiency and potential hazards. Finally, new processing methods, new technologies and new consumers' demands will provide modified or new by-products, which are to be evaluated. A typical example, mainly as a consequence of the European common agricultural policy, is the by-product from the production of starch and gluten out of wheat instead of maize. This emphasizes the continuing requirement for the evaluation of by-products.

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133 N.R.C., 1983. Underutilized resources as animal feedstuffs. National Research Council, National Academy Press, Washington, DC, 253 pp. Oltjen, R.R., Dinius, D.A. and Goering, H.K., 1977. Performances of steers fed crop residues supplemented with nonprotein nitrogen, minerals, protein and monensin. J. Anim. Sci., 45: 1442-1452. Oostendorp, D. and Smits, B., 1985. Ensiled maize gluten feed as a feedstuff for beef cattle. In: Ch.V. Boucqu~ (Editor), Feeding Value of By-products and their Use by Beef Cattle. Com. Eur. Community, Luxembourg, pp. 113-123. Oster, A., Thomke, S. and Gyllang, H., 1977. A note on the use of brewers' dried grains as a protein feedstuff for cattle. Anim. Prod., 24: 279-282. Paturau, J.M., 1969. By-products of the cane sugar industry. Elsevier, Amsterdam, 274 pp. Peavy, A.H., Harris, B., Van Horn, H.H. and Wilcox, C.J., 1980. Complete rations for dairy cattle. IX. Effects of percent ground corrugated boxes and citrus molasses solubles - soybean millfeed product on milk production and ration digestibility. J. Dairy Sci., 63: 405-411. Portsmouth, J. and Marengos, T., 1986. Feed facts. Rations to meet all requirements. Poult. World, December 1986: 9-11. Potter, S.G., Moya, A., Henry, P.R., Palmer, A.Z., Becker, H.N. and Ammerman, C.B., 1985. Sugarcane condensed molasses solubles as a feed ingredient for finishing cattle. J. Anim. Sci., 60: 839-846. Prasad, J.R., Prasad, D.A., Reddy, P.G. and Reddy, R.R., 1980. Spent coffee cake in concentrate mixtures for crossbred dairy cows. Indian J. Dairy Sci., 33: 67-70. Preston, R.L., 198 la. Typical composition of feeds for cattle and sheep. Feedstuffs, 53 (36): 18-21. Preston, T.R., 1981b. The use of by-products for intensive animal production. In: A.J. Smith and R.G. Gunn (Editors), Intensive Animal Production in Developing Countries. Br. Soc. Anim. Prod., Occas. Publ. No. 4: 145-150. Qu~m~r~, P., Fourdrinier, R., Lefranc, A. and Willequet, F., 1983. Utilisation de la dr~che de brasserie dgshydrat~e par le porc en croissance-finition. J. Rech. Porcine France, 15: 325-334. Quicke, G.V., Bentley, O.G., Scott, H.W., Johnson, R.R. and Moxon, A.L., 1959. Digestibility of soybean hulls and flakes and the in vitro digestibility of the cellulose in various milling byproducts. J. Dairy Sci., 42: 185-186. Rao, A.S., Sundareshan, K., Prabhu, U.H. and Sampath, S.R., 1984. Chemical composition and nutritive value of spent citronella grass and cotton seed hulls. Indian J. Anim. Sci., 54: 1064-1065. Razzaque, M.A., Aboaysha, A.M. and Omar, F.E., 1980. Olive oil cake as feed for barbari lambs. Proc. Nutr. Soc., 39: 34A. Reyne, Y. and Garambois, X., 1985. Nutritive value of whole grape marc silage for sheep. In: Ch.V. Boucqu~ (Editor), Feeding Value of By-products and their Use by Beef Cattle. Com. Eur. Community, Luxembourg, pp. 283-290. Rijkens, B.A. and Timmers, H., 1983. Inventarisatie van agrarische afvalstoffen ten behoeve van de Energiekaart NEOM. Instituut voor Bewaring en Verwerking van Landbouwprodukten, Wageningen, 45 pp. Sansoucy, R., 1985. Olive by-products for animal feed. F.A.O. Anim. Prod. Health Pap. No. 43, F.A.O., Rome, 44 pp. Sarwar, G., Bell, J.M., Sharby, T.F. and Jones, J.D., 1981. Nutritional evaluation of meals and meal fractions derived from rape and mustard seed. Can. J. Anim. Sci., 61: 719-755. Satter, L.D., Baker, A.J. and Millet, M.A., 1970. Aspen sawdust as a partial roughage substitute in a high concentrate dairy ration. J. Dairy Sci., 53: 1455-1460. Satter, L.D., Lang, L., Baker, A.J. and Millet, M.A., 1973. Value of aspen sawdust as a roughage replacement in high concentrate dairy rations. J. Dairy Sci., 56: 1291-1297. Sauvant, D., Giger, S., Betrand, D. and Chapoutot, P., 1985. Variations of the by-products degradation in the rumen. Consequences for feed formulation. In: Ch.V. Boucqu~ (Editor), Feed-

134 ing Value of By-products and their Use by Beef Cattle. Com. Eur. Community, Luxembourg, pp. 61-67. Sina, P., Breschi, R., Cavani, C. and Manfredini, M., 1986. Utilizzazione zootecnica degli affiuenti di distilleria: la borlanda di melasso di bietola concentrata (BMBC) nell' alimentazione del suino leggero. Zootec. Nutr. Anim., 12: 339-345. Smith, K.J., 1977. Soybean meal: production, composition and utilization. Feedstuffs, 49 (3): 22-25. Smits, B. and Oostendorp, D., 1984. Ensiled maize gluten feed as a feedstuff for pigs and beef cattle. In: E.H. Ketelaars and S. Boer Iwema (Editors), Animals as Waste Converters, Pudoc, Wageningen, pp. 75-76. Stanhope, D.L., Hinman, D.D., Everson, D.O. and Bull, R.C., 1980. Digestibility of potato processing residue in beef cattle finishing diets. J. Anim. Sci., 51: 202-206. Staples, C.R., Davis, C.L., McCoy, G.C. and Clark, J.H., 1984. Feeding value of wet corn gluten feed for lactating dairy cows. J. Dairy Sci., 67: 1214-1220. Steg, A. and Oostendorp, D., 1985. Grain stillage and spent mycelium slurry for beef bulls. In: Ch.V. Boucqud (Editor), Feeding Value of By-products and their Use by Beef Cattle. Com. Eur. Community, Luxembourg, pp. 263-274. Steg, A., Oostendorp, D. and Smits, B., 1984. Grain stillage and spent mycelium slurry for beef bulls and pigs. In: E.H. Ketelaars and S. Boer Iwema (Editors), Animals as Waste Converters. Pudoc, Wageningen, pp. 77-78. Sullivan, T.W., Kuhl, H.J. and Holder, D.P., 1978. Evaluation of brewers' dried grains and yeast in turkey diets. Poult. Sci., 57: 1329-1336. Sundstol, F., 1988. Straw and other fibrous by-products. Livest. Prod. Sci., 19: 137-158. Thdridz, M. and Boule, G., 1970. Feeding value of olive cakes. Ann. Zootech., 19: 143-157. Thdwis, A., Renard, J., Paques, J. and Renaville, R., 1985. Feeding value of ensiled pressed sugarbeet pulp added with urea and molasses and their use by beef cattle. In" Ch.V. Boucqud {Editor), Feeding Value of By-products and their Use by Beef Cattle. Com. Eur. Community, Luxembourg, pp. 133-143. Thomke, S., 1981. Review of rapeseed meal in animal nutrition: ruminant animals. J. Am. Oil Chem. Soc., 58: 805-810. Tisserand, J.L., 1985. Feeding value and utilization of chemically treated sawdust for young beef bulls. In: Ch.V. Boucqud (Editor), Feeding Value of By-products and their Use by Beef Cattle. Com. Eur. Community, Luxembourg, pp. 107-111. Todorov, N.A., 1988. Cereals, pulses and oilseeds. Livest. Prod. Sci., 19: 47-95. Utley, P.R. and McCormick, W.C., 1972. Level of peanut hulls as a roughage source in beef cattle finishing diets. J. Anim. Sci., 34: 146-151. Utley, P.R., Hellwig, R.E., Butler, J.L. and McCormick, W.C., 1973. Comparison of unground, ground and pelleted peanut hulls as roughage sources in steer finishing diets. J. Anim. Sci., 37: 608-611. Vijchulata, P., Henry, P.R., Ammerman, C.B., Potter, S.G. and Becker, H.N., 1980. Effect of monensin with cottonseed hulls and energy supplements for growing steers. J. Anim. Sci., 50: 41-47. Vogt, H., 1981. Rapeseed meal in poultry rations. In: E.S. Bunting (Editor), Production and Utilization of Protein in Oilseed Crops. Martinus Nijhoff Publishers, The Hague/Boston/London, pp. 311-343. Vogt, H., Stute, K., Harnisch, S., Krieg, R. and Torges, H.-G., 1979. Der Einsatz von Leinextraktionsschrot im Gefliigelfutter. Arch. Gefluegelkd., 43: 150-159. Wagner, J.J., Lusby, K.S. and Horn, G.W., 1983. Condensed molasses solubles, corn steep liquor and fermented ammoniated condensed whey as protein sources for beef cattle grazing dormant native range. J. Anim. Sci., 57: 542-552. Waldroup, P.W. and Rutherford, H.O., 1971. Acceptability of corn dried steep liquor concentrate for laying hens and turkeys. Poult. Sci., 50: 1863-1867.

135 Waldroup, P.W., Hillard, C.M. and Abbott, W.W., 1970. Evaluation of corn dried steep liquor concentrate in the diet of broiler chicks. Poult. Sci., 49: 1203-1208. Weigand, E., 1985. Composition of various molasses residues and their feeding value for ruminants. In: Ch .V. Boucqu~ (Editor), Feeding Value of By-products and their Use by Beef Cattle. Com. Eur. Community, Luxembourg, pp. 185-194. Wenk, C., 1979. Kaffee-Extraktionsrtickst~inde als Futtermittel. Z. Tierphysiol., Tierernaehr. Futtermittelkd., 42: 14-17. Wolter, R., Durix, A., Letourneau, J.C. and Carcelen, M., 1979. Evaluation chez le poney de la digestiblit~ du ma'fs-fourrage d~shydratd, des pulpes s~ches de betteraves, de la luzerne d~shydrat~e, du son de bid, de la paille de bld et des pulpes de raisins. Ann. Zootech., 28: 93-100. W.P.S.A., 1986. European table of energy values for poultry feedstuffs. World's Poultry Science Association - European Federation, Het Spelderholt, Centre for Poultry Research and Extension, Beekbergen, The Netherlands, 1st edn., 24 pp. Yehya, N.M. and Jelen, P., 1985. Industrial processing of canola. Agric. For. Bull., Univ. Alberta, 8(3): 11-13. Zoiopoulus, P.E., Raptis, B.L. and Kamarinou, E.P., 1985. Chemical parameters of nutritional importance in a screened solvent extracted olive cake used in animal feeding in Greece. Proc. 36th Ann. Meeting E.A.A.P., p. 352.

Livestock Production Science, 19 (1988) 137-158 Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands

137

II. 5. S t r a w and Other Fibrous B y - P r o d u c t s FRIK SUNDSTOL

INTRODUCTION

Straw and other fibrous crop residues have been used as feed for farm animals in Europe for centuries. With increasing quantities of high-quality forages supplemented with grain and other concentrated feeds, straw has become less and less important over the last decades. This has occurred in spite of the fact that more and more straw is produced, because of the increasing area of land used for cereal production. Because of the high technology introduced in grain production in Europe, feed grain can be produced at a very low cost, making it difficult for low-quality feeds such as straw to compete. In years with low forage (and grain) crops, for example when there is drought, straw still has an important role to play as an emergency feed. If the conditions change, so that the high level of technology cannot be maintained e.g. lack of fertilizer, herbicides, pesticides or petrol, the potential for the underutilized straw, stover etc. would rapidly increase. The geographical separation of animal production from cereal production is a factor which influences the extent of utilization of the crop residues. Since straw has a low value and is a bulky feed it cannot be transported over long distances without being uneconomical. If the animal production for environmental or other reasons becomes more scattered, the possibility of greater byproduct utilization is improved. Furthermore, if the food resources of the world were evenly distributed a better utilization of the crop residues would be crucial. In many Asian countries, where practically all land has to be used for production of human food, straw is the staple feed for the farm animals (ruminants). In Europe, straw burning in the field is prohibited in some countries. In Italy straw burning is prohibited before 15 August. The burning of straw in ovens for heating is practised at many farms in Denmark. The most common use of straw in animal production is as bedding. Straw is also used to some extent as mulch, and as raw material for paper, wall boards, chemical products etc. The excess straw, not used for any other purpose, is normally chopped and ploughed under. 0301-6226/88/$03.50

© 1988 Elsevier Science Publishers B.V.

138 TABLE I Sources for some of the more common fibrous by-products in Europe Cereal straw Wheat straw Summer wheat Winter wheat Spelt wheat Barley straw Summer barley Winter barley Oats straw Rye straw Summer rye Winter rye Rice straw Upland Rice Swamp rice Chaff Grass seed straw Potato (haulms) Stover Maize stover Sorghum stover Millet stover Sunflower stems Rape straw Rape straw Turnip rape straw

Leguminous plants Bean straw Horse beans Garden beans Pea straw Lentil straw (lens) Lupin straw Bitter lupin Sweet lupin Soya bean straw Straw from other leguminous plants Clover Lucerne Vetch Heather Shavings (bark) Rowan tree Aspen tree Foliage Faggot (birch) Prunings (olive, citrus, apple and other fruit trees) Wood (cellulose byproducts and sawdust) Cotton (stalks) Vegetables

TYPES OF CROP RESIDUES

To make a complete list of fibrous crop residues available in Europe is almost impossible. Table I shows some of the most common plants produced in Europe from which fibrous crop residues originate. QUANTITIES OF STRAW AND OTHER FIBROUS BY-PRODUCTS IN EUROPE

The amounts of straw, stover and other fibrous by-products available on a field, vary a great deal with area and commodity. Since it is difficult to measure directly, the normal procedure for estimation of produced crop residues and by-products is to apply conversion factors to multiply with the amount of seeds or product. Examples of such conversion factors e.g. straw/grain ratios are shown in Table II.

139 TABLE II Multipliers used in converting the yields of cereal grain and other commodities into dry-matter yields of their fibrous by-products in Europe

Wheat Barley Maize Rye Oats Millet Sorghum Roots and tubers (fresh) Pulses (dry) Nuts (dry) Oilseeds, oilplant products (dry) Vegetables, melons etc. (fresh) Fruits, berries (fresh)

Kossila (1984)

Adjusted {60%)

1.0 1.2 2.0 (2.0) 1.3 4.0 4.0 0.20 4.00 2.00 4.00 0.25 0.40

0.6 0.72 1.2 (1.2) 0.78 2.4 2.4 0.12 2.4 1.2 2.4 0.15 0.24

It is self evident that these multipliers are average figures which cover large variations owing to variety, weather conditions etc. It is a well-known fact that in a dry climate the straw is shorter than it is when rainfall is plentiful. The stubble length may also vary from one farm to the other and this influences the amount of straw available. The use of straw shortener is another factor which reduces the amount of straw relative to grain. According to Kossila (1984) the multipliers used for the U.S.S.R. are the same as those given in Table II except for barley (1.3) and maize (3.0). Since the conversion factors given by Kossila (1984) probably cover all the aerial part of the plant, except the grains, the amount of straw actually available for feeding will be less when subtracting for stubbles and other losses. If we assume that these losses etc. account for 40%, the conversion factors may be adjusted by multiplying by 0.60. Straw and stover are the dominating crop residues (by-products) of the world and this is also the case in Europe. The estimated amounts of straw available in the European countries in 1981-1984 are presented in Table III. Stover is available primarily in the South-east and the Mediterranean countries and amounts to a total of 84 million tonnes. Rice production is also located in the southern parts of Europe and the estimated amount of rice straw produced annually is slightly above 5 million tonnes of which about 3 million tonnes are produced in the U.S.S.R. Otherwise, the grain production is scattered over all European countries except Iceland. The northmost limit for economical grain production (barley) is

140 TABLE III Production of cereal straw and stover in Europe 1981-1984, thousand metric tonnes per yeara Region and country

Barley

Maize

Wheat

North and West France The Netherlands Bel~um÷Luxembourg Denmark U.K. Ireland

20 912 7305 156 590 4126 7582 1153

12 118 12 061 2 54

25 025 15 877 604 657 910 6718 259

2155 1340 73 112 115 431 84

908 392 32 40 412 31 1

61 118 36 975 867 1453 5563 14 763 1497

Central F.R.G. G.D.R. Poland Czechoslovakia Hungary Switzerland Austria

16 473 6728 2846 2521 2520 663 183 1012

12 610 1154 7 77 992 8425 179 1776

18 144 5425 2000 2978 3138 3549 278 776

5217 1939 516 2012 365 105 44 236

15 778 2069 2492 9853 776 140 29 419

68 222 17 315 7861 17 441 7791 12 882 713 4219

1218 908 55 255

2654 1297 371 986

359 263 4 92

7517 4194 881 2442

Northern Sweden Norway Finland South-East and East Bulgaria Romania Yugoslavia U.S.S.R. Mediterranean Portugal Spain Italy Greece Albania

1

3286 1726 451 1109

Oats

Rye

Total

35 335 1024 1857 504 31 950

45 105 3581 14 849 12 875 13 800

57 532 2485 3731 3091 48 225

12 072 38 64 211 11 759

14 500 40 53 97 14 310

164 544 7168 20 554 16 778 120 044

6414 50 4929 873 541 21

13 815 566 2639 8232 1952 426

10 300 235 2720 5447 1569 329

880 88 418 296 55 23

482 136 288 35 12 11

31 891 1075 10 994 14 883 4129 810

aSource: F.A.O. Production Yearbook 1981-1984 (see also Chapter II.3 (Todorov, 1988)). Adjusted conversion factors from Table II. a t a b o u t 6 5 ° N . W h e a t is t h e m a j o r c e r e a l w i t h a n a n n u a l p r o d u c t i o n o f 112 m i l l i o n t o n n e s o f s t r a w f o l l o w e d b y b a r l e y 82, r y e 32 a n d o a t s 23 m i l l i o n t o n n e s . T h e U . S . S . R . is b y f a r t h e m o s t i m p o r t a n t p r o d u c e r o f s t r a w a n d s t o v e r i n E u r o p e , w i t h a n e s t i m a t e d a m o u n t o f 120 m i l l i o n t o n n e s p e r y e a r , a n d is foll o w e d b y F r a n c e , 37, R o m a n i a , 21, Y u g o s l a v i a , 17, F e d e r a l R e p u b l i c o f G e r -

141 TABLE IV Leaves and twigs available from pruning of olive trees in Mediterranean Europe (after Sansoucy, 1985) Country

Plants ~

Leaves and twigs2

Albania France Greece Italy Portugal Spain Yugoslavia Total

1.5 3.8 79.0 160.0 26.0 180.0 4.7 455.0

22 500 57 000 1 185 000 2 400 000 390 000 2 700 000 70 500 6 825 000

1Plants in production (millions). 2Quantity of leaves and twigs, assuming 15 kg tree -1 year -~ (tonnes).

many, 17, Italy, 15 and the U.K., 15 million tonnes. The Netherlands (0.9), Norway ( 0.9 ) and Switzerland (0.7) are at the bottom of the list. The cereal production in Europe (U.S.S.R. not included) has increased over the last 10 years. For wheat, the production increased from 85 million tonnes in 1974-1976 to 102 million tonnes in 1983. The corresponding increase for maize was from 45 to 57 million tonnes. For the other cereals there were only minor changes (F.A.O., 1983). The amounts of fibrous by-products available from grass-seed straw, haulms (vines), seed production on leguminous plants, foliage, chippings, heather and other feeds which can be collected on uncultivated land are not known. From the review of Sansoucy (1985) the amounts of leaves and of twigs from pruning of olive trees can be estimated (Table IV). THE QUALITY OF FIBROUS BY-PRODUCTS

General The greatest limitation for the use of fibrous by-products as feed is their low nutritive value. Characteristic for these crop residues is a low protein content ( Table V) and a high degree of lignification of the cell walls ( Table VI ). As can be seen from the tables the variation between types of straw and sites of production can be considerable (see also Nicholson, 1984). If the grain is grown under conditions where it does not reach full maturity, more of the readily-available nutrients remain in the straw. This gives a straw of higher quality than that of fully-matured grains. Likewise low temperature seems to have a positive effect on the quality of the straw, compared with high temperature. If the straw is contaminated with weeds or green grass sown together with the

142 TABLE V Chemical composition of cereal straw and stover according to the Weende procedure (g kg-~ DM unless otherwise stated) Type of straw

Wheat straw Mediterranean countries Northern Europe, Denmark Spring wheat, U.K.

Dry matter (gkg -~)

Crude protein

890

36

850

33

19

453

40

5

38

9

Winter wheat, U.K. Barley straw Mediterranean countries Northern Europe, Denmark Spring barley, U.K.

Crude fiber

Ash

OMD a (%)

Reference

80

45.3

464

31

45.0

446

441

68

412

446

75

Alibes and Tisserand (1983) Andersen and Just (1983) Wainman et al. (1984) Wainman et al. (1984)

44

850

40

19

452

51

12

35

12

402

30 850

Winter oats, U.K.

N-free extracts

424

858

Winter barley, U.K. Oat straw Mediterranean countries Northern Europe, Denmark Spring oats, U.K.

Ether extract

85

45.4

445

44

50.0

420

467

50

376

522

55

420

82

47.9 49.0

37

20

414

469

60

49

10

371

512

58

37

11

371

519

62

Alibes and Tisserand (1983) Andersen and Just (1983) Wainman et ah (1984) Wainman et al. (1984) Alibes and Tisserand (1981) Andersen and Just (1983) Wainman et al. (1984) Wainman et al.

(1984) Rye straw Northern Europe, Denmark

850

38

888

45

19

440

467

36

44.0

Andersen and Just (1983)

64

53.7

Alibes and Tisserand (1983)

Maize stover

Mediterranean countries

366

aOMD-- organic matter digestibility.

grain this may also improve the quality of the mixture as animal feed because the digestibility as well as the protein content of the green material is higher than that of the straw. The ratio of straw/leaves also influences the nutritive value of the straw. Weather conditions after harvest of the grain can also influence the quality of the straw in the field. Kjos et al. (1987) compared the digestibility of wheat, barley and oat straw collected just after combining and collected after 1 month in the field (see Table XI). In general, the digestibility of the untreated straw was very high in this ex-

143 TABLE VI Content of structural carbohydrates and lignin in straw (Theander and Aman, 1978) {g kg -1 DM) Cultivar Barley Cilia Ingrid Senat Sarla Wing Oats Titus Winter wheat Holme Spring wheat Drabant Rye Petkus II

Hemicellulose

Cellulose

Klason lignin

270 240 230 270 260

290 300 280 280 330

200 220 240 220 230

220

300

230

210

270

210

210

270

190

230

370

200

periment. The results showed clear differences between species, with oat straw as the best and wheat straw as the poorest. Exposure to weather for 1 month, including 168 m m of rain, reduced the digestibility of straw by 3-4 units regardless of cereal species. Chemical treatment, especially NaOH treatment, caused a considerable increase in organicmatter digestibility ( OMD ), but it also evened out the differences caused by type of straw and weather damage. Differences may also occur between cultivars of the same species of grain. Since the cultivars are often quite country specific we shall not dwell more with these, but rather characterise the straw from various plant species. Wheat straw

Wheat straw, which is available in the greatest quantities in Europe, is less desirable as animal feed than other straws. It is often coarser and has an OMD of about 40%. The quality of the straw as feed may, however, be inversely related to the height of the straw. In Italy, Martillotti et al. (1980) reported that the in vivo digestibility of untreated wheat straw was 41.9 for organic matter. In Northern Europe the digestibility of the straw is often higher than in the south, maybe because of different cultivars and differences in stage of maturity when harvested ( see Table XI).

144

Rye straw

Rye straw is also considered a poor-quality straw by feeders. In a study in Sweden, Eriksson (1981) found that the in vitro OMD for 11 samples of rye straw varied from 31 to 50 with 42 as an average, which was lower than that for wheat, barley and oat straw. Barley straw

Barley straw is usually ranked second to oat straw, although some cultivars of barley may have straw of higher nutritive value than that of some oat cultivars. The organic-matter digestibility of barley straw is often 45-50%. Lufadeju et al. (1985) in Scotland, found that the digestibility of some cultivars of spring-barley straw, e.g. Corgi and Doublet, was as high as that of ammoniatreated straw from other cultivars, indicating that these cultivars could be recommended for direct feeding without treatment. Oat straw

Oat straw is often considered best among the cereal straws. As for barley the digestibility of organic matter is 45-50%, sometimes higher. This straw is therefore preferred among feeders. Straw from barley and oats is also softer than straw from rye and wheat, and this may be the reason why animals tend to take more barley and oat straw. The lack of awns is probably another reason why oat straw is more popular than that of barley and some cultivars of wheat. In some European countries the acreage of oats is declining. Rice straw

Rice straw is different from other straws in that it has a lower lignin content (6-7%) and a higher silica content (12-16%). Also there is a considerable variation in the nutritive value of rice straw. The general impression is, however, that the digestibility of organic matter is at least as high as that of barley and oat straw. The high ash content of rice straw inevitably reduces the overall feeding value of the straw. According to Tartari and Benatti (1981) the OMD of rice straw was 47.6%, and the ash content was 17.9%. Maize stover

Maize stover is a coarser material than straw from small-grain cereals. Nevertheless, it has a relatively high digestibility of organic matter, 46-56% (Alibes and Tisserand, 1981 ). The protein content is also slightly higher than

145 TABLE VII Some energy values for straw and maize stover (per kg DM)

Southern Europe ' Metabolizable energy (MJ) Fattening feed units (FFU) Lactation feed units (LFU) Northern Europe Organic-matter digestibility2 (%) Metabolizable energy (MJ) 2 Scandinavian feed units3

Wheat

Barley

Oats

6.08 0.34 0.46

6.06 0.34 0.45

6.39 0.38 0.49

45.0 6.00 0.24

43.1 5.82 0.30

46.1 6.31 0.31

Rye

Maize

7.53 0.48 0.58

0.24

1Alibes and Tisserand, 1983. 2Wainman et al., 1984. 3Andersen and Just, 1983.

that of most grain straws, 47-54 g kg- 1. It has a high content of cell walls but low lignin content. Chopping is more profitable with stover than with straw to improve the intake by the animals. In order to estimate the potential feeding value of various fibrous by-products some replacement values are needed. Such values are given for some straws and maize stover in Table VII. The feed units show the value (if the straw relative to 1 kg barley when used either for growth and fattening (FFU) or for maintenance and lactation (LFU). For further information regarding the energy measures, see Chapter III. For estimation of the energy value of other fibrous by-products, i.e. Tables VIII and IX, an approximation can be made by using the following equation given by van Es (1978) : ME, MJ kg -1 D M = 15.06 DOM kg -1 DM

(1)

where ME = metabolizable energy; DM = dry matter; DOM = digestible organic matter. Table VIII shows the chemical composition of some other straws which are available in smaller or larger amounts in Europe. These by-products are all residues from seed production. Most of them have a higher protein content and digestibility than that of cereal straw. Exceptions are the straw of beets and species of brassica, which show very low digestibility. In addition to straw, there are a number of fibrous by-products which from time to time are used as feeds for animals. Many of these can be classified as wastes from production of vegetables, fruits, berries etc. The available quantities of these by-products are hard to assess and it is even more difficult to estimate the amounts used as feed. The chemical composition and digestibility of prunings of olive trees, by-products from forest trees plus heather are summarized in Table IX.

792 897

921 913 847

814 852 789 884 874 865 895 880 865

Millet straw Common Panick grass

Buck wheat

Grass-seed straw T i m o t h y ( Phleum pratense ) Rye-grass (Loliumperenne) Meadow fescue (Festucapratensis) R e d fescue (Festuca rubra) S m o o t h meadow-grass (Poa pratensis) Wood poa (Poa nemoralis) S m o o t h brome (Bromus inermis) Cocksfoot ( Dactylis glomerata ) Reed-grass ( P h a l a r i s arundinacea)

Dry matter ( g k g -1)

Ricestraw Swamp Upland

Type of straw

42 41 51 41 57 64 53 56 24

55

43 83

68 68

Crude protein

16 11 20 6 20 26 -

14

22 18

21 21

Ether extract

386 380 412 445 408 348 363 427 494

462

357 366

487 404

Crude fiber

514 515 447 463 (469) (514) 491 422 (384)

404

513 414

248 321

N-free extracts

42 53 70 45 65 74 73 69 98

65

65 119

176 186

Ash

Chemical composition of some o t h e r straws ( f r o m B e c k e t a n d Nehring, 1965) (g kg-1 D M unless otherwise s t a t e d )

T A B L E VIII

47 52 46 33

47 50 48

48-52

58 45-71

50 44

(%)

OMD

Other seed straws Sugar beet (Beta vulgaris ) Sunflower (Helianthus annus) Stem Head Rape ( Brassica napus oleifera ) Turnip rape (Brassica campestris) Swede ( Brassica napus rapifera ) Poppy ( Papaver}

Legume-seed straw Horse bean (Viciafaba) Garden bean (Phaseolus vulgaris ) Pea ( Pisum sativum ) Vetch, Feed vetch (Vicia) Summer vetch Winter vetch Lupin ( Lupinus ) Bitter Sweet (Yellow) Lentil (Lens esculenta ) Soya bean ( Glycine max) Red clover (Trifoliumpratense)

Type of straw

106 134 56 67 46 72

922 871 800 84O 85O 85O

66 82 166 62 97

910 862 855 894 853

66

104 142 119

867 927 889

815

69 108 91

Crude protein

841 863 878

Dry matter (gkg-')

8 38 9 8 12 18

11

9 14 21 10 28

20 13 15

4 14 17

Ether extract

367 86 509 489 532 414

432

425 425 406 446 454

472 385 427

429 336 425

Crude fiber

377 466 362 366 342 389

389

426 409 325 414 358

343 347 354

426 420 395

N-free extracts

142 276 64 70 68 106

102

74 70 82 68 63

61 113 85

73 122 72

Ash

62-74 32-37 34-36 (32-37) 49

34

38-56 47 49-51 58 42

45-48

51-55 61 51

OMD (%)

110-130 70-110 77 70- 90

Crude protein

560

530 520 850

Shavingas (bark) Aspen Rowan

Heather, young dried

82

61 50

82

(harvestedgreen) 850 211 850 148 850 160 850 165 850 146 850 125 850 135 850 146 450 70 450 73

500-580 950 680 870-920

Dry matter (g k g - 1)

Faggots Birch

Willow leaves, dried Pine needles, with small twigs Spruce needles, with small twigs

Poplar leaves, dried Rowan leaves, dried

Leaves and needles from forest trees Alder leaves, dried Aspen leaves, dried Birch leaves, dried

Olive prunings Green leaves Air dried leaves Green branches Dry branches

Type of material

76

110 46

54

59 68 102 111 53 60 65 29 122 63

70 50 112 60

Ether extract

289

327 319

376

206 232 281 165 274 175 173 185 331 318

150-180 130-230 245 230-290

Crude fiber

524

466 546

465

473 484 512 507 448 584 565 553 457 514

570-620 560-700 466 475-555

N-free extracts

29

36 39

23

51 68 45 52 79 56 62 87 20 33

50 50 100 85

Ash

Chemical composition of some fibrous by-products other than straw (g kg-1 DM unless otherwise stated)

TABLE IX

36

44 48

35

43 41

67

46 55 44

60 45 60 55

OMD (%)

(1985) (1985) (1985) (1985)

Sundstol et al. (1986)

Sundstol et al. (1986) Sundstol et al. (1986)

Sundstol et al. (1986)

Pettersen and ./Ersoe (1941) Pettersen and/Ersoe (1941) Pettersen and/Ers~e (1941) Sundst~l et al. (1986) Pettersen and/Ersoe (1941) Sundstol et al. (1986) Sundstol et al. (1986)

Sundstol et al. (1986) Sundstol et al. (1986)

Sansoucy Sansoucy Sansoucy Sansoucy

Reference

Oo

149

Judged from the protein content and the organic-matter digestibility, fresh olive leaves and twigs are of relatively high nutritive value. Conservation ( drying and ensiling) seems to have a negative influence on the nutritive value of olive leaves and branches. Forests, bushes and moors

Forests, bushes and moors have for centuries been valuable sources of feeds for farm animals. In Northern Europe many farmers have collected feeds from the forest for their animals, almost up to our generation. In most cases, it has not been the main feed for the winter season but certainly it used to be a valuable feed supplement. Particularly when the spring was "late", feeds collected in the wild contributed significantly to the survival of the livestock at many farms. Today these resources as feedstuffs are not utilized to any great extent in Europe, but they could be regarded as potential sources in case of emergency. In order to provide enough net energy and absorbable protein for maintenance and production, the animals have to consume large quantities of straw. Because of a low degradability and rate of passage through the intestinal tract the voluntary feed intake of these feeds is low. HANDLING AND STORING

Straw and stover may be utilized as feed simply by letting the animals into the fields after harvest of the grains or seeds (stubble grazing). In Southern Europe, especially with wheat straw, this is a common practice. The advantage of this is that no handling or storage of the material is needed. On the other hand, a greater proportion of the by-product is spoiled through contamination with soil, manure etc. Because of the low palatability of straw stubble, grazing contributes significantly to the energy supply of the animals mainly when there is no other alternative source of feed. For a better utilization of the crop residues as feed they have to be collected and stored for use during winter time or in the dry periods of the year. The traditional way of storing straw was to stack loose straw outdoors or indoors. Loose straw is, however, difficult to handle in great quantities and it is very bulky. Modern baling machines have made this work much easier, first with rectangular bales and later with round bales (Hilmersen et al., 1984). If the straw is to be transported over long distances the high density bales are to be preferred. Conventional rectangular bales are easy to handle by hand and also by some specifically-designed equipment. They can be fitted into any type of store and are easy to handle indoors. For proper handling of big bales a tractor with a fork made for this purpose is required. Handling of big bales may sometimes be a problem indoors if a tractor cannot be used. Straw, stover etc. may be stored in barns and under different kinds of shelter

150

as long as it is covered and not penetrated by rain. A plastic cover under open air may also be a cheap but sufficient store for straw. In order to keep properly the straw has to be dry i.e. about 15% moisture or less, otherwise mould will grow in the straw. TREATMENT TO IMPROVE THE NUTRITIVE VALUE OF STRAW AND OTHER FIBROUS PRODUCTS

Chemical treatments

The idea of treating straw and other low-quality roughages to improve their nutritive value has attracted people for more than a hundred years. At the beginning of this century a method was developed whereby straw was treated in a 1.5% NaOH solution for 3 days and thereafter rinsed with water (Beckmann, 1919). By this method the OMD of rye straw increased from about 46 to 71%. During this treatment 15-20% of the straw dry matter is lost with the rinsing water. A modified version of this method was used by Norwegian farmers from the beginning of World War II onwards (Homb, 1984). Besides Norway, the Beckmann procedure has not been used to any great extent by other countries in Europe. Treatment of straw with NaOH according to the Beckmann procedure was at its height in the mid-sixties and has since declined, mainly because of pollution problems. It has now been replaced by a modification of the Beckmann procedure, the Dip-treatment method (Sundstol, 1981 ). By this method the straw is also soaked in a 1.5% solution but for 1/2-1 h only, after which it is stored for 4-6 days instead of rinsing. The OMD of dip-treated straw is increased from 45-50% to 70-75%, rendering about 1.4 kg organic matter to a fattening feed unit equivalent to the net energy of 1.0 kg barley. With this method there is no loss of dry matter and the pollution problems are negligible. The stack method for ammonia treatment of straw was developed in Norway in 1970-1975. Stacks of straw are wrapped with polyethylene and injected with 3% of anhydrous ammonia (Sundstol et al., 1978). This method has become popular and is used in a number of European countries. The effect of treatment is improved by increased temperature, time of treatment, level of ammonia (up to 3-4% ) and moisture content of the material. One of the greatest advantages of the method is that ammonia has a fungicidal effect. In other words, the straw need not be dry before stacking if ammonia is added. The effect of ammonia treatment on the digestibility of straw is less than that of dip treatment with NaOH. An improvement in OMD of 10-12 percentage units, bringing the digestibility of barley straw and oat straw up to 60-62%, is common. Ammonia treatment of straw can also be carried out in ovens at tempera-

151

tures of about 90 ° C. At such high temperature the treatment can be completed within 24 h. When materials with a high sugar content ( > 5% ) are treated with anhydrous ammonia at high temperatures ( > 70 °C) the poisonous component 4methyl imidasol can be formed which may cause hyperexcitability in farm animals and may also be transferred into the milk of dairy cows (Perdok and Leng, 1985). With pure straw, treated at low temperatures, the risk of this disturbance should be negligible. When hay is conserved with anhydrous ammonia the risk is higher, firstly because the sugar content may be higher and, secondly because the treatment is done at a time when the temperature is higher at least in Northern and Central Europe. Other names of this disorder are crazy-cow or angry-cow syndrome or bovine bonker. Another advantage associated with chemical treatment of straw is that weed seeds such as wild oats are killed by the treatment. Aqueous ammonia ( 20-35% ) is also used commercially for treatment of straw in Europe. One advantage here is that at ammonia concentrations of about 20% the solution can be transported and handled at normal temperatures without using pressure containers. If the material is very dry, aqueous ammonia is better than anhydrous ammonia because of the added water which may be necessary in order to obtain the potential improvement in nutritive value. Other sources of ammonia, for example ammonium bicarbonate (NH4HC03) or urea ( ( NH2 ) 2CO ), have proved to be effective in upgrading straw in industrial plants in Eastern Europe (Bergner, 1981). Studies in Northern Europe have not shown much effect of urea on the nutritive value of straw ( Orskov et al., 1981; Wanapat et al., 1985) while experiments in southern Europe have been more favourable (Dias-da-Silva and Sundstol, 1986). Here the straw is "ensiled" with a urea solution (4-6% urea) at a ratio of 1:1 on a weight basis. Time of treatment may be 1-6 weeks depending on the temperature. In addition to the upgrading effect of ammonia treatment the non-protein nitrogen added may be used by the rumen microorganisms for protein synthesis. Calcium is another nutrient, required by farm animals, which occurs in alkali form e.g. Ca ( OH ) 2. This is, however, a weak alkali and even if some results have shown a positive effect on the digestibility of straw the general opinion is that it is too weak to be really profitable. For further information about this and other chemicals ( SO2, acids, peroxides and others ) see Owen et al. (1984). -

Comparison of chemical methods Wanapat et al. (1985) compared a number of methods for treatment of straw, and some of the results are presented in Table X. It can be concluded from these experiments that wet treatment of straw with NaOH is the most efficient way of improving the digestibility of straw. "Dry" treatment with NaOH and ammonia treatment showed a similar effect in these

152 TABLE X In vivo digestibility of barley straw treated according to different methods 1 (Wanapat et al., 1985 )

Untreated straw Untreated straw + urea at feeding Urine-treated straw Urine-treated straw+soya bean (urease) Urea-treated straw Urea-treated straw+soya bean (urease) Anhydrous NH3, stack Aqueous NH3, stack Anhydrous NH3, vacuum-stack Anhydrous NH3, oven Beckmann (NaOH)-treated straw Wet (NaOH)-treated straw {circulation method) Dip (NaOH)-treated straw Dip (NaOH)-treated straw+urea Dry (NaOH)-treated straw Dry (NaOH) -treated straw, pelleted Significance ( P < ) SEM

Organic matter

Crude Fiber

52.4 52.0 56.3 57.1 56.4 59.0 67.8 59.0 66.7 63.6 75.7 72.8 73.6 74.8 67.8 64.7

50.6 60.8 66.9 65.0 66.8 71.4 79.0 71.4 79.0 74.5 83.5 86.8 88.9 91.1 81.8 74.9

0.001 1.4

0.001 2.3

1Three sheep per treatment. TABLE XI Organic-matter digestibility (%) of good-quality straw and weather-damaged straw of wheat, barley and oats fed untreated and alkali treated to two sheep (Kjos et al., 1987) Quality of straw

Treatment

Wheat straw

Barley straw

Oat straw

Good quality straw

Untreated Ammonia-treated Dip-treated (NaOH) Untreated Ammonia-treated Dip-treated (NaOH)

50.6 62.5 70.9 46.2 56.9 69.5

54.9 61.8 69.1 50.7 60.7 69.9

58.7 66.3 71.9 56.0 65.5 70.9

Weather-damaged straw

e x p e r i m e n t s , w h e r e a s u r e a t r e a t m e n t s h o w e d t h e p o o r e s t effect. I n o t h e r studies, c a r r i e d o u t in N o r w a y , a m m o n i a t r e a t m e n t has b e e n less effective t h a n " d r y " t r e a t m e n t of s t r a w w i t h N a O H . T h e s u p e r i o r i t y o f t h e dip t r e a t m e n t over a m m o n i a t r e a t m e n t is also clearly d e m o n s t r a t e d in T a b l e XI. T h e O M D of t h e s t r a w was i n c r e a s e d to a b o u t 70% b y dip t r e a t m e n t , regardless o f its initial digestibility.

153

Physical treatment Besides chemical treatment there are also several physical methods for the treatment of feed straw. Simple chopping of straw has been practiced for generations with the purpose of reducing the bulkiness of the straw and also to improve the intake of straw by the animals. The intake may also be improved by milling and/or pelleting of the straw. These physical treatments give no improvement in the digestibility of the straw. With milled straw it may even be reduced owing to an increased rate of passage. On the other hand, some experiments have indicated that the utilization of the digested nutrients is enhanced. Physical treatment also includes hydrolysis of fibrous material at high temperature and pressure e.g. steam treatment. Such treatment may also be combined with acids. There is no doubt that this treatment can be effective if it is done properly (Walker, 1984;). The economic viability of this method seems, however, to be more questionable. Similar conclusions may be drawn from experiments with ionizing radiation of straw.

Concluding remarks Many methods have also been developed in which the material undergoes a combination of physical and chemical treatment. One example is the industrial method whereby straw is milled, NaOH, urea or other chemicals are added and the straw is then pelleted (Rexen and Bach Knudsen, 1984). A similar kind of treatment may be carried out at farm level. For this purpose, mobile straw processors are constructed for chopping and NaOH treatment of straw (without pelleting) on the individual farm (see Wilkinson, 1984a). Straw may also be "ensiled" with other chemicals such as NaOH, Ca ( OH ) 2 etc. at a relatively-high moisture content (Wilkinson, 1984b). The straw is normally chopped before treatment and the treatment time may be from one week to several months. Because of the high moisture content there is a risk of moulding of the material if the air is not removed properly by compaction. Mould may also attack when opening the container (silo). Fibrous materials may also be treated with microorganisms or enzymes ( Zadrazil, 1984 ). No practical method for microbial treatment of fibrous materials has been developed yet, but the scope for such a method may prove to be great. The improvement in digestibility is frequently used to express the effectiveness of straw treatment. In most cases, this improvement is accompanied by a significant increase in the straw intake. Flachowsky et al. (1985) found that the dry-matter intake (DMI) increased 18-45% by chemical treatment whereas physical treatment, i.e. grinding and grinding followed by pelleting, increased DMI by 7 and 37%, respectively. Highest intake ( + 92% ) was measured when

154

the straw was treated with 2-3% NaOH and thereafter pelleted. Dias-da-Silva and Sundst~l (1986) found that the intake of straw DM increased by 27-28% as a result of ammonia treatment ( anhydrous or urea). When straw is abundant, the intake of digestible organic matter is what really counts. CONSTRAINTS AND ADVANTAGES OF USING STRAW AND FIBROUS PRODUCTS AS FEED

As already mentioned, the feeding value of straw, stover and other fibrous feeds is low because of the low protein content and the highly-lignified cellulose and hemicellulose. This in turn also has a negative influence on the voluntary intake of these feeds. Experiments have shown that straw is the first feed to be refused if the animals have an option (Mo, 1978; Garmo, 1981). If the animals are offered nothing but straw, experiments have shown that animals can consume large quantities of such feeds (Orskov et al., 1981). If animals are adapted to a straw diet for many generations, it seems that they are able to develop a greater capacity to consume straw e.g. cattle in Bangladesh. In spite of high intakes, European cattle are barely able to maintain their body weight on an all-straw diet. Therefore, in order to enable the animals to produce milk or gain weight the untreated straw should be supplemented with either green material, e.g. grass, or with concentrates. Because of the fibrous nature the

1.0

L~.~

/ J , ./.

0

• Unfr~afed ~ r a w

Co*zcenf~ai~ l~v~l (119/hd/day of unified feed)

Fig. 1. Response of liveweigBt gain ( L W G ) to level of concentrate fed to steers as a supplement to rice straw (Creek et al.,1984). (A) The horizontal distance between regression lines estimates difference in feed input for same L W G after straw istreated. (B) Vertical distance between regression lines estimates increase in animal performance after straw is treated.

155 feeding value of the straw may be reduced when fed together with large quantities of cereal grain, which causes a low pH in the rumen and inhibits the cellulolytic activity. The role of the straw will then mainly be to cover the need for structural feed. In order to cover a greater part of the animal's need for maintenance and production, the straw should be upgraded in one way or another. In an experiment (165 days) with steers, Sundstol and Matre (1980) found that steers fed ammonia-treated straw plus minerals and vitamins gained more than 400 g day- 1. To obtain similar growth rates on untreated straw the animals had to be fed 1.5-2.0 kg concentrate in addition. Similar results were obtained by Creek et al. (1984) in Egypt as seen in Fig. 1. Based on this experiment, they found that 1 tonne of ammonia could save at least 7 tonnes of imported-feed grain. In Europe this will be of importance mainly in countries which import animal products or feed grain e.g. Greece and some Eastern European countries. In Western Europe where there is a surplus of cereals the advantages of straw treatment are not so obvious. If the aim was to produce a maximum amount of food for a starving population of the world, treatment of straw to improve its nutritive value would make more sense. Then more grassland could be used for the production of human food. In areas with low rainfall, i.e. less than 500 mm year-1, the sodium in faeces and urine from animals fed NaOH-treated straw may be harmful to the soil (salinity). THE SIGNIFICANCEOF STRAWAND STOVERFOR LIVESTOCKPRODUCTIONIN VARIOUSREGIONS OF EUROPE For Europe as a whole, straw is important as bedding for pigs, cattle and other types of livestock. In Northern and Western Europe less untreated straw is used as feed today than previously. The role of untreated straw as feed is greater in Eastern and Southern Europe. Latvietis and Ruvalds (1980) reported that about 1 million tonnes of straw were collected and stored each year in Latvia (U.S.S.R.). Of this, 60-85% was used as feed, largely without any kind of treatment. Similar information is also available from Czechoslovakia. Treated straw is used as feed to some extent in Norway, Denmark, United Kingdom, East Germany and other eastern countries. The dominating method today is treatment with ammonia but "dry" treatment and "wet" treatment with NaOH is also practiced to some degree. In Poland about 100 000 tonnes of straw are treated with NaOH yearly. Very little is treated with ammonia in spite of the fact that important studies with ammonia were done in Poland more than 30 years ago (J. Kowalczyk, personal communication, 1986). In Latvia 11.1% (75 000 tonnes) of the straw fed to farm animals was treated with ammonia in 1977, whereas a similar amount was treated according to other methods. In the G.D.R. more than 1 million tonnes of straw are treated

156

chemically and used as feed every year ( H. Bergner, personal communication, 1985). In Bulgaria, ammonia treatment of maize stover is advocated and according to Sandev (1980) digestibilities above 70 have been obtained after such treatment. Ammonia treatment also efficiently prevented mould growth which otherwise is relatively common in such material. In Norway, about 15% (120 000 tonnes) of the straw produced each year is treated with ammonia whereas 3-4% (15-20 000 tonnes) is treated in other ways. Feeding of straw has a long tradition in Denmark and during the last decade there has been a rapid increase in the amount of ammonia-treated straw used as feed. In the U.K. "dry"-treated straw with NaOH is still more common than ammonia-treated straw but this may change with the years to come.

PROMISING DEVELOPMENTS IN BY-PRODUCT QUALITY AND UTILIZATION WHICH MAY FIND APPLICATION IN EUROPEAN LIVESTOCK PRODUCTION

Many technical problems in handling, storing, treatment and utilization of straw and other fibrous by-products as feed are solved today, but many improvements will certainly appear in the future. The greatest obstacles for an increased utilization of these resources as feed, seem to be of an economic and perhaps political nature. As long as high-energy concentrates are available in western Europe at a low price there is little incentive among the farmers to use more straw etc. in the diet. The experience from countries where this is not the situation shows that treatment of straw to improve its nutritive value is of much greater interest. With increasing oil production in the world, the price of oil may drop, which would reduce the cost of producing chemicals such as ammonia and NaOH as well as that of polyethylene. There is also an increasing awareness of the fact that straw may be a valuable by-product. Perhaps the quality and quantity of the straw can also be taken into consideration when plant breeders select the cereal cultivars of the future. As far as chemical treatment is concerned, the potential for use of urea, calcium hydroxide and alkaline hydrogen peroxide (Kerley et al., 1985) should be investigated further. As the cost of getting rid of wastes and by-products increases, the relative cost involved in including such products in the diets of animals decreases. Better equipment for handling and densification of fibrous by-products and for the transportation of such materials will also encourage utilization in the future. Most interesting in the future will perhaps be to see what impact new techniques, including biotechnology, may have on the utilization of the vast resource that fibrous by-products in Europe represent.

157 REFERENCES Alibes, X. and Tisserand, J.L., 1981. Tableaux de la valeur alimentaire pour les ruminants des fourrages et sous-produit d'origine Mediterran~enne. Centre International de Hautes Etudes Agronomiques M~diterran~ennes. Institut Agronomique Mediterran~en de Zaragoza, Spain. Alibes, X. and Tisserand, J.L., 1983. Tableaux de la valeur alimentaire pour les ruminants des fourrages et sout-produit d'origine MediterranSenne. Centre International de Hautes Etudes Agronomiques M~diterraneennes. Institut Agronomique Mediterran~en de Zaragoza, Spain. Andersen, P.E. and Just, A., 1983. Tabeller over foderstoffers sammenssetning m.m. Kvseg. Svin. Det Kgl. danske Landhusholdningsselskab, Copenhagen. Becker, M. and Nehring, K., 1965. Handbuch der Futtermittel. II. Paul Parey, Hamburg, Berlin. Beckmann, E., 1919. Beschaffung der Kohlenhydrate im Kriege. Reform der Strohaufschliessung. Preussische Akad. Wiss., Berlin. Sitzungsber., pp. 275-285. Bergner, H., 1981. Chemical treatment of straw. Plant Res. Dev., 14: 61-81. Creek, M.J., Barker, T.J. and Hargus, W.A., 1984. The development of a new technology in an ancient land. World Anim. Rev., 51: 12-20. Dias-da-Silva, A.A. and Sundstol, F., 1986. Urea as a source of ammonia for improving the nutritive value of wheat straw. Anim. Feed Sci. Technol., 14: 67-79. Eriksson, S., 1981. Nutritive value of cereal straw. Agric. Environ., 6: 257-260. F.A.O., 1983. F.A.O. Production Yearbook Vol. 37, F.A.O. Statistics Series No. 55, Rome. F.A.O., 1981-1984. Production Yearbook. F.A.O. Statistics Series, Rome. Flachowsky, G., Hennig, A., Ochrimenko, W.I., Lohnert, H.-J., Richter, G. and Leonhardt, J., 1985. Digestibility and fattening results of treated wheat straw. Agricultural waste utilization and management. Proc. 5 Int. Symp. Agric. Wastes, Chicago, A.S.A.E. Publication, pp. 13-85. Garmo, T.H., 1981. Milk production of cows fed on NaOH and NH3- treated barley straw. Proc. Workshop "Utilization of Low Quality Roughages", Arusha, Tanzania, 18-22 January 1981. Hilmersen, A., Dolberg, F. and Kjus, 0., 1984. Handling and storing. In: F. Sundstol and E. Owen (Editors), Straw and Other Fibrous By-products as Feed. Elsevier, Amsterdam, pp. 25-44. Homb, T., 1984. Wet treatment with sodium hydroxide. In: F. Sundstol and E. Owen (Editors), Straw and Other Fibrous By-products as Feed. Elsevier, Amsterdam, pp. 106-126. Kerley, M.S., Fahey, G.C., Berger, L.L., Gould, M.J. and Lee Baker, F., 1985. Alkaline hydrogen peroxide treatment unlocks energy in agricultural by-products. Science, 230: 820-822. Kjos, N.P., Sundst~l, F. and McBurney, M.I., 1987. The nutritive value of weather-damaged and good-quality straw of barley, wheat and oat, untreated and treated with ammonia or sodium hydroxide. J. Anim. Physiol. Anim. Nutrit., 57: 1-15. Kossila, V., 1984. Location and potential feed use. In: F. Sundst~l and E. Owen (Editors), Straw and Other Fibrous By-products as Feed. Elsevier, Amsterdam, pp. 4-24. Latvietis, J. and Ruvalds, I., 1980. Verfahrens des Strohaufschlusses in der Lettischen SSR. Arch. Tierernaehr., 30: 267-271. Lufadeju, E.A., Blacket, G.A. and Orskov, E.R., 1985. The effect of variety of spring barley straw and of ammonia treatment on nutritive value. Proc. Nutr. Soc., 44: 98A. Martillotti, F., Bartocci, S., Malossini, F., Conte, L. and Santoro, G., 1980. Una macchina per il trattamento meccanico e chimico della paglia. Inf. Agrario, 36: 12499-12504. Mo, M., 1978. Ammoniakbehandlet halm i fSrrasjonen til melkekyr. Scand. Assoc. Agric. Sci., Straw Seminar, Middelfart, Denmark, March 1978. Nicholson, J.W.G., 1984. Digestibility, nutritive value and feed intake. In: F. Sundstol and E. Owen (Editors), Straw and Other Fibrous By-products as Feed. Elsevier, Amsterdam, pp. 340-372. Orskov, E.R., Tait, C.A.G. and Reid, G.W., 1981. Utilization of ammonia- or urea-treated barley straw as the only feed for dairy heifers. Anim. Prod., 32:388 (abstract). Owen, E., Klopfenstein, T. and Urio, N.A., 1984. Treatment with other chemicals. In: F. Sundstol

158 and E. Owen (Editors), Straw and Other Fibrous By-products as Feed. Elsevier, Amsterdam, pp. 248-275. Perdok, H.B. and Leng, R.A., 1985. Hyperexcitability in cattle fed (thermo-)ammoniated rice straw or wheat crop. Proc. 3 AAAP Animal Sci. Congress, Seoul, Korea, pp. 357-366. Pettersen, H.M. and .~Ers~e, H., 1941. Erstatnings- og Hjelpefodermidler. Det Kgl. danske Landhusholdnings, Copenhagen, 120 pp. Rexen, F.P. and Bach Knudsen, K.E., 1984. Industrial-scale dry treatment with sodium hydroxide. In: F. Sundst~l and E. Owen (Editors), Straw and Other Fibrous By-products as Feed. Elsevier, Amsterdam, pp. 127-161. Sandev, S., 1980. Ueber die Perspective der Bearbeitung und Verwendung des Stroh's als Futtermittel in der VR Bulgarien. Arch. Tierernaehr., 30: 293-297. Sansoucy, R., 1985. Olive by-products for animal feed. FAO, Anim. Prod. Health Paper, No. 43. Sundst~l, F., 1981. Methods for treatment of low quality roughages. Proc. Workshop "Utilization Low Quality Roughages", Arusha, Tanzania, 18-22 January 1981. Sundst~l, F. and Matte, T., 1980. Bruk av ammoniakkbehandlet halm i kj~ttproduksjonen. Husdyrfors~ksmotet, Agric. Univ. Norway, pp. 399-404. Sundstol, F., Coxworth, E. and Mowat, D.N., 1978. Improving the nutritive value of straw and other low quality roughages by treatment with ammonia. World Anim. Rev., 26: 13-21. Sundst~l, F., Homb, T., Ekern, A. and Breirem, K., 1986. Sammensetning og n~eringsverdi av norske f6rmidler. K.K. Heje Lommeh~ndbok. P.F. Steensballes Forlag. Tartari, E. and Benatti, G., 1981. Valutazione della digeribilit~ in vivo della paglia di riso integrata con urea e melasso, formellata e trinciata. Ann. Fac. Torino, 12: 109-115. Theander, O. and/kman, P., 1978. Chemical composition of some Swedish cereal straws. Swedish J. Agric. Res., 8: 189-194. Todorov, N., 1988. Feedstuffs. 3. Cereals, pulses and oilseeds. Livest. Prod. Sci., 19: 47-95. Van Es, A.J.H., 1978. Feed evaluation for ruminants. I. The system in use from May 1977 onwards in The Netherlands. Livest. Prod. Sci., 5: 331-345. Wainman, F.W., Dewey, P.J.S: and Brewer, A.C., 1984. Feedingstuffs Evaluation Unit. Fourth Report 1984. Rowett Research Institute, Dep. Agriculture and Fisheries, Scotland. Walker, H.G., 1984. Physical treatment. In: F. Sundst~l and E. Owen (Editors), Straw and Other Fibrous By-products as Feed. Elsevier, Amsterdam, pp. 79-105. Wanapat, M., Sundstol, F. and Garmo, T.H., 1985. A comparison of alkali treatment methods to improve the nutritive value of straw. I. Digestibility and metabolizability. Anim. Feed. Sci. Technol., 12: 295-309. Wilkinson, J.M., 1984a. Farm-scale dry treatment with sodium hydroxide. In: F. Sundst~l and E. Owen (Editors), Straw and Other Fibrous By-products as Feed. Elsevier, Amsterdam, pp. 162-180. Wilkinson, J.M., 1984b. Ensiling with sodium hydroxide. In: F. Sundstol and E. Owen (Editors), Straw and Other Fibrous By-products as Feed. Elsevier, Amsterdam, pp. 181-195. Zadrazil, F., 1984. Microbial conversion of lignocellulose into feed. In: F. Sundst~l and E. Owen (Editors), Straw and Other Fibrous By-products as Feed. Elsevier, Amsterdam, pp. 276-292.

Livestock Production Science, 19 ( 1988) 159-196 Elsevier SciencePublishers B.V., Amsterdam-- Printed in The Netherlands

159

II. 6. By-Products of Animal Origin E.L. MILLER and F. DE BOER

INTRODUCTION

Economic importance of animal by-products The production of food for human consumption, whether of animal or of plant origin, increasingly involves the processing of raw materials with consequent production of waste by-products. The proper disposal of these organic wastes is of major importance, both in terms of maintenance of the environment and of economic production of human food. By-products of vegetable origin have been dealt with in Chapters II. 4 and II. 5 (Boucqu~ and Fiems, 1988; Sundstol, 1988). This chapter deals with the by-products arising in the course of animal production and during subsequent processing of foods of animal origin. A notable feature of animal waste products is their high moisture content. This makes them particularly sensitive to deterioration by endogenous enzymes released from the animal tissue and to microbial putrefaction. Simply disposing of such materials incurs high costs which would have to be a charge against the finished food. Consequently, there are continuous attempts to convert such wastes into economically-viable products, with priority given to those suitable for human consumption, followed by industrial products, pet foods, animal feeds and finally fertilizers. However, the great bulk of the waste is used in animal feed. The most common method of preservation of the initial waste is by drying, but the high moisture content inevitably means that this is an expensive process. Fortunately, the majority of animal waste material, unlike plant waste, has a high content of digestible protein and energy in the dry matter (DM) which may justify the cost of drying. Alternative methods of processing the waste are continually being sought to reduce costs or to increase the value of the end product. One such alternative is preservation of waste with acid as a silage. Although drying costs are obviated, the final product incurs high transport costs, is difficult to trade and is restricted in use to areas close to the site of production. The economic processing of these animal waste products into animal feed depends on the nature of the raw material, its potential feeding value, the alternative costs of disposal and the market price of competitive feed ingredients. 0301-6226/88/$03.50

© 1988ElsevierSciencePublishersB.V.

Animal by-products Whey powder Skim milk powder Blended animal meal N.L., fat > 12% N.L., fat < 12% Blended animal meal U.K., protein '52' U.K., protein '60' U.K., protein '68' N.L. meat and bone, fat < 12% U.K. meat and bone 47/13 Animal fat Blood meal Hydrolysed feather meal White fish meal3 Herring-type5 fish meal South Americans fish meal 153 82 132 105 74 I01

60 56 98 100

614 642 547 632 716 513 495 -970 946 722 783 722

948 919

950 950 950

947

950 995 907

905 900

920

900

137 1000 19

7 12

XL (g kg ~ D M)

140 360

XP (g kg -~ DM)

956 946

DM 1 (g kg -~)

--

--

---

----

---

---

---

XF (g k g - i DM)

29

-42

30 29

752 543

XX (g kg -1 DM)

178

109

23 222

316 -53

384

284 221 158

204 247

100 85

ASH (g kg -1 D M)

18.7

20.1

21.1 17.3

13.3 35.4 19.7

12.3 12.8 13.3

19.2 16.4

15.4 17.4

DE pigs ( M J kg -~ DM)

18.4

33.7 17.1

17.2 14.5

15.1 16.4

ME pigs ( M J kg -~ D M)

Proximate analysis and energy content of products of animal origin compared to representative products of vegetable origin

TABLE I

14.64

17.84

14.5 15.14

12.3 34.2 15.42

10.4

11.1 11.4 11.8

14.2 12.1

12.3 13.3

ME ruminants ( M J kg -1 DM)

14.7

15.2

12.0 13.4

11.4 37.4 13.5

10.1

11.3 11.6 12.0

14.2 12.0

12.0 12.2

ME poultry ( M J kg -1 DM)

FAO, 1986

FAO, 1986

VT, 1979 FAO, 1986

P de M VT, 1979 VT, 1979

VT, 1979

P de M P de M P de M

VT, 1979 VT, 1979

VT, 1979 VT, 1979

Source 1

400

898

558

479

925

875

263

184

905

874

21

28

14

88

46

37

134

156

155

94

318

363

280

443

618

67

75

71

51

58

18.6

13.8

14.4

9.9

13.2

16.8

12.6

12.9

9.1

12.7

13.2

10.8

10.6

10.8

11.2

11.0

8.1

8.6

VT, 1979

VT, 1979

VT, 1979

VT, 1979

VT, 1979

~Generic term including whole fish of species capelin, mackerel, sprat, sand eels, Norway pout. Herring-type meals may have a protein content in the range of 680-740 g kg-1 fresh weight and a fat content in the range 70-120 g k g - ' fresh weight. 6Fish meals made primarily from whole anchoveta; fish meals made from whole sardine or horse mackerel are similar in nutrient analysis. DM = Dry matter; XP = crude protein; XL = crude fat; XF = crude fibre; XX = nitrogen-free extract; N.L. = The Netherlands.

1VT = Veevoedertabel; DE and ME for pigs calculated according to Schiemann et al. (1971 ) ; P de M = Prosper de Mulder, Doncaster, U.K. (personal communication, 1987). 2Metabolic energy/gross energy ( M E / G E ) assumed at 0.66. 3produced from offal and whole fish. 4Wainman and Dewey (1985).

dehulled

dried Sunflower seed meal, extracted; decort. Rapeseed meal, extracted Soya bean meal, extracted

Vegetable by-products Wheat middlings Brewers grains,

162

Government and E.E.C. support and subsidy for some of the competitive materials, e.g. production of rape, sunflower, peas and beans, can markedly affect the viability of animal waste by-products. This is illustrated by comparing the situation within the E.E.C. in 1987 and in 1982. Production of protein by the rendering industry remained about constant at an estimated 1.1 Mt of protein, whereas the protein yield from rapeseed meal increased during that period from 0.6 to 1.2 Mt.

Composition of animal by-products and comparison with plant by-products The variable nature of the raw material used in the production of animal byproducts results in a range of different materials which must be considered separately by type and source to ensure consistency of nutritional value. For example, meat and bone meals, as well as fish meals, can vary greatly from one source to another. However, these are traded by source and according to contract for specified protein and oil content. Blended products are also produced. In this way, customers can be assured of a consistent quality. Generally, animal by-products have a high content of good quality protein, a high energy value and are devoid of poorly-digested crude fibre. Typical values for the proximate constituents and energy of the main types of animal by-product are given in Table I and their amino-acid content in Table II. In contrast, plant by-products TABLE II

Amino-acid content of the protein (g per 16 g N) of typical feeds of animal origin Skim Blended milk animal powder 1 meal'

Lysine Methionine Methionine plus cystine Tryptophan Histidine Leucine Isoleucine Arginine Phenylalanine Tyrosine Threonine Valine Glycine Crude protein (g k g - ' DM)

Meat and meal 2

Blood meal'

Feather meal 1

White fish meal 2

Herringtype meals 2

South Americantype fish meal s

8.2 2.6

5.8 1.5

4.5 1.1

9.6 1.3

1.9 0.7

6.90 2.60

7.73 2.86

7.75 2.95

3.5 1.3 2.8 9.8 5.6 3.6 4.8 5.0 4.6 6.9 2.0

2.4 0.9 2.2 6.7 3.4 6.6 3.7 2.7 3.7 5.1 11.8

1.9 0.4 1.3 5.0 2.4 7.1 3.0 2.0 2.9 3.9 15.8

2.6 1.3 5.7 13.4 1.2 4.6 7.3 3.3 5.4 9.6 4.2

4.6 0.6 0.6 8.2 5.3 6.9 4.7 2.8 4.9 8.4 8.0

3.53 0.94 2.01 6.48 3.70 6.37 3.29 2.60 3.85 4.47 9.92

3.83 1.15 2.43 7.50 4.49 5.84 3.91 3.13 4.26 5.41 5.97

3.89 1.20 2.43 7.62 4.68 5.82 4.21 3.40 4.31 5.29 5.62

360

642

1Source: Veevoedertabel (1986). 2Source: F.A.O. (1986).

513

970

946

722

783

722

163

usually have a lower protein content, with a poorer balance of amino acids, and a lower energy value owing to the high content of indigestible cell-wall material. FEEDS FROM MILK AND DAIRY PROCESSING

National milk and dairy production Cows' milk, which is the dominant type of milk consumed in Europe, is largely transported to, and processed in, dairy factories. Only small amounts, depending on local economic circumstances, remain on the farm of origin for human consumption and for feeding to calves. At the factory, part of the milk is processed for consumption as liquid milk but the greater part is converted into butter and cheese with the production of skimmed milk, butter milk and whey as valuable by-products. Market conditions, which vary greatly from country to country, dictate the proportions processed into the different products. Table III shows the quantities of milk, butter and cheese produced in various European countries and Fig. 1 the partitioning of national milk production into products for some countries. The rinse water from a dairy factory contains small amounts of milk solids. Allowing such rinse water to drain away into the sub-soil or local rivers threatens the quality of surface water in the area. Consequently, a precipitation process to recover the milk solids in rinse water has been developed. The resultant flocculation sludge has a good feed potential, provided it is handled hygienically (ten Have, 1983).

Partitioning of milk in butter and cheese The considerable variation in the way milk is processed into various foods and by-products means that a simple scheme describing the quantities of byproducts becoming available as feedstuffs for livestock in Europe is not possible. However, flow diagrams for butter and cheese production enable an estimate of the amounts of the resulting by-products to be made. Here again, substantial variation occurs, depending on the composition of the milk and the process technology used. Figs. 2 and 3 show flow diagrams for some countries. Part of the liquid by-products may be fed directly to livestock, particularly pigs, in the close vicinity of the dairy factory. Part may be further processed to produce lactose, casein and isolated whey proteins for inclusion in processed foods for human consumption. The remainder is dried to give skimmed milk and whey powders, which are primarily used in human foods but variable surplus amounts are used in the manufacture of calf-milk replacers, principally for rearing veal. The production of milk replacers in some E.E.C. countries during recent years is shown in Fig. 4. Although non-dairy ingredients, principally tallow, will be included, these statistics reflect the combined use of skim

164 TABLE III Production of cows' milk, butter and cheese in European countries1

Northern Europe (N) Finland Iceland Norway Sweden Northwest and Western Europe (NW/W) Belgium/Luxembourg Denmark France F.R.G. Ireland The Netherlands U.K. Central Europe (C) Austria Czechoslovakia G.D.R. Hungary Liechtenstein Poland Switzerland Mediterranean Europe (M) Albania Greece Italy Malta Portugal Spain Southeast and Eastern Europe (SE/E) Bulgaria Romania Yugoslavia Europe U.S.S.R.

Milk2 ( 106 kg)

Butter 3 ( 103 kg)

Cheese 4 ( 103 kg)

8913 3174 130 2028 3581 102 547 4075 5068 33 000 25 675 5920 12 559 16 250 42 244 3719 6883 8900 2723 19 16 300 3700 19 291 345 678 11 000 28 740 6500 10 833 2138 4100 4595 183 828 97 765

176 097 76 000 1250 24 000 74 847 1 889 336 107 000 110 100 570 000 515 114 158 000 229 122 200 000 887 135 42 999 152 026 315 000 31 109 -310 000 37 000 110 700 3700 5000 83 000 -4000 15 000 83 000 24 000 47 000 12 000 3 146 268 1 699 999

272 130 80 000 4400 71 730 116 000 3 375 899 52 000 256 100 1 275 000 939 103 76 000 521 696 256 000 1 097 147 100 400 195 249 248 200 80 898 -346 000 126 400 1 093 220 12 700 196 400 669 940 80 38 100 176 000 425 300 182 800 98 500 144 000 1 710 050 1 719 959

1Source, F.A.O. (1985). 2Milk, fed to livestock included. 3Ghee included. 4All kinds of cheese. m i l k a n d w h e y p o w d e r s . T h e i n t r o d u c t i o n o f m i l k q u o t a s i n 1984 h a s r e s u l t e d i n b o t h a d e c r e a s e i n s u r p l u s p r o c e s s e d - m i l k p r o d u c t s for u s e i n c a l f - m i l k rep l a c e r s a n d a n i n c r e a s e d u s e o f l i q u i d m i l k for r e a r i n g c a l v e s o n i n d i v i d u a l farms which are over t h e i r quota, at the expense of m a n u f a c t u r e d m i l k replacers.

165 Total production on farms1 =

i00

I Utilized on farms CH 20

Utilized in dairies and factories CH 80

DK

6

DK

94

FRG

9

FRG

91

I

30

NL UK

2.5

I

70

Nh

97.5

UK

12

=

I

l Liquid consumptior CH

19

DK

6

FRG

ii

I

21

NL

5

UK

44

88

100

Manufactured for butter cheese others total CH 13 49 19 81

I DK

43

29

22

94

FRG

48

15

26

89

I

17

50

12

79

NL

46

28

20

94

UK

30

17

9

56

Fig. 1. Utilisation of whole milk in some countries. CH -- Switzerland; N L = T h e Netherlands; UK-- United Kingdom; I = Italy; FRG = Federal Republic of Germany; DK = Denmark. Sources: Statistisch Jaaroverzicht (various years); Statistische Erhebungen und Sch~tzungen (1987); United Kingdom E.E.C. Dairy Facts and Figures (1987). Cow's milk =

i00

I

I.

I Butter

Skimmed milk and buttermilk

CH

4.16

CH

95.84

NL

5.1

NL

94.9

UK

4.52 - 4.70

UK

95.3 - 95.48

Fig. 2. Partition of cows' milk for production of butter. NL-- The Netherlands; CH = Switzerland; UK = United Kingdom. Sources: Landbouwcijfers (1986); Rendementsberekeningen 8601-8613 (1987); United Kingdom E.E.C. Dairy Facts and Figures (1987); Statistische Erhebungen und Sch~itzungen (1987).

166

I J

= 100

1 CH

8 - 9.3

NL

9.411)-10.482) 9.9 - 11.2

UK

Skimmed milk and buttermilk

Butter

Whey

Cheese

83,1 - 84

CH

0.7-

NL

82.771)-84.97

NL

2.52 I)- 1.462:

UK

88.8 - 90.1

CH

1.0

CH

6.9 - 7.0

NL

3.43 ~)- 1.992)

Fig. 3. Partition of cows' milk for production of cheese. NL = The Netherlands; CH = Switzerland; UK=United Kingdom. Sources: Rendementsberekeningen 8601-8613 (1987); United Kingdom E.E.C. Dairy Facts and Figures (1987); Statistische Erhebungen und Schiitzungen (1987). 140% Fat in DM of cheese; 248% fat in DM of cheese. 1000-

800.

03 UJ Z Z O I-

600"

E3 Z 03

400"

O "I" I-

I

200"

I

! !

34" 8 7 8

1982

2

12345678

48678

1984

1983

2345878

1985

12345678

1986

YEAR

Fig. 4. Production of milk-replacers in some E.E.C. countries. 1 = France; 2 = Holland; 3 = F.R.G.; 4 = Italy; 5 = Belgium; 6 = Ireland; 7 = U.K.; 8 = Denmark. Source: Digest of Feed Facts and Figures, 1987/88.

167 FEEDS FROM SLAUGHTERHOUSESAND FROM THE RENDERING INDUSTRY

Slaughtered livestock All farm livestock are ultimately slaughtered and become sources of meat for human consumption or use as pet food. However, a proportion of the animal population dies prematurely by illness or accident. Except for those with proscribed diseases, these animals can be collected, the hides removed and the carcases transported to special processing (rendering) plants for conversion into animal feed. However, the vast majority of material handled by these plants are the intestines, trimmings and residual carcase and bones from abattoirs, meat packing and processing plants, and smaller butchers' shops. Table IV shows the quantity of livestock slaughtered annually in Europe and its regional distribution.

Slaughterhouse offal An estimate of the amount of slaughterhouse offal available for processing may be made by multiplying the known number of animals slaughtered by estimates of the proportional yield of different components of the body. However, a considerable proportion may go directly, for example, to fur-animal farming or to the pet-food industry. Part of the fat and bone may also go to special processing industries. The proportion of these alternative methods of utilization is variable because of specific market conditions in various countries, and this means that calculations as referred to may deviate substantially from reality. Part of these discrepancies are bones and fat trim from that part of the carcass marked for human consumption. It must also be stressed that the reliability and consistency of statistics vary greatly between countries. Data for partitioning slaughtered animals are scarce, but estimates are given for cattle, sheep, pigs and poultry in Tables V, VI, VII and VIII, respectively. As in the case of the dairy industry, rinse water from slaughter houses contains small, but still appreciable, amounts of protein and fat, which, if not disposed of carefully will affect the quality of the water supply of the locality. Again, these nutrients can be recovered as a sludge and fed to livestock. Smits and Steg (1983) have shown that this flocculation sludge is a suitable feed for pigs, provided appropriate hygienic precautions are taken.

Input and output of the rendering industry The input and output of rendering plants in three countries in 1985 are shown in Fig. 5. For the Dutch livestock industry, where the numeric ratio of slaughtered cattle and calves to pigs is 1 : 7 and where there are relatively few sheep, the slaughterhouse offal input is estimated to be distributed between cattle,

168 TABLE IV Slaughtered livestock in Europe (1985) Beef and veal

Pigs

Head S1. weight Product Head (×108 ) {kghead -1) {×108kg) (×103 ) Northern Europe Finland Iceland Norway Sweden

Sl. weight Product (kghead -1) (×106kg)

1790 626 27 401 736

203 201 89 195 214

364 126 2 78 158

7664 2265 20 1096 4283

76 74 60 77 77

583 168 1 84 330

Northwest and Western Europe Belgium/Luxembourg Denmark France F.R.G. Ireland The Netherlands U.K.

23 514 1000 1040 7810 5684 1440 2390 4150

257 305 229 243 277 276 211 272

6046 305 238 1898 1574 397 504 1129

117 100 8587 15 298 20 640 38 731 2100 16 670 15 074

80 87 71 88 84 64 84 64

9402 747 1086 1816 3253 134 1400 965

Central Europe Austria Czechoslovakia G.D.R. Hungary Poland Switzerland

10 411 860 1804 1854 531 4520 842

194 273 229 206 276 148 204

2017 235 413 382 147 669 172

58 177 5250 8180 14 289 10 89O 16 100 3468

91 91 101 87 88 93 83

5291 478 826 1243 958 1497 288

Mediterranean Europe Albania Greece Italy Ma~a Portug~ Spain

8090 201 422 5280 6 415 1766

223 135 204 230 270 214 216

1800 27 86 1214 2 89 381

32 235 192 2245 11 350 48 2750 15 650

84 48 65 105 71 65 75

2703 9 146 1192 3 179 1174

Southeast and Eastern Europe Bulgaria Romania Yugoslavia

4683 709 1700 2274

162 179 165 154

758 127 281 350

30 657 4550 11 667 14 440

69 75 78 60

2118 341 910 866

Europe

48 488

227

10 984

245 833

82

20 096

U.S.S.R.

40 900

181

7403

74 100

80

5928

1Source, F.A.O. (1985).

169

Mutton and lamb Head Sl. weight (×103 ) ( k g h e a d - ' )

Product (X106kg)

2621 79 950 1264 328

17 17 14 19 16

44 1 13 24 5

27 515 382 26 8420 1315 1800 452 15 120

20 21 22 21 21 24 25 19

374O 202 1380 585 320 1052 201

Goats

Poultry

Horses

Head S1. weight Product (×103 ) (kghead -~) (×lO~kg)

Product (×106kg)

Product (×106kg)

35

11

0

35

11

0

555 8 1 177 28 43 11 287

699

12

8

660

12

8

39

12

0

16 18 8 26 19 19 20

60 4 11 15 6 20 4

162 33 50

11 11 9

2 0 0

28 51

14 12

29 367 955 7130 7380 2 2500 11 400

11 19 11 9 16 9 11

311 18 78 66 0 23 125

7024 333 4300 550 1 590 1250

16 000 6495 4705 4800

14 12 17 13

220 78 80 62

79 243

15

52 630

15

81 21 1 12 47

3203 154 112 1281 366 57 395 838

55 6 1 28 7 2 2 9 16

0 1

1146 81 200 153 4OO 285 27

9 25 9 7 18 6 8

64 8 39 4 0 4 10

2120 14 157 1057 4 131 757

66

842 374 468

12 11 13

10 4 6

956 165 475 316

4

1190

8762

10

85

7506

147

789

1613

15

24

2790

1 2 12 1

3 54 1 8

4

170 TABLE V Partitioning of slaughtered dairy cows, heifers, fattened bulls and veal calves

Breed2 Liveweight(kg) Carcassweight(kg) Non-carcassportion(kg) Consumable part 3 (kg) Hide (kg) Ingesta (kg) Offalto renderer (kg) For human consumption ( % of liveweight) For feed (% ofliveweight) Hide (% of liveweight) Waste (% ofliveweight)

Vealcalves

Dairy cows

Heifers

Fattened bulls

B~

T

T

T

Ti

D

D

T

T

T

B

D

F 550 285 265 12 39 100 114

? 501 260 241 48 29 117 47

Br 411 245 166 38 26 58 44

DB 376 217 159 40 31 50 38

CF 540 323 217 9 51 70 87

F 588 335 253 16 50 66 121

S 590 343 247 16 61 67 103

Br 450 261 189 43 38 81 27

HF 504 293 211 51 42 72 46

DB 487 281 205 44 34 85 42

F 200 132 68 6 12 18 33

F 152 90 62 5 13 14 30

54 21 7 18

61 9 7 23

89 11 6 14

68 10 9 13

61 17 9 13

60 21 8 11

61 18 10 11

68 6 8 18

68 9 9 14

67 9 6 18

69 16 6 9

62 20 9 9

~Source: B, BergstriJm (unpublished data, 1987 ); D, Daenicke (personal communication, 1987 ) ; Ti, Tilsch et al. (1986) ; T, Todorov (personal communication, 1987 ). 2Breed: Br,. Bulgarian red; HF, Holstein Friesian; DB, Cross of dairy and beef breeds; F, Friesian; S, Simmenthai; CF, Charollais and cross of Charollais and Friesian. 3The proportion of non-carcass portion consumed by humans differs in various regions of Europe. T A B L E VI P a r t i t i o n i n g of slaughtered sheep 1 Sheep Liveweight (kg) Carcass weight (kg) Non-carcass portion (kg) 2 Consumable p a r t (kg) Hide a n d wool (kg) Ingesta (kg) Offal to renderer p l a n t (kg) For h u m a n c o n s u m p t i o n (% of liveweight) For feed (% of liveweight) Hide a n d wool ( To of liveweight) Waste (To of liveweight)

45 23.6 21.4 4.6 3.4 6 6 62.7 13.3 7.6 16.4

1Source, G. Alderman, personal c o m m u n i c a t i o n (1987) based on data of the M e a t a n d Livestock Commission. 2About 1.4 kg is lost in t h e cooling process,

pigs and poultry in the ratios 0.2-0.25: 0.5-0.55: 0.2-0.25, respectively. Of those animals processed owing to premature death, pigs (mainly piglets) account for about 90% and cattle (mainly calves) for about 6% (den Braver, 1987,

171 T A B L E VII Partitioning of slaughtered pigs'

Piglets

Number of observations Liveweight (kg) Carcass weight (kg) Non-carcass portion (kg) Consumable part (kg) Bristles (kg) Ingesta (kg) Offal to renderer (kg) For h u m a n consumption ( % of liveweight) For feed ( % of liveweight) Bristles ( % of liveweight) Waste ( % of liveweight)

Fattened pigs

36 20 13.5 6.5 1.4 0.01 5.1 74.5 25.5 ---

Females

Barrows

105 88.9 69.3 19.6 5.8 0.1 5.0 8.7 84.5 9.8 -5.7

103 88.7 69.2 19.5 5.8 0.1 5.3 8.3 84.6 9.4 -6.0

1Source, Jorgensen et al. (1985).

TABLE VIII Partitioning of slaughtered poultry Hens

Liveweight (g) Percentage of liveweight for food Percentage of liveweight for feed (rendering industry) Including: Head3 Feet3 Feathers Blood Viscera Waste 5

Broilers

T'

U

1157

1745 1809 2410 3548 1736 1193 1591 1454 1000-1800

78

70

68

71

75

69

77

77

73

73

19

27

27

25

21

27

18

18

27

262

4.3 2.8 5.1 2.3 12.5 3

3.8 2.9 4.7 2.7 12.9 4

3.2 2.9 3.0 3.2 4.6 3.2 2.6 2.5 1 1 . 6 10.2 2 2

3

U

U

U

U

3.7 3.6 5.0 2.8 11.9 2

T

5

T

5

V

--5.1 3.8 17.44 --

U

3.6 5.1 5.7 3.8 7.8 3

iSource: T, Todorov (personal communication, 1987); Uyttenboogaart (1979, 1985); V, Vogt et al. (1986). 2Dependent of liveweight;per 100 g increase of liveweight 0.4% lessoffal. 3Used as food occasionally. 4Head and feet included. SLosses in the slaughtering process; often recovered from rinsing water. Food = human food; feed = animal feed.

172 Prematurely dead animals

Slaughterhouse offal tons

tons

DK

515000

DE

50000

NL

590000

NL

I01000

UK

1240000

UK

60000

[ Rendering industry = i00

I

.=

i Blended animal meal

I

I

F a t s and tallows

Others

Evaporated water

DK

28

DK

9

DK

5

DK

58

NL

20

NL

7

NL

3.5

NL

69.5

UK

23

UK

13

UK

I. 5

UK

62.5

Fig. 5. Input and output of the rendering industry in some countries. NL = The Netherlands; DK =Denmark; U K = U n i t e d Kingdom. Sources: F.C.A. den Braver (personal communication, 1987); A. Just (personal communication, 1987) ; P.D. Foxcroft (personal communication, 1987). TABLE IX Estimates of the production of animal by-products by rendering plants (thousand tonnes) 1 Meat and bone meal

Belgium Denmark France F.R.G. Ireland Italy The Netherlands Spain U.K. Sweden G.D.R. 2

100 110 495 390 60 350 140 250 400 45 15

Blood meal

4 7 12 0 6 4 6

Animal fat

Animal protein silage

100 55 200 160 150 48 100 250 15 2803

iSource, Foxcroft (personal communication, 1987). 2Source, Poppe et al. (1987). Meat and bone meal production has decreased from 35 000 tonnes while acid-preserved silagehas increased from 5000 tonnes since 1973. 3 D M 230 g kg- I.

173 personal communication ). In other countries, with different livestock proportions, the relative contribution of species to the raw material input to the rendering plants will, of course, differ. Estimates of the production of rendered animal by-products from a knowledge of the trade in different countries are given in Table IX.

Processing in the rendering industry Slaughterhouse offal, processing scraps and livestock casualties processed by the rendering industry give rise to a number of products. The main rawmaterial types are fat trim, bone and offal. The best quality fat trim may be separately processed by refining plants to produce lard, dripping and other edible-grade fat for human consumption and also for use in calf-milk replacers. Where possible, the better quality fat trim from shops and meat processors may also be processed separately within a rendering plant to give the highgrade, low colour, tallows demanded by the refining and soap industries. Some bones may also be processed separately to produce gelatine, bone glue and other products as well as bone meal and bone fat. These processes yield a small amount of high-protein meat meal which is used mainly in pet foods. The bulk of the offal, bone and poorer-quality fat trim are processed to yield meat and bone meal, and tallow. Wet rendering, in which the raw material was cooked under steam pressure at 110-130°C for 3-6 h then the mix allowed to settle before drawing off the fat, has largely been superseded by a dry-rendering process. This consists of pre-breaking or chopping the raw material, to assist heat penetration and the release of fat, then cooking on a batch or continuous basis, with initial temperatures of 100°C rising as the water evaporates to give a predominantly dry meal in an oil phase at about 125°C. This is followed by the separation of oil and meal by screw pressing and occasionally by solvent extraction, and finally by grinding and screening the finished meal. Pressure may be applied in the early stages to bring about partial hydrolysis, particularly of bone materials. In some countries the temperature and time of heating are decreed by law, to ensure sterilization. In other countries these variables are under the control of the processor and sterility is ensured by frequent bacteriological checks. Dangerous pathogens, such as Clostridia, Anthrax and Salmonella are destroyed completely. Salmonella, for example, is killed by heating above 82 °C for 20 min. Blood is collected at some abattoirs and dried to blood meal. Drying by prolonged heating in a vat results in considerable heat damage to the protein with loss of digestibility and protein quality. More modern processes of ring or flash drying yield material of good digestibility and with a high content of available lysine (Waibel et al., 1977; Batterham et al., 1986a). Typical proximate analysis and energy values for blood meal are given in Table I. The amino-acid content of blood-meal protein is shown in Table II.

174 Poultry by-product meal, consisting of the rendered parts of the carcass of slaughtered poultry, such as heads, feet, undeveloped eggs and intestines, but excluding feathers, may be separately produced. Feathers may also be processed under conditions of high pressure during the initial phase of cooking, which brings about partial hydrolysis of the keratin to yield a very high-protein product (Table I ) but with only moderate digestibility (in vitro pepsin digestibility of 68% ) and poor amino-acid balance (Table II). Increasing the pressure during cooking can increase digestibility further (in vitro digestibility of 80% ) but the meal will be overheated and of reduced protein quality. Although hydrolysed feather meal sold by trade must consist of nothing but processed feathers, m a n y large integrated poultry units will process feathers and other poultry by-products into a meal which is returned into feed used by the plant. There are no statistics as to the extent to which such material is recycled.

Meat and bone meal Although the raw material available to the rendering industry is variable, that originating from any one source tends to be fairly constant. Consequently, individual plants can achieve a good degree of consistency of product, while there can be distinct differences between products from different plants. This is illustrated in Table X, where the mean proximate constituents are given for 22 samples of meat and bone meal, collected over a period of 3 months from each of 6 Danish factories, together with the within-factory, the pooled withinfactory and the between-factory standard deviations (Just et al., 1982 ). Comparable results for 5 U.K. factories are included in a recent report on metabolizable energy ( M E ) value for ruminants of meat and bone meal (Wainman and Dewey, 1986). TABLE X Between- and within-plant standard deviations (SD) of meat and bone meals collectedover 3month period from 6 Danish factories (22 samples per plant) 1 Plant

DM(g kg-1) Mean SD XP (g kg-1DM) Mean SD ASH(g kg-1DM) Mean SD

A

B

C

D

E

F

930 15

912 10

912 10

946 12

929 6

904 10

10.8

73.1

538 12

538 24

544 26

528 22

566 36

567 20

24.4

75.4

328 14

339 14

333 27

296 30

269 26

302 22

23.0

126.3

1Data from Just et al. (1982).

Pooled within-plant SD

Between-plant SD

175 T y p i c a l p r o x i m a t e c o m p o s i t i o n a n d e n e r g y values for a r a n g e of t y p e s of m e a t a n d b o n e m e a l s are given in T a b l e I. A m i n o - a c i d c o n t e n t o f the c r u d e p r o t e i n is s h o w n in T a b l e II. I n c r e a s i n g ash c o n t e n t of t h e meal reflects t h e p r o p o r t i o n o f b o n e in t h e raw m a t e r i a l w h i c h influences t h e n a t u r e a n d digestibility o f t h e protein. C o n s e q u e n t l y , ash c o n t e n t is a good i n d i c a t o r of t h e a m i n o - a c i d c o m p o s i t i o n , a p p a r e n t digestibility of t h e p r o t e i n a n d of the e n e r g y value of m e a t a n d b o n e meals ( J u s t et al., 1982). T h e analysis of m e a t a n d b o n e meals with d i f f e r e n t a s h c o n t e n t is i n d i c a t e d in T a b l e XI. TABLE XI Analysis of meat and bone meals prepared with different proportions of bone 1 Chemical composition per kg DM Ash (g) XP (g) XL, acid hydrolysed (g) GE (MJ)

12 233 623 114 19.2

Amino-acid content of the protein (g per Lysine Methionine Cystine Threonine Mineral content per kg DM Calcium (g) Phosphorus (g) Magnesium (g) Sodium (g) Potassium (g) Manganese (mg) Copper (mg) Iron (mg) Zinc (mg) Selenium (mg) Apparent digestibility ratio for pigs XP XL, acid hydrolysis Energy

16 g-1 N) 5.2 1.4 1.0 3.4

63 34 1.9 13.8 6.0 21 15.1 842 117 0.4 0.81 0.81 0.78

2 277 573 114 18.0

3 322 538 120 16.9

4 372 494 101 15.5

5 429 473 83 13.7

5.0 1.4 0.9 3.3

4.8 1.3 0.8 3.1

4.7 1.2 0.8 3.0

4.4 1.1 1.0 2.9

81 42 2.2 13.8 5.3 23 12.1 873 118 0.4

102 50 2.5 14.0 4.6 19 10.0 781 116 0.3

123 60 2.7 13.1 4.1 16 8.7 597 115 0.2

148 73 3.0 11.2 3.2 11 8.3 433 116 0.2

0.80 0.72 0.73

Apparent digestible nutrient content for pigs per kg DM DE (MJ) 15.0 13.2 ME (MJ) 13.4 11.8 DXP (g) 505 458 Digestible lysine (g) 26.9 23.8 Digestible methionine (g) 7.0 6.3 Digestible cystine (g) 4.4 3.4 Digestible threonine (g) 17.1 15.1 1Data from Just et al. (1982). 2Lowest % of bone: Column 1. Highest % of bone: Column 5.

0.80 0.70 0.72 12.2 10.8 431 21.7 5.5 2.8 13.2

0.81 0.59 0.69 10.7 9.4 400 18.8 4.5 2.1 11.1

0.75 0.22 0.53 7.3 6.1 355 15.2 3.5 1.9 9.2

176

Prolonged heating of raw material during manufacture of meat and bone meals reduces the lysine content, the chemically-reactive lysine as determined with fluorodinitrobenzene (FDNB) or Acid Orange 12 dye binding, the digestible energy and the biologically-available lysine as measured by growth bioassays with pigs, chicks or rats (Batterham et al., 1986b). Continuing cooking at 125°C for 4 h compared with discharging from the cooker as soon as this temperature was reached, resulted in a 10% loss of total lysine, a 16% decrease in FDNB-available lysine and a 22% decrease in available lysine measured by rat and chick bioassays. Commercial meals produced in Australia by either batch or continuous dry-rendering processes varied in availability of the total lysine from 0.77 to 0.91 for FDNB-available lysine, from 0.48 to 0.88 for pigs, from 0.49 to 0.88 for rats and from 0.66 to 0.88 for chicks. These differences in availability were unrelated to ash content, suggesting heat damage as a major component of the variation in quality (Batterham et al., 1986a). Clearly, care needs to be taken to control the processing to prevent unnecessary loss of protein quality. Legislation which demands excessive cooking times and temperatures to ensure sterility needs re-examination to specify the conditions necessary to achieve both objectives of sterility and high-protein quality.

Animal fat and tallow Interest in animal fats as an ingredient in compound-feed production has grown considerably in the last decade (Lowe and Howells, 1985 ). The production potential of livestock has been rising continuously, requiring in consequence, a higher nutrient intake. However, in many cases, the feed-intake capacity of the animal is limited, and feeds with a higher energy and nutrient density are increasingly used to meet the higher nutrient requirements of highproducing livestock. Animal fats, with their high energy density, are well suited to raising the energy content of rations, including rations for dairy cattle. Plant oils are normally too expensive to include in animal feeds, although the acid oils, containing the free fatty acids removed during refining, are used as feed ingredients. Spent cooking oil from deep frying, both of animal and vegetable origin, is also available as animal feed, but polymerization of the oil seriously decreases its digestibility and energy value. Therefore, extra energy is usually achieved by the addition of animal fat or tallow in the range of 2-4%, but sometimes as high as 7-8% (Atkinson, 1985). Rendered fat which does not achieve certain standards of colour and of ability to refine and bleach that are required by the food and cosmetic industries is used in animal feeds. The Society of British Soap Makers specify 6 grades of tallow and one of grease. Grade 1 tallow is primarily used in the manufacture of margarine and frying fats. Grade 2-5 tallow is used in the cosmetic and chemical industry. Grade 6 tallow and grease are used in animal feed. The distinction between tallow and grease is primarily the temperature of resolid-

177 ification. The m i n i m u m temperature is 40 °C for tallow whereas grease solidifies between 36 and 40 ° C, reflecting a higher content of unsaturated fatty acids in the grease. Atkinson (1985) quotes four chemical and physical characteristics which are important for animal fats intended for use in animal feeding: stability; purity; free fatty-acid content (FFA) ; fatty-acid profile.

Stability. Oxidation and rancidity should be prevented by adding anti-oxidants such as butylated hydroxytoluene, butylated hydroxyanisole and ethoxyquin, resulting under normal storage conditions in stability of the fat for approximately 300 days. Although oxidative rancidity is characterised by production of free radicals and peroxides as intermediates in a chain reaction, the peroxide value is an unreliable parameter as low values may be obtained with both fresh material and those which have been oxidised with consequent loss of nutritive value. Oxidative stability may be determined by the active-oxygen method which determines the induction time before oxidation is initiated, but again this is not a reliable parameter.

Purity. Good quality animal fat (Grade 6 tallow) must contain less than 4% impurities, namely a maximum 1% moisture plus insoluble material and 2% unsaponifiable matter. Grease has a maximum 2% moisture plus insolubles and 2% unsaponifiables. Higher amounts of water encourage hydrolytic and oxidative rancidity and the presence of insoluble and unsaponifiable material simply dilutes the energy.

Free fatty-acid content (FFA). The hydrolysis of neutral fats, which are triglycerides, results in the production of free fatty acids. Although up to 50% of dietary fat can be as FFA without detriment to digestibility in monogastric animals, the presence of large amounts of FFA in rendered fat indicates poorquality raw material or delay in processing, resulting in microbial spoilage and hydrolysis of the raw material. A high FFA content causes corrosion of storage tanks and machinery. For these reasons, feed-grade fats with low FFA content (less than 15% ) are preferred although the maximum specification for grade 6 tallow and grease is 20% FFA.

Fatty-acidprofile. The proportions of saturated, monounsaturated and polyunsaturated fatty acids affect the melting point and hence the ease of emulsification of the fat in the stomach and digestibility in the small intestine. In addition, the content of essential fatty acids, principally linoleic acid (C 18: 2, n-6), is particularly important for poultry, both to achieve high growth rates in broilers and maximum egg size and hatchability in laying hens. For the ruminant a high melting-point saturated fat is required. Fats or oils rich in either medium-chain-length fatty acids (lauric, C 12: 0 and myristic, C 14: 0) or long-chain polyunsaturated fatty acids are toxic to the rumen microflora and depress digestibility of fibre. The ruminant is also better able to digest

178 TABLE XII Chemicaldata on feed-gradeanimal fat (FGAF) a Fat source

FGAF For all feeds For milk replacers All beef tallow All pig fat All poultry fat

C titre 2

34-38 38-41 38-42 32-38 28-35

MIU3 ( %)

2 1 1 2 2

Iodine value

55 45 40 58 65

Max

Fatty acids (%)

FFA4 (%)

Saturate

Monounsat.

Polyunsat. linoleic

15 5 5 15 15

44 50 56 36 28

46 46 42 52 52

10 4 2 12 20

'Source of data, National Renderers Association, 1985. N.B. Data are relevant to rendered fat produced in the U.S.A. The fatty-acid composition of pig and poultry fat, and of mixed FGAF derived from these species is greatlyaffectedby the fatty-acid compositionof the diet, principally the use of maize grain instead of wheat or barley. ~Solidificationtemperature. 3Moisture, insolublesand unsaponifiables. 4Free fatty acids. long-chain saturated fatty acids t h a n the monogastric animal. Consequently, high melting-point tallows are preferred for dairy compounds while low melting-point grease, poultry fat or blends of animal fat with plant oils or plant acid oils are required for poultry. Typical chemical characteristics of feed-grade animal fats are given in Table XII. FEEDS FROM THE FISH INDUSTRY

General The fishing industry provides a number of products for animal feeding. The annual world catch of fish is steadily increasing from 70 million tonnes in 1970 to 85 million tonnes in 1985. Current predictions of the future sustainable world fish catch are around 100 million tonnes. Approximately 80% of this catch is used directly for h u m a n consumption but processing activities such as canning and filleting provide by-product material which is processed into fish meal, fish liver oil and fish silage. During fishing for h u m a n consumption a proportion of u n w a n t e d species may be caught (bycatches) which can be separated and processed into fish meal and fish-body oil. Approximately 20% of the world catch is fished directly for conversion to fish meal and fish-body oil. These are mainly small pelagic species such as menhaden, capelin, sand-eel, sardine, anchoveta and pout which are, at present, unmarketable in large quantities as h u m a n food. Almost any fish or shellfish can be used to make fish meal

179

and other by-products. Of world fish-meal production, about 90% is produced from oily species such as the small pelagic species indicated above and less than 10% from white fish such as cod and haddock. Only about 1% of meal is produced from other sources such as krill and shellfish.

Availability offish meal in Europe While the total world production of fish meal has been increasing, the production in Europe, particularly the E.E.C. countries bordering on the North Sea, has declined. In 1975, production in Europe accounted for 39% of world production but by 1984 this had declined to 30% (Table XIII). The major producing countries are the U.S.S.R., Denmark, Norway and Iceland. The major consuming countries in Europe are the U.S.S.R., the U.K., the F.R.G., Sweden and Poland (Table XIII). Approximately 25% of fish-meal supplies in Europe are imported. At the beginning of the decade this rose to 40% when industrial fishing of herring from the North Sea was temporarily banned to control fish stocks. Increased production of other vegetable-protein sources in Europe has resulted in a decreased usage of fish meal in animal diets, particularly of pigs. This is reflected in the marked reduction of fish-meal usage in both the F.R.G. and the G.D.R. and in the U.K. The recognition of the value of a minimum inclusion of fish meal in diets for a wide range of livestock, both ruminant and non-ruminant, has resulted in the maintenance or slight increase in usage by a number of other countries.

Types of fish products Products from large white fish The large white fish store their energy as oil in the liver. Cod and halibut liver are removed at filleting and processed to extract the liver oil which is a rich source of Vitamins A and D, widely used as a supplement for humans and in animal diets. The heads, intestines and frames remaining after filleting white fish are cooked to coagulate the protein, dried and ground to produce white fish meal. As the raw material is low in oil, no attempt is usually made to press or extract oil, and the end product contains only 3-6% ether extract. There is no longer a requirement to market white fish meal with less than 6% oil. Each consignment of fish meal must be labelled with the oil (determined after prior acid hydrolysis ), protein and ash content. If filleting waste is mixed with bycatch oily fish, the oil content of the resultant meal may exceed 6%. In addi~ tion, recent legislation requires use of acid hydrolysis, which releases phospholipids, prior to ether extraction such that the oil content of the meal is apparently increased 2% units above that determined by petroleum or diethyl-ether extraction.

560 1826 4682

Total E.E.C. Total Europe Total World

521 1650 4975

3 318 21 20 41 0 2 6 0 10 36 64 0 0 194 319 10 0 0 7 0 0 0 66 10 523 526 1605 5221

2 327 20 17 37 0 2 7 0 23 35 57 0 0 89 310 12 0 0 8 0 0 0 62 12 586 508 1720 6195

2 303 26 20 35 0 1 4 0 25 40 54 0 0 174 263 12 0 0 8 0 0 0 80 12 666 461 655 227

29 -281 -27 44 281 5 10 83 49 21 16 231 36 48 - 120 -401 64 89 66 9 47 155 50 118 50 -17 365 614 137

18 -262 -21 40 222 2 11 86 41 10 6 213 36 76 - 189 -295 91 96 81 24 44 83 42 132 49 -21

1978-80

232 551 - 3

9 -258 -20 44 150 17 8 55 40 3 4 181 30 93 - 81 -259 107 95 97 38 54 40 56 19 41 -11

1981-83

303 576 - 185

9 -222 -26 52 136 21 8 52 55 3 13 203 31 88 - 150 -211 118 77 90 21 50 34 83 26 28 -9

1984-85

1Source, I n t e r n a t i o n a l Association of Fish Meal M a n u f a c t u r e r s (personal c o m m u n i c a t i o n , 1987 ).

3 332 27 19 53 0 3 1 0 10 34 77 0 0 127 422 13 0 0 10 0 0 0 61 8 625

Belgium Denmark Faeroe Islands France F.R.G. Greece Ireland Italy The Netherlands Portugal Spain U.K. Austria Finland Iceland Norway Sweden Switzerland Yugoslavia Bulgaria Czechoslovakia G.D.R. Hungary Poland Romania U.S.S.R.

1984-85

1975-77

1981-83

1975-77

1978-80

I m p o r t s - exports

Fish meal production

1021 2481 4909

33 51 0 63 334 5 13 84 49 31 50 308 36 48 7 21 78 89 66 19 47 155 50 178 58 608

1975-77

886 2264 5112

21 55 0 60 262 2 13 92 41 20 42 277 36 76 6 24 101 96 81 30 44 83 42 199 59 502

1978-80

1984-85 11 81 0 71 171 21 9 56 55 27 53 257 31 88 24 52 130 77 90 29 50 34 83 106 39 657 810 2295 6010

1981-83 11 68 0 61 187 17 10 62 40 26 39 238 30 93 8 51 119 95 97 46 54 40 56 81 52 576 758 2156 5218

Fish meal supplies for c o n s u m p t i o n a n d stocks

Fish-meal production, balance of imports a n d exports a n d supplies for c o n s u m p t i o n a n d stocks in Europe (1000 t o n n e s ) 1

TABLE XIII

O

181

Products from oily fish species The oily species store their energy as oil in the body muscles and around the internal organs. The fish are cut into pieces, cooked to coagulate the protein and to release the oil, then pressed to remove as much as possible of the oil and water. The latter is centrifuged to separate the oil, the resultant stickwater is concentrated by evaporation to about 50% dry matter and the concentrated solubles are usually added back to the pressed cake before the drying stage. Occasionally, the condensed fish solubles are sold separately, primarily as a source of unidentified growth factors (UGF), but also as a useful source of protein, amino acids, energy, minerals and vitamins. Pressing does not remove all the oil and the resultant meal contains approximately 9% ether extract or 11% oil, after prior acid hydrolysis. Antioxidant (ethoxyquin) is usually added to such meals, either before or immediately after the final drying stage, to stabilize the residual fat against oxidation. The production of fish meal and oil has been described in detail (F.A.O., 1986).

Specific products Fish meals The bulk of fish meal is fed to poultry and pigs. Continued research into the nutritional requirements of livestock has identified the need for specially-produced fish meals. Meals high in rumen undegradable protein (see paragraph on modern systems for protein evaluation of feeds and protein requirements of ruminants on Page 235 {Chapter III.2, van der Honing and Alderman, 1988) are produced specifically for feeding to ruminants. These need to be low in soluble protein and without an excessive oil content. In contrast, trout and salmon require easily-digested protein and oil rich in specific fatty acids, which are found only in plankton and fish, as their main source of energy. Speciality meals for inclusion in calf-milk replacers, for feeding mink and for early-weaned pigs are also produced (Opstvedt et al., 1978; Pike, 1987).

Fish oil Fish-body oil is primarily used as a raw material for conversion to margarine and edible fats. During this process any free fatty acids present in the crude fish oil, produced during autolysis of the raw fish between catching and processing, are removed and the resultant fish-acid oil is available as an animal feed. It is usually blended with other oils, vegetable-acid oils and animal tallow or grease prior to sale under brand names.

Fish silage An alternative process is to convert surplus fish or filleting waste into fish silage. As this process has a low capital requirement it is suitable where only small amounts of surplus fish or waste are available. Whole fish or fish offal is

182 minced and mixed with mineral (sulphuric) or organic (formic) acid to reduce the pH to 2 or 4, respectively. Enzymes released from the fish bring about autolysis within 2 days at 20 ° C. The added acid gives stability and prevents microbial putrefaction. Where oily fish are used, the oil can be separated by centrifugation after liquefaction. The liquid product may be fed to pigs, particularly where liquid feeding systems are used. It may also be used as part of a milk-replacer for calves and lambs. The low DM content makes it costly to transport over large distances and, therefore, its use is likely to be limited to the immediate locality of production. Present production is small, principally in Denmark, where it is used in pig feeding. In a further commercial development of the fish silage process, white fish are hydrolysed by adding proteolytic enzymes and the resultant hydrolysate is spray-dried. The resultant product is claimed to be highly digestible and particularly suited for use in milk-replacers, in diets for the early weaning of pigs and in diets for rearing trout and salmon fry (S~ve et al., 1978).

Specific features offish meal Energy content The energy content of fish meal depends upon the protein and oil content. Calculated values of metabolizable (ME) and digestible energy (DE) for poultry and pigs, respectively, corresponding to the typical analysis of 3 main types of meal, are given in Table I. Recent determinations of the ME for ruminants of typical representative meals are also given in Table I. For poultry, the calculated ME is based on the determined average ME, adjusted to zero nitrogen retention, of a number of fish meals together with the determined ME value of fish protein and fish oil (ether extract). For offal meals and South Americantype meals the mean determined value for 10 meals with average protein content of 62.6% and average oil content of 9.8% was 12.97 MJ kg- 1 ( Cuppett and Soares, 1972 ). For herring-type meals the mean determined value for 40 meals with average oil content of 7.7% and average protein content of 71.4% was 13.60 MJ kg- 1 (Opstvedt, 1976 ). The determined ME of fish ether extract and fish protein were 27.00 MJ kg-1 and 16.52 MJ kg-1, respectively, (Opstvedt, 1973). Using these values the formulae for calculating the ME, corrected to zero nitrogen retention, of a meal of given ether extract and protein content are: ME ( M J k g -1) =12.97+0.27 ( 9 . 8 - E ) + 0 . 1 6 5 2 ( 6 2 . 6 - P ) for white fish meals and South American-type meals and

ME (MJ kg -1) =13.60+0.27 ( 7 . 7 - E ) + 0 . 1 6 5 2 ( 7 1 . 4 - P ) for herring-type meals, where E and P are the ether extract ( % ) and protein ( % ), respectively.

183 Similarly, the DE for pigs can be calculated using the regression equation: DE(MJ/kg) =3.06+0.306E+0.17P where E and P are the ether extract % and protein % respectively. The regression equation was determined from the direct measurement of DE for pigs of 12 fish meals representing the main types currently in world trade. Protein value The amino-acid composition of fish muscle protein (expressed as g per 16 g N) is constant from one species to another (Table II). In comparison with meals made from whole fish, fish-offal meals contain more protein from head, skin, bone and intestines. The higher collagen content is reflected in a slightly lower content of lysine and of sulphur-containing amino acids (Table II). Nevertheless, fish meals of all types are very rich sources of lysine and the sulphur-containing amino acids which are usually the limiting ones in mixed diets. The protein content of fish meals varies owing to seasonal variations in proportion of protein, oil and bone in the fish and to processing conditions. As each consignment is traded on a determined protein content, it is recommended that the corresponding amino-acid content of the meal be calculated from the product of the known protein content and the amino-acid composition of the protein given in Table II. As explained in the paragraph on protein on Page 235 (van der Honing and Alderman, 1988), not all the protein or amino acid of a feedstuff is digested or absorbed. The best estimate of the amount absorbed is obtained by determining the true digestibility at the terminal ileum. Dierick et al. (1987) have shown that using ileal digestibility values gave a better prediction of determined growth rate and feed conversion in pigs than faecal-digestibility values. Too few determinations of ileal digestibility of feeds have been made so far to indicate either the average values or the variability within a feed type. The determinations that have been made indicate that the apparent ileal digestibility of lysine for the pig is in the range of 80-90% for fish meals (Buraczewska et al., 1979; Jorgensen et al., 1984; Partridge et al., 1987) and considerably greater than values of 58-81% recorded for vegetable-protein concentrates and cereals. Part of the improved performance obtained when fish meals are included in animal diets may be explained by this better digestion in the small intestine. The use of total amino-acid content, digestible crude-protein content (DCP) or even digestible amino acids determined by analysis of the faeces, underestimates the relative value of fish meal compared to vegetable-protein concentrates. Entirely different criteria of protein quality are required where fish meal is to be fed to ruminants ( see the paragraph on digestion and absorption of proteins in ruminants on Page 236). As indicated in Table XIII in Chapter III.2 on Page 241 (van der Honing and Alderman, 1988) fish meal generally has a

184 low degradability of its protein in the rumen. About 60-70% of fish-meal protein passes through the rumen undegraded but it is still very well digested in the small intestine, where its high sulphur amino-acid content complements the digested bacterial protein which is known to be low in these amino acids. Special fish meals for ruminant feeding, with a high content of undegradable protein ( U D P ) , can be prepared by using fresh raw material to limit the extent of autolysis and amount of stickwater produced (Mehrez et al., 1980), and by varying the amount of stickwater added back into the meal. Consequently, a simple measure of the water-soluble nitrogen content of fish meals is a good indicator of the degradability and conversely of the U D P content (Opstvedt, 1984a).

Fatty-acid composition The origin, composition and nutritional value of fish oil and of lipids in fish meal were extensively reviewed by Opstvedt (1984b). The content of the nutritionally-important fatty acids in separated fish oil and residual lipids in fish meal is shown in Table XIV. The composition of oil and residual lipids in the meal are broadly similar b u t whereas the former are triglycerides the latter contains 20-40% of phospholipid. The lower the oil content of the meal, the greater the proportion of phospholipids which is reflected in a greater proportion of polyunsaturated fatty acids ( P U F A ) . M o s t of the P U F A in fish oil and fish meal are of the n-3 family. These are derived by chain elongation and desaturation of the parent fatty acid, linolenic acid (18:3 n-3), found predominantly in green tissue including plankton. Small crustacea, feeding on plankton, chain elongate and desaturate linolenic acid to produce a 20-carbon fatty TABLE XIV Nutritionally-important fatty acids in fish oil and residual lipids of fish meals ( % w/w) a Fatty acid

14:0 16:0 18:0 16:1 18" 1 20:1 22:1 20:5 n-3 22:6 n-3 Total n-6 Total n-3

White fish meal 3.2 11.1 1.7 6.8 16.9 9.7 9.1 12.0 19.2 3.4 35.5

aData from Opstvedt.

South American-type

Herring-type

oil

meal

oil

meal

7.5 17.5 4.0 9.0 11.6 1.6 1.2 17.0 8.8 2.1 33.7

6.3 19.9 4.8 7.3 11.4 3.0 1.8 14.6 17.4 4.1 34.3

6.1 10.8 1.4 7.3 10.3 13.4 21.3 7.5 6.8 1.3 21.4

4.9 14.8 2.1 5.8 14.4 10.9 11.9 10.1 15.4 3.5 27.1

185

acid with 5 double bonds, eicosapentaenoic acid. Fish at the top of the food chain are unable to synthesize this fatty acid, and normally obtain and accumulate it by consumption of smaller fish or crustacea. For farmed fish, these long-chain, polyunsaturated fatty acids of the n-3 series are essential nutrients best supplied by fish meal and fish oil. For mammals, the main essential fatty acids are linoleic acid (18:2 n-6), which is primarily found in seeds, and its chain-elongation products of the n-6 series, but smaller amounts of the n-3 fatty acids are also accumulated in the brain, eye and testis. The relative iraportance of the n-3 fatty acids compared with those of the n-6 series has long been a matter of debate. By comparison with response to maize oil as a source of n-6 essential fatty-acid activity in growth and egg production in poultry, the essential fatty-acid content (linoleic equivalent) of fish lipids has been suggested as 50% (Barlow and Windsor, 1983). The high content of polyethylenic acids makes fish oil and fish meal subject to oxidation. Treatment with antioxidant maintains the content of these fatty acids, maintains digestibility and energy value and enhances the transfer of these fatty acids into body lipids. One disadvantage is the increased risk of oxidative rancidity, or fishy off flavour developing in meat products either during prolonged storage or during cooking. For this reason the use of fish oil and fish meal with a high oil content must be carefully controlled, particularly in the later periods of growth of mammals and poultry. Mineral content

The average content of essential minerals and trace elements is given in Table XV. In general, the higher the ash content of fish meal the greater the content of calcium, phosphorus and to a lesser extent magnesium, which are predominantly part of the bone structure. In cereals and vegetable-protein concentrates phytic-acid phosphorus is poorly absorbed and by binding with other elements reduces the availability of calcium, zinc and iron. In contrast, the major minerals in fish meal and also those of meat and bone meals, are available as inorganic standards. Fish meals are an important source of selenium. Furthermore, the selenium in fish meal is of greater availability than that in vegetable-protein sources (Gabrielsen and Opstvedt, 1980 ). Vitamin content

The vitamin content of fish meals is given in Table XVI. Of particular importance are B12, biotin and choline, which although available in vitamin premixes are relatively expensive components. Addition of B12 and selenium to all vegetable diets largely, but not completely, accounts for the unidentified growth factors response attributed to fish meal (Potter et al., 1980). Poultry diets are routinely supplemented with choline without regard to the contribution from natural feedstuffs, largely because reliable analytical data are not available. Fish meal is one of the best feed sources of choline and extensive

186 TABLE XV Mineral content of typical fish mealsa White fish meal Calcium ( % ) Phosphorus (%) (total) Phosphorus (%) (available) Sodium ( % ) Chloride ( % ) Magnesium ( % ) Potassium ( % ) Selenium (mg kg -1) Iron (rag kg- 1) Copper (mg kg -~) Zinc (mg kg- ~) Manganese (mg kg- 1)

Herring-type fish meals

South American-type fish meals

8

2

4

4.80

1.90

2.60

4.80 1.30 2 0.15 0.90 1.50 300 7 100 10

1.90 0.70 1.03 0.11 1.20 2.20 150 5 120 2

2.60 0.87 1.82 0.25 0.70 1.40 246 11 111 10

aData from F.A.O. (1986). TABLE XVI Vitamin content of typical fish mealsa

Choline (mg kg- 1) Pantothenic acid (mg kg -1) Riboflavin (rag kg -1) Nicotinic acid (rag kg - ' ) Folic acid (mg k g - ' ) B 12 ( m g k g - ' ) Biotin (mg kg -~) Pyridoxine (rag kg- 1) Essential fatty acids ( % )

White fish meal

Herring-type fish meals

South American-type fish meals

4400 15 6.50 50 0.50 0.07 0.08 3.30 2.30

4400 30.60 7.30 126 0.50 0.25 0.42 3.70 4.50

4400 9.30 6.60 95 0.16 0.18 0.26 3.50 4.5O

aData from F.A.O. (1986). a n a l y s e s of fish m e a l s o f v a r i o u s origins are p r o v i d e d b y B a r l o w et al. (1979). T h e o p p o r t u n i t y n o w e x i s t s to r e d u c e t h e s y n t h e t i c choline a d d e d in v i t a m i n p r e m i x e s . W h o l e fish m e a l s h a v e a good c o n t e n t o f b i o t i n b u t it a p p e a r s to h a v e o n l y m o d e r a t e a v a i l a b i l i t y in a c h i c k b i o a s s a y , a s i t u a t i o n c o m m o n to m a n y o t h e r v e g e t a b l e - p r o t e i n c o n c e n t r a t e s . I n c o n t r a s t , t h e a v a i l a b i l i t y o f biot i n in m e a t a n d b o n e m e a l a n d s o y a - b e a n m e a l a p p e a r s to be high ( A n d e r s o n a n d W a r n i c k , 1970; W h i t e h e a d et al., 1982; Frigg, 1984).

187 USE OF ANIMAL BY-PRODUCTS IN ANIMAL DIETS

By-products of the rendering industry Suggested minimum and maximum inclusion rates of animal by-products in animal diets are given in Tables XVII and XVIII. Practical inclusion rates depend upon relative prices of feedstuffs. Animal by-products are price comTABLE XVII Indicative maximum rates of inclusion (%) of by-products of the rendering industry, based on data of trade experience Diet

Meat and bone meal

Feather meal

Poultry Chick Grower Layer Breeder Broiler starter Broiler finisher Turkey starter Turkey grower Turkey finisher Duck starter Duck finisher

2.5-5 5 6 5 3-6 5-6 3 5 5 5 5

2 2 2 2 1 2 2 2 2 2 2

Pig Weaner, 3 week-20 kg Grower, 20-50 kg Finisher, > 50 kg Sows

0-5 2.5-5 4-5 4-5

Ruminant compounds Calf Dairy Beef Sheep, goat

0 2.5-5 5 5

Fish Salmon, trout Carp

15 18

Blood meal

Poultry by-product meal

2 2 2 2 1 2 2 2 2 2 2

2-2.5 2-5 5 0 2-2.5 4-7.5 0 5 5 2 4-5

0 0-1 0-2 0-2

0 0 2.5 2.5

0 0-2.5 0-2.5 0-2.5

0 2.5-5 2.5-5 2.5-5

0 2.5 2.5 2.5

0 2.5-5 2.5-5 0-5

2 2

15 18-20

5 5

N.B. Tallow may be included in poultry diets at up to 4-6% and in dairy compounds at up to 2-3%; more usually fat blends are used in which tallow may be a component depending on price. Economic constraints and physical ability to include tallow usually limit inclusion of tallow.

188 TABLE XVIII Minimum and maximum recommended levels of fish-meal inclusion 1 Diet

Minimum inclusion 2 (%)

Maximum inclusion ( % ) 2 Low-fat fish meal (<6%)

Medium-fat fish meal (7-10%)

High-fat fish meal (>10%)

In poultry diets 3 Broiler starter 4 15 10 8 Broiler grower 4 15 8 6 Broiler finisher 2 15 8 6 Turkey starter 6 15 12 9 Turkey grower 4 15 10 7 Turkey finisher 1 8 5 3 Hen layer 2 15 15 15 Hen breeder 4 15 15 15 In pig diets 4 Weaner (3 weeks, 20 kg) 5 No limit 12 12 Grower (20-50 kg) 2 12 8 5 Finisher ( > 50 kg) 1 10 4 3 Breeding and lactating 4 No limit 12 12 In fish diets (%) 30 60 60 60 In cattle dietss,particularly those based on grass silage (g head-' day- ') Young growing cattle 200 250 250 250 Store and finishing cattle gaining 200 250 250 250 < 0.7 kg d a y - 1 High yielding dairy cows 500 750 750 750 In sheep diets 6 based on cereals or roots or grass silage or alkali-treated straw (g head- ' day- ' ) Growing lambs 50 100 100 100 Late pregnancy 50 150 150 150 Lactating ewes, 120 390 390 first 6 weeks 1Fish meal need not be included but economic responses have been obtained, when suggested minimum inclusion levels have been used under certain circumstances. 2Maximum inclusion levels indicate levels above which problems of unacceptable taint or flavour in meat and milk are certain to exist. Practical inclusion rates in most European countries are much lower. ~Data adapted from Barlow and Windsor (1983). 4Data from Pike (1987). 5Data from Miller and Pike (1985; 1987). 6Data from Orskov (1982); Marchment and Miller (1983, 1984); Gonzalez et al. (1984); Yilala and Bryant (1985) ; Hassan and Bryant (1986a, b, c) ; Robinson (1987).

petitive where animal production rates are greatest and the nutrient density r e q u i r e d is c o r r e s p o n d i n g l y h i g h a s i n s t a r t e r d i e t s f o r p o u l t r y a n d p i g s . A n i m a l products are also used where the digestive system of the animal requires highly-

189

digestible feed or is not well adapted to deal with vegetable cell wall structures, as in the pre-ruminant calf, mink and fish. The low allergenicity of milk byproducts and fish meal compared with vegetable products such as soya is further reason for their inclusion in diets for early-weaned pigs (Newby et al., 1984). Reduced palatability and constraints on calcium and phosphorus content limit the inclusion of meat and bone meal in diets. Poor digestibility and aminoacid balance restrict the inclusion of hydrolysed feather meal. The dark colour and restricted market supplies of blood meal limit its inclusion rate. The inclusion of animal fat or of fat blends in poultry diets is limited primarily by the physical effect on pellet quality. For ruminants, the adverse effect of low melting-point fats on rumen fermentation limits inclusion.

By-products from the fish meal and oil industry Minimum inclusion rates are used to force fish meal into least-cost diets where the additional cost of so doing is more than offset by an improvement in feed conversion beyond that expected on the basis of the current nutrient analyses of feeds. This applies particularly to diets for poultry (Pike, 1975) and for high-yielding ruminants (Miller and Pike, 1985, 1987 ). The high content of UDP with a good amino-acid balance in fish meals make them valuable supplements in ruminant diets, especially at times of peak need and when the basal-energy ingredients supply little UDP. Maximum constraints for fish meal relate to problems of taint in the meat of monogastrics if the fish-oil content of the diet exceeds 0.4-1.0% depending on animal species, stage of growth, degree of polyunsaturation of the fish oil and amount of other dietary fats or oils. Care needs to be taken to ensure that fish-acid oil is not included in a fat blend to be fed in a diet where the maximum amount of fish meal is used, otherwise the limit on fish oil will be exceeded and the risk of taint greatly increased. There are differences between populations in perception of what is a desirable or an undesirable flavour. For this reason, the suggested maxima in Table XVIII are guidelines only, which may be varied according to local preferences. Recent evidence of the benefits of including n-3 fatty acids in the human diet to modulate eicosanoid metabolism with consequent effects upon blood clotting, blood pressure, cardiovascular and auto-immune diseases (Lands, 1986) may result in a fishy flavour being more acceptable and consumption of pigs and poultry fed on fish meal or with added fish oil as being one method of enhancing intake of these n-3 fatty acids in a palatable form. For lactating cows, the daily intake of fish oil should be less than 100 g, otherwise the fat content of the milk is depressed. Maximum levels for cattle and sheep reflect amounts shown to give production responses when given as the main source of supplementary UDP. Practical amounts will depend on availability and relative cost of alternative sources of UDP.

190

Laboratory tests of protein quality in animal by-products Protein quality may easily be adversely affected by the processing of animal by-products. Laboratory methods to assess protein quality in these by-products are therefore very important. These methods include determination of pepsin digestibility (A.O.A.C., 1975), dilute pepsin digestibility (Olley and Pirie, 1966 ), rate of digestion by multi-enzymes ( Pedersen and Eggum, 1983 ), FDNB-reactive lysine (Roach et al., 1967; Carpenter and Booth, 1973) and dye-binding lysine (Hurrell et al., 1979). The use and limitations of some of these methods as applied to animal by-products have been discussed by Carpenter and Booth (1973), Waibel et al. (1977), Barlow et al. (1984), Opstvedt (1984a) and Batterham et al. (1986a, b ). It should be noted that the A.O.A.C. pepsin-digestibility method uses 100 times as much pepsin as the dilute method. Consequently it does not discriminate adequately between samples of moderate to good quality. DEVELOPMENTS AND FUTURE PRODUCTS FROM BY-PRODUCTS OF THE ANIMAL INDUSTRY

Feed potential of animal excreta Increased livestock production and increased intensification of production has given rise to difficulty in achieving satisfactory and economic disposal of manure without causing environmental pollution. For example, legislation is to be introduced in Holland from 1988 restricting the amount of waste, measured in terms of phosphate content, applied to land, so as to control pollution of water supplies. As a consequence, extensive research has been carried out to determine whether processed animal manures might have potential as an animal feed. The results, so far, have shown that artificially-dried poultry manure is useful as a nitrogen and phosphorus supplement for ruminant diets. The high uric acid content is a better source of non-protein nitrogen than synthetic TABLE XIX Chemical composition and feeding value of wastes from livestock

Manure, cow Manure, pig Manure, poultry Rumencontents

DM kg -1

XP (gkg -1 DM)

XL (gkg -~ DM)

XF (gkg -1 DM)

Digestibility of OM (%)

161 230 225 110

186 200 350 164

50 60 25 25

238 200 125 301

c. 25 c. 50 60-70 35-45

Steg (1979) Fontenot (1983) Steg (1979) Steg (1976)

191

urea, as it degrades more slowly and provides the rumen micro-organisms with a steadier supply of ammonia. Manure from caged birds is better than that from birds housed in deep-litter systems, where indigestible litter reduces the energy value of the resultant dried feed. Up to 20-30% of dried poultry manure has been successfully included in compound feeds fed to dairy cows, beef cattle and sheep (A.D.A.S., 1975; de Boer, 1980) and up to 25% in complete diets for intensively-reared beef cattle (Oliphant, 1974; Tagari, 1976). Problems of control of toxic contaminants from the use of chemically-treated wood shavings as litter and from medication of the poultry feed exist. Moreover, fear of causing a consumer aversion to meat from animals fed in this way has prevented any acceptance of dried poultry manure as an animal feed. Table XIX shows some data on the chemical composition and feeding value of various wastes arising from livestock husbandry on farms. More detailed analyses on dried poultry manure are given in A.D.A.S. (1975).

Potential products from the dairy industry The dairy industry has already developed a range of new methods, ultrafiltration, microfiltration, ion-exchange chromatography and electrophoresis, for the separation of principally the casein and whey protein fractions to provide a new range of products for the food, dietetic and pharmacological industries ( Maubois, 1986). The production of so called zero-milk replacers for calves, based on isolated whey proteins with some vegetable proteins, is already established. Immunoglobulins can be separated from whey and used as a substitute for, or to enhance the protective effects of colostrum. While the new processes will be engineered to produce high-value products, undoubtedly new by-product materials will become available to the animal-feed industry. For example, separation of whey proteins by ultrafiltration produces a residual permeate consisting primarily of lactose and minerals. Development of economic methods for using the permeate in animal feed will markedly affect the economics of preparation of the isolated whey products. However, in the E.E.C. area, current legislation needs to be modified in order to allow the economic use of the new by-products in animal feeds and thereby facilitate the development of novel dairy products for human consumption.

Potential products from the rendering industry Although there are advantages in producing high-energy diets, there are physical constraints on the amount of liquid fat that can be included in diets without reducing pellet quality. Dry-fat powders have advantages in ease of handling and facilitating higher fat-incorporation levels in pelleted diets. New processes, in which protein and fat are emulsified together prior to drying, produce dry fat supplements with good pelleting characteristics. Blood or meat

192

scraps can provide a suitable source of protein and animal scraps tallow as the fat source. Improved meat and bone meals can be manufactured by better control of processing temperatures to avoid protein damage and the use of enzymes to bring about partial hydrolysis of the more indigestible proteins. Special products suitable for the expanding fish-farming market are likely to be developed. Techniques for the extraction of immunoglobulins from pig blood obtained from the slaughterhouse have been developed. Initial trials show the product can be fed to piglets and reduce mortality. Heated blood is known to be resistant to microbial degradation in the rumen. Use has been made of this property to coat other proteins, amino acids and fats in an attempt to protect these nutrients from degradation in the rumen.

Potential products from the fish meal and oil industry Reference has already been made to a range of special-product fish meals which have recently appeared on the market (Pike, 1987). Their importance is likely to increase. Already, in 1986 they accounted for 45% of Norwegian fish meal production (S.S.F., 1987). Continuing research is expected to lead to further refinement of products specifically tailored for culture of prawns and salmon fry, for rearing salmon smolts, early weaned pigs and mink, for inclusion in milk-replacers and for feeding to ruminants (Gulbrandsen, 1986). In addition, every effort is being made to increase the production of food-grade products. These developments are expected to lead to reduced availability of the normal fish meal for feeding to pigs and poultry.

REFERENCES A.O.A.C., 1975. Pepsin digestibility of animal protein feeds - - official final action. Official Methods of Analysis, 12th edn. Association of Official Analytical Chemists, Washington, DC, pp. 133-135. A.D.A.S., 1975. Dried poultry manure as a feedingstuff. Agricultural Development and Advisory Service, Short Term Leaflet 175. Ministry of Agriculture, Fisheries and Food, London, 5 pp. Anderson, J.O. and Warnick, R.E., 1970. Studies of the need for supplemental biotin in chick rations. Poult. Sci., 49: 569-578. Atkinson, R.E., 1985. Feed Grade Animal Fats (FGAF) in Feeds. In: R.E. Atkinson (Editor), Feed Grade Animal Fats (FGAF) in Feeds. The National Renderers Association in cooperation with the U.S. Dept. Agric., Des Plaines, IL, pp. 1-16. Barlow, S.M. and Windsor, M.L., 1983. Fishery by-products. In: Handbook of Nutritional Supplements, Vol II, pp. 253-272. Barlow, S.M., Pike, I.H. and Nixon, F., 1979. Choline content of fish meals from various origins. J. Sci. Food Agric., 30: 89-92. Barlow, S.M., Collier, G.S., Juritz, J.M., Burt, J.M., Opstvedt, J. and Miller, E.L., 1984. Chemical and biological assay procedures for lysine in fish meals. J. Sci. Food Agric., 35: 154-164. Batterham, E.S., Lowe, R.F., Darnell, R.E. and Major, E.J., 1986a. Availability of lysine in meat

193 meal, meat and bone meal and blood meal as determined by the slope-ratio assay with growing pigs, rats and chicks and by chemical techniques. Br. J. Nutr., 55: 427-440. Batterham, E.S., Darnell, R.E., Herbert, L.S. and Major, E.J., 1986b. Effect of pressure and temperature on the availability of lysine in meat and bone meal as determined by slope-ratio assays with growing pigs, rats and chicks and by chemical techniques. Br. J. Nutr., 55: 441-453. Boucqu~, Ch.V. and Fiems, L.O., 1988. Feedstuffs. 4. Vegetable by-products of agro-industrial origin. Livest. Prod. Sci., 19: 97-135. Buraczewska, L., Lachowicz, J. and Zebrowska, T., 1979. Kryl antarktyczny, przetworstwo i wykorzystanie. Stud. Mater., Ser. S, No. 1,146-153. Carpenter, K.J. and Booth, V.M., 1973. Damage to lysine in food processing: its measurement and its significance. Nutr. Abstr. Rev., 43: 423-451. Cuppett, S.L. and Soares, J.H., 1972. The metabolizable energy values and digestibilities of menhaden fish meal, fish solubles, and fish oils. Poult. Sci., 51: 2078-2083. De Boer, F., 1980. Dried poultry manure (DPM) in Dutch ruminant feeding. In: Livestock Waste: A Renewable Resource. 4th International Symposium on Livestock Wastes. Amarillo, U.S.A. A.S.A.E., St. Joseph, Michigan, pp. 22-26, 30. Dierick, N.A., Vervaeke, I.J., Decuypere, J.A., van de Heyde H. and Henderickx, H.K., 1987. Correlation of ileal and fecal digested protein and organic matter to production performances in growing pigs. Proc. 5th Int. Symp. on Protein Metabolism and Nutrition, Rostock (in press). Digest of Feed Facts and Figures, 1987/88 edn. HGM Publications, Baslow, U.K., 30 pp. F.A.O., 1985. Production Yearbook, Vol. 39. Food and Agricultural Organisation, Rome. 330 pp. F.A.O., 1986. The production of Fish Meal and Oil. Fisheries Technical Paper, 142, Food and Agricultural Organisation, Rome, 63 pp. Fontenot, J.P., 1983. Utilisation of animal wastes by feeding: special emphasis on United States of America. In: E.H. Ketelaars and S. Boer Iwema (Editors), Animals as Waste Converters. Pudoc, Wageningen, pp. 12-22. Frigg, M., 1984. Available biotin content of various feed ingredients. Poult. Sci., 63: 750-753. Gabrielsen, B.O. and Opstvedt, J., 1980. Availability of selenium in fish meal in comparison with soybean meal, corn gluten meal and selenomethionine relative to selenium in sodium selenite for restoring glutathione peroxidase activity in selenium-depleted chicks. J. Nutr., 110: 1096-1100. Gonzalez, J.S., Robinson, J.J. and McHattie, I., 1984. The effect of level of feeding on the response of lactating ewes to dietary supplements of fish meal. Anim. Prod., 40: 39-45. Gulbrandsen, K.E., 1986. Special qualities offish meal in feed for mink and fish. Proceedings 26th Annual I.A.F.M.M. Conference. International Association of Fish Meal Manufacturers, Potters Bar, U.K., pp. 87-93. Hassan, S.A. and Bryant, M.J., 1986a. The response of store lambs to protein supplementation of a roughage-based diet. Anim. Prod., 42: 73-79. Hassan, S.A. and Bryant, M.J., 1986b. The response of store lambs to dietary supplements of fish meal. 1. Effects of forage-to-concentrate ratio. Anim. Prod., 42: 223-232. Hassan, S.A. and Bryant, M.J., 1986c. The response of store lambs to dietary supplements of fish meal. 2. Effects of level of feeding. Anim. Prod., 42: 233-240. Hurrell, R.F., Lerman, P. and Carpenter, K.J., 1979. Reactive lysine in foodstuffs as measured by a rapid dye-binding procedure. J. Food Sci., 44: 1221-1231. Jorgensen, H., Sauer, W.C. and Thacker, P.A., 1984. Amino acid availabilities in soybean meal, sunflower meal, fish meal and meat and bone meal fed to growing pigs. J. Anim. Sci., 58: 926-934. Jorgensen, J.N., Fernandez, J.A., Jorgensen, H.H. and Just, A., 1985. Anatomical and chemical composition of female pigs and barrows of Danish Landrace, related to nutrition. Z. Tierphysiol., Tierernaehr. Futtermittelk., 51: 252-263.

194 Just, A., Fernandez, J.A. and Jorgensen, H., 1982. Kodbenmels vaerdi til svin (The value of meat and bone meal for pigs.) Beret. Statens Husdyrbrugsfor., No. 525, pp. 1-52. Lands, W.E.M., 1986. Fish and Human Health. Academic Press, 170 pp. Lowe, S. and Howells, D., 1985. Fats for Feed; a suppliers view. In: National Renderers Association, Des Maines, IL. NRA Bull., No. 769, pp. 2-5. Marchment, S.M. and Miller, E.L., 1983. The response of store lambs to protein supplementation of a low quality diet. Anim. Prod., 36: 508. Marchment, S.M. and Miller, E.L., 1984. The response of store lambs to protein supplementation of alkali-treated straw-based diets. Anim. Prod., 38: 522. Marchment, S.M. and Miller, E.L., 1985. Voluntary food intake and growth responses in store lambs given protein supplements to grass silage. Proc. Nutr. Soc., 44: 47A. Maubois, J.L., 1986. Separation, extraction and fractionation of milk protein components. In: W.F. Raymond and P. Larvor (Editors), Alternative Uses of Agricultural Surpluses, Elsevier, Barking, U.K., pp. 77-85. Mehrez, A.Z., Orskov, E.R. and Opstvedt, J., 1980. Processing factors affecting degradability of fish meal in the rumen. J. Anim. Sci., 50: 737-744. Miller, E.L. and Pike, I.H., 1985. Milk quotas - - new feeding strategies to reduce milk production costs: Use of fish meal to improve feed efficiency and reduce feeding costs. International Association of Fish Meal Manufacturers, Potters Bar, U.K., pp. 1-24. Miller, E.L. and Pike, I.H., 1987. Feeding for profitable beef production: Use of fish meal to improve feed efficiency and reduce feeding costs. International Association of Fish Meal Manufacturers, Potters Bar, U.K., pp. 1-79. National Renderers Association, 1985. Pocket Information Manual and Exporters List. National Renderers Association Ltd., London. 94 pp. Newby, T.J., Miller, B.G., Stokes, C.R., Hampson, D. and Bourne, F.J., 1984. In: W. Haresign and D.J.A. Cole (Editors), Recent Advances in Animal Nutrition. Butterworths, London. pp. 49-59. Oliphant, J.M., 1974. Feeding dried poultry waste for intensive beef production. Anim. Prod., 18: 211-217. Olley, J. and Pirie, R., 1966. The pepsin digestibility method at low pepsin strengths. Fish. News Int., 5: No. 12. Opstvedt, J., 1973. Influence of residual lipids on the nutritive value of fish meal. IV. Effect of drying and storage on the energy value of the protein and lipid fractions of herring meal. Acta Agric. Scand., 23: 200-208. Opstvedt, J., 1976. Energy value of Norwegian herring fish meals for poultry. Feedstuffs. Miller Publishing Co., Minneapolis, 48(11 ) : 19, 22, 24. Opstvedt, J., 1984a. Use of chemical methods to assess quality of proteins in fish meal. Symposium on Use of Fish Meal in Animal Feeding, Budapest, Hungary. International Association of Fish Meal Manufacturers, Potters Bar, U.K. pp 8-27. Opstvedt, J., 1984b. Fish fats. In: J. Wiseman (Editor), Fats in Animal Nutrition. Butterworths, London, pp. 53-82. Opstvedt, J., Sobstad, G. and Hansen, P., 1978. Functional fish protein concentrate in milk replacers for calves. J. Dairy Sci., 61: 72-82. Orskov, E.R., 1982. Protein Nutrition in Ruminants. Academic Press, London 160 pp. Partridge, I.G., Low, A.G. and Matte, J.J., 1987. Double-low rapeseed meal for pigs: ileal apparent digestibility of amino acids in diets containing various proportions of rapeseed meal, fish meal and soya-bean meal. Anim. Prod., 44: 415-420. Pedersen, B. and Eggum, B.O., 1983. Prediction of protein digestibility by an in vitro enzymatic pH-stat procedure. Z. Tierphysiol., Tierernaehr. Futtermittelk., 49: 265-277. Pike, I.H., 1975. The role of fish meal in diets for poultry, Tech. Bull. No. 3. International Association of Fish Meal Manufacturers, Potters Bar, U.K., 40 pp.

195 Pike, I.H., 1987. Special product fish meals. The Feed Compounder, February 1987, pp. 13-14. Poppe, S., Meier, H. and Kiehn, J., 1987. The production and feed value of mixed protein silage. Proc. 5th Int. Sym. on Protein Metabolism and Nutrition, Rostock (in press). Potter, L.M., Shelton, J.R. and Parsons, C.M., 1980. The unidentified growth factor in menhaden fish meal. Poult. Sci., 59: 128-134. Roach, A.G., Sanderson, P. and Williams, D.R., 1967. Comparison of methods for the determination of available lysine value in animal and vegetable protein sources. J. Sci. Food Agric., 18: 274-278. Rendementsberekeningen 8601-8613 (1987); Produktschap voor Zuivel, Den Haag. Robinson, J.J., 1987. Energy and protein requirements of the ewe. In: W. Haresign and D.J.A. Cole (Editors), Recent Advances in Animal Nutrition - - 1987. Butterworths, London, pp. 187-204. Schiemann, R., Nehring, K., Hoffmann, L., Jentsch, W. and Chudy, A., 1971. Energetische Futterverwertung und Energienormen. VEB/DLV. Berlin. S~ve, B., Aumaitre, A., Jaubert, P. and Tord, P., 1978. Solubilization des proteines de poisson, supplementation en tryptophane et valeur alimentaire pour le porcelet. Ann. Zootech., 27: 423-438. Smits, B. and Steg, A., 1983. Flotation sludge from slaughterhouses as a feedstuff for pigs. In: E.H. Kebelaars and S. Boer Iwema (Editors), Animals as Waste Converters. Pudoc, Wageningen, pp. 101-103. S.S.F., 1987. Arsberetning S.S.F., 1986. Sildolje og Sildemelindustriens, Forsknings Institut, Bergen, Norway, 40 pp. Statistische Erhebungen und Sch~itzungen, 1987. Schweizerisches Bauernsekretariat, Brugg (CH), 64 Jahresn. Statistisch Jaaroverzicht 1985, 1986. Publ. Produktschap voor Zuivel, Den Haag. Steg, A., 1976. Onderzoek naar de voederwaarde van pensinhoud en flotatieslib. Vleesdistributie en Vleestechnologie, pp. 1-4. Steg, A., 1979. Hervoedering van mest. Syllabus PAO cursus "Veehouderij en Milieu". Sundstol, F., 1988. Feedstuffs. 5. Straw and other fibrous by-products. Livest. Prod. Sci., 19: 137-158. Tagari, H., Levy, D., Holzer, Z. and Ilan, D., 1976. Poultry litter for intensive beef production. Anim. Prod., 23: 317-327. Ten Have, P.J.W., 1983. De bruikbaarheid van flotatieslib van slachterijen als veevoeder. Rijks Agrarische Afvalwater Dienst (R.A.A.D.), Arnhem. Tilsch, K., GSrlich, L. and Ender, K., 1986. Mastleistung und Schlachtwert von Fleischrindbullen bei unterschiedlichem Schlachtalter. Arch. Tierz., 29: 253-259. United Kingdom, E.E.C., Dairy Facts and Figures, 1987. The Federation of United Kingdom Milk Marketing Boards, Thames Ditton, U.K. Uyttenboogaart, Th.G., 1979. Gewichtssamenstelling van slachtkuikens (Body composition of broilers.) Vleesdistributie en Vleestechnologie, 2: 36-39. Uyttenboogaart, Th.G., 1985. Gewichtssamenstelling van soepkippen. (Body composition of hens.) Vleesdistributie en Vleestechnologie, 3:30-31. Van der Honing, Y. and Alderman, G., 1988. Feed evaluation and nutritional requirements. 2. Ruminants. Livest. Prod. Sci., 19: 217-278. Veevoedertabel, 1979; 1986. Gegevens over voederwaarde, verteerbaarheid en samenstelling. Centraal Veevoeder Bureau in Nederland, Lelystad. Vogt, H., Krieg, R. and Harnisch, S., 1986. Versuche zur Beeinfltissung der SchlachtkSrperzusammensetzung von Broilern. Landwirtsch. Forsch., Kongressband 1984, pp. 577-596. Waibel, P.E., Cuperlovic, M., Hurrell, R.F. and Carpenter, K.J., 1977. Processing damage to lysine and other amino acids in the manufacture of blood meal. J. Agric. Food Chem., 25: 171-175.

196 Wainman, F.W. and Dewey, P.J.S., 1985. Metabolizable energy values: fish meals. Feedingstuffs Evaluation Unit Brief Report No. 18. The Rowett Research Institute, Aberdeen, 2 pp. Wainman, F.W. and Dewey, P.J.S., 1986. Metabolizable energy values: meat and bone meals. Feedingstuffs Evaluation Unit Brief Report No. 19, The Rowett Research Institute, Aberdeen, 2 pp. Whitehead, C.C., Armstrong, J.A. and Waddington, D., 1982. The determination of the availability to chicks of biotin in feed ingredients by a bioassay based on the response of blood pyruvate carboxylase (EC 6.4.1.1) activity. Br. J. Nutr., 48: 81-88. Yilala, K. and Bryant, M.J., 1985. The effects upon the intake and performance of store lambs of supplementing grass silage with barley, fish meal and rapeseed meal. Anim. Prod., 40:111-121.

Livestock Production Science, 19 (1988) 197-209

197

Elsevier SciencePublishers B.V., Amsterdam-- Printed in The Netherlands

II. 7. C o m p o u n d A n i m a l Feed and Feed A d d i t i v e s A.P. NAMUR,J. MORELand H. BICKEL

INTRODUCTION The feeding of compound feed and the use of feed additives for animal production in Europe have grown considerably since the beginning of this century, especially over recent decades. These were developed by independent national and international companies as well as by agricultural cooperatives and by food-processing companies valorizing their own by-products. Today a strong compound-feed industry is marketing compound feed as complete rations, large supplements and premixes all over Europe. It has contributed significantly to the technical revolution and economical improvement of European livestock production. Animal feed is the largest single item of expense in the production of milk, meat and eggs, often accounting for up to 70% of total cost. The high efficiency of present day animal production is achieved by the combined efforts of all concerned: (1) livestock farmers readily accept new techniques for improving the efficiency of their operations; (2) research has achieved valuable results in genetics, nutrition and management to produce quality products at the least possible cost; (3) governments foster the developments in research, advise livestock farmers and issue the necessary regulations. The feeding of compound feed, based on scientifically-calculated formulae, especially as complete rations (all-mash or pellets), to pigs and poultry can put the results of nutrition research and innovations to work in practice, very quickly and efficiently. Complete rations save labour on the farm, improve the efficiency of the feed and help to utilise new feed resources. The feed industry has a big impact, not only on the introduction of new feed resources into livestock production, but generally on the whole trade with feedstuffs. This became even more important with the application of least-cost formulation by linear programming on computers. The mixing of authorized feed additives into compound feeds to meet the requirement of the animal for specific minor nutrients, to improve performance and to prevent disease, became a wide-spread practice. Moreover, compound feed can be used by veterinarians as medicated feed to prevent or cure diseases in large herds of animals, where individual treatments are very time and labour consuming.

198

The cost of transportation, particularly of roughages, puts an economic limit on the use of complete rations on the farm. In many areas, livestock production depends essentially on home-grown feed, supplemented by feedstuffs not available on the farm. UTILIZATION OF COMPOUND FEED

General Compound feeds can be classified according to their quantitive importance in the ration of the various animals. They are fed: (1) as complete diets (allmash, pellets, crumbles ); (2) as basic diets to be supplemented by home-grown feed or by-products; (3) as quantitatively-important supplements to homegrown feed by-products; (4) as a vitamin/mineral pre-mix, representing quantitatively a minor component of the ration. The proportion of compound feed in the total ration, i.e. compound feed supplemented with a minor percentage of home-grown feed or, on the other extreme, home-grown feed with a minor part of supplements is highly variable. It depends on the feeding system for the particular livestock and on the resourses of feedstuffs available in the area under consideration. Therefore, we prefer to distinguish roughly between a complete diet and various types of supplements and pre-mixes.

Complete diet A complete diet is the usual method of feeding poultry in modern production systems. It contains all essential nutrients and micro-ingredients to meet the requirements of the animals. Usually it is offered either as mash, crumbles or pellets. Egg production is based primarily on feeding mash or crumbles. However, because of animal-welfare considerations a trend to supplement all-mash with whole grains, as was common in the past, may again become important. Broilers are mainly fed crumbles or small pellets, owing to the fact that intake and growth are enhanced compared with all-mash feeding. Complete-diet feeding also is very common in intensive pig production, especially in pig-fattening units. Pellets are often used, owing to their easy, dustless handling, reduced separation and because intake, and thus efficiency, is often considerably increased. For lactating sows, complete diets are prefered because of the high requirement for readily-available nutrients. However, for gestating sows complete diets may provoke problems of poor satiety, if offered according to requirement. Complete diets, in the shape of pellets or crumbles, are often used for fish farming. Extruded feeds to fit in with the feeding habits of certain fish are becoming popular.

199 There is a definite trend to use complete diets, manufactured by compounders, for non-ruminant herbivores, like rabbits and horses. Whilst fattening rabbits with complete pellets is quite common and practical, disturbance of the digestion can occur with does if there is a lack of coarse structure in the pelleted feed. With horses and game animals, pellets are fed as a supplement to roughage. Feeding cobs with a coarse structure is another possibility for meeting the requirements of horses. Complete-diet feeding to ruminants can increase nutrient intake which is important for high-producing cows and finishing beef cattle. However, a coarse structure is essential. As home-grown forage is the basal feedstuff for ruminants, preparation of complete diets is usually done on the farms and not by the compound industry. The compound-feed industry tries to comply with the widely varying demands of the user. Standardizing the animal-production systems, as has been achieved in several countries, by concentrating animals in large units, simplifies the task of the compound-feed industry. The limits of these simplifications are the need to meet the requirements of the individual animal.

Supplements As mentioned above, the exclusive feeding of compound feed as a complete diet may interfere with problems of physiology and satiety of the animals and may not be economically feasible. The energy value of industrially-manufactured compound feed is generally relatively high, owing to the fact that the manufacturing costs are judged by the market in relation to the cost of the energy or nutrient unit. Including high amounts of coarse-structured ingredients to overcome physiological problems, as, for example, roughage in compound feed, is in general too costly, and often not able to compete with roughage on the farm. Thus the compound-feed industry produces a wide variety of supplements and pre-mixes to be added to various feed stuffs, such as cereals, byproducts and forage: (1) for poultry, to be supplemented with whole cerealgrain; (2) for sows and pigs, to be fed with cereals, especially maize (kernels, cobs, whole plants, dry or silage) and/or with by-products of the dairy and meat industries (dried skim milk, dried whey and slaughter offal), sometimes also with roughage and kitchen waste; (3) for ruminants and other herbivores as supplement to forage (green or conserved as silage, hay etc.); (4) protein and mineral/vitamin pre-mixes often including the necessary additives to upgrade home-mixed and home-grown feed stuffs. The accuracy of proportioning between supplements and pre-mixes on the one hand and other feedstuffs on the other, on the farm itself may cause some problems. It requires knowledge of the value and the intake of the basal feed.

200 QUANTITATIVE IMPACT OF COMPOUND FEED

Raw materials In the world, ruminants for milk and meat production represent 80% of the total livestock. According to Wheeler et al. ( 1981 ) cattle, buffaloes, sheep and goats consume about 68 and 78% of concentrates (grains, oil meals) and forage, respectively, available for livestock (Table I). The percentage of concentrates and roughage in the years 1970-1983 used for livestock in the E.E.C. countries is shown in Table II. About 30% of the concentrates, calculated on an energy basis, were imported from outside the E.E.C. Calculated on a protein basis the percentage amounts TABLEI Partition of feed for livestock groupsa, Wheeler et al. (1981) Concentrates

Cattle b Sheep Pig Poultryc Other d Total

Forage

Cereals

Oil meal

Other

Total

35 2 32 27 4 100

21 3 28 45 3 100

37 7 39 13 4 100

56 12 10 7 15 100

63 15 2 1 19 100

aBased on metabolizable energy (1979/80 data). bFor meat and milk production only. CFor egg and meat production. °Mainly draught animals. TABLE II Mean percentage of forage and concentrates over a period of 13 years, estimated for E.E.C. countries

Forage • Permanent pasture Other grassland Maize silage Total Concentrates Cereals Other marketable feedstuffs Total

Energy basis (%)

Protein basis (%)

44.5 7.3 4.7 56.5

51.3 6.2 3.0 60.5

24.8 18.7 43.5

13.1 26.4 39.5

201

to 56%, showing that residues of oil/seed extraction and corn gluten especially are imported. During these years, a significant trend in the increased production of maize silage and home-produced cereals and of increased importation of other marketable feedstuffs appears. The upward trend of imports of protein-rich feedstuffs seems to have been broken in the last few years (1983-1985). This can, in part, be attributed to the price relationship between oilseeds and grains. On the other hand, pasture and grassland production decreased during the last 15 years, which is true for the imports of cereals because of large surpluses in the E.E.C.

Compound feed The proportion of compound feed in the total feed intake is less for cattle than for pigs and poultry. Table III shows that about 50 and 70% of the rations for pigs and poultry, respectively, consists of compound feed. In general, about 50% of the cereals produced in 10 E.E.C. countries are fed to animals. About one third of the production is used for human consumption and the rest is exported to countries outside the E.E.C. Table IV shows the estimation of the production and utilization of cereals in the year 1986/1987. About 42% of the cereals fed to animals are processed by the compound industry. The amount of cereals in compound feed is shown in Table V. From the data in Table V it can be concluded that a great part of compound feed consists of by-products from the food-processing industry (flour milling, oilseed extraction, meat- and fish-processing). The compound-feed industry helps, to a great extent, to recycle the offal of food processing into animal production, whilst meeting the best possible quality-price relation and maintaining at the same time the price level of the basic raw material. The use of compound feeds by various classes of animals is shown in Table VI. The allotment of the compound feed to the various livestock classes differs TABLE III Amount and proportion of compound feed in the total consumption, calculated on the basis of feed units (1 kg barley= 1 FU) in 8 E.E.C. countries Year

1973 1978 1983 1984 1985

Cattle

Pig

Poultry

Others

Total

Mt

(%)

Mt

(%)

Mt

(%)

Mt

(%)

Mt

(%)

16.9 24.6 29.2 29.5 29.0

9.8 14.3 17.1 17.4 17.2

21.4 25.0 26.8 26.7 26.5

50.4 53.9 53.5 51.0 50.9

18.3 19.1 21.9 21.1 21.0

67.5 68.0 70.0 70.4 68.2

2.0 3.0 3.5 3.7 3.6

9.5 11.8 13.8 14.0 13.3

58.6 71.7 81.4 81.1 80.1

22.2 26.4 29.3 29.1 28.1

202 TABLE IV Production and utilization of cereals in 10 E.E.C. countries in Mt

Production Utilization Consumption Human Animal Compounded Not compounded

1974/75

1977/78

1980/81

1983/84

1986/87"

111.0 117.8

105.6 114.9

124.8 117.7

123.3 116.4

134.8 114.1

45.3 72.5

45.2 69.7 28.7 41.0

46.9 70.8 30.2 40.6

46.2 70.2 29.8 40.4

44.8 69.3 29.0 40.3

b b

aEstimated. bNot stated. TABLE V Amount of cereals in compound feeds in 9 E.E.C. countries in Mt 1975/76

1977/78

1980/81

1983/84

1986/87"

Cereals Other components

27.0 34.7

29.2 49.3

29.4 50.1

29.0 53.3

28.2 52.3

Total Percent cereals

61.7 44

78.5 37

79.5 37

82.3 35

80.5 35

aEstimated. TABLE VI

--"

Compound-feed production in the year 1985 in various European countries (F.E.F.A.C., 1986) Cattle Mt F.R.G. France Italy The Netherlands Belgium U.K. Ireland Denmark Austria Switzerland Portugal Spain a Total Mean (x) SD (%) a1984.

7.1 3.5 3.9 5.7 1.4 4.5 1.2 1.7 0.1 0.2 0.6 2.5

Pig (%) 43 24 36 35 28 44 60 39 11 25 25 21

32.4

Mt 5.8 4.3 2.4 6.9 2.6 2.1 0.4 2.0 0.3 0.4 0.9 4.2

Poultry (%) 35 29 22 42 52 20 20 47 33 50 38 36

32.3 33 13

Mt 3.2 5.5 4.1 3.4 0.9 3.2 0.3 0.5 0.4 0.1 0.8 4.0

Other (%)

Mt

(%)

19 38 38 21 18 31 15 12 45 13 33 34

0.5 1.3 0.4 0.3 0.1 0.5 0.1 0.1 0.1 0.1 0.1 1.1

3 9 4 2 2 5 5 2 11 12 4 9

26.4 35 11

4.7 26 11

6 4

203 TABLE VII Compound-feed production in Europe compiled from various sourcesa Country

Year

Austria Belgium Bulgaria C.S.S.R. Cyprus G.D.R. Denmark Finland France F.R.G. Greece Hungary Ireland Iceland Italy Luxemburg The Netherlands Norway Poland Portugal Rumania Spain Sweden Switzerland Turkey U.K. U.S.S.R. Yugoslavia

1981 1985 1980 1980 1979 1980 1982 1981 1983 1983 1983 1983 1982 1982 1983 1985 1986 1976 1980 1980 1975 1985 1985 1986 1983 1982 1985 1981

Total

Mt year- 1 1.1 5.4 4.4 5.0 0.4 4.5 4.6 1.5 15.4 17.8 2.4 4.0 1.8 1.9 11.2 0.1 16.5 1.3 4.2 3.5 4.0 11.8 2.2 1.3 2.3 11.8 70.0 3.4 214.0

~Personally communicated by F.E.F.A.C.; Buhler; Boucqu$; V.S.F. (1987).

considerably between the countries. This could be taken as reference to the different production specialization and feeding systems in the respective countries. As a mean about one third of compound feed is processed for cattle and pig feeding, respectively, one quarter for poultry and the rest for various animal species. A complementary estimation of total compound-feed production is shown in Table VII.

204

FEED ADDITIVES

General The inclusion of minor quantities of specific components of natural or synthetic origin into compound feed is a common practice in industrial nations. To prevent possible adverse effects to the animal, to human beings and to the environment, the feed additives have to be approved by the various state-registration authorities. The requirements for clearance of a specific additive are based on the various national laws as well as on European and international conventions. The strictness of the requirements depends, in the main, on the type of the substance and the potential risk of adverse effects for man, animals and the environment. This policy is nowadays widely, but not always unanimously accepted. In general the following information on the additive concerned is required for clearance: (1) identification based on good laboratory practice; (2) chemical, physico-chemical and technological properties; (3) assignment of application concerning animal species as well as time and quantity of application; (4) methods of qualitative and quantitative analysis in the feed as well as of residues in the animal product, including metabolites of the substances; (5) metabolism, pharmacological and biological effects or side effects and possible toxicological effects, including mutagenicity, teratogenicity and carcinogenicity; (6) possible hazard of build-up populations of pathogenic microorganisms which are resistant or cross-resistant to antimicrobial agents, indispensable for medical use; (7) efficiency in respect to the desired effect on the animal. The strict and very extensive requirements for the clearance of a substance as a feed additive can be met only with laborious screening of new substances by technical specialists of all kinds. Thus the development of a new additive can take between 8 and 10 years, at great expense.

Types of additives General Substances which are allowed to be added to compound feed in small quantities can be classified in two principal categories: (1) Additives, which are essential for the maintenance of the biological functions of the animals. Vitamins and trace elements are typical examples of this category. The requirements for approval of these additives are in general less severe. However, they have to be more severe if adverse effects are expected from feeding in excessive quantities or if there are traces of undesirable substances in the additives which appear subsequently in meat, milk or eggs. (2) Additives, which are not essential for the biological function of the animal, but which have a specific, positive effect on the clinical healthy organism.

205 Growth promoters are the most typical example of this kind of additive. Substances which directly modify the hormonal or nervous regulation of metabolism are another example of non-essential additives. Both categories of additives have no nutritive value per se but they improve the nutritive value of the feed and thus the performance of the animal and the efficiency of feed conversion. The inessential feed additives of the second category can be grouped as follows: technological additives; absorption enhancers; antimicrobial agents; other growth promotors; metabolic modifiers; probiotics; prophylactics. We use this pragmatic classification, bearing in mind, that several additives could be classed with more than one group. Besides, feed additives, having a prophylactic effect, are on the borderline between nutritional and medicinal use. The feed industry and animal nutritionists also make use of a third category of feed products, which are added in small quantities to compound feed. This group includes individual amino acids and other organic acids, propyleneglycol, urea and others. The addition of such components may be looked on as being essential for a specific production system but not for the maintenance of the biological function. Apart from propyleneglycol, which is used for feed processing reasons, they have a specific nutritive value and may enhance animal performance.

Technological additives Preservatives. Based mostly on organic acids (e.g. propionic acid, fumaric acid) these components can reduce or prevent the development of bacterial or mycological spoilage of feed. However, they may conceal the presence of spores and thus the possible former growth of microorganisms, which may have produced toxins.

Antioxidants. Antioxidants are frequently added to protect components of the feed, which are sensitive to oxidation. They include natural or synthetic tocopherols and lecithin as well as various synthetic products. Antioxidants are used especially to protect unsaturated fatty acids in fats and oils, Vitamin A, carotene and carotinoids.

Pelleting, free-flowing agents and dust preventives. To improve the pelleting of feeds, various agents, mostly of negligible or very low nutritive value, are added to compound feed. They include argillaceous earths as for example montmorillonite or various derivatives of lignosulfate and cellulose. To improve the flow characteristics of compound feeds, flowing agents (various silicates) are added.

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Flavours. Flavours are single spices or mixtures of spices, as well as synthetic aromatic compounds. They are sometimes used to conceal unattractive natural smells, tastes or structures of feed, to enhance feed intake. Opinions on the advantage of using flavours in animal production are still controversial.

Colours. For poultry and fish production, colouring agents, mostly carotinoids of natural or synthetic origin, are often added to the feed for a distinct colouring of the animal product, to make it more attractive to the consumer. This affects the colouring of the egg yolk, skin of broilers or meat of fish. To distinguish clearly medicated feed from other feed colouring agents are sometimes added.

Absorption enhancers Enzymes. The addition of proteolytic and amylolytic enzymes to the feed is sometimes done, to increase the digestion and absorption of less digestible feedstuffs. Until now, tests with various enzymes, produced by extraction from organs of animals (rennin, pancreatic juice) or from microorganisms did not prove consistent efficacy.

Emulsifiers. To reduce the particle size of fats for better digestion and absorption, emulsifiers are incorporated into milk replacers. Emulsifiers are also used to administer fat-soluble vitamins to animals in aqueous solution. Natural emulsifiers such as lecithin and saponin as well as synthetic emulsifiers are customary.

Antimicrobial agents (growth promotors) Antimicrobial agents are added in comparatively small amounts to improve daily weight gain and feed-conversion ratio of fattening animals. Two classes of antimicrobial agents may be distinguished: (1) antibiotics, which are metabolites of living cells ( fungi, bacteria); (2) chemotherapeutics, which are chemically synthesized. This distinction is widely accepted, although antibiotics produced by bacteria are sometimes modified by stepwise chemical transformation. Thus several products could be allocated to either class. Since about 1970, most authorities have striven for a clear distinction between antimicrobial agents used for growth promotion and others for therapeutic use, either for human or animal therapy. But this distinction is not strictly maintained. The antimicrobial agents used for growth promotion are nowadays not significantly absorbed in the intestine. They are qualitatively and quantitatively effective on the microbial population of the intestine, including the rumen. This entails in principle an increased efficiency of utilisation of nutrients, al-

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though variable for various animal species and age classes. The greatest effect is observed with young animals. The following mean improvement of the daily weight gain at a given feeding level has been estimated: (1) poultry, broiler 2-5%; (2) pigs, piglet 10-20%, weaner 5-10%, finishing 2-5%; (3) cattle, suckler calf 10-15%, bull 2-10%. Simultaneous improvement of the feed-conversion ratio occurs. The degree of this improvement depends on the feeding level (restricted or ad libitum feeding) and the response of the animal in respect of the composition of the product (liveweight gain, milk). A wealth of literature exists on this subject. The use of antimicrobial agents for growth promotion, with or without veterinarian prescription, is subject to strict regulations in all European countries. As these regulations differ between countries and may be altered at short notice, the reader is referred to national authorities for precise information.

Other growth promotors Copper. The addition of copper to pig feed in higher amounts than are necessary to cover its requirement as a trace element has a growth-promoting effect. Especially in feeds for young growing pigs 75-175 mg k g - 1 feed may be added. Higher amounts may be harmful to the function of the liver of the pig. Using such high amounts of copper increases the danger of pollution of the environment through the manure of the pigs. Therefore a maximum level of 35 mg k g - 1 feed is applied now for growing pigs in some countries.

Metabolic modifiers Metabolic modifiers consist of substances which directly influence the cellular metabolism of the animal, rather than the activity of the digestive tract, or the microbial population therein. The present generation of metabolic modifiers includes hormones and hormone-like substances, as well as synthetic compounds which have a direct effect on the nervous regulation of metabolism. Steroidal hormones, of either natural (testosterone, oestradiol and progesterone), or synthetic origin (trenbolone and zeronal), have been widely used. The stilbene compounds, diethylstilboestrol, hexoestrol and dienostrol were also used at one time, but since 1981 their use has been widely prohibited. All these compounds positively affect the metabolism of growing and fattening animals, especially cattle, reducing the deposition of fat and increasing the proportion of protein in the liveweight gain. Such an effect is regarded as desirable from the human dietary viewpoint. Because steroidal hormones are also active by mouth in humans, their use was restricted to slow-release implants of materials with lower levels of oral activity, and withdrawal periods were instigated, as well as the discarding of the site of the implant. If the recommended procedures were followed, the level of steroidal hormones detected in meat from treated animals presented no haz-

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ard to the health of the consumer (E.E.C. 1982). Nevertheless, the E.E.C. introduced a complete ban on the use of steroidal sex hormones in animal production in December 1985. The trigger for this decision was probably the evidence that withdrawal periods and procedures for the discarding of tissues in the area of the implant were not always being followed. Research is currently in progress on growth hormone, or bovine somatotropin, BST, a protein hormone which is species specific and not effective by mouth, since the protein molecule is digested by the enzyme systems of the animal. BST is secreted by the pituitary gland, and has a profound influence on many bodily functions, particularly lactation, as well as growth. Milk yield increases of 2-4 kg day- 1 have been recorded, accompanied, after some delay, by an increase in feed intake to maintain energy balance. The manufacture of BST on a commercial scale is now possible, using recombinant-DNA techniques. The levels of the hormone in the meat and milk of treated animals are of the same order as in untreated animals, since all animals secrete the hormone themselves. Bovine, ovine or porcine BST are not effective for humans, whatever the route of administration. The search for other metabolic modifiers for more profitable animal production continues, with the aim of replacing not only the steroid hormones and other directly-acting hormones, but also the antimicrobial growth promoters. Research is being directed to hormone-releasing factors and substances, which would alter the level of secretion of the hormones of the animal, or alter or depress nervous signals. As an example, the beta-agonists, Clenbuterol and Cimaterol can have such effects, but some are known to influence the cardiovascular system or the motility of the digestive tract. Since such compounds are also active in the human, residues in meat may be a problem. It is evident that the authorities should approve such substances only after very careful and conscientious verification of all possible harmful effects on animals, man and the environment. For the time being, it would be premature to promote the general use of substances which have a direct effect on the physiology of the animal at the cellular level, although some promising research results are available.

Probiotics The term 'probiotics' is used for deep-frozen bacteria which are revived if fed to the animal. They are claimed to have a regulatory effect on the microbial micro flora. Their effect on growth promotion is until now not clearly proven. They may have a certain impact on the reconstitution of the intestinal microflora after antibiotic treatment.

Prophylactics According to official regulations, only agents to prevent coccodiosis in poultry and rabbits may be used as prophylactic feed additives. However, the use

209 of antimicrobial agents in slightly higher dosages than those effective for growth promotion is often claimed to have a disease-preventing effect. This is often debated between veterinarians and nutritionists, bearing in mind t h a t some antimicrobial agents are also effective against protozoa.

REFERENCES E.E.C., 1982. Interim Report of the Scientific Working Group on Anabolic Agents in Animal Production, No. 2924/IV/82. F.E.F.A.C., 1986. Statistical Yearbook, European Federation of CompoundAnimalFeedingstuffs Manufacturers, Brussels. Wheeler, R.O. et al., 1981. The WorldLivestockProduct, Feedstuffand Food Grain System.Winrock International, Morrilton, AR, U.S.A.

Livestock Production Science, 19 (1988)211-216 ElsevierSciencePublishersB.V., Amsterdam-- Printed in The Netherlands

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III. F E E D E V A L U A T I O N A N D N U T R I T I O N A L REQUIREMENTS III. 1. I n t r o d u c t i o n H. BICKEL GENERAL The production potential of feedstuffs has to be expressed above all by the energy content of the feed, representing the whole of the organic matter. It is well known that, besides this, potential has to be defined simultaneously by the protein content as a specific component of the organic matter, and more precisely by the contents of the essential amino acids, especially in feedstuffs for non-ruminants. Thus feed evaluation was, and is, always orientated on the energy value and the protein value of the feed, although other components are to be considered for their specific effects in nutrition, e.g. lipids, dietary fibre, vitamins, minerals, trace elements etc. NUTRITIVE VALUE All modern feed-evaluation systems approach the production potential in a similar way. They are all based on two common principles: (1) definition of the digestibility of both the energy and the nutrients; (2) distinction between animal species and between type of production. Calorimetric measurements and/or proximate chemical analysis of feed and faeces are necessary to determine digestibility. The use of standard caloric values of the individual nutrients may replace calorimetry. Taking additionally into account the energy loss as urine (and methane) a more precise base is attained. Moreover, several systems make allowance for dietary-induced heat production. Energy

The amount of energy available for the animal is thus estimated conventionally according to the following models: (1) digestible energy (DE) = gross energy (GE) of f e e d - GE of faeces; (2) metabolizable energy (ME) = DE - ( GE of urine and methane); (3) net energy (NE) = ME - dietary-induced thermogenesis (heat increment). 0301-6226/88/$03.50

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A comprehensive model, examining the true biological partition of GE was proposed by Harris (1963) and further developed by the CAN subcommittee on biological energy (N.A.S., 1981). DE and ME are relatively easy to measure, especially if the measurement of methane is omitted. Both energy terms are in use for ruminants and pigs. Poultry feed is generally evaluated as ME, because birds excrete faeces and urine together through the cloaca. Thus quantitative distinction is complicated. The measurement of the dietary induced thermogenesis cannot be done independently of the basal-heat production. Thus, it has to be estimated as heat increment (HI), attributable to a definite increment of feed intake. Conventionally, this heat increment is indirectly expressed by the partial efficiency of utilization of ME, assigned by the symbol k. HI=ME-NE k = NE/ME

Usually linearity of k over the possible range of production is assumed: NE=MExk

Heat increment and thus the value of k are dependent on the type of production involved. Thus, for the estimation of the energy value of feedstuffs and for the estimation of energy requirement, the various types of production to consider are, e.g. km for maintenance, k~ for lactation, ko for egg production, kr for reproduction tissue, kg for gain (generalized), kf for fat deposition, kp for protein deposition. In summing up, metabolizable energy seems to be the most universal term to define the overall production potential of the feedstuff for the various animal species and the various production systems. Protein

As far as protein evaluation is concerned, apparent digestible crude protein (DXP) is conventionally thought to be the most simple way to express the production potential of protein. DXP is defined correspondingly to digestible energy D X P = c r u d e protein of feed ( X P ) - X P of faeces

where XP stands for total nitrogen, multiplied by 6.25, the average ratio of protein to nitrogen. Looking at the anatomy and the physiology of the various animal species, e.g. ruminants, pigs and poultry, the limits of this evaluation system can be recognized. Modern concepts to express the potential of the feed to cover the protein requirement of ruminants consider the quantity of amino acids absorbable in the small intestine and the pattern of these amino acids. Allowance

213 for microbial metabolism in the rumen is thereby made. For pigs, digestible protein, defined more precisely as apparent digestible protein, is still a fair approach to protein evaluation. However progress is focused to consider absorbability of amino acids in the small intestine, as well as the amino-acid pattern of the digested feed. For poultry, the evaluation of protein on the basis of digestible protein is not very practicable, owing to the combined excretion of faeces and urine. Therefore evaluation systems tend to consider crude protein and in addition amino-acid availability when defining the protein potential of the feedstuffs. In summary, protein-evaluation systems of feedstuffs for the various animals tend to consider as precisely as possible the amino acids absorbable in the intestine, in replacement or in addition to crude or digestible protein.

Standardization in feed evaluation It is generally recognized that substantial progress in the knowledge of feed utilization came about during the last decades, and valuable evaluation systems are offered by scientists. However, it is unavoidable that standardization and even some simplifications have to be accepted. As an example, additivity of the values of the individual feedstuffs in the ration is assumed as a rule, which seems to be true in most cases, although some exceptions cannot be excluded. How far this standardization can or should go depends on judging the applicability of the evaluation system for practical ration formulation. One main difference between the feed-evaluation systems, proposed and applied in various countries both for energy and protein evaluation as well as for the various types of animals and productions, is thus based on this judgement. One of the goals of the following chapters is to identify the common basis and the main differences between the feed-evaluation systems in use in Europe. NUTRIENT REQUIREMENTS

Factorial approach Feed evaluation is always aimed at meeting the requirements of the animal. Animal nutritionists approach the estimation of the requirement by splitting the total requirement into various components, e.g. requirement for maintenance and activity, for milk production, for body gain, for egg production, etc. This is the factorial approach. Total requirement is obtained by summing up the partial requirements.

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Standardization in nutrient requirements As with the procedure for feed evaluation some standardization and simplification may be judged to be necessary for practical application. Besides, real differences in the requirements and gaps in knowledge, sometimes masked by so-called safety margins, exist for different production systems. Thus, feeding standards are often based on feeding trials rather than on the factorial approach, especially for pigs and poultry. The variabilities of nutrient utilization and of animal requirements, including interactions of nutrients and protein to energy relationship, are sometimes understood and allowed for by results from carefully-planned feeding experiments as accurately as by the factorial approach. Therefore, it is obvious that recommended allowances and feeding standards in the various countries are often difficult to compare in a simple way. FEED INTAKE

To set up rations and feeding rules for a desirable level of animal performance, which corresponds to the genetic potential, requires knowledge of the intake of the animal. Whilst in some production systems the intake is accurately known by restricting the daily amount of feed, other systems are based on ad libitum feeding where intake can be estimated but not measured. Besides, in many systems, group feeding dominates over individual feeding and determination of the requirements of groups only, and not of individuals, is possible. Thus recommended allowances are often expressed not at a per diem rate but as the recommended content of the ration, e.g. of the feed mixture. This is especially the case in poultry feeding, but also applies in some systems of ruminant and pig feeding. Thus the practical application of the science of animal nutrition deals with the formulation of diets from a selection of feeds which, when given to the group of animals under consideration, will result in achievement of the desired level of animal performance at an economic level of cost in relation to the expected returns. As has been stated above, two quite separate sets of information are needed, expressed in a common set of units. The first relates to the nutritive value of feeds as measured by their voluntary intake, digestibility, chemical composition, content of anti-nutritional factors etc. The scientific units used vary between countries, although many are derived from common scientific measurements or principles. Data are then assembled into tables of feed composition and nutritive value, expressed per kilo of feed, either as fed to the animal, or on a dry matter basis, since water, although essential, has no nutritive value. The second set of data relates to the requirement for nutrients of many types, by the various classes of ruminant livestock, for various levels of animal pro-

215 duction, for the production of meat, milk or reproduction. This must include data about the amounts of feed that animals can consume, and their reaction to short- or long-term deficits or surpluses of nutrients. RATION FORMULATION Ration formulation consists of assembling feeds in such amounts that the sum of the particular nutrients supplied by the individual feeds is equal to the animal's requirement for that nutrient. Mathematically, each nutrient is handled in a linear equation of the form: aX1 + bX2 + cX3 + d X 4 = R ( X )

where a,b,c, and d are the amounts of each feed in the diet; X1,X2,X3 and X4 are the content of Nutrient X in feeds A,B,C and D and R (X) is the animal's requirement for Nutrient X. A large number of nutrients have to be considered, especially when trace elements and vitamins are included and a matrix of linear equations has to be solved. Whilst simple rations can be formulated by hand or with simple calculators, the use of the computer is common, using the technique of linear programming to devise diets which are of least cost for the feed prices extant at the time. Within this matrix, certain nutrients such as protein and energy tend to dominate costs, whilst trace elements are usually a minor cost. For nutrients such as the major minerals and trace elements, there is almost world-wide agreement on the units to be used, usually either g kg -1 or mg kg -1, although the use of percentages (%) and parts per million (ppm) still continues. Requirements for these minor nutrients are also much more generally agreed, with exceptions such as phosphorus. SYSTEMS In the following chapters the main lines of the various systems of feed evaluation and nutritional requirements, including recommended allowances, proposed and used in the various countries are explained. Similarities and differences between the systems for the various types of animals and productions are identified, as far as information from the various countries is available. A glossary of terms and the relevant symbols are given by van der Honing and Alderman in the following chapter (III.2) on Page 225 (Table III). Space does not permit the explanation of the full background of all feed-evaluation and nutrient-requirement systems. Therefore readers are referred to standard texts on animal nutrition for a detailed explanation.

216 REFERENCES Harris, L.E., 1963. Symposium in feeds and meats terminology. III. A system for naming and describing feeds, energy terminology and the use of such information in calculating diets. J. Anim. Sci., 23: 535-547. N.A.S., 1981. Nutritional Energetics of Domestic Animals and a Glossary of Energy Terms. National Academy of Science, Washington, DC. Van der Honing, Y. and Alderman, G., 1988. Feed evaluation and nutritional requirements. 2. Ruminants. Livest. Prod. Sci., 19: 217-278.

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III. 2. R u m i n a n t s Y. VAN DER HONING and G. ALDERMAN

GENERAL

There are many different systems for the measurement of the energy and protein contributed by feeds, and the ruminant animals' need for these major nutrients, in use in Europe. The intention of this chapter is to outline briefly the many European systems for estimating the energy and protein requirements of ruminants, to indicate the common basis of the recently-introduced systems, and to discuss methods of conversion of one unit to another. The terminology and symbols used are detailed in Table I. SYSTEMS FOR ENERGY EVALUATION OF FEEDS AND ENERGY REQUIREMENTS FOR RUMINANTS

Introduction Two decades of calorimetric measurements of the energy requirements of dairy and beef cattle and of sheep, at several centres of excellence, resulted in the publication of a number of new systems for calculating energy requirements of farm livestock. In the decade 1970-1980, the majority of European countries replaced their existing energy systems. The latter were based on the Kellner starch-equivalent system (Kellner, 1905) or on fodder units calculated from it. The newer systems use a common concept, based on the proposition of Blaxter, that metabolizable energy (ME), i.e. gross energy minus energy in faeces, urine and methane, is the basis for energy evaluation. Net energy (NE) systems are derived from metabolizable energy, involving the partial efficiency of utilization (k) of ME. Net energy of feeds for maintenance, lactation and gain are calculated using coefficients k ~ k~ and ks, respectively. The magnitude of these coefficients depends on the metabolizability (q) of the gross energy. Because of the variation of k for various production forms, some simplifications are necessary to define energy values, which can be used for maintenance and lactation or maintenance and gain together. Systems for dairy cows were rather easy to simplify because of similar slopes for the equations for k~ and kl. Van Es (1975) used 1.2 for the proportion between km and kl. McHardy (1966) proposed the use of a common king for 0301-6226/88/$03.50

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218 TABLEI Terminology and symbols used Chemical analyses of animal feed ADF ADL DCHO DM DMF DMI DMTP DOM DOMD DTP ds DUDP DXF DXL DXP DXX GE IDOM MXP MTP NDF NPN OM RDP TDN TP UDP XF XL XP XX

Acid detergent fibre (van Soest) Acid detergent lignin (van Soest) Digestible carbohydrates Dry matter Faecal dry matter output (g or kg day -1) Dry matter intake (g or kg day -~ ) Digestible microbial true protein Digestible organic matter Digestible organic matter in dry matter Digestible true protein Digestibility coefficient of nutrient indicated by subscript Digestible undegraded protein Digestible crude fibre Digestible crude fat Digestible crude protein Digestible nitrogen-free extract Gross energy Indigestible organic matter Microbial crude protein Microbial true protein Neutral detergent fibre (van Soest) Non-protein nitrogen Organic matter Degraded dietary crude protein Total digestible nutrients True protein Undegraded protein Crude fibre Crude fat Crude protein Nitrogen-free extract

Energy units and coefficients used to describe systems APL DE dE

Eg Em Ep SVg FL FM FU

Animal production level,usually expressed as a multiple of maintenance requirement Digestible energy Digestibilityof energy = D E / G E Net energy required for body gain (MJ day -I ) Net energy required for maintenance (MJ day-i) Net energy required for production (MJ day -I) Energy value of gain (MJ kg- i) Level of feeding, relativeto maintenance Fasting metabolism (MJ day- I) Fodder unit, i.e.the starch equivalent of i kg barley as fed

219 TABLE I (continued)

kf kg kl k~

krag k~ kp LWG Mcal ME ME/DM MEm MJ NE NEg NE~ NEm

NEmg q SE W

Efficiency of utilization of ME for fattening Efficiency of utilization of ME for body gain Efficiency of utilization of ME for lactation Efficiency of utilization of ME for maintenance Efficiency of utilization of ME for maintenance and gain Efficiency of utilization of absorbed amino acids Efficiency of utilization of ME for protein deposition Liveweight gain ( kg d a y - 1 ) Megacalorie -- 1000 kcal -- 418.4 kJ Metabolizable energy ME concentration of dry matter (MJ kg- 1) ME required for maintenance (MJ d a y - 1) MegaJoule = 1000 kJoule Net energy of a feed or ration Net energy value of a feed or ration for body gain (MJ kg- 1) Net energy value of a feed or ration for lactation (MJ kg- 1) Net energy value of a feed or ration for maintenance ( MJ kg- 1) Net energy value of a feed or ration for maintenance and gain ( MJ kg- 1) Ratio of ME to gross energy, metabolizability of gross energy ( % ) Starch equivalent, defined as the fattening potential of 1 g digestible starch, which is equal to 2.36 kcal or 9.88 kJ Liveweight in kg

Energy system code letters EFr FFU ME(GB) ME(IRL) ME(S) ME(SU) MSV NEL(CH) NEL(D) NEL(GR) NEL(H) NEL(US) NEL(YU) NEM(YU) NEV(CH) OFU SFU(DK) SE(NL) SEK TDN UF UFL UFV UN(RO) VEM VEVI

Energy for fatteningof ruminants from German Democratic Republic Scandinavian fatteningfeed unit,used in Norway and Finland Metabolizable energy from M.A.F.F. Bulletin 33 Metabolizable energy (Ireland) Metabolizable energy (Sweden) Metabolizable energy (U.S.S.R.) Net energy fat,modified starch unit (EFt) in Greece Net energy lactationin Switzerland Net energy lactation1982 in the Federal Republic of Germany Net energy lactationin Greece Net energy lactation1986 in Hungary Net energy lactatingcows N.R.C. 1978 (used in Israel) Net energy lactation1984 in Yugoslavia Net energy for growth and fattening 1984 in Yugoslavia Net energy growth and fatteningin Switzerland Oat feed unit in the Union of Soviet SocialistRepublics (U.S.S.R.) Scandinavian feed unit system according to the Danish procedure Starch equivalent system (Dutch modification) Starch equivalent system according to Kellner Total digestiblenutrients Unith foraggere in use in Italy French net energy unit for dairy cows French net energy unit for beef cattle Net energy lactation1984 in Rumania Dutch net energy unit for dairy cows Dutch net energy unit for beef cattle

220 growing cattle by introducing the concept of Animal Production Level (APL) which calculated a variable NEmg depending on level of production, first adopted by the U.K. This concept was also used in the internal arithmetic of the Belgian, French, Dutch and Swiss systems, but using a fixed level of APL, 1.5. The majority of countries tested their new energy systems on feeding trials with breeds of livestock and feeds native to their countries and farming systems. In a number of cases, strict adherence to a factorial model has not been possible, particularly for growing and fattening cattle. The common ground for all new European systems is the measurement of the ME of feeds, from which the specific country energy units are calculated. Thus a set of ME values of feeds is basic to all systems. Brief details of the units introduced and the relevant mathematical functions will be given for Belgium, Denmark, Ireland, Finland, France, Israel, Italy, Germany: the Federal Republic of Germany (F.R.G.) and German Democratic Republic ( G.D.R. ), Greece, The Netherlands, Norway, Rumania, Sweden, Switzerland, the U.K. and Yugoslavia (see Appendix for details). Development of new energy systems, 1969-1980 Until the 1960s most European countries were using energy systems for ruminants essentially based on the work of Kellner (Kellner, 1905). The starch equivalent was defined by Kellner as the production potential of 1 kg digestible starch to form fat in adult male castrated steers. Thus the feed was evaluated as net energy fattening (NEf). Basically, this concept is still used by the energy system of ruminants (EFr) in the G.D.R., claiming that kg and km or kl are quite proportional together. The starch equivalent (SE) (either in kg or lb) was used, but the commonest unit was the fodder unit (FU), based on the SE of 1 kg of barley as fed, all other feeds being expressed as a proportion of the SE of barley. The unit was introduced as one that farmers could comprehend and is now firmly entrenched in many countries, although the methods of its calculation have been totally revised. A major variation, the Scandinavian feed unit (SFU) remains in use today in Denmark and Norway. A variation is the oat unit based on I kg of oats, since barley was not a familiar grain for farmers in Eastern Europe. The weight of evidence accumulating, and discussed in depth at the E.A.A.P. Energy Metabolism Symposia held every three years from 1958 onwards, weakened support for the existing SE and FU systems, because it was shown that no proportionality of kg and km occurs. It was quite clear that the use of NEf or SE values for meeting maintenance and lactation needs resulted in the under-evaluation of forages which Forbes and Wood had noted some 30 years before. An E.A.A.P. Feed Evaluation Working Group was formed under the leadership of A.J.H. van Es, with the objectives of seeking to formulate a new European standard system for the energy requirements of ruminants.

221

Events had already moved too far however, but van Es was able to secure a good deal of agreement on the central relationships now in use in The Netherlands, Belgium, France, Germany (F.R.G.), Switzerland, the U.K. and Yugoslavia, as can be seen in the Appendix to this paper. Van Es' net energy lactation system was published in 1975 (van Es, 1975 ), but the system adopted in The Netherlands appeared later (van Es, 1978). Details for France and Switzerland were published at the same time (Vermorel, 1978; Bickel and Landis, 1978). The Netherlands, Belgium and France all changed to a feed unit system based on 1 kg of barley, but with separate units for milk production and beef cattle. This eased the problems of change at the farm and advisory level, since most of the changes in calculation were hidden from view. Details of the following feed evaluation systems will be given in the Appendix on energy systems for ruminants: (1) starch equivalent according to the Kellner procedure (SEK), at this time still in use for beef cattle in the F.R.G. (D) and in several other countries; (2) the Dutch modification of starch equivalent ( SE (NL), until 1977 in use in the Netherlands (NL) and Belgium (B), and still used in Belgium for beef production; (3) Scandinavian feed unit according to the Danish procedure; SFU (DK) ; (4) fattening feed unit, used in Norway (N) and Finland ( SF ) : FFU; (5) energy system for fattening of ruminants (EFr), adopted in the German Democratic Republic (GDR); (6) metabolizable energy according to the Swedish procedure: M E ( S ) ; (7) metabolizable energy according to M.A.F.F. Bulletin: 33 ME ( GB ), used in the United Kingdom (GB). This system is also compared with the requirements described by the A.R.C., 1980; (8) net energy lactating cows, used in Israel (IL), described by the N.R.C., 1978: NEL ( US ); (9) metabolizable energy, ME (IRL), used in Ireland; (10) Dutch feed unit for milk production (VEM), and for body gain (VEVI), adopted in 1977 in The Netherlands and in 1978 VEM (only) adopted in Belgium; (11) French feed unit for milk production (UFL), and for body gain (UFV), adopted in 1978 in France (F) and revised i 1987 (see Addendum); (12) net energy for lactation, NEL (D), as adopted in the F.R.G. in 1982; (13) net energy lactation, NEL (GR), and modified starch unit, MSV, used in Greece; (14) Netto Energie Milch, NEL (CH), and Netto Energie Mast, N E V ( C H ) , used in Switzerland since 1979; (15) net energy lactation, N E L ( Y U ) , and net energy for growth and fattening, N E M ( Y U ) , used in Yugoslavia since 1984; (16) Unith foraggere, UF, in use in Italy; (17) net energy lactation, N E L ( H ) , and net energy beef (NEro and NE~), used in Hungary since January, 1986; (18) net energy for ruminants expressed as a new feed unit, U N ( R O ) used in Rumania since 1983; (19) (a) Oat feed unit (OFU) and (b) metabolizable energy, M E ( S U ) , used in the U.S.S.R.

The efficiency of utilization of metabolizable energy The concept of calculating net energies for growth, pregnancy and lactation from the measured ME available above maintenance requirements was put

222

forward by Blaxter (Blaxter, 1962). This was formalised in an A.R.C. Technical Review (A.R.C., 1965), where the following equations were published: Efficiency for maintenance (%), km = 1.6 ME/DM+ 54.6

(1)

Efficiency for fattening (%), kg = 4.4 ME/DM+ 3.0

(2)

Efficiency for lactation, k~, varied from 62 to 70% as a curvilinear function of ME/DM. Table values only were given. In 1972, Moe et al. (1972) published an NEI system based on a large data base of dairy cow energy balance trials. In this system, ME values are measured at the production level and converted to NE~ by the function: NE~(MJ kg -1 DM) =0.703 M E - 0 . 7 9 5

(3)

This implies an efficiency for lactation, kl, of 0.59-0.64. Another version of the NE1 system was proposed by van Es (1975), who preferred to use efficiencies for maintenance, growth and lactation to calculate relevant NE values. His equations are shown graphically in Fig. 1. The similarity of slope between km and k~ is quite obvious. Van Es therefore also proposed that variations in maintenance net energy due to variations in q 0.8-

km

0.7/

,," f

I

" kl

0.6-

Efficiency of utillisation of ME, k 0.5-

s /

/

/

0.4-

/ /

0.3-

/

0.2'

0.1 q

0 0

ME/DM

0.2 I

0.3 I g

0.4 I

0,5 I

0.6 I l~D

0.7 I

0.8 I 1'5

Fig. 1. Utilization of metabolizable energy for maintenance (kin), lactation (k~), fattening (kf) and maintenance+fattening (kmf) as a function of ME concentration in DM (ME/DM) and gross energy (q), ME/GE.

223 could be accommodated by calculating in terms of NEI and adjusting for the difference in intercept. To estimate q, the ratio between ME and gross energy {GE), in several countries the following equation from the work of Schiemann et al. (1971) is generally used:

GE=5.77 XP+8.74 XL+5.0 X F + 4.06 X X - 0.15 sugars

(4)

where GE is in kcal kg-1 and XP,XL, etc. are in g kg-1 and XP, XL, XF and XX are crude protein, crude fat, crude fibre and nitrogen-free extract, respectively. As a result of an E.A.A.P. Working Group led by van Es during the early 1970s, these equations formed the basis of new energy-evaluation systems introduced by The Netherlands, France, Belgium and Switzerland in 1977. They were later followed by Germany in 1981, Yugoslavia in 1984, and by Greece. The U.K. adopted a simplified version of the A.R.C. (1965) system in 1976 (M.A.F.F., 1975). Constant values were taken for km of 0.72 and k~ of 0.62, since the small variation due to M E / D M was not thought worth taking into account for the majority of mixed diets. Whilst the formulation of an NE~ system was fairly straightforward, because of the similar rates of change with q of both kr. and k~, the problem of growth and fattening net energies was much more complex. The coefficient for q in the kf equation was 2-3 times that for k~,, and therefore the calculation of a joint efficiency king was necessary. Obviously, the relative proportions of ME being utilized for each function would affect the calculated net energies. The problem was solved by McHardy ( 1966 ) but further developed and published by Harkins et al. (1974). McHardy introduced the concept of Animal Production Level (APL) which was the ratio of the total net energy to the net energy for maintenance

APL= (NEro + NEg) ~NEro

(5)

Net energy requirements of animals are independent ofq or ME/DM, whereas ME requirements depend upon q or ME/DM, making ration formulation rather complex and time consuming. Using this concept of APL, a function can be derived to calculate the joint efficiency of ME utilization for maintenance and growth/fattening as follows:

km X kg X APL k~g-kg+k~ (APL-1)

(6)

The results using the van Es equations for km and k~ over the range APL 1-2 ( maintenance to a liveweight gain of over I kg day- 1) and for M E / D M values ranging from 6 to 14 are shown in Table II. Whilst the general theory was concerned with rations, McHardy suggested that individual feed ME values could be transformed to feed NE~g values and

224 TABLE II Joint efficiency of ME used for maintenance and growth, king Animal production level (APL) 1.0 1.2 1.4 1.6 1.8 2.0

Ration energy concentration ME/DM, (MJ kg -1 DM) 6

8

10

12

14

0.65 0,52 0.45 0.41 0,39 0.37

0.68 0.59 0.53 0.50 0.47 0.46

0.71 0.64 0.60 0.57 0.55 0.53

0.75 0.69 0.66 0.64 0.62 0.61

0.78 0.74 0.72 0.70 0.68 0.67

used in a purely additive manner to formulate a ration of desired NEmg content, without incurring any significant error. This system was adopted by the U.K. as a solution to the problem of ration formulation for growing and fattening beef cattle in M.A.F.F. Technical Bulletin 33 (M.A.F.F., 1975, pp. 9-12 ). Van Es and his co-workers in the E.A.A.P. Feed Evaluation Working Group, who were concerned to have a single NE value for growing animals, decided after consideration of the variation in kmg as affected by APL and q (see Table II), on proposition of the French colleagues to choose a single level of APL, 1.5, at which to calculate NEmg values. This is equivalent to formulating for a liveweight gain of about 0.9 kg day-1 (van Es, 1978) for animals of any liveweight in various breeds, since APL values vary relatively little with the animars liveweight. This is because increases in maintenance energy requirements are paralleled by an increased energy content of the liveweight gain made by heavier animals. Having decided to use this simplification, deviations for lower and higher liveweight gains were allowed for by correcting the net energy requirements accordingly. An alternative proposal was to use NEl values at low levels of APL ( and liveweight gain) for rearing lactating cattle where the values for king approximate to those for kl ( see Table II). Table III compares the energy requirements of a 600-kg dairy cow at 4 levels of production in the various countries. A similar comparison for bulls gaining 1 kg day- 1 at 3 different levels of body weight is presented in Table IV.

Plane of nutrition effect McHardy's general theory was applied by him to the original A.R.C. (1965) ME model, which included a correction factor which depended on a definition of plane of nutrition (FL) in terms of ME intake. Obviously APL is closely correlated to multiples of maintenance ME, so that the expression (eqn. (6))

TABLE III Energy requirements for a 600-kg cow producing 4%-fat milk, calculated for the different energy systems No. in Appendix

Country

System

Unit

Maintenance

Milk yield day -1 (kg) 10

1 3 4

11 12 13 14 15 16 17 18

F.R.G. Denmark (DK) Norway (N) and Finland (SF) G.D.R. Sweden (S) U.K. (GB) U.S.A., Israel (US) Ireland (IRL) The Netherlands and Belgium France F.R.G. (D) and Austria Greece (GR) Switzerland ( CH ) Yugoslavia (YU) Italy Hungary (H) Rumania

19 19

U.S.S.R. (a) (SU) U.S.S.R. (b) (SU)

5 6 7 8 9 10

20

30

Starch equivalent Scandinavian feed unit Fattening feed unit

SEK (g) SFU (DK) (kg) FFU (kg)

3168 4.0 4.6

5918 8.0 8.6

8668 12.0 12.6

11418 16.0 16.6

Net energy fattening Metabolizable energy Metabolizable energy Net energy lactation Metabolizable energy Feed unit for milk

EFr (g) ME(S) (Mcal) ME (GB) (MJ) NEL ( US ) (Mcal) ME ( IRL ) (MJ) VEM (g)

3152 14.7 63 9.7 63 5013

6002 26.7 116 17.1 116 9486

8852 38.7 169 24.5 169 14105

11702 50.7 222 31.9 222 18869

Unit~ fourag~re lait Net energy lactation Net energy lactation Netto Energie Milch Net energy milk Unith foraggere Net energy lactation Unitatilor nutritive la rumetagoare Oat feed unit Metabolizable energy

UFL (kg) NEL(D) (MJ) NEL(GR) (MJ) NEL(CH) (MJ) NEL(YU) (MJ} UF (kg) NEL (H) (MJ) UN (kg)

5.0 35.5 35.5 35.5 35.5 5.0 40.6 3.7

9.3 67.2 67.2 66.9 66.5 9.3 71.5 6.7

13.6 98.9 98.9 98.3 97.5 13.6 102.5 9.7

17.9 130.6 130.6 129.7 128.5 17.9 133.5 10.7

OFU (kg) ME (SU) ( M J)

5.1 65

10.1 125

15.1 177

21.2 237

bO

t~ bD

TABLE IV Energy requirements for growing bulls gaining 1 kg d a y - 1, calculated for different European energy systems No. in Appendix

Country

1 2 3 4 5 6 7 9 10

F.R.G. and Austria Belgium Denmark (DK) Norway and Finland G.D.R. Sweden (S) U.K. (GB) Ireland (IRL) The Netherlands

11 13 14 15

France Greece Switzerland (CH) Yugoslavia (YU)

16 17

Italy Hungary

18

Rumania

19 19

U.S.S.R.(a) (SU) U.S.S.R.(b) (SU)

System

Starch equivalent Starch equivalent Scandinavian feed unit Fattening feed unit Net energy fattening Metabolizable energy Metabolizable energy Metabolizable energy Feed unit for growth and fattening Unitd fourag~re viands Modified starch value Netto Energie Mast Net energy for growth and fattening Unith foraggere Net energy for beef Unitatilor nutritive la rumetagoare Oat feedunit Metabolizable energy

Unit

Liveweight (kg) 200

400

SEK (g) S E ( N L ) (kg) S F U ( D K ) (kg) FFU (kg) EFr (g) M E ( S ) (Mcal) M E ( G B ) (MJ) ME(IRL) (MJ) VEVI (g)

2800 3.5 3.5 3.8-4.0 2313 58 56 56 4100

4300 4.9 5.8 5.8-6.0 3830 88 93 93 7400

UFV (kg) MSV (g) NEV(CH) (MJ) NEM (YU) (MJ)

3.8 3500 28.5 27.9

6.1 5500 43.8 44.8

8.2 6500 57.9 60.2

UFV (kg) NEm and NEg (MJ) UN (kg)

3.8 28.1

6.1 47.2

8.2 64.1

3.3

4.8

6.2

OFU (kg) ME (SU) (MJ)

6.6 55.0

9.1 85.0

notavailable notavailable

600

58OO 6.4 9.7 5034 115 114 114 1O500

227

above can be modified to accomodate plane of nutrition correction as well if desired. APL and FL are correlated by

APL=km+kg ( F L - 1) km

(7)

The Dutch/Swiss/Belgian systems for growing cattle do not include a variable plane-of-nutrition correction factor in the calculation of NEmg. In fact a correction should be included in these beef systems, but it was decided not to do so because the correction factor would be very small, fluctuating between 0.996 and 0.986 for FL between 1.2 and 1.8, respectively. However in the case of dairy cattle, a correction of 1.8% per multiple of maintenance was applied in the Dutch/Swiss/Belgian systems, and an average plane of nutrition of 2.38 × maintenance (requirement of a 550-kg cow producing 15 kg FCM) assumed. All NE~ values are therefore corrected by 0.9752 to allow for this. This correction for plane of nutrition should be applied to the ration consumed. Therefore a fixed level is chosen to express the energy value and deviations from that level of feeding are taken into account in the standards both for dairy and beef cattle. Feeding trials have been used to test or derive these standards.

Measurement or calculation of metabolizable energy content of animal feeds Measurement of M E The accurate measurement of the ME of a feed requires the use of a respiration calorimeter to measure the methane production over a 24-hour period or longer. Calculation of ME as a constant proportion of DE Because of the high cost and limited availability of such facilities, approximations have been introduced, to calculate either methane energy from digested organic matter (Blaxter and Clapperton, 1965), or methane and urine energy as a constant fraction, 0.19 of digested energy, DE (Armstrong, 1964) ME=0.81 DE

(8)

Calculation of M E from digestible organic matter Since the organic matter of many cereals and forages has a GE of about 19 MJ kg -1, eqn. (8) above can be converted into a general conversion factor applicable to the results of nearly all digestibility trials and to in vitro results from the Tilley and Terry (1963) technique, i.e. M E (MJ kg -1 D M ) = 0 . 0 1 5 DOMD (g kg -1 DM)

(9)

Alternatively, the results of digestibility trials, where full Weende chemical analyses (XP, XL, XF, XX) (Henneberg and Stohmann, 1960) have been

228 TABLE V Equations used for the calculation of ME as an intermediary step or as a final equation in the system concerned (ME (in kJ kg-1 DM) =a.DXP+b.DXL+c.DXF+d.DXX+e). Country

System code

a

b

c

G.D.R. Sweden (S)

EFr ME(S) ME(GB) NE(D) NE(US) VEM

37.9 20.9/ 36.81 34.2 34.2 41.9

13.4 14.8 12.1 15.5

U.K. (GB) F.R.G. (D) U.S.A. The Netherlands (NL) Fodder maize products Other fresh or preserved green fodders Other feedstuffs France (F)

17.7 18.0/ 18.8' 15.2 15.2 18.6 15.5 20.1 15.9 23.9

15.5 14.2 37.7 39.7

15.5 14.2 13.8 20.0

UFL

d

e

12.8 15.9 12.8 15.9 3 18.6 18.6 -1883 15.5 14.2 ,.2 14.6 3 17.4 1

1SeeAppendix I of the report of van der Honing and Steg (1984). 2With exceptions. 3Minus mono- and disaccharides if > 8%. DXP, DXL, DXF and DXX are in g kg- 1DM. carried out on feed and faeces, can be used to predict M E c o n t e n t of feeds, using regression equations derived from the results of bot h chemical analyses and calorimetric measurements. M a n y are derived from the work at the Oskar Kellner Institute at Rostock, G.D.R. ( S c h i e m a n n et al., 1971 ). Examples of equations used in various countries are shown in Table V. T h e results of calculating M E values of feeds by the various equations are tab u lated in Table VI for about 30 c o m m o n feeds for ruminants. T h e y are also expressed as a percentage of t he value for barley in each different system.

Comparison of energy values from different systems and conversion between units Nearly all energy units, w h e t h e r starch equivalent or based on metabolizable energy values of feeds, as in the r ecent l y-i nt roduced systems, are derived from digestibility trials with sheep or cattle. Variations in the digestibility of animal feeds are large, varying from 35% for cereal straws to over 85% for maize grain, a greater t h a n 2-fold variation. N o t surprisingly, therefore, there is a high degree of correlation between units, when expressed as the correlation coefficient, r. Values greater t h a n 0.90 are usually found, statistically highly significant (Van der H o n i n g and Steg, 1984, Table I X ) . T h i s implies t h a t relatively small errors are incurred when converting from one unit to another, providing the correct equation is used (see below). T o assist the reader in

TABLE VI ME-values according to 7 systems ( see appendix ) in MJ kg ' and relative to barley ( % ) (for system codes see Table I ) Feedstuff

ME in system ( MJ k g - l DM )

ME in system relative to barley ( % )

EFr

ME(S)

ME(GB)

NEL(H)

NEL(US)

VEM

NEL(D)

EF t

ME(S)

ME(GB)

NEL(H)

NEL(US)

VEM

NEL(D)

Fresh grass: early cut Fresh grass: late cut Grass silage: unwilted Grass silage: unwilted late Wilted grass silage Wilted grass silage: mod. qual. Grass hay: good qual. Grass hay: mod. qual. Fresh alfalfa: early cut Fresh alfalfa: late cut Alfalfa hay: reed. qual. Maize silage: milky stage Maize silage: dough stage Wheat straw Barley straw Fodder beets Barley (grain) Maize (grain) Peas Wheat bran Maize gluten feed Beet pulp Beet molasses Cane molasses Brewers' grains Citrus pulp Tapioca Coconut expeller Coconut meal' Rapeseed meal' Soyabean meal' Fat (veg. origin)

12.1 10.2 10.5 9.1 10.5 9.3 10.0 8.8 9.8 8.6 8.4 10.1 10.6 5.8 6.5 12.6 12.9 13.7 13.3 11.2 12.9 11.8 12.1 10.4 11.2 12.6 11.9 13.8 11.7 11.4 14.0 35.9

12.0 10.1 10.0 8.6 10.1 8.8 9.9 8.6 9.7 8.5 8.3 9.9 10.5 5.6 6.3 13.1 13.4 14.2 13.9 11.5 13.3 12.1 12.6 10.9 10.9 12.8 12.5 14.0 12.1 11.9 14.6 34.9

11.7 10.1 10.4 9.0 10.4 9.1 9.9 8.8 9.5 8.4 8.2 10.3 10.9 5.8 6.5 13.3 13.4 14.3 13.3 11.2 12.7 12.3 12.7 11.2 10.6 13.1 12.8 13.4 11.5 10.8 13.1 32.5

11.8 10.3 10.5 9.3 10.5 9.3 10.1 9.0 9.7 8.7 8.5 10.4 10.8 6.2 6.9 12.8 12.9 13.7 13.0 10.9 12.5 12.1 12.1 10.7 10.6 12.8 12.2 13.3 11.4 10.6 13.0 32.3

12.7 10.8 11.1 9.6 11.1 9.6 10.5 9.2 10.0 8.8 8.6 10.9 11.4 5.7 6.6 13.9 14.0 15.0 14.1 11.6 13.5 13.1 13.1 11.2 ll.1 13.9 13.2 14.5 12.2 11.2 14.1 37.9

11.8 9.9 9.9 8.7 10.1 8.9 9.7 8.7 9.9 8.7 8.6 9.9 10.4 5.8 6.5 12.0 12.6 13.5 12.8 10.9 12.5 11.6 11.5 9.9 10.8 12.3 11.8 13.4 11.3 10.8 13.1 35.7

11.7 10.1 10.4 9.0 10.4 9.1 9.9 8.8 9.5 8.4 8.2 10.3 10.9 5.8 6.5 12.8 13.4 14.3 13.3 11.2 12.7 12.1 12.3 10.7 10.6 12.9 12.8 13.3 11.4 10.8 13.1 32.4

93.3 79.0 81.1 70.6 81.6 71.6 77.0 67.8 75.7 66.9 65.2 78.4 82.0 44.8 50.2 97.2 100.0 106.3 103.0 86.8 100.0 91.7 93.8 80.6 86.4 97.4 92.4 106.7 90.8 88.2 108.1 278.2

89.2 74.9 74.0 64.1 74.9 65.8 73.3 64.3 72.2 63.5 61.9 73.4 77.9 41.5 46.6 97.1 100.0 106.0 103.4 85.9 98.6 89.9 94.1 81.2 81.0 95.1 92.9 104.3 89.9 88.7 108.8 259.9

87.7 75.3 77.5 67.6 77.7 68.3 73.8 65.5 70.7 62.9 61.4 77.0 81.3 43.2 48.6 99.7 100.0 107.1 99.5 83.9 95.3 91.6 95.0 83.8 79.5 97.9 96.0 99.9 86.1 80.8 97.9 242.7

91.8 80.2 81.8 72.2 81.9 72.5 78.2 70.0 75.0 67.4 65.9 80.5 84.1 47.9 53.6 99.7 100.0 106.7 100.8 84.9 97.2 94.3 94.4 82.8 82.1 99.9 95.0 103.2 88.9 82.7 100.7 251.1

90.7 77.5 79.3 68.4 79.5 68.8 75.2 66.0 71.6 63.0 61.4 77.9 82.0 40.8 47.3 99.7 100.0 107.6 100.9 82.8 96.8 93.5 93.6 80.5 79.6 99.8 94.3 103.6 87.4 80.3 100.8 271.5

93.1 87.7 78.6 75.3 78.3 77.5 69.1 67.6 79.6 77.7 70.4 68.3 76.9 73.8 69.0 65.5 77.9 70.7 68.9 62.9 67.6 61.5 78.4 77.0 82.6 81.3 46.1 43.3 51.6 48.6 94.7 96.0 100.0 100.0 106.9 107.1 101.5 99.6 86.1 83.9 98.9 95.3 91.9 90.9 90.7 91.7 78.3 80.3 85.2 79.5 97.6 96.8 93.5 96.0 105.7 99.4 89.2 85.5 85.1 80.8 103.7 97.9 282.5 242.8

Average ( N = 3 2 ) SD (N-=32)

11.7 4.9

11.7 4.8

11.6 4.3

11.5 4.2

12.3 5.2

11.4 4.8

11.5 4.3

90.4 37.6

87.3 35.7

86.7 32.4

89.6 32.7

88.2 37.1

~D

1Solvent extracted.

90.0 38.1

86.3 32.4

t,D

TABLE VII

O

Energy values according to different feed evaluation systems (for system codes see Table I) Feedstuff

SEK

Fresh grass: early cut 700 Fresh grass: late cut 575 Grass silage: unwilted 602 Grass silage: unwilted late 503 Wilted grass silage 564 Wilted grass silage rood. qual. 470 Grass hay: good qual. 501 Grasshay: mod. qual. 414 Fresh alfalfa: early cut 536 Fresh alfalfa: late cut 446 Alfalfa hay: med. qual. 365 Maize silage: milky stage 594 Maize silage: dough stage 630 Wheat straw 143 Barley straw 203 Fodder beets 634 Barley (grain) 817 Maize (grain) 890 Peas 825 Wheat bran 567 Maize gluten feed 776 Beet pulp 615 Beet molasses 548 Cane molasses 514 Brewers'grains 575 Citrus pulp 747 Tapioca 800 Coconut expeller 855 Coconut meal' 710 Rapeseed meal 1 644 Soyabean meal' 804 Fat (veg.origin) 2287 Average (N--32) SD (N--32) ~Solvent extracted.

651 345

SE(NL)

SFU(DK)

FFU

TDN EFt

ME(S)

ME(GB)

NEL(H)

NEL(US)

VEM

UFL

NEL(D)

673 555 572 479 537 448 484 402 522 436 358 575 614 135 194 631 821 925 800 567 808 709 589 545 631 755 792 857 677 598 787 2847

0.974 0.722 0.745 0.650 0.757 0.670 0.715 0.567 0.716 0.561 0.541 0.725 0.760 0.196 0.276 0.919 1.129 1.177 1.212 0.935 1.088 0.941 0.952 0.799 0.855 1.012 1.067 1.293 1.073 1.075 1.339 3.050

0.900 0.697 0.741 0.658 0.746 0.664 0.694 0.565 0.642 0.510 0.494 0.749 0.790 0.204 0.289 0.967 1.142 1.220 1.146 0.911 1.040 0.969 0.968 0.856 0.801 1.067 1.143 1.260 1.014 0.930 1.126 3.267

78.1 639 68.2 561 69.5 587 61.4 517 69.7 582 61.6 513 66.5 545 59.5 487 63.8 510 57.3 459 56.1 445 68.5 570 71.6 591 40.7 336 45.6 377 84.8 678 85.0 693 90.7 762 85.7 671 72.2 607 82.6 693 80.2 637 80.3 635 70.4 567 69.8 633 84.9 707 80.8 650 87.7 797 75.6 612 70.3 548 85.6 643 213.5 2855

2.87 2.41 2.38 2.06 2.41 2.11 2.36 2.07 2.41 2.04 1.99 2.36 2.50 1.34 1.50 3.12 3.21 3.40 3.32 2.76 3.17 2.89 3.02 2.61 2.60 3.06 2.99 3.35 2.89 2.85 3.50 8.35

11.72 10.07 10.37 9.04 10.39 9.13 9.86 8.76 9.46 8.41 8.22 10.29 10.87 5.78 6.49 13.33 13.37 14.32 13.31 11.21 12.74 12.25 12.70 11.20 10.63 13.09 12.83 13.35 11.51 10.81 13.09 32.46

8.190 7.088 7.233 6.331 7.255 6.353 6.899 6.120 6.598 5.875 5.741 7.121 7.466 4.028 4.573 8.935 8.958 9.592 9.036 7.533 8.691 8.423 8.435 7.333 7.266 8.947 8.490 9.258 7.912 7.322 9.024 23.259

1.793 1.550 1.584 1.384 1.587 1.390 1.509 1.338 1.443 1.284 1.254 1.557 1.633 0.877 0.996 1.957 1.964 2.103 1.980 1.648 1.904 1.845 1.847 1.606 1.590 1.960 1.860 2.030 1.732 1.602 1.977 5.112

1026 832 829 712 845 729 810 712 823 710 694 858 915 444 506 1084 1126 1221 1137 928 1097 1029 1036 877 899 1108 1063 1179 971 904 1147 3524

1.022 0.845 0.878 0.743 0.872 0.752 0.841 0.730 0.713 0.685 0.825 0.885 0.435 0.502 0.965 1.148 1.224 1.147 0.911 1.106 1.035 1.096 0.923 0.830 1.146 1.050 1.140 0.965 0.918 1.176 2.938

7.18 6.00 6.31 5.35 6.27 5.39 5.87 5.11 5.54 4.83 4.69 6.18 6.62 3.11 3.56 8.39 8.55 9.30 8.43 6.81 7.94 7.71 7.99 6.88 6.25 8.33 8.35 8.28 7.00 6.43 8.10 21.95

666 436

0.922 0.471

0.912 0.501

659 2.81 413 1.14

11.60 4.34

7.978 3.095

1.747 0.682

992 499

0.977 0.405

7.15 3.09

76.2 27.8

0.820

231 making inter-conversions, tables of values for 30 common animal feeds, expressed in each of the units in use in Europe have been calculated. Table VI shows the results of ME values, calculated from digestible nutrients according to Table V. Since the values for the ME of barley grain vary between systems, the values are also tabulated in percentage terms, with the energy value of barley in the relevant unit set at 100 to compare between systems. The energy values of 30 feeds expressed in units of the various systems are given in Table VII. To allow comparison between the systems all these values are also scaled on the respective value of barley. This permits the use of specific factors of conversion between the systems for each particular feed. These conversion factors are not constant for the various feeds. Although constant conversion factors between systems do not exist, one can use average conversion factors or a regression equation derived from a great variety of feeds and accept at the same time minor inaccuracies. Average conversion factors are given in Table VIII. An even more accurate conversion requires the derivation of the appropriate regression equation, because both the slope and intercept need to be known in order to convert accurately at the extremes. These can be derived from the information tabulated, but space does not permit their inclusion here.

Description of European energy systems The authors have attempted to summarize the essential features of the energy systems at present in use in Europe. Use has been made of the published proceedings of a C.E.C.-funded seminar (C.E.C., 1980) on the energy and protein standards for beef cattle, particularly of the survey of energy feeding standards therein (Neimann-S~rensen, 1980), and of a review of feed evaluation systems for dairy cows, (de Brabander et al., 1983; van der Honing and Steg, 1984). Details of other systems have been obtained by correspondence with scientists, using the good offices of the E.A.A.P. Secretary General to establish contact. The diversity and complexity of the systems described may strike the reader as confusing and unnecessary. It is necessary, however, to remember the diverse range of crops, feeds and byproducts in each country, and also the indigenous native breeds of cattle and feeding practices which are of a longestablished nature. If workers in various countries have felt it necessary to adjust or modify published standards, to ensure a good fit to their own feeding trials, this is difficult to criticize on practical grounds, whatever difficulties it presents to the reviewer or to the peripatetic European nutritional adviser. The individual systems are described in the Appendix on energy systems for ruminants.

t~

TABLE VIII

tO

Energy values according to different feed evaluation systems relative to barley (for system codes see Table I ) Feedstuff

SEK

SE(NL)

S F U ( D K ) FFU

TDN EFr

ME(S)

ME(GB)

NEL(H)

N E L ( U S ) VEM UFL

Fresh grass: early cut Fresh grass: late cut Grass silage: unwilted Grass silage: unwilted late Wilted grass silage Wilted grass silage: mod. qual. Grass hay: good qual. Grass hay: mod. qual. Fresh alfalfa: early cut Fresh alfalfa: late cut Alfalfa hay: reed. qual. Maize silage: milky stage Maize silage: dough stage Wheat straw Barley straw Fodder beets Barley (grain) Maize (grain) Peas Wheat bran Maize gluten feed Beet pulp Beet molasses Cane molasses Brewers grains Citrus pulp Tapioca Coconut expeller Coconut meal I Rapeseed meal 1 Soya bean meal ~ Fat (veg.origin)

85.7 70.4 73.7 61.6 69.0 57.5 61.3 50.7 65.6 54.6 44.7 72.7 77.1 17.5 24.8 77.6 100.0 108.9 101.0 69.4 95.0 75.3 67.1 62.9 70.4 91.4 97.9 104.7 86.9 78.8 98.4 279.9

82.0 67.6 69.7 58.3 65.4 54.6 59.0 49.0 63.6 53.1 43.6 70.0 74.8 16.4 23.6 76.9 100.0 112.7 97.4 69.1 98.4 86.4 71.7 66.4 76.9 92.0 96.5 82.5 72.8 95.9 346.8

86.3 64.0 66.0 57.6 67.1 59.3 63.3 50.2 63.4 49.7 47.9 64.2 67.3 17.4 24.4 81.4 100.0 104.3 107.4 82.8 96.4 83.3 84.3 70.8 75.7 89.6 94.5 114.5 95.0 95.2 118.6

91.9 80.2 81.8 72.2 82.0 72.5 78.2 70.0 75.1 67.4 66.0 80.6 84.2 47.9 53.6 99.8 100.0 106.7 100.8 84.9 97.2 94.4 94.5 82.8 82.1 99.9 95.1 103.2 88.9 82.7 100.7

89.4 75.1 74.1 64.2 75.1 65.7 73.5 64.5 75.1 63.6 62.0 73.5 77.9 41.7 46.7 97.2 100.0 105.9 103.4 86.0 98.8 90.0 94.1 81.3 81.0 95.3 93.1 104.4 90.0 88.8 109.0

87.7 75.3 77.6 67.6 77.7 68.3 73.7 65.5 70.8 62.9 61.5 77.0 81.3 43.2 48.5 99.7 100.0 107.1 99.6 83.8 95.3 91.6 95.0 83.8 79.5 97.9 96.0 99.9 86.1 80.9 97,9

270.2

78.8 61.0 64.9 57.6 65.3 58.1 60.8 49.5 56.2 44.7 43.3 65.6 69.2 17.9 25.3 84.7 100.0 106.8 100.4 79.8 91.1 84.9 84.8 75.0 70.1 93.4 100.1 110.3 88.8 81.4 98.6 286.1

242.8

91.4 79.1 80.7 70.7 81.0 70.9 77.0 68.3 73.7 65.6 64.1 79.5 83.3 45.0 51.0 99.7 100.0 107.1 100.9 84.1 97.0 94.0 94.2 81.9 81.1 99.9 94.8 103.4 88.3 81.7 100.7 259.6

91.3 78.9 80.7 70.5 80.8 70.8 76.8 68.1 73.5 65.4 63.8 79.3 83.1 44.7 50.7 99.6 100.0 107.1 100.8 83.9 96.9 93.9 94.0 81.8 81.0 99.8 94.7 103.4 88.2 81.6 100.7 260.3

91.1 73.9 73.6 63.2 75.0 64.7 71.9 63.2 73.1 63.1 61.6 76.2 81.3 39.4 44.9 96.3 I00.0 108.4 101.0 82.4 97.4 91.4 92.0 77.9 79.8 98.4 94.4 104.7 86.2 80.3 101.9 313.0

79.8 42.3

81.2 53.2

81.6 41.8

79.8 43.9

86.7 32.4

89.1 34.5

88.9 34.7

88.2 44.3

Average (N = 32 ) SD ( N = 3 2 ) 1Solventextracted.

104.4

92.2 81.0 84.7 74.6 84.0 74.0 78.6 70.3 73.6 66.2 64.2 82.3 85.3 48.5 54.4 97.8 100.0 110.0 96.8 87.6 100.0 91.9 91.6 81.8 91.3 102.0 93.8 115.0 88.3 79.1 92.8

251.2 412.0 260.1

89.6 32.7

95.2 59.6

87.5 35.7

NEL(D)

89.0 84.0 73.6 70.2 76.5 73.8 64.7 62.6 76.0 73.3 65.5 63.0 73.3 68.7 63.6 59.7 71.4 64.8 62.1 56.5 59.7 54.9 71.9 72.2 7 7 . 1 77.4 37.9 36.4 43.7 41.6 84.1 98.1 100.0 100.0 106.6 108.8 99.9 98.5 79.4 79.6 96.3 92.9 90.2 90.2 95.5 93.5 80.4 80.5 72.3 73.1 99.8 97.4 91.5 97.7 99.3 96.8 84.1 81.8 80.0 75.2 102.4 94.7 255.9 256.7 85.1 35.3

83.6 36.2

233

Approach to a common energy feed unit F o r p l a n n i n g p u r p o s e s o n a large scale in a region, a c o u n t r y or a n u m b e r o f countries, t h e r e is a n e e d for a c o m m o n u n i t for t h e n u t r i t i v e value o f feed resources to be able to p r e d i c t t h e p o t e n t i a l for a n d scale of a n i m a l p r o d u c t i o n . A u n i t b a s e d o n e n e r g y value is v e r y suitable, a l t h o u g h t h e p r o t e i n resources m i g h t also be a vital e l e m e n t o f such p l a n n i n g . T h e e n e r g y available to t h e a n i m a l will be used for d i f f e r e n t p u r p o s e s e.g. m a i n t e n a n c e , milk yield, wool p r o d u c t i o n , m e a t p r o d u c t i o n , egg p r o d u c t i o n etc., b u t with differences in efficiencies o f utilization of digestible or m e t a b o l izable energy. T h u s it is a p p r o p r i a t e to use M E as a c o m m o n base a n d c o n v e r t b y m e a n s of t h e efficiency of utilization to t h e d i f f e r e n t t y p e s of a n i m a l production. T o e s t i m a t e t h e a n i m a l p r o d u c t i o n p o t e n t i a l which is possible with a c e r t a i n q u a n t i t y of feed, r e l e v a n t average values could be used regardless of t h e f o r m u l a t i o n of t h e r a t i o n a n d l i m i t a t i o n s to feed c o n s u m p t i o n . F o r p l a n n i n g on a f a r m scale or for individual animals, however, one needs a precise calculation w i t h m u c h m o r e d a t a for a d e q u a t e prediction. S t u d y i n g the i n f o r m a t i o n in this c h a p t e r it is clearly n e c e s s a r y to define a u n i t which can easily be u n d e r s t o o d b y non-specialists. T h u s we p r o p o s e as a c o m m o n e n e r g y feed u n i t t h e q u a n t i t y o f M E in 1 kg of barley. T h e average M E of b a r l e y in t h e tables o f t h o s e c o u n t r i e s or systems, w h e r e m e a s u r e m e n t s TABLE IX ME and NE values of barley for dairy cattle presented in some national feed tables (I) or calculated using standardized composition and digestibility coefficients (II) (van der Honing and Steg, 1984) Country/system

Denmark, SFU (DK) France, UFL F.R.G., NEL (D) G.D.R., EFr Hungary, NEL (H) The Netherlands, VEM Rumania, UN (RO) Sweden, ME (S) Switzerland, NEL (CH) U.K., ME (GB) U.S.A., Israel, NEL (US) Average1 SD

ME in MJ kg-1 DM

NE in MJ kg- 1 DM

I

II

I

II

12.7 13.26 13.07 13.07

13.5 12.62 12.8 13.56

13.13 13.36 12.92 12.9 12.65 13.44 12.65 13.37 13.96

9.1 8.40 8.33 7.35 7.76 7.77 7.80 7.99

8.91 8.31 8.55 7.28 8.96 7.76 7.76 8.22

13.07 + 0.39

13.18 _+0.45

7.84 ___0.35

8.26 _+0.46

12.65

ISFU and EFr-values, which are based on fattening animals, are omitted.

234 TABLE X Quantity of barley dry matter (kg) to meet the energy requirements of a 600 kg cow, producing 20 kg of energy corrected milk without body energy gain or loss Country/system

Denmark, SFU (DK) France, UFL F.R.G., N E L ( D ) G.D.R., EFr The Netherlands, VEM Sweden, M E ( S ) Switzerland, NEL (CH) U.K., M E ( G B ) U.S.A., Israel, NEL (US)

Requirement ( MJ )

Energy value of barley (MJ k g - 1 DM)

ME

ME

NE 94.7 98.4 98.9 92.9 97.4

161.9

AverageI SD

NE 9.10 8.40 8.33 7.35 7.76

13.5 98.3

169.0 171.2

Quantity of barley required (kgDM)

102.5

7.80 12.8 13.56

7.99

10.41 11.71 11.87 12.65 12.55 11.99 12.60 13.20 12.63/12.832 12.42 + 0.52

1SFU and EFr omitted (see Table IX). 212.63 from ME, 12.83 from NE.

in vivo have been performed, is close to 13 MJ ME kg -1 DM of barley (Table IX). There is some variation between countries owing to small differences in the composition and digestibility of nutrients in barley. As the DM content of barley can vary, it is necessary to define this energy feed unit on a DM basis, although it can be converted to 11.2 MJ ME in 1 kg barley with 86% DM. Variations in the ME value of barley may be compensated for by differences in the requirements of the animal. Therefore we calculated the amounts of barley which would be necessary to meet the requirements of a cow and a bull with standardized performance, notwithstanding that the farmer would not feed barley as the only feedstuff in the ration for ruminants. Table X shows that the theoretical quantity of barley to meet the requirements of a cow (600 kg liveweight, 20 kg energy-corrected milk) varies between 11.7 kg DM and 13.2 kg DM (average 12.4 kg DM), omitting those values which are based on fattening values. The calculation for a growing bull (400 kg, gaining 1000 g day- 1) shows a larger variation (5.0-6.9 kg DM) in quantity of barley required than for the cow (Table XI). This is understandable because energy per kg liveweight gain varies widely across Europe owing to differences in breed and feeding system.

235 TABLE XI

Quantity of barley dry matter to meet the energy requirement of a growing bull of 400 kg liveweight, gaining 1000 g d a y Country/system

Requirement (MJ)

ME Belgium, SE (NL)

Quantity of barley required

(MJ kg -1 DM)

{kg DM)

ME

49.0 45.8 47.3 43.0 40.2 47.2 51.1 47.0 50.2

Denmark, SFU ( D ) France, UFL F.R.G., SEK G.D.R., EFr Hungary (NEro; NE~) The Netherlands, VEVI Norway, Finland, FFU Rumania, UN (RO) Sweden, ME (S) Switzerland, NEV (CH) U.K., ME (GB)

NE

Energy value of barley

88.0

8.21 9.07 9.00 8.00 7.35 8.20; 5.48 8.47 7.89 7.77 13.5

43.8 81.8

NE

8.50 12.8

6.0 5.0 5.3 5.4 5.5 6.9 6.0 6.0 6.5 6.5 5.2 6.4

SYSTEMS FOR PROTEIN EVALUATION OF FEEDS AND PROTEIN REQUIREMENTS OF RUMINANTS

Introduction In the last decade, a number of new protein requirement systems have been published from research workers in the U.S.A. and Europe. These introduce new concepts and require new methods for the evaluation of the protein content of ruminant feeds. They are replacing the Digestible Crude Protein (DXP) system which has been in use in Europe for nearly a century. Crude protein is measured in the laboratory as total nitrogen ( N ) , multiplied by 6.25, the average ratio of protein to N in animal feeds. Non-protein nitrogen compounds ( N P N ) , such as urea, ammonia and nitrate, are included in this method of calculation. Since the ruminant is able to utilize such N P N compounds to some degree in the rumen, this introduces variability on the responses to diets which contain them, when they are evaluated by their D X P content. Attempts have been made to adjust for this by assigning a value of only one half to crude protein present as NPN. The responses obtained from varying the D X P intake of ruminants have been shown to be influenced by the source of the crude protein and by the energy supply as well as other factors. Accurate D X P requirements can only be determined by feeding trials for each class of animal, level of production

236 and basal forage fed. Advisers vary in their interpretation and use of DXP allowances, using their experience of particular animal production systems and feeds. The DXP system ignores the central role of microbial fermentation in the 2-stage digestive system of ruminants. Responses to changes in dietary intake which may be due to microbial responses in the rumen, or to the nature of the undegraded feed particles undergoing digestion in the abomasum and intestines of the animal, are not explained satisfactorily by changes in DXP intake.

Digestion and absorption of protein in ruminants Ruminants are so called because they have a 4-compartment stomach, the largest compartment, 85% in volume, being the rumen. This contains a specialized microbial population, both bacteria and protozoa, which digest the feed eaten, producing metabolites of use to the animal. Digestion of cellulose, starch and sugar in the feed give rise to large amounts of volatile fatty acids, acetic, propionic and butyric acids, which are absorbed and used by the animal. Much of the feed protein is broken down or "degraded" via peptides and amino acids to ammonia. These are then partly used for the synthesis of microbial protein, which cannot be absorbed in the rumen. On average about 65 % of the digestible organic matter in a diet will be "degraded" in the rumen. The contents of the rumen are continually being passed on to the fourth compartment, the abomasum, and thence to the intestines, where a non-ruminant type of digestion by the use of secreted enzymes takes place. The digesta, however, consists of a mixture of "undegraded" feed protein and microbial protein, with the latter being 50-70% of the total protein flow. Microbial protein has an amino-acid composition which is generally well suited to the animals' needs. The protein actually digested by the ruminant animal therefore differs considerably from the composition of the protein in the original diet. Because of this ability, ruminants can utilize feed resources containing poorer quality protein than other farm animals, but still produce high-quality proteins such as milk and meat. Ruminants can also utilize sources of non-protein nitrogen, such as urea and ammonia, because these can enter the synthetic pathways of the rumen microbes, provided adequate energy is available to the microbes from carbohydrate degradation. This interdependence of energy supply and microbial protein synthesis is central to the protein metabolism of ruminants. The DXP system contains no such relationship.

New systems: concepts and definition of terms General A total of six new national protein-requirement systems have been published since 1977. In chronological order, these are: (1) the British R D P / U D P system

237 of Roy et al. (1977), subsequently published as A.R.C. (1980) and revised A.R.C. (1984) ; (2) the French "Protein digested in the Intestine" or PDI system, I.N.R.A. (1978, revised 1987); (3) the Swiss ("Absorbable Protein in the Intestine" or API system of Landis (1979, 1984), derived from the French PDI system; (4) the F.R.G. "Crude Protein Flow at the Duodenum" system; Rohr et al., Anschuss fiir Bedarfsnormen (1986), see Addendum; (5) the Nordic AAT-PBV system, based on "Amino acids truly absorbed in the small intestine", AAT and "Protein balance in the tureen", PBV; N K J / N K F (1985); (6) the U.S.N.R.C. "Absorbed Protein", AP system, based on absorbed true protein requirements, N.R.C. (1985).

Terminology All the new systems are based on the same concepts, illustrated diagrammatically in Fig. 2, and in tabular form in Table XII, identified by the conventional country code letters. The essential elements of all systems are outlined in the following section, using mainly the terminology of Waldo and Glenn (1982a). (a) Degraded dietary crude protein, RDP. This part of crude protein will be metabolized by rumen microbes to peptides and ammonia. Most of it may be converted to microbial crude protein ( M X P ) . (b) Microbial crude protein, MXP. The synthesis of microbial protein depends on sufficient energy being available to the microbes mainly from the degradation of carbohydrates in the feed. It is usually postulated that MXP can be predicted from energy intake expressed as ME or NE as MJ day -1, or alternatively from digestible organic matter (DOM) as kg day-1. ME or NE and DOM are correlated, depending upon the nature of the feed. As a mean value, 1 kg DOM could be taken to be equivalent to 15.6 MJ ME or 9.4 MJ NE~. The Nordic system is unique in predicting MXP from digestible carbohydrates. This is because fat and protein are not sources of energy for rumen microbes. (c) Efficiency of conversion of RDP to MXP, MXP/RDP. Most systems define an efficiency of capture of N from feed protein into microbial crude protein as being 1.0 when XP intake is limiting. Only the U.S.N.R.C. system gives a lower maximal efficiency, 0.9. When XP intake is in excess, efficiency is < 1, but MXP synthesis is then limited by energy supply. The efficiency of capture of N P N is stated to be only 0.8 by A.R.C. (1980). (d) Undegraded dietary crude protein. The remainder of the feed crude protein that is not degraded by microbial action in the rumen, passes unchanged to the abomasum and intestines. It is there subjected to enzymatic digestion, resulting in further absorption of amino acids into the animal body. (e) Proportion of true protein in microbial crude protein, M T P / M X P . Microbial crude protein contains a significant proportion of nucleic acid N, which cannot be used by the animal to synthesize tissue proteins or milk. The pro-

238 Crude protein intake (IXP)

Energy intake I (as HE or DOM or DCHO)

I

Ef feccive degradability, p

HXPIME

or MXPIDOM

l-p

Degraded dietary XP (RDP)

8.4 - 10.3 g/Md .13 - .16

I Undegraded dietary i XP (UDP) I

I

or MXP/DCHO .179

~e/ZDP,

, o.8-1.o

I

l -I

'

Microbial crude protein (~c~)

~/~'

i I

1

I

'I

MTPIHXP, 0.7-0.8

I

l I

[

_J

Microbial true protein

~///~//~

(MTp)

[

I

)

I DUDP/UDP, 0.6-0.9 ]

L

DMTP/MTP, 0.7-0.9

Digestible ~P

,....,F+~,lXP I

,

-

p'/~

D

~J

/

~

MFN related to DMI

I Metabollc faecal N (MFN)

I

I

Total absorbed amlnoacids (TAA)

I

kn, 0.6-0.8 (u~) Tissue

proteins:

maintenance,

l a c t a t i o n , growth

- indicates losses since the preceeding step

Fig. 2. Scheme showing terms used to describenew ruminant protein systems and how they relate to one another (see also Table VII).

239 TABLE XII Factors in the utilization of protein by ruminants Factor

Microbial crude protein/ degraded dietary crude protein Microbial crude protein/digestible organic matter Microbial crude protein (g MJ -1 metabolizable energy) Microbial crude protein/digestible carbohydrate Microbial true protein/microbial crude protein Digestible microbial true protein/microbial true protein Digestible microbial true protein/microbial crude protein Digestible undegraded dietary protein/ undegraded dietary protein Metabolic faecal protein/feed dry matter Metabolic faecal protein/indigestible feed dry matter Tissue protein (amino acid)/absorbed amino acids: Maintenance Lactation Growth Wool/hair

Protein system GB

F1

CH

D

NKJ/ NKF

US

0.81.0

1.0

1.0

0.95

V

0.9

0.130

0.135

0.135

0.161

8.4

8.7

8.7

10.1b

10.3

9.6c

n.s.

n.s.

n.s.

n.s.

0.179

n.s.

0.80

0.80

0.80

0.73

0.70

0.80

0.85

0.70

0.70

0.90

0.85

0.80

0.68

0.56

0.66

0.80

0.66

0.60 0.530.702

0.64

0.85

0.56 0.600.952

n.s.

n.s.

n.s.

0.0182

n.s.

n.s.

n.s.

0.79 0.80 0.80 0.80

(M) 0.67 0.60 n.s.

(M) 0.67 0.60 n.s.

0.165

0.14a

0.80

n.s.

n.s.

n.s.

n.s.

0.09

0.80 0.80 0.80 n.s.

(M) 0.75 n.s. n.s.

0.67 0.65 0.50 0.15

~System revised late 1987, see Addendum to Appendix. 2Variation according to class of feed. n.s. = Not stated; 000 (figures underlined) -- an approximation; V = variable; (M) -- maintenance requirement estimated from N-balance or feeding trials. For a, b, c, see Appendix for full relationship. p o r t i o n M T P / M X P is s t a t e d to be e i t h e r 0.7 or 0.8, d e p e n d i n g on t h e s y s t e m under consideration. (f) Digestibility of m i c r o b i a l t r u e protein, D M T P / M T P . Values for t h e prop o r t i o n of M T P digested a n d a b s o r b e d in t h e i n t e s t i n e s v a r y f r o m 0.7-0.9 in t h e d i f f e r e n t systems. (g) Digestibility o f u n d e g r a d e d d i e t a r y protein, D U D P / U D P . U n d e g r a d e d feed p r o t e i n varies in c o m p o s i t i o n a n d digestibility in t h e a b o m a s u m a n d intestines, d e p e n d i n g o n t h e origin a n d t r e a t m e n t o f t h e feed. N e v e r t h e l e s s , m o s t

240 systems assign a constant value of either 0.8 or 0.85 to this parameter. The Nordic system gives values of 0.53 for forages and 0.7 for concentrates, whilst the I.N.R.A. (1978) system values vary over the range 0.6-0.95, depending on the feed. (h) Efficiency of utilization of absorbed amino acids, kn. The efficiency of utilization of absorbed amino acids is stated in the various systems on the assumption that all absorbed amino acids are used specifically for protein synthesis in the organism. Non-specific use for other components of metabolism, such as fat synthesis, are not considered.

Measurement of protein degradability in ruminant leeds Laboratory methods of determining protein degradability have usually been based on measurements of protein solubility in buffer solutions (Henderikx and Martin, 1963; Burroughs et al., 1975; Crooker et al., 1978). Rumen liquor and purified bacterial-protease enzyme preparations have been used (I.N.R.A., 1978; Mahdevan et al., 1980), but the latter authors concluded that solubility or insolubility of protein is not of itself an indication of the protein's susceptibility to hydrolysis by rumen bacterial proteases. This view is now widely accepted, as a result of the use of the in situ dacron

1.0

L G

0.8

"~

i

0.6

0.4 0.2

F

0

TIME (t)

Fig. 3. Examplesof the relationshipbetweendegradabilityand time of incubation for 3 protein supplements. (G = Groundnutmeal;L = linseedmeal;F = fishmeal).

241 TABLE XIII Protein degradability values for ruminant feeds, after Madsen and Hvelplund (1985) and Rohr et al. (1985). (protein degradability, p, for an outflow rate, k, of 0.08 h- ~) Type of feed

Mean

SD

Group 1:p--0.40 (0.30-0.50) Blood meal Coconut meal Dried beet pulp Fish meal Maize grain Palmkernel meal

0.40 0.37 0.38 0.43 0.31 0.34

Group 2:p=0.55 (0.45-0.65) Dried brewers' grains Dried grass Cottonseed meal

0.49 0.54 0.56

Group 3:p=0.65 (0.55-0.75) Linseed meal Soya bean meal Meat and bone meal Molasses Maize silage Red clover silage

0.60 0.59 0.66 0.65 0.64 0.67

Group 4:p=0.75 (0.65-0.85) Barley grain Peas Rapeseed meal Sunflower meal Pasture grass Red clover Grass hay

0.70 0.77 0.68 0.73 0.70 0.76 0.74

0.07 0.04 0.06 0.05 0.11 0.03

Group 5:p=0.85 (0.75-0.95) Wheat Beans Fodder beet Grass silage Grass/clover silage

0.82 0.86 0.82 0.73 0.75

0.03

0.07 0.09 0.04 0.06

0.05 0.09

0.04 0.19 0.03

0.03 0.06 0.06

b a g t e c h n i q u e d e v e l o p e d b y O r s k o v a n d M e h r e z (1977). T h i s m e a s u r e s t h e loss of n i t r o g e n f r o m a s a m p l e of t h e feed p l a c e d in a d a c r o n b a g a n d s u s p e n d e d in t h e r u m e n for p e r i o d s o f u p to 72 hours. T h e zero t i m e v a l u e is o b t a i n e d b y w a s h i n g t h e b a g u n d e r cold w a t e r only. T y p i c a l r e s u l t s are p l o t t e d as s h o w n in

242

Fig. 3, and show the very different characteristics of some feeds. The proportions of soluble N, the rate of degradation and the amount not degraded differ between feeds. The average retention time in the rumen also affects the likely true degradability in vivo. In order to calculate a single parameter to use in the protein systems, Orskov and Mehrez used the exponential function

d g = a + b ( 1 - e -ct)

(1)

where dg = degradability; a = cold-water-soluble N; a + b = asymptote of curve, the potential maximum degradable N; c= rate of disappearance of N per hour; t = time in hours. Subsequent studies on outflow rates of feed particles from the rumen (Orskov et al., 1979), showed the necessity to correct for this factor. Rates vary from 0.02 h - 1 for animals at maintenance to 0.08 h - 1 for high producing dairy cows. This is done by substituting the constants fitted to the data by the use of eqn. (1) above, into eqn. (2) below to calculate the effective degradability, p, for the mean outflow rate h-1 from the rumen, k

p=a+bc/(c+k)

(2)

Because the dacron bag technique is an in vivo one and influenced by both type of animal and diet fed, standardization of the procedure is needed to get accurate results. Typical degradability values for some common feeds are shown in Table XIII. FUTURE DEVELOPMENTS IN FEED EVALUATION AND NUTRIENT REQUIREMENTS IN RUMINANTS

Analysis of feedstuffs The routine analysis of feedstuffs is still far from ideal (e.g. Weende analysis) and should be improved to measure well-defined components, in order to improve the quantification of the building blocks and energy sources which are utilized by the animal.

Information technology The scientific basis of protein and energetic feed evaluation systems is very important, particularly for application in practice, but farmers and feed manufacturers often focus their interest on accurate, but simple prediction methods for nutritive value. Moreover these methods should be quick and easy to execute. Developments in information technology have enabled the development of large databases, which contain a lot of accurately-measured data on energy, protein and other nutrients and their digestibilities from a wide range of feedstuffs.

243 Prediction of energy and protein values Energy and protein values of feedstuffs can be most accurately predicted from information on the digestibility of nutrients. The laborious and expensive nature of the technique required to measure digestibility coefficients with animals resulted in a search for alternatives to predict them from chemical analysis, which are still in use. Crude fibre predicts digestibility of organic matter ( doM ) in forages reasonably well if regression equations were derived for each type of forage. The van Soest analysis with detergents (ADF, NDF, ADL) aiming at a better description of the fibrous components, however, did not result in a successful improvement in the prediction of doM, mainly because the reproducibility and precision of these analyses (of ADL in particular) was rather poor (van Es, 1986). A subsequent trend was to imitate the ruminant's digestive processes in vitro, either with rumen liquor (Tilley and Terry, 1963) or with industriallyavailable enzymes. If sufficient precautions were taken to standardize for variation in the enzyme concentration of rumen liquor and for other factors (by using reference samples of known doM in vivo in each run) these methods result in a better prediction (van der Meer, 1984). These methods are still laborious, and require days of incubation before results can be obtained. This is also the case with "Menke's Gasbildungstest", where dOMhas to be derived from the amount of gas produced during incubation of a feed sample with rumen liquor (Menke et al., 1979). All these methods require careful calibration with sufficient samples with a known doM in vivo of the same feedstuff as is to be tested. A rapid prediction within a few minutes seems to be possible with reasonable accuracy by the method of near-infrared reflectance (NIR) spectroscopy, as was concluded at a C.E.C. seminar in Brussels and at a workshop at Braunschweig in 1985. This method is based on the absorption of near-infrared light (1100-2500 n m ) at various wavelengths dependent on the composition of the sample. The reflected light can be analysed and used to predict chemical composition. Even more than with the earlier methods, extensive calibration is required using a large set of samples of the type of feedstuffs to be tested of known composition or digestibility with a wide range of variation. From this calibration, regression equations are derived to predict with sufficient precision, in similar samples, the required parameter. In the beginning this method was used to predict the chemical composition of feeds, and digestible organic matter or protein was derived indirectly from that predicted chemical parameter. More recently, direct prediction of doM has been investigated and will be introduced in practice in the near future (van Es, 1986). One problem is the lack of sufficient samples of known doM in vivo to calibrate the NIR-method properly, but the idea is that additional samples with known doM in vitro can be used successfully as complementary information ( van Es, 1986).

244

Similar trends as with doM will certainly be utilized in the prediction of digestible protein. Besides techniques to predict from chemical analysis, or incubation with chemicals or enzymes to determine the protein solubility, in situ techniques are also used. In these methods some feedstuff in a small nylon bag is placed into the rumen for some time, or into the duodenum, to study degradation, or digestion, respectively. It is not yet known whether results from these studies can be used to calibrate the NIR equipment so that a rapid prediction of the protein quality of feeds can also be made.

Energy systems for growing and fattening cattle A number of countries have changed or modernized their energy systems recently. This was possible because the basis for feed evaluation for lactating cows became more reliable owing to the increased amount of data collected with dairy cattle. However, the basis is much weaker for growing and fattening ruminants, since, for cattle especially, sufficient data on body composition are lacking and the available information shows a large variability. Improvement of this database is needed before a better feed evaluation system can be developed. New methods with modern equipment to quantify the body composition of live animals, and to measure the composition of liveweight gain with regard to fat, protein, etc. during growth, are urgently needed to improve feed evaluation for growing and fattening animals.

Feeding high-yielding ruminants Although nutrient requirements are defined as average figures, it is necessary to increase our knowledge of the variation in requirement for various levels of animal production under various dietary and environmental conditions. Also a better quantification of the effect of factors involved and their interactions is required. Sufficient accurate, well-proven information is lacking in particular from high-yielding animals, where measurement of the required data will easily disturb the animal and decrease its production. Some countries have already introduced a modern protein-evaluation system based on recent knowledge and ideas; other countries are still hesitating. Improvement of the systems is still hampered by the lack of sufficient quantitative information to construct applicable equations, which describe accurately enough processes such as the degradation of protein in the forestomachs, microbial protein synthesis and the digestion and absorption of amino acids from undegraded feed protein and microbial protein under various conditions. Such information will enhance the introduction and updating of protein evaluation systems. So far the prediction of animal production is based on the energy and protein

245 supply from the diet. For a more accurate prediction and a better understanding of feed conversion under more extreme conditions, this may be insufficient. Therefore future research has to provide more quantitative information on the absorbed nutrients and macro molecules, which become available at the organ and tissue level of the animal. Highly sophisticated techniques are required to study these processes in high-yielding ruminants. Interacting factors from the diet, animal and environment involved in the regulation of animal production processes also need to be quantified. Progress in science and technology may lead to processing of feedstuffs or the use of additives in order to optimize the ration to improve the conversion of feed into animal products. Examples are the protection of easily-degradable protein or of fats and the reduction of the effects of anti-nutritional factors. Measuring techniques to study digestive processes in the live animal do not show much improvement apart from the in situ digestion studies with feedstuffs in nylon bags introduced into the digestive tract of fistulated animals. Also re-entrant cannulae need to be replaced by T-shape cannulae in highyielding cattle, if the level of production is to be maintained and flow of digesta not reduced. Studies of net absorption of nutrients from portal-drained viscera may extend our knowledge at that level ( H u n t i n g t o n et al., 1986). However, the number of such experiments has to be reduced as much as possible owing to legislation and the actions of animal welfare groups. The so-called in situ techniques, which look promising to enlarge our knowledge of digestion of individual feedstuffs and the variation in nutrient availability for microbes and host animal, may help to reduce the total number of digestion studies with cattle and sheep. The in situ technique is widely used, especially for information on protein quality and degradability.

REFERENCES Energy and future developments in feed evaluation

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247 I.N.R.A., 1987. Alimentation des Ruminants: R~visions des syst~mes et des tables de I'INRA. Bull. Technique No. 70 C.R.Z.V., de Theix, 222 pp. Johnson, S. and Ohlmer, B., 1972. Feeding Levels, Slaughter Weights and Feed Conversion Ratio in Beef Cattle Production. Lantbrukshogskolans meddelanden, Ser. A, No. 180. Kalashnikov, A.P. and Kleimenov, N.I. (Editors) (1985). Standards and Rations for Feeding Domestic Animals, Agropromizdat, Moscow, Kellner, O., 1905. Die Ern~ihrung der landwirtschaftlichen Nutztiere. Verlagsbuchhandlung. Paul Parey, Berlin, 594 pp. Kellner, 0. and M. Becker, 1966. Grundztige der Fiitterungslehre. Publ. Parey, Hamburg, 374 pp. Lindell, L. and Knutsson, P.G., 1976. Rapeseed meal in rations for dairy cows. Swed. J. Agric. Res., 6, 5-63. Lindhe, B. and Henningson, T., 1967. Cross breeding for beef with Swedish red and white cattle. Landbr. Hogsk. Annlr., 34: 517-550. Lofgren, G.P. and Garrett, W.N., 1968. Net energy tables for use in feeding beef cattle. University of Califnornia, Davis, CA, 25 pp. M.A.F.F., 1975. Ministry of Agriculture, Fisheries and Food. Energy Allowances and Feeding Systems for Ruminants. Tech. Bull. No. 33, H.M.S.O., London, 79 pp. M.A.F.F./A.D.A.S., 1984. Reference book 433. Energy Allowances and Feeding Systems for Ruminants. H.M.S.O., London, 85 pp. McHardy, F.V., 1966. Simplified ration formulation. 9th Int. Congr. Anita. Prod., Edinburgh, Scientific programme and abstracts, Oliver and Boyd, Edinburgh, p. 25 (abstract). Menke, K.H., Raab, L., Salewski, A., Steingass, H., Fritz, D. and Schneider, W., 1979. The estimation of the digestibility and metabolizable energy content of ruminant feedingstuffs from the gas production when they are incubated with rumen liquor in vitro. J. Agric. Sci. Camb., 93: 217-222. Moe, P.W., Flatt, W.P. and Tyrell, H.F., 1972. Net energy value of feeds for dairy cattle. J. Dairy Sci., 55: 945-958. MSller, P.D., Andersen, P.E., Hvelplund, T., Madsen, J. and Thomson, K.V., 1983. A New Method of Calculating the Energetic Value of Feedstuffs for Ruminants. Report No. 555, National Institute of Animal Science, Copenhagen, 60 pp. Nehring, K. and Friedel, K., 1985a. Gedanken zur Sch~itzung des energetischen Futterwertes. 1. Mitt.: Sch~itzungdes energetischen Futterwertes for Rinder. Arch. Tierernaehr., 35: 295-319. Nehring, K. and Friedel, K., 1985b. Gedanken ziir Sch~itzung des energetischen Futterwertes. 2. Mitt.: Erweiterte Betrachtungen zur Sch~itzung des energetischen Futterwertes des Rindes. Wissensch. Zeitschr. der Wilhelm-Pieck-Universita't, Rostock, 34: 24-35. Neimann-Sorensen, A., 1980. Survey of the energy feeding standards used in the C.O.S.T. countries and of the experimental background. Ann. Zootech., 29 no. h.s.: 17-26. Nordisk Jordbrugsforskning, 1969. Fodermiddeltabel 51.1 Publ. Mariendals Boktrykkeri A/S, Gjovik, 62 pp. Norrman, E., 1977. Notkott, production och ekonomi. Helmenius ed. L T, Stockholm. N.R.C., 1978. Nutrient Requirements of Dairy Cattle, 5th revised edn. Publ. N.R.C., National Academy Press, Washington DC, 76 pp. N.R.C., 1984. Nutrient Requirements of Beef Cattle, 6th revised edn. Publ. N.R.C., National Academy Press, Washington DC, 90 pp. Obracevic, C., 1984. New Systems of Feed Evaluation. Feed Manufacturers Association, Zagreb, 60 pp. Schiemann, R., Nehring, K., Hoffmann, L., Jentsch, W. and Chudy, A., 1971. Energetische Futterbewertung und Energienormen. VEB/DLV Berlin, 344 pp. Schneeberger, H. and Landis, J. (Editors), 1984. Ftitterungsnormen und Niihrwerttabellen ftir Wiederk~iuer, 2rid ed., Landwirtschaftliche Lehrmittelzentrale (LMZ), CH-3052 Zollikofen, Switzerland, 119 pp. Thorbeck, G. and Henckel, S., 1976. Energetisk vedlige holdelsesbehov hos calve. Report No. 125, National Institute of Animal Science, 4 pp.

248 Tilley, J.M.A. and Terry, R., 1963. J. Brit. Grassl. Soc., 18: 104-111. Van Es, A.J.H., 1975. Feed evaluation for dairy cows. Livest. Prod. Sci., 2: 95-107. Van Es, A.J.H., 1978. Feed evaluation for ruminants. I. The systems in use from May 1977 onwards in The Netherlands. Livest. Prod. Sci., 5, 331-345. Van Es, A.J.H., 1986. Energy values of feeds for livestock and their prediction. Neth. J. Agric. Sci., 34" 405-412. Van der Honing, Y. and Steg, A., 1984. Relationship between energy values of feedstuffs predicted with thirteen feed evaluation systems for dairy cows. I.V.V.O. Report No. 160, 66 pp. Van der Honing, Y., Steg, A. and Van Es, A.J.H., 1977. Feed evaluation for dairy cows: tests on the system proposed in The Netherlands. Livest. Prod. Sci., 4: 57-67. Van der Meer, J.M., 1984. C,E.C. Workshop on Methodology of Feedingstuffs for Ruminants. European "In Vitro" Ringtest 1983-Statistical Report. I.V.V.O. Report No. 155, 42 pp. Van Soest, P.J., Fadel, J. and Sniffen, C.J., 1979. Discount factors for energy and protein in ruminant feeds. In: Proc. Cornell Nutrition Conference for Feed Manufacturers, Ithaca, NY, pp. 63-75. Vermorel, M., 1978. Feed evaluation for ruminants. II. The new energy systems proposed in France. Livest. Prod. Sci., 5: 347-365.

Protein Anschuss ffirBedarfsnormen, 1986.Energie und N~ihrstoffbedarfLandwirtschaftlicherNutztiere, No. 3. Milchkiihe und Aufzuchtrinder,DLG-Verlag, Frankfurt am Main, 92 pp. A.R.C., 1980. The Nutrient Requirements of Ruminant Livestock.Technical Review by an AgriculturalResearch Council Working Party, Commonwealth AgriculturalBureau, Farnham Royal, U.K., 351 pp. A.R.C., 1984. The Nutrient Requirements of Ruminant Livestock. Suppl. No. 1. Report of the Protein Group of the A.R.C. Working Party. Commonwealth AgriculturalBureau, Farnham Royal, U.K., 45 pp. Burroughs, W., Nelson, D.K. and Mertens, D.R., 1975. Evaluation of protein nutritionby metabolisableprotein and urea fermentation potential.J. Dairy Sci.,58, 611-619. Crooker, B.A., Sniffen,J., Hoover, W.H. and Johnson, L.L., 1978. Solvents for solublenitrogen measurements in feedstuffs. J. Dairy Sci., 61,437-447. Henderickx, H. and Martin, J., 1963. In vitro study of the nitrogen metabolism in the rumen. C.R. Rech. Inst. Rech. Sci. Ind. Agric., 31: 7-14. I.N.R.A., 1978. Alimentation des Ruminants. I.N.R.A. Publications, Versailles, 597 pp. Kristensen, E.S., Moller, P.D. and Hvelplund, T., 1982. Estimation of the effective degradability in the rumen using the nylon bag technique combined with outflow rate. Acta Agric. Scand., 32: 123-127. Landis, J., 1979. Die Protein und Energieversorgung der Milchkuh. Schweiz. Landwirtsch. Monatsch., 57: 381-390. Landis, J., 1984. Bewertung des Proteins in Wiederkiiuerfutter. In: Schneeberger, H. and Landis, J. (Editors), Ffitterungsnormen und Nii_hrwerttabellen Rir Wiederkiiuer. LMZ, Zollikofen (CH), pp. i4-18. Madsen, J. and Hvelplund, T., 1985. Protein degradation in the rumen. A comparison between in vivo and in vitro and buffer measurements. In: Protein Evaluation for Ruminants. Acta Agric. Scand., Supp. 25, pp. 103-124. Mahdevan, S., Erfle, J.D. and Sauer, F.D., 1980. Degradation of soluble and insoluble proteins by Bacteroides amylophilus protease and by rumen microorganisms. J. Anita. Sci., 50: 723-728. N.K.J./N.J.F., 1985. Protein Evaluation for Ruminants. Acta Agric. Scand., Suppl. 25, 220 pp.

249 N.R.C., 1985. Ruminant Nitrogen Usage. U.S. National Academy of Science, Washington, DC, 138 pp. Orskov, E.R. and Mehrez, A.Z., 1977. Estimation of extent of protein degradation from basal feeds in the rumen of sheep. Proc. Nutr. Soc., Vol. 36, 78A. Orskov, E.R. and MacDonald, I., 1979. The estimation of protein degradability in the rumen from incubation measurements weighted according to rate of passage. J. Agric. Sci., 92: 499-503. Rohr, K., Lebzien, P., Schafft, H. and Schulz, E., 1986. Prediction of duodenal flow of non-ammonia nitrogen and amino acid nitrogen in dairy cows. Livest. Prod. Sci., 14: 29-40. Roy, J.H.B., Balch, C.C., Miller, E.L., Orskov, E.R. and Smith, R.H., 1977. In: S. Tamminga (Editor), Protein Metabolism and Nutrition. E.A.A.P. Publ. No. 22, PUDOC, Wageningen, pp. 126-129. Waldo, D.R. and Glenn, B.P., 1982a. Foreign Systems for Meeting the Protein Requirements of Ruminants. In: F.N. Owens (Editor), Protein Requirements for Cattle, Oklahoma State University, Stillwater, OK, pp. 296-309. Waldo, D.R. and Glenn, B.P., 1982b. Comparison of New Protein Systems for Lactating Dairy Cows. J. Dairy Sci., 1115-1133.

Appendix: Energy Systems for Ruminants Note: Countries in the E.A.A.P. which have adopted one or more systems from other countries that have been described below are not mentioned in this appendix. The systems mentioned relate to cattle unless otherwise stated.

(1) Starch equivalent, SE~o according to the KeUner procedure, as used in Germany (F.R.G. ) and Austria One unit SEK is equivalent to 2.36 kcal or 9.88 kJ net energy; the original starch equivalent is defined as the "fattening potential" of 1 g digestible starch, which equals 2.36 kcal or 9.88 kJ.

Nutritive value Roughages. SEK= 0.94 D X P + 1.91 D X L + D X F + D X X - X F *x (units kg-1; D X P etc. as g kg -~ ) The value of x depends upon type and crude-fibre content of the product. Concentrates. SEK= (0.94 D X P + f , D X L + D X F ÷ D X X ) (units k g - 1)

•V

Remarks. The value o f f depends upon the type of product; varying 1.91-2.41. The value of V (value number according to Kellner) depends upon the type of product and varies between 0.7 and 1.0.

250

Requirements Growth and fattening cattle ( D.L.G., 1982). Total requirement, as starch equivalent (SEK) , dependent on W and liveweight gain is presented in Table V of D.L.G. (1982). See also Table IV in this chapter.

Sheep. (D.L.G., 1982). (Abstract from Table VI in D.L.G., 1982). Maintenance at W = 60 kg: 480 SEK. Pregnancy including maintenance at W = 60 kg: < 105 days pregnancy; 550 SEK; > 105 days pregnancy; 800 SE K. Lactation including maintenance at W -- 60 kg: single lamb (gain 300 g), 1140 SEK; twin lambs (gain 200 g), 1570 SEK'I-additional feed. Growth and fattening requirements (SEK) are shown below Daily gain (g day - 1)

Lambs (male) Lambs (female)

W=20 kg W=40 kg W=20 kg W=40 kg

100

200

300

400

375 620

480 755 510 840

595 930 650 1060

720 1120 -

References C.E.C., 1980. Futterwerttabelle flit Wiederkiiuer, 1982. Kellner, 0., and Becker, M., 1966.

(2) Dutch starch equivalent, S E ( N L ) , system used for beef cattle in Belgium SE ( N L ) unit based on the net energy for fattening similar to starch equivalent SEK, b u t with major modifications to equations. 1 unit SE ( N L ) is equivalent to 2.36 kcal or 9.88 kJ.

Nutritive value Roughages. The same equation as for SEE or the shorter equation (when all digestible nutrients are not available ) as follows:

SE ( NL ) = DOM-O.06 D X P - X F . x ( units k g - 1, DOM, D X P etc. as g k g - 1) The value of x depends upon type and crude-fibre content of the product.

251 Concentrates. SE ( N L ) = (0.94 D T P + 3 D X L + D X F + D X X - 0 . 2 4 sugars) • V (units k g - 1 ) Remarks. D T P is generally calculated as D T P = D X P - ( X P - T P ) . Correction for sugars only if sugar content exceeds 80 g k g - 1 ( dry or air-dry matter). The value of V (value number according to Kellner) depends upon the type of product and varies between 0.7 and 1.0. Note: classification of feedstuffs in roughages and concentrates is not always clear. Requirements Milk production. Maintenance: ( 3.33 W + 1000) SE {NL). For each kg fat-corrected milk ( 4% fat): 286 SE (NL). Beef production. Tables with a S E ( N L ) requirement for 1000-g daily gain at different age and liveweight are presented. See Table IV. Maintenance ( kg SE (NL)): 0.8 + 0.0045 W (Alderman et al., 1974 ). Growth ( kg SE ( NL )) per kg gain: 1.22 + 0.00273 W ( Buysse, 1974 ). References Aldermanet ai., 1974. Buysse, F.X., 1974. Verkorte Tabel: Voedernormenen voederwaarde,1975. (3) Scandinavian feed unit, SFU(DK), system used in Denmark Essentially a modification of the Kellner starch equivalent system. Scandinavian feed unit, SFU (DK) based on the net energy of 1 kg of barley at 85% dry matter. 1 unit SFU (DK) is equivalent to 1650 kcal or 6.91 MJ net energy. Nutritive value Fresh forage, hay and straw. S F U ( D K ) = (1.43 D X P + 1 . 9 1 D X L + D X F + D X X - 0 . 6 4 ( feed units k g - 1, D X P etc as g k g - 1)

X F ) ,1.333/1000

Ensiled forage. S F U ( DK) = (1.43 D X P + D X L + D X F + D X X ) . l . 3 3 3 . 0 . 8 / l O00 Concentrates. S F U ( D K ) = (1.43 D X P + f , D X L + D X F + D X X ) , 1.333, V/1000

252

Remarks. The value o f f depends on the type of products, varying from 1.91 to 2.41. The value of V depends on the type of product, varying from 0.7 to 1.0. A new method has been proposed by M611er et al. (1983) to calculate the net energy from an equation with digestible energy and crude fibre as dependent variables.

Requirements Milk production. Maintenance: ( ( 0.0033 W + 1 ) • 1.333 ) S F U ( D K ) . For each kg fat-corrected milk (4% fat ) : 0.40 S F U ( D K ) .

Growth and fattening. Bulls: ADG = 2 0 6 . 5 - 4 . 2 7 W + 0 . 0 0 2 W 2 + 5 7 4 . 7 E - 3 6 . 9 E 2 + 0 . 0 3 8 ( W , E ) Heifers: ADG =550.8 - 3.83 W+O.OO6W2+312.5E-lO.3 E 2 - 0 . 2 7 ( W . E ) where ADG = daily gain in g and E = S F U ( D K ) day - 1.

Sheep. SFU(DK) kg at W

Maintenance and pregnancy: Lactation: Days 1-60 Single lamb Twin lambs Days 61-120 Single lamb Twin lambs

60 kg

80 kg

100 kg

0.70

0.85

0.95

1.50 1.90 1.30 1.70

1.65 2.00 1.45 1.80

1.75 2.15 1.55 1.95

References Andersen, H.R., 1975. Andersen and Just, 1975. Andersen and Just, 1983. C.E.C., 1980. Fodermiddeltabel, 1969. Frederiksen, J.H., 1984. Handbuch der Tierernaehrung, 1972, Vol. 2. Page 341. MSller et al., 1983.

(4) Fattening feed unit, FFU, system used in Norway and Finland F F U fattening feed unit based on the net energy for fattening of 1 kg of barley ( 85% dry matter) primarily based on Kellner's system. 1 F F U is equivalent to 6910 kJ net energy.

253

Nutritive value Roughages. F F U = ( 9 . 3 8 D X P + 1 8 . 8 4 D X L + 9 . 8 8 D X F + 9 . 8 8 D X X - X F ,3x)/6910

(units kg -1, DXP etc. as g kg -1) Concentrates. F F U = ( 9.38 D X P + f , D X L + 9.88 D X F + 9.88 D X X ) • V/6910 Remarks. The factors below have to be included in the equations.

Feeds of animal origin Cereals, other concentrates Wheat bran, etc. Silages Hay Straw

Fat factor / ( k J g -1)

Value number (Y)

23.85 20.92 20.92 9.87 18.84 18.84

1.00 0.95 0.90 0.80

Crude-fibre deduction x ( k J g -1)

- 4.2 -6.3 - 5.7

Requirements Milk production. Finland and Norway: maintenance (W°7~/500 °'75) • 4.0 FFU.

For each kg fat-corrected milk (4% fat): 0.40 FFU. Liveweight change _+ 2.5-3.0 FFU per kg change. Growth and fattening. (1) Finland, separate tables of FFU requirement for bulls and heifers are in use in Finland (C.E.C., 1980). See also Table IV in this chapter. (2) Norway, separate tables for growing steers and heifers, examples: steer 300 kg, gain 0.5-0.8 kg day -I 4.0-5.0 FFU day-I; heifer 300 kg, gain 0.5-0.7 kg day- 1 4.0-4.5 F F U / d a y - 1. Sheep. Data are shown below.

(1) Finland 60-kg liveweight ewe Maintenance requirement Pregnancy requirement

Lactation requirement

FFU day- 1 indoors grazing Months 1-3 Month 4 Month 5 I lamb 2 lambs 3 lambs

0.6 0.8 0.6 0.9 1.1 1.1 1.5 1.8

254 (2) Norway 60-kg liveweightewe

FFU day- 1

Maintenance, including wool growth Production feed, last 6 months of pregnancy: ewes in good condition ewes in poor condition Production feed, milk production (3-4 weeks) 1 lamb 2 lambs

0.57-0.69 0.1-0.2 0.3-0.4 1.1 1.7

Growing lambs, including maintenance in FFU day- 1 Liveweight (kg)

Females Males/finishing

30-35

35-40

40-45

45-50

50-55

55-60

0.62 0.88

0.65 0.91

0.69 0.95

0.72 0.98

0.75 1.02

0.78 1.05

Goats. Data are shown below (1)

F in lan d

Maintenance Pregnancy Lactation Growing kids

0.01 W + 0 . 1 F F U day -~ Month: 4 + 0.2 F F U d a y Month: 5 + 0.5 F F U d a y 0.37 F F U kg -~ 3.5% fat milk 0.30 F F U d a y - 1 up to 1.5 m o n t h s 0.40 F F U day-~ 1.5-3 m o n t h s 0.55 F F U day-1 3-4.5 m o n t h s

(2) No r way Maintenance

FFU day- 1

Live weight (kg) 30

40

50

60

70

0.41

0.51

0.60

0.69

0.77

P r o d u c t i o n feed, pregnancy, "change over" and growth M a t u r e goats 8-3 weeks before kidding 0.2 F F U day - 1 M a t u r e goats last 3 weeks before kidding 0.5 F F U d a y - 1

255

0.4 FFU day-1 3.0 FFU day- 1 0.1 FFU day-

Pregnant young goats Per kg liveweight gain Lactating young goats ( for growth) Production feed, milk production Fat content of milk ( % ) 3.0 FFU kg-1 milk 0.34

3.5 0.37

Growing kids, maintenance plus growth Age in weeks 0-6 6-12 12-18 Liveweight (kg) 3-8 8-12 12-17 FFU day -1 0.30 0.40 0.55

4.0 0.40

18-34 17-27 0.75

34-44 27-35 0.85

44-kidding 35-45 0.90

References C.E.C., 1980. Eriksson, Sanne and Thomke, 1976. Fodermiddeltabel, 1969. Handbuch der Tierernaehrung, 1972. Vo. 2. p. 341. Touri, M., personal communication, 1986. Sundstol, F., personal communication, 1986.

(5) Rostock system, EFr, developed and used in the G.D.R. EFr is a feed unit based on the net energy for fattening (NEFr) of I kg of barley as fed. Nutritive value EFr (kcal) = 0.68 D X P + 3.01 D X L + 0.80 ( D X F + D X X ) , which is based on: NEFr = 1.71 D X P + 7.52 D X L + 2.01 ( D X F + D X X ) and EFr (feed u n i t s ) = N E F r (kcal)/2.5 For the calculation of the nutritive value of rations, sometimes an additional correction is needed, depending upon dE of the ration. Instead of this correction of the nutritive value of rations, Nehring and Friedel (1985a, b) proposed the calculation of NEFr and EFr from DOM and indigestible organic matter (IDOM), supposing additivity of the feedstuffs in the ration. Requirements Milk production. Maintenance: 26 W °75 EFr. For each kg fat-corrected milk (4% fat): 285 EFt. Growth and fattening. Maintenance: 24.8 W°75EFr. Daily gain of 1000 g (including maintenance) :

256

(1204 + 24.849 W - 0.0097962 W 2)/2.5 ) EFr

Sheep. Maintenance: 41.4 kcal NEFr k g - l W °'75. Pregnancy: 64.4+5.413 t + 0.0555426t 2 kcal NEFr d a y - 1 ( t-- number of days pregnant). Lactation: 940 kcal NEFr kg-1 milk. Growth and fattening of growing lambs: 100 g daily gain: 372 + 23.788 W - 0.074048 W 2 200 g daily gain: 416 + 33.967 W - 0 . 1 0 6 1 9 0 W 2 300 g daily gain: 461 + 44.145 W - 0 . 1 3 8 3 3 3 W 2 Mature sheep: 6 Mcal NEFr kg-~ liveweight gain Practical allowances are + 10% for cattle and + 25% for sheep above requirements stated here, see Schiemann et al., 1971.

References Autoren Kollektiv, 1977. Beyer, M. et al., 1986. Nehring, K. and Friedel, K., 1985a. Nehring, K. and Friedel, K., 1985b. Schiemann et al., 1971.

(6) Scandinavian metabolizable energy, ME(S), system developed from A.R.C. (1965) and used in Sweden Sweden used the Scandinavian fodder unit, SFU, but adopted a simplified version of A.R.C. (1965) for dairy and beef cattle in the early 1970s. After the publication of the M.A.F.F. (1975) standards, these were mainly adopted but with modifications based on feeding trials (Norrman, 1977). Maintenance requirements were based on the work of Thorbek and Henckel (1976). Metabolizable energy ( ME ), Mcal k g - 1 DM, taken from tables, or predicted from in vitro digestibility measurements of forages.

Nutritive value See Table V.

Requirements Milk production. Maintenance: 0.121 W °'75 Mcal ME ( S ). For each kg fat-corrected milk (4% fat): 1.2 Mcal ME (S). Plane of nutrition effect: none. Efficiencies of ME utilization: as U.K. (M.A.F.F., 1975 ).

Growth and fattening. Standards are mainly based on the British recommen-

257 dations as they appear in Technical Bulletin 33 ( M.A.F.F., 1975 ), modified in the light of feeding trials (Normann, 1977). Maintenance-energy requirements are as Thorbeck and Henckel (1976). See Table IV. Testing of system: Requirements for beef cattle derived from feeding trials, rather than factorial approach (Johnsson and Ohlmer, 1972; Lindhe and Kenningson, 1967).

References C.E.C., 1980. Eriksson, Sanne and Thomke, 1976. Fodermiddeltabel,1969. Lindell L. and Knutsson, P.G., 1976. Normann, E., 1977. Thorbek, G. and Henckel,S., 1976.

(7) British metabolizable energy, ME ( GB ), system used in the U.K. An ME system was introduced in 1976, based on the A.R.C. (1965) proposals simplified and adjusted to fit the results of feeding trials. This replaced the U.K. version of SEK,expressed as pounds of SEK. Metabolizable energy ( ME ), MJ kg-1DM, measured at maintenance with sheep.

Nutritive value Calculation of ME value: (1) from Weende digestibility data using an equation published by Schiemann et al. (1971) (see Table V); (2) from digestible organic-matter data, assuming organic matter has an energy value of 19 MJ k g - 1, and that M E / D E = 0.81; (3) direct measurements with sheep at maintenance; (4) prediction from chemical and in vitro analysis, used particularly on forages of variable ME value. Efficiencies of ME utilization: maintenance, km= 0.72; lactation, k~= 0.62; growth, kg= 0.0435. ME/DM.

Requirements Milk production. Maintenance: (8.3 + 0.091 W) MJ ME (GB). For each kg fat-corrected milk (4% fat): 5.3 MJ M E ( G B ) . Plane of nutrition effects: no allowance made. Energy value of liveweight change in cows = 20 MJ k g - 1. Efficiency of utilization of mobilized body energy for milk = 0.82. Efficiency of ME utilization for gain for lactating cow = 0.62.

Growth and fattening. These are expressed as MJ of NEmg, to facilitate ration formulation. Feed ME values are converted to appropriate NEm~ values by the use of the Animal Production Level (APL) defined as:

258

A P L = 1 -~

LWG(6.28+O.0188 W) ( 1 - 0 . 3 LWG) (5.67 + 0.061 W)

Net energy of feed or ration,

NEmg ( MJ k g - 1 DM ) =

(ME/DM) 2×APL 1.39 M E / D M + 23 ( A P L - 1 )

Maintenance, Em = 5.67 + 0.061 W MJ of NEmg Production,

Ep =

LWG(6.28+O.188 W) (1-0.30LWG)

MJ of NEmg

Testing of system: the simplified system was developed using a database of suitable feeding trials with dairy cows and beef cattle (Alderman et al., 1974). No database for sheep was used.

Sheep. Maintenance: indoors 1.2+0.13 W MJ day-l; outdoors 1.4+0.15 W MJ day- 1. For liveweight gain: liveweight gain energy value, EVe: logloEVg= 1.11 logloLWG+0.004 W+0.88 MJ kg -1 where LWG is in g day -1. ME for gain: EVg/kg.

References Aldermanet al., 1974. M.A.F.F., 1975. M.A.F.F., 1984.

Requirements according to The Nutrient Requirements of Ruminant Livestock, A.R.C. (1980). Maintenance and milk production. Requirement for maintenance = Z /km where fasting metabolism, Z = ( 0.53 ( W/1.08 ) o.67+ 0.0043 W) and km -- 0.35q + 0.503. For milk production, Z is calculated as above. Energy retention in M kg milk (R):

R = M . (1.509+0.0406 F) where F= g fat kg -1 . kl = 0.35q- 0.420 Level of feeding FL = 1 + ( R/kl ) / ( Z/km) Correction for level of feeding: 1 + 0.018 ( F L - 1 ) Total requirement= (1 + 0.018 ( F L - 1 ) ) (R/kl + Z/km)

Growth and fattening. Maintenance requirements for castrates and heifers as above, 15% more for bulls. Energy value of liveweight gain, EVg, as MJ k g - 1 given by:

259

EV~= (4.1 +0.0332 W - 0.000009 W2)/(1-0.1475 LWG) where LWG is liveweight gain as kg day-1. Estimate is to be reduced by 15% for bulls and for large breeds, or increased by 15% for heifers and for small breeds. Energy retention (ER) = EVJk~, where kf= 0.78 q + 0.006 at a plane of nutrition of 2 × maintenance.

Sheep. Maintenance: Z/km MJ ME day-1 where Z= 0.251 (W/1.08) o.7~ Growth and fattening: EVJkg MJ ME d a y where EV~=2.5+0.35 Wfor males: 4.4+0.32 Wfor castrates; 2.1+0.45 Wfor females. Pregnancy: maintenance: Z = 0.226 ( W/1.08 ) 0.75 Daily energy retention, R: log~oR = 3.322 - 4.979 exp ( - 0.00643 t) where t is number of days pregnant. Lactation: maintenance: Z = 0.226 (W/108) o.v5+ 0.0106 W For each kg of milk: ME--EVJkl resulting in 7.5 MJ ME E Vg= 4.5 + 0.0025d MJ kg-~ where d is days of lactation and a fat content of 70 g kg-~ is assumed. Level of feeding correction factor: 1 + 0.018 ( F L - 1 )

Reference A.R.C., 1980.

(8) Net energy lactating cows, NEL(US), U.S. N.R.C., 1978 (used in Israel) Net energy lactation, NEL (US), expressed as Mcal kg- 1DM, calculated from TDN, DE or ME values

Nutritive value NEL(US) (in Mcal) = 0.703 M E - 0 . 1 9 NEL(US) (in Mcal) = 0.710 D E - 0 . 5 1 NEL(US) (in Mcal) = 0.0245 TDN%-0.12 (assuming 1 kg TDN = 4.409 Mcal DE) Requirements Milk production. Maintenance: 0.08 W °'75 Mcal NEL ( US ): for each kg of fatcorrected milk (4% fat) : 0.74 Mcal NEL ( US ); for each kg liveweight gain, add 5.12 Mcal; for each kg liveweight loss, deduct 4.92 Mcal.

260

Reference N.R.C., Washington,1978. Nutrient Requirementsof Dairy Cattle, 5. (9) Metabolizable energy, ME(IRL), used in Ireland Both the starch equivalent and the Scandinavian feed unit were used in Ireland, but there was no officially-adopted system. The M.A.F.F. (1975) standards were unofficially introduced, but a joint committee proposed minor revisions (Griffiths, 1980).

Nutritive value Metabolizable energy, M E ( I R L ) MJ k g - l D M taken from tables or predicted from in vitro digestibility. Plane of nutrition effects: none. Efficiencies of ME utilization: as U.K. ( M.A.F.F., 1975 ). Testing of system: maintenance requirements were estimated by regression of ME intake on energy and N retention in Friesian cattle. For energy value of body gains, EVg, the data of Lofgren and Garrett (1968) were preferred. Requirements Milk production. As in M.A.F.F. (1975). Growth and fattening. MEmg = MEre + E Vg/kg see Table IV. (10) Feed unit for milk production, VEM, and for growth and fattening, VEVI, used in The Netherlands since 1 May 1977 Feed unit for milk, VEM, expressed as g kg-1 of barley, using net energy for lactation, NE1 as Mcal kg -1 as the reference. Feed unit for fattening, VEVI, expressed as g k g - 1 of barley using net energy for maintenance and gain NEmg as the reference.

Nutritive value GE(kcal kg -1) =5.77XP + 8.74XL + 5.0XF + 4.06XX - 0.15 sugars q = 100 ME/GE ME values of feeds calculated as in Table V. Net energy for lactation, NEI values, kcal kg-1, calculated as: NE1=O.6(l+O.O4(q-57)) .0.9752 M E ( k c a l kg -1) VEM= NE 1/1.65 Net energy for growth and fattening, NEg values (kcal k g - 1), calculated as:

261

0.00493 q-0.584 ) N E e (kcal) = M E (0.0078 q + 0.006 ) / (0.00287 q + 0.554) 1.5 t- 1

VE VI= NEJ1.65 Requirements Milk production. Maintenance: 42.4 W °75 VEM. Milk production: 442 M VEM at plane of nutrition FL = 2.38. M-- kg fat-corrected milk (4% fat). Including effect of plane of nutrition of the total requirement for a cow weighing 600 kg is to be calculated as: V E M = 5013 + 440 M + 0.7293 M 2 Growth and fattening. Maintenance: 78.87 W °'75 as kcal d a y - 1. Growth, as retained energy, REg: ( 500 + 6 W) ADG REg (kcal) = 0.3 ( 1 - A D G ) ADG = average daily gain, kg. For correction to allowances for practice see van Es (1978).

Sheep. (C.V.B., 1983). Maintenance, lactation and pregnancy of ewes (in VEM) : Non-pregnant, non-lactating ewes 7.5W + 170 Ewes pregnant during 0-2.5 month 8.0W + 170 Ewes pregnant (single) during 2.5-4.5 month 10.5W+270 Ewes pregnant (twin) during 2.5-4.5 month 12.5W+250 Lactating ewes

Single lamb: Twin lambs: Triplet lambs:

Month 1

Month 2

Month 3

1920 2460 2660

1780 2190 2340

1520 1720 1860

Growth and fattening: male lambs (20-50 kg) (in VEVI). W °'75 • 65 VE VI maintenance -

1.65

V E V I growth=

( ( 6 0 0 + 6 0 , W) , L W G ) 1-1.2,LWG ,0.985/1.65

262

V E V I = ( V E V I maintenance + V E V I growth) • C where C is a correction factor dependent on LWG (daily gain in kg) : at LWG=0.2, 0.25, 0.30, 0.35 and 0.40; C is respectively 1.04, 1.07, 1.10, 1.12 and 1.14. Goats. ( C.V.B., 1983 ). Maintenance: at W = 60 kg: 800VEM Non-lactating pregnant including maintenance (last months) at W = 65 kg: 1250 VEM Young pregnant goats (age 10 months) at W = 45 kg: 1070 VEM. Young pregnant goats (age 12 months) at W = 55 kg: 1250 VEM. Lactation, including maintenance, W = 60 kg: 747 + 463 • FCM (FCM = fat-corrected milk 4% fat). References Manual for the calculation of the nutritive value of roughages, 1977. Van Es, A.J.H., 1978. Veevoedertabel, 1977. Verkorte tabel. Voedernorraen en voederwaarden, 1977, 1983.

(11) Unitd fourrag~re lait, UFL, and Unitd fourrag~re viande, UFV, used in France since 1978 Feed unit for milk (UFL) expressed as kg kg- 1 of barley, using net energy for lactation, NE1 as Mcal kg-1 as the reference. Feed unit for meat (UFV) expressed as kg kg- ~ of barley, using net energy for maintenance and gain, NEm~ as Mcal kg- 1 as the reference. Nutritive value Gross energy ( GE). (1) Roughages: GE = 4531 + 1.735 X P +p ( values in organic matter ) ( kcal kg- 1 ) p depends upon the type of product. ( 2 ) concentrates: GE=5.72 X P + 9 . 5 XL+4.79 XF+4.17 X X + p (in dry matter) (kcal/kg -1) The value ofp depends upon the type of product (according to Schiemann et al., 1971 ). Digestible energy (DE). DE = G E . DE/GE DE/GE calculated: Roughages: DE/GE = 1.O087DOM/OM- 0.0377. Cereals and cereal by-products: DE/GE = D O M / O M - 0.013.

263 Oil seeds and oil cakes: DE/GE-- D O M / O M - 0.020. Other products: DE/GE = D O M / O M - 0.015. Metabolizable energy values (ME). ME=DE,ME~DE M E / D E calculated: M E / D E = 0.86991 - 0.0000877 X F - 0.000174 X P ( in dry matter). See also Table V. UFL. NE1 values, kcal kg-1, calculated as: N E I = (0.6+0.24(q-0.57)) ME(kcal kg -1) where q = ME/GE UFL ( kg kg- ~) = NEJ1730 Note: for sugarbeets and fodderbeets the above value is multiplied by 0.9. UFV. APL = 1.5: Net energy of barley: 1855 kcal. UFV= ( M E × king)/1855 ( M E in kcal ) kin • kg • A P L where king- kg + ( A P L - 1) k~ UFV ( kg kg- ~= NEmJ1855 Requirements Milk production. Maintenance: (1.4 + 0.006 • W ) UFL For each kg fat-corrected milk (4% fat): 0.43 UFL. For each kg liveweight gain, add 3.5 UFL. On a ration basis additional corrections are needed, dependent upon feeding level and quality of the ration (q value and percentage of concentrates in the ration). Remark: plane of nutrition effect applied at a whole ration. Growth and fattening. NEmg values kcal kg- 1 calculated as: NEmg = kmg, M E ( kcal kg- 1) See Table IV of this chapter. Sheep. Maintenance: 0.033 UFL/kg°75; or 0.397 MJ ME/kg °'7~.

264

Pregnancy UFL day- 1per kg foetus Month 1-3 Month 4 Month 5

0.0017 0.044 0.070

Lactation UFL kg-' milk Month 1 Month 4

0.61 0.68

Growth and fattening: table values only in I.N.R.A. (1978), p. 429. For a liveweight gain of 200 g d a y - 1, U F V d a y - 1 requirements for male lambs of liveweight W are: 15, 0.58; 25, 0.93; 35, 1.27.

Goats. Maintenance: 0.01 W + 0.21 U F L d a y Lactation: 0.41 UFL kg-1milk of 3.5% fat Pregnancy: 0.01 W + 0 . 5 6 U F L day -1 Growing kids: data shown below Age ( months )

UFL day- 1

1 3 5 7

0.44 0.57 0.68 0.71

References I.N.R.A., Alimentation des Ruminants (1978). Vermorel, M. (1978). (12) Net energy for lactation, N E L ( D ) , system used in F.R.G. and Austria since 1982 Net energy for lactation N E L ( D ) as M J k g - ' as fed, calculated from ME as in the Dutch V E M system.

Nutritive value ME calculated from D X P , DXL, D X F and D X X as in Table V. GE ( M J kg -1) = O.0242XP+O.O366XL + 0.0209XF + 0.0170XX - 0.0007 sugars ( g k g - 1) Note: correction for sugars is only applied if product contains more than 80 g k g - 1 DM.

265

q = 100 ME/GE

NEL(D) =ME(O.6+O.OO24(q-57)) MJ kg -1 Requirements Milk production. Maintenance: 0.293 W °75 MJ N E L ( D ) . Milk production: Per kg fat-corrected milk (4% fat) 3.17 MJ N E L ( D ), which figure includes a correction of 0.07 MJ NEL (D) for increased plane of nutrition.

References D.L.G., 1982. Energie- und N~ihrstoffbedarf Landwirtschaftliche Nutztiere, 1986.

(13) Net energy lactation, N E L ( GR ), and modified starch value ,MSV, systems used in Greece Net energy for lactation, (NEL(GR)), as MJ kg -1, calculated from ME. Modified starch value (MSV) as kg kg -1 based on net energy fat (NEFr) of Schiemann et al., 1971.

Nutritive value N E L ( G R ) is calculated from ME values of feeds (see Table V and VI), as defined in the system used in The Netherlands ( see p. 260). MSV is calculated from NEFr: M S V = NEFr/2.60 kg-1. NEFf is calculated as in the Rostock system, see p. 255.

Requirements Milk production. As for N E L (D) of the F.R.G., see p. 264. Maintenance NEL(GR) = 0.293W °'Ts MJ NEL(GR) Per kg FCM milk 3.17 NEL (GR), which includes a plane of nutrition effect.

Growth and fattening. Calculated from NEFr requirements of GDR, converted to MSV for 1 kg daily gain: MSV= (1024 + 24.849 W - 0.0086314 W 2) 1.1/2.4 See Table IV. (14) Netto Energie Milch, NEL(CH), and Netto Energie Mast, NEV(CH), systems used in Switzerland since 1979 Switzerland introduced the NEt and NEg system developed by van Es (1978) in 1979 (Bickel and Landis, 1978) but expressed as M J kg -I not as feed units.

266

Netto Energie Milch (Energie nette lactation), NEL (CH) Netto Energie Mast, (Wachstum) ( Energie nette viande ), NEV ( CH ) both as MJ kg- 1. Conversion factors: N E L ( C H ) = 0.0069 V E M = 6.90 UFL; N E V ( C H ) = 0.0069 V E V I = 7.34 U F V Nutritive value Both values are calculated from ME values as for The Netherlands, using the same formula, but using actual values for GE, not calculated ones, to obtain q, as far as possible. Plane of nutrition effects: as for The Netherlands, but no adjustments for requirements above and below 2.38 times maintenance. Efficiencies of ME utilisation: as for The Netherlands. Testing of system: for dairy cattle, the tests of van der Honing et al. (1977) were relied upon. For beef cattle the standards were derived from Swiss feeding trials. Requirements Milk production. Maintenance: 0.293 W °75 MJ NEL (CH), or W/20 + 5 MJ day -1. Per kg fat-corrected milk (4% fat): 3.14 MJ N E L ( C H ) . Growth and fattening. Requirement is calculated on the basis of 0.330 W °~5 MJ day -1 for maintenance and REg for gain. As APL is seldom exactly 1.5, as accepted for NEV (CH)-system, difference between effective APL value and APL-- 1.5 is taken into account. So for total of maintenance and gain N E V ( C H ) =0.495 W°'75+ (RE~-0.165 W °75) k~,Jkg REg data are derived from feeding trials and it is assumed that kg can replace kf. See Table IV. Sheep. Maintenance: 0.228 MJ NEL (CH) kg- ~W °'75 Pregnancy: 60-kg ewe MJ NEL ( CH ) day- 1 Total required Month 1-3 5.7 Month 4 6.7 Month 5 7.3 Lactation: 4.7 MJ NEL (CH) kg- ~milk Growth and fattening: Table values only. For a liveweight gain of 200 g day-1, MJ N E V ( C H ) day- ~ requirements for lambs of liveweight W are: 20, 4.9; 30, 7.0; 40, 9.2. Goats. Data shown below. Maintenance: 0.24 MJ NEL (CH) kg- 1WO.75 Pregnancy: 1-3 months:+0.8 MJ N E L ( C H ) day-l; 4-5 months:+l.2 MJ N E L ( C H ) day -~.

267

Lactation: 2.7 MJ N E L ( C H ) kg -1 milk of 3% fat. Growth: 2-3 months 3.7 MJ NEL (CH) day-1; 4-5 months 4.3 MJ N E L ( C H ) day-l; 6-7 months 5.1 MJ N E L ( C H ) day -1.

References Bickel, H. and Landis, J., 1978 Schneeberger, H. and Landis, J. (Editors), 1984.

(15) Net energy lactation, NEL( YU), and net energy for growth and fattening, N E M ( YU), systems used in Yugoslavia since 1984 Net energy for lactation ( NEL (YU) as MJ kg- 1, calculated from ME. Net energy for growth and fattening ( N E M ( Y U ) ) , as MJ kg-1, calculated from ME.

Nutritive value Both values are calculated from ME values of feeds, using coefficients kin, k~ and kg as defined in the system used in The Netherlands (see p. 260).

Requirements Milk production. Maintenance in MJ: 0.293 W °75 NEL (YU), or W/20 + 5 MJ NEL(YU). Per kg FCM milk: 3.1 N E L ( Y U ) . See Table III.

Growth and fattening. Requirements for young animals expressed as MJ of N E L ( Y U ) , converted from UFL, (UFL=6.9 MJ N E L ( Y U ) ) as used in France. Requirements for older cattle are expressed as MJ of NEM (YU), converted from UFV, (1 UFV = 7.34 MJ NEM ( YU ) ) as used in France ( I.N.R.A., 1978 ). See Table IV.

Reference Obracevic, C., 1984. New Systems of Feed Evaluation, pub. Feed Manufacturers Association, Zagreb.

(16) Unit~tforaggere ( UF) used in Italy Up to 1986 Unith Foraggere (UF), as kg kg- 1, similar to Scandinavian feed units (SFU) based on Kellner starch equivalent (SEK). In 1986 the French system of UFL and UFV was adopted as the Italian system by the Commission "Feed evaluation" of the A.S.P.A. National tables are being prepared. See UFL and UFV system as used in France since 1978.

268

(17) Net energy for lactation, NEL ( H ), and net energy for beef, NEro and NEg, systems used in Hungary since January 1986 A multiple net energy system based on the U.S.N.R.C. dairy and beef cattle systems was introduced in January 1986. Net energy lactation ( N E L ( H ) ) expressed as MJ kg- ~dry matter, calculated from TDN or DE values. The van Soest and Sniffen modifications of the U.S.N.R.C. NEL (US) system for dairy cattle are used, in which NEL (US) values for individual feeds are discounted according to their cell-wall content. Net energy for beef and growing ruminants (NEro and NEg) are as N.R.C. 1984, converted to MJ kg- 1 dry matter, calculated from DE or ME values.

Nutritive value DE=0.1845 TDN% (MJ k g - l D M ) ME=0.82 DE (MJ kg-~DM) N E L ( H ) =0.6032 DE ( 1 - 2 d r ) -0.502 (MJ kg-~DM) where dr= discount factor for depressions in digestibility for feeding level above maintenance NEro = 1.37 ME - 0.033 ME 2+ 0.0006 ME 3_ 4.686 MJ dayNEg = 1.42 ME - 0.0416 ME 2+ 0.0007 ME 3_ 6.904 MJ day -

Requirements Milk Production. For maintenance: 0.3347 W °75 MJ day- 1 NEL ( H ) For each kg of fat-corrected milk: 3.10 MJ NEL (H).

Growth and fattening. For maintenance: 0.3222 W °75 MJ d a y - 1 NEro For liveweight gain: Medium-size bulls, Large-size bulls, Medium-size heifers, Large-size heifers,

N E g -- (0.20627 W °'~5) * ( L W G 1"°97) MJ day -1

NEg = (0.18280 W °'7~) • (LWG 1"°97) MJ day -1 NEg = (0.28702 W °'75) • (LWG 1"119) MJ day -1 NEg = (0.25439 W °'75) • (LWG 1"119) MJ day -1

References N.R.C., 1978. N.R.C., 1984. Van Soest, P.J. and Sniffen, C.J., 1979.

269

(18) Unitatilor nutritive la rumegatoare, UN(RO), new feed unit for ruminants), used in Rumania since 1983. Feed unit for ruminants (UN (RO)) kg kg- 1, based on a mean net energy in kcal kg-1 dry matter, divided by 2500 to give a ratio to the net energy of 1 kg of grain.

Nutritive value ME value is calculated as the mean value of the ME in the systems of F.R.G., U.K., U.S.A. and France as specified in Tables V and VIII. Net energy for ruminants (ENR) kcal kg-1 DM, is calculated as the mean value of: NEFr, Rostock; NEmp, M.A.F.F. 1975 at APL 1.5, converted to kcal; NEro and NEp, N.R.C. 1975/1976, calculated to NEmp at an APL of 1.5; UFL, I.N.R.A. 1978, converted to kcal; UFV, I.N.R.A. 1978, converted to kcal; New feed unit, UN ( RO ) = ENR/2500.

Requirements Milk production. For maintenance: 75.5 W °75 kcal day-~ ENR, or 0.0302 W °7~ kg U N ( R O ) day -1. For each kg milk: 106.4 fat%+323.2 kcal ENR, or 0.0426 fat%+0.1293 kg UN (RO) or 0.30 kg UN (RO) kg - ~FCM.

Growth and fattening. Maintenance, heifers 85 W °'7~ kcal day-1 ENR, bulls: 80 W °75 kcal day -1 ENR. For liveweight gain: Heifers ( 2.645 - 2.291 W+ 0.0109 W 2) .LWG kcal ENR day- 1 Bulls (1.106+9.157 W-0.0002W 2) .LWG kcal ENR day -1

Reference Burlacu, G., 1983.

(19) Oat feed unit, OFU, and metabolizable energy, ME( SU), systems in use in the U.S.S.R.. Oat feed unit, as kg kg - 1 feed. Metabolizable energy ME ( SU ) MJ kg- 1 feed.

Nutritive value Oat feed unit values are calculated from Kellner starch equivalent values SEK see p. 249, using 1 0 F U = 0.6 kg SEK. Metabolizable energy values are calculated from the EFr system as in Table V, converted to MJ (Schiemann, 1971, p.129).

270

Requirements Milk production. Maintenance: 5.1 kg OFU or 65 MJ of ME ( SU ) for a 600-kg COW.

Lactation: 0.5-0.55 kg OFU per kg FCM or 5-5.5 MJ M E ( S U ) kg -1 FCM, depending on yield level, see Table III.

Growth and fattening. Numerous tables published. See Table IV. Sheep. (1) Ewes: Maintenance and pregnancy. 60-kg liveweight.

Unit

Meat and wool ewes

First 12-13 weeks

OFU (kg) ME{SU) (MJ) OFU (kg) ME(SU) (MJ)

1.05 12.1 1.35 16.0

Last 7-8 weeks

( 2 ) Ewes: Lactation. 60-kg liveweight.

Unit

Meat-type ewes

First 6-8 weeks

OFU (kg) ME(SU) (MJ) OFU (kg) ME(SU) (MJ)

2.10 22.0 1.55 18.4

After 8 weeks

Reference Kalashnikov, A.P. and Kleimenov, N.I., 1985.

Appendix: Protein Systems for Ruminants In this section the authors have attempted to summarize the essential features of the protein systems now being used or implemented in several European countries. Particular use has been made of the review papers of Waldo and Glenn (1982a,b) in this respect.

(1) Degraded dietary crude protein/undegraded dietary protein, RDP/UDP, system used in the U.K. Crude protein XP g kg-1 DM; degraded dietary crude protein, RDP, g kg-1 DM; undegraded dietary protein, UDP, g kg -1 DM.

271

Nutritive value In situ measurement. From in situ dacron bag measurements of N loss from feed with time, Orskov and Mehrez (1977), corrected for outflow rate, (see section on measurement of protein degradability in ruminant feeds, p. 272 ). Then RDP =p XP g kg- ~DM, and UDP - XP - RDP g kg- ~ DM.

Calculation of dietary specification. RDP d a y - 1= 8.38 ME intake, MJ d a y UDP g d a y - l = 1.47 T P - 10.32 ME intake, MJ day -~ where TP is tissue protein, g day-1 XP g d a y - 1= RDP + UDP Degradability of dietary protein required, p-- RDP/XP.

Requirements Milk production. Maintenance protein, TP = 2.3 g kg- 1 W o.75g d a y - 1 Milk tissue protein, TP--3.3 g kg -1 milk Liveweight gain or loss, T P - - 150 or 112 g kg-1

Growth and fattening. Maintenance tissue protein, T P = 2.3 g kg- ~ W °75 g d a y - 1 Liveweight gain tissue protein, T P = 1 0 0 - 220 g d a y From equation: TP g day -1 =LWG(168-0.169 W+0.000163 W 2) (1.12-0.122 LWG)

References A.R.C., 1980. A.R.C., 1984.

(2) Protein digested in the intestine, PDI, system used in France, 1978-1988 Protein digested in the intestine (PDI) calculated from: (1) the N content of the diet (PDIN) g kg- 1 DM; (2) the DOM content of the diet (PDIE) g kg- 1 DM. This system was revised in late 1987 (see Addendum (I.N.R.A., 1987) ).

Nutritive value Calculation from the protein solubility. From the solubility ( S ) in buffer solution, corrected for differences with in vitro incubations in rumen liquor for particular classes of feeds.

272

Calculated from the tabulated true digestibility of proteins. From the tabulated true digestibility of dietary proteins in the small intestine (ddp) calculated from XP, S, DOM, indigestible organic matter, IOM and faecal protein, FP: ddp --

0.65 (1 - S) X P - ( F P - 0.025 D O M - 0.057 IOM) 0.65 (1 -- S) XP

From this is calculated the undegraded dietary protein which is truly digestible in the small intestine (PDIA) P D I A = X P ( 1 - S ) (0.65ddp), g kg -1 DM

Calculation from DOM and X P content. From the DOM and XP content of the feed are calculated two values for the microbial true protein which is truly digested in the small intestine ( P D I M ) . (1) PDIME, that owing to the energy content of the feed as indicated by DOM content: PDIME, g k g - 1= 75.6 DOM. (2) PDIMN, that owing to the dietary protein content (XP) g kg-~ DM and the solubility (S): PDIMN, g k g - l = X P ( 0 . 1 9 6 + 0 . 3 6 4 S ) . Then PDIN=PDIA+PDIMN, g kg-~DM and PDIE=PDIA+PDIME, g k g - 1 DM. The actual PDI content of a diet is the lowest of the separate summation of PDIN or PDIE values for the feeds comprising the diet. Requirements Milk production. Maintenance PDI = 3.25 g k g - ~ W °'75 g day- ~ for cattle. Milk PDI = 50 g kg - 1 FCM. Growth and fattening. Maintenance PDI -- 3.25 g k g - 1 WO.75 g day- 1 for cattle. Liveweight gain, PDI, g d a y - ~- protein content of gain/0.60 dayReferences I.N.R.A., 1978. I.N.R.A., 1987 (see Addendum). (3) Absorbable protein in the intestine, API, system used in Switzerland System is based on the French I.N.R.A. system, but without using PDIN. Minimum X P to energy ratios are specified instead. Absorbable protein in the intestine, API, g kg-1 DM.

273

Nutritive value The API value of a feed is calculated from: (1) digestible organic-matter content (DOM) kg kg-lDM; (2) crude-protein content, g kg-lDM; (3) degradability (D) calculated from solubility (S) as I.N.R.A. 1978: D=0.35+0.65S. Then API=75.6 DOM+0.8 X P ( 1 - D ) g kg -1 DM where 0.8 is the mean true digestibility of undegraded feed protein, DUDP/UDP. API values are only valid if the N requirements of rumen microorganisms are met. This implies at least 18-20 g XP MJ -1 N E L ( C H ) , or 10-12 g MJ -1 ME, depending on the class of livestock.

Requirements Milk production. Maintenance API = 3.25 g kg- ~ W °'75 d a y - 1 for cattle. Milk API = 50 g kg-1 FCM.

Growth and fattening. Maintenance API = 3.25 g kg- 1 WO.75g d a y - ~ for cattle. Liveweight gain API g d a y - l = protein content of gain/0.6 g day-1

Reference Landis, J., 1979. 1984.

(4) Crude protein flow at duodenum, XPD, system used in the F.R.G. Crude protein at duodenum ( XPD ) g d a y - 1.

Nutritive value The XPD value of a diet is calculated from: (1) metabolizable energy content, MJ d a y - 1; (2) undegraded protein content (UDP) g d a y - 1, calculated from tabulated data from in vivo measurements; (3) dry-matter intake, kg d a y - ~, from which endogenous contributions from the stomachs are calculated as 15.0 g XP kg-lDMI. Then XPD, g d a y - 1_- 11.92 ME + U D P - 15.0 DMI. With an adequate ME intake, XPD supply calculated from the above equation will be adequate unless degradability values (p) exceed the following values for dairy cattle: 0.88 at 15 kg FCM; 0.81 at 25 kg FCM; 0.75 at 35 kg FCM.

274

Requirements General. The following values have been adopted in calculating the X P D required for dairy cattle: ( M T P + U D P ) / X P D = 0.7; D M T P / M T P = 0.9; DUDP / U D P = 0.9; k~t-- 0.8. T h e n X P D , g d a y - ~= T P × 1.25 × 1.11 × 1.43 = 1.984 TP. Milk production. Maintenance tissue protein, T P , g day -~ =6.25 ( E U N + D N L + M F N ) where E U N , endogenous urinary N loss = 5.92 log W - 6 . 7 6 g day-1 DNL, dermal N loss = 0.018 W °'75 g day -1 M F N , metabolic faecal N loss = 2.91 g kg-~ D M I Milk protein, T P = 34 g k g - ~ F C M Liveweight gain tissue protein, T P = not stated. For a 600-kg dairy cow with no change in body protein, crude-protein at duodenum ( X P D ) requirements are calculated to be as follows: Milk yield (kg FCM day -1 )

XPD requirement (gday -1 )

10 15 20 25 30 35

1255 1665 2060 2465 2875 3270

Growth and fattening. A crude protein supply of 12 g X P M J - 1 M E appears to be sufficient, for all feeding conditions, after allowing for the recycling of about 0.3 g N M J -1 ME. N o t less than 90 g X P k g - l D M should be fed. Detailed requirements for fattening are not yet published. References Anschuss fur Bedarfsnormen (1986). Rohr, K. et al. (1986}.

(5) Amino acids truly absorbed/protein balance in the rumen, AAT/PB V, system used in Denmark, Finland, Iceland, Norway and Sweden since 1986. Amino acids truly absorbed in the small intestine: ( T y n d t a r m e n ) , AAT, g kg -1 DM; protein balance in the rumen ( V o m m e n ) , PBV, g kg -1 DM.

275

Nutritive value The AAT value of a feed is calculated from: (1) microbial true protein ( M T P ) synthesis from digestible carbohydrate (DCHO) defined as the sum of digestible crude fibre (DXF) and digestible N-free extract (DXX) i.e. D C H O = D X F + D X X . Then M T P = 0 . 1 0 6 DCHO g k g - 1 DM; ( 2 ) true digestibility of M T P in small intestine, D M T P / M T P = 0.85; ( 3 ) crude protein, (XP) content of feed, g k g - 1 DM; (4) degradability (p) of feed XP, as measured by the in situ dacron bag technique of Kristensen et al. (1982 ), and corrected for an outflow rate of 0.08 h - 1, as Orskov and MacDonald (1979) (see p. 272 on measurement of feed degradability). T h e n undegraded crude protein, UDP = X P (1 - p ) ; (5) true protein ( T P ) proportion within X P content of feed, T P / X P ; (6) digestibility of UDP, D U D P / U D P = 0.82. T h e n AAT, g k g - 1 DM = 0.106 DCHO+0.82 UDP× TP/XP where T P / X P is 0.85 for concentrates and 0.65 for roughages. The PBV value of a feed is calculated from: (7) microbial crude protein (MXP) synthesis, calculated from M T P (1) above, where M T P / M X P - 0.70. (8) rumen degradable crude protein (RDP) calculated from XP content and degradability (p) as in (3) and (4) above: RDP = XP ×p. T h e n PBV g k g - 1 DM-- R D P - 0.179 DCHO. Requirements Milk production. Maintenance AAT-- 3.3 W °'75 g day- 1 Milk AAT = 45 g k g - 1 FCM. Maintenance + milk production PBV = - 200 g day- 1. Growth and fattening. Not yet published. References Kristensen, E.S. et al. (1982). Protein Evaluation for Ruminants (1985). (6)) Absorbed true protein, AP, system used in the U.S.A. since 1985. Absorbed true protein (AP) g day- 1.

Nutritive vale The AP value of a diet is calculated from: (1) microbial crude protein ( M X P ) calculated from the NEL (US), TDN, (or

276

ME) content: MXP, g d a y - l = 7 1 . 6 N E L ( U S ) (Mcal) - 1 9 3 or M X P = 1 0 . 6 ME M J - 193. For diets with less than 40% forage, an alternative function is suggested, with a term for forage and concentrate intake as percentage of liveweight ( see N.R.C., 1985); ( 2 ) undegraded protein content ( UDP ) g day- ~calculated from in situ dacron bag measurements, corrected for outflow rate, as in the U.K. system; ( 3 ) metabolic faecal protein (FXP) g k g - ~ of indigestible dry matter (IDM) calculated from T D N value of diet: FXP = 90 (1 - 0.92TDN ) g day- '; The following values have been taken, in calculating the digested microbial true protein, D M T P or AP in this system, and digestible UDP, DUDP: M T P / M X P = 0.8; D M T P / M T P = 0.8; D U D P / U D P = 0.8. Then AP, g day= 0.64 M X P + 0.8 UDP - FXP.

Requirements General. The efficiency of capture of RDP by the microbes in the rumen is assumed to have a maximum value of 0.9: M X P / R D P = 0.9. Allowance is also made for the proportion of recycled protein N, RP, with the function R P = 1.22-0.012 XP+0.0000324 XP 2, which for XP levels of 100, 120, 140, 160 g kg -1 DM gives values for RP of 0.34, 0.25, 0.18 and 0.13, an alternative function is suggested, with team for forage then XP, g d a y - ~ = ( R D P + U D P ) / ( I + R P ) . Or assume value for recycled protein (RP) is 0.15, then XP, g d a y - l = ( R D P + U D P ) / 1 . 1 5 .

Milk production. Maintenance AP, g day- 1 = (EUP + DPL)/0.67 + M F P where EUP (endogenous urinary protein) loss = 2.75 W °5 g day- 1; DPL (dermal protein loss ) = 0.2 W °'6 g day- ' and 0.67 is the value for knm, the efficiency of utilization of absorbed amino acids for maintenance. Milk AP = milk protein 0.65g/kg-1 milk = 50 g kg-1 milk where 0.65 is the value of kn~,the efficiency of utilization of AP for milk protein synthesis. Live-weight loss AP, g day -1 = 160 g k g - ' , assuming an efficiency of 1.0 for mobilization and utilization of tissue protein.

Growth and fattening. Maintenance AP, g day -1 = ( E U P + D P L ) / 0 . 6 7 + MFP. Liveweight gain AP, g day- ~= tissue protein in gain/0.5 g daywhere T P is 140-160 g kg-* liveweight change, depending on liveweight, W, and 0.5 is the value of kng, the efficiency of utilization of AP for lean tissue deposition.

Reference N.R.C., 1985.

277 Addendum Revision of French energy and protein requirement systems for ruminants

As this chapter went to press, details were received of a comprehensive revision of the I.N.R.A. 1978 energy and protein requirements of ruminants, given in the Appendix to this Chapter. Full details are in I.N.R.A. 1978 and 1988. The main changes are briefly outlined below. Energy requirements Nutritive value Gross energy (GE). Roughages: new equation for grass silage GE = 3.910 + 2.450 X P + 169.6pH (values in organic matter) (kcal kg -1) Maize silages: 4678 kcal kg -1 OM if DM > 30%; 4772 kcal kg -1 OM if DM < 30%. Digestible energy (DE). Calculation of DE/GE: All previous equations replaced with feed/species-specific equations. Metabolizable energy (ME). Calculation of ME/DE M E / D E = 0.8417 - 9.9 × IO-~XF - 1.96-4XP + 0.0221NA (on OM basis) NA = niveau d'alimentation, or feeding level, FL) UFL (kg kg -1) = NE~/1700 (net energy of barley), was 1730 kcal kg -1. UFV (kg kg-1 = NEmJ1820 (net energy of barley), was 1855 kcal kg-1. Requirements Milk production. For each kg fat-corrected milk (4% fat): 0.44UFL (was 0.43). For each kg liveweight gain, add 4.5UFL (was 3.5). Corrections made to the total ration have also been modified. Growth and fattening. Revised factorial method, based upon breed, sex and rearing system. (1) Sheep. Factorial requirements for pregnancy and lactation vary with weight and number of foetuses carried, or lambs suckling. (2) Goats. Maintenance: 0.0384 UFL kg-1 WO.75 Lactation: 0.385 UFL kg-1 milk of 3.5% fat (was 0;41) Pregnancy: 0.0095 UFL kg-1 WO.V5during last 5 weeks Weight gain: 3.9 UFL kg-1 gain

278

Growing kids: Age (months)

Weight (kg)

Weight gain (g day-1)

UFL day-1

1 3 5 7

6.5 16.3 24.5 30.0

165 155 115 70

0.42 0.55 0.66 0.69

Protein requirements N u t r i t i v e value

Calculated from (1) XP content, (2) fermentable organic matter, (FOM), where F O M = D O M - U D P - X L - fermentation products in silage, (3) standardised degradability measurements, (p), with nylon bags, (4) true digestibility of dietary protein in the small intestine, (dr), calculated from new data, ranging from 0.55-0.95. (5) true digestibility of microbial protein (80% of XP): 0.80. Revised equations for PDIA, PDIMN a n d P D I M E are given P D I A = 1.11 ( 1 - p ) d r × X P P D I M N = 0.64 (p-0.10) X P P D I M E = 0.093 F O M Calculation of PDIN and PDIE remains as before. Requirements M i l k production.

Milk PDI = 48g kg -1 (was 50) (based on knl = 0.64, was 0.67)

G r o w t h a n d fattening.

Protein content of gain defined by factorial approach

and tables. knp = 0.50 in cattle, 0.42 for sheep. kng varies 0.28-0.68, with breed, sex and liveweight (was 0.60).

Pregnancy.

References I.N.R.A., 1987. R. Jarrige (Editor), Alimentation des ruminants: revision des syst~mes et des tables de I'I.N.R.A. Bull. Techn. No. 70. CRZV, Theix, I.N.R.A., 217 pp. I.N.R.A., 1988. R. Jarrige (Editor), Alimentation des bovins, ovins et caprins. I.N.R.A., Paris, 370 pp.

Livestock Production Science, 19 (1988) 279-288

279

Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands

III. 3. N o n - R u m i n a n t Herbivores; Horses and Rabbits III.3.1. H o r s e s

J.L. TISSERAND

INTRODUCTION The horse is an herbivorous animal which principally digests cytoplasmic and reserve carbohydrates, proteins and lipids in the same manner as a pig. Besides, the a b u n d a n t bacterial population in its large intestine permits the horse to use structural carbohydrates to some extent, mainly for energy supply. H o w energy-yielding nutrients are divided between the two parts of the digestive system remains uncertain, b u t it may vary with the rhythm of feed distribution. It is generally admitted that cereals and concentrates are degraded for the greater part in the small intestine, whereas forages, rich in cell walls, are degraded in the large intestine. Table I shows estimates of the site of digestion and net adsorption, as reported by Hintz (1977). The stomach of the horse is not very voluminous: less than 10% of the total volume of the digestive tract. In contrast, the large intestine (caecum, colon) is very well developed: 60% of the total volume of the digestive tract. This organ is the site of microbial digestion, similar to the rumen function in ruminants. As in ruminants, volatile fatty acids: acetic, propionic and butyric acids, are TABLE I Estimates of site of digestion and net absorption (Hintz, 1977) Dietary fraction

Small intestine (%)

Caecum and colon (%)

Protein Soluble carbohydrates Fiber Fats Calcium/magnesium Phosphorus Vitamins

60-70 65-75 15-25 Primary 90-99 20-50 Primary

30-40 25-35 75-85

0301-6226/88/$03.50

© 1988 Elsevier Science Publishers B.V.

1-10 50-80

280 TABLE II Mean digestibilityof organic matter of various feedstuffsin horses and ruminants (Loeweand Meyer,1974)

Straw Hay Greenforage Oat Other cereals Fodderbeet

Horse (%)

Ruminant (%)

35 50 65 70 80-85 85

50 55-6O 70 70 80-90 85-90

produced there by fermentation. Normally, their ratios are 75:15:8. Depending on the proportion of concentrate in the diet the ratios may shift and in exceptional cases (rations with abundant starch content) lactic acid may be produced in addition. Differences between horses and ruminants with regard to apparent digestibility are shown in Table II. The apparent digestibility of organic matter is quite similar for horses and ruminants. For protein, differences between horses and ruminants regarding the site of microbial proliferation have to be considered. Absorbability of feed protein by horses is about 10 percentage units lower than apparent digestibility (Jarrige and Tisserand, 1984). Feeds pass through the digestive system of the horse in an average period of 2-3 days. Rate of passage depends on composition and volume of the ingested feeds. When the ration is voluminous, the ingesta arrive in the caecum 1.5-2 h after the beginning of the meal. When concentrates precede forage, the average time of passage to the caecum is about 9.5 h. Information on the specific phenomena of digestion in horses was scarce until some years ago. Specific feed-evaluation systems for horses were not available and therefore, in many countries, feed rationing for horses was defined by analogy with ruminants, particularly with bovines. A number of similarities, as mentioned above, in the digestive process of horses, mainly heavy breeds for work, and bovines were the obvious reason to do so. However, in the last 15 years specific studies have been carried out in various countries. Knowledge of the digestive mechanism in horses has grown considerably in this period and has resulted in adequate methods for evaluating nutrient supplies and requirements for energy and protein. Generally, horses are fed with the same type of feedstuffs as ruminants: forages with varying fiber contents, supplemented with concentrates for particular performances, such as riding, racing, jumping and so on. The units used in feed evaluation in horse feeding are based on the principles

281 described in Chapter III.1 (Bickel, 1988). As with ruminants and pigs, various feed-evaluation systems are in use in various countries in Europe. SYSTEMS OF FEED EVALUATION

Energy Historic systems From the beginning of the century onwards, when the systems for estimating energy supply and expenditure were being developed, values calculated for the large ruminants (bovines) were applied to horses. In many countries, the starch unit or the Scandinavian unit, referring to the net energy of potato starch or to that of barley were used; sometimes they are still used. Present systems Present systems are mainly, but not always completely, based on experimentation with horses. Digestible energy N.R.C. (1978) proposed a system which starts with the ruminant T D N values of feedstuffs. The value is multiplied by 4.0 for forages and by 4.41 for other feedstuffs, resulting in DE values for horses, expressed in kcal. Loewe and Meyer (1974) used a similar approach, but expressed DE for horses in Mcal instead of kcal. Net energy The research workers of the Oskar Kellner Institute in Rostock (G.D.R.) (Laube, 1977) recommend the use of the feeding value 'Netto Energie-Fett Rind' (NEFf), expressed in terms of fodder units EFt. Thus, the same method of calculation is used as for ruminants, although the system is not specific for horses. 1 EFt is equal to 10.5 kJ or 2.5 kcal NEFf. In France, feed values are expressed in terms of horse feed unit (HFU) corresponding to the net energy value for the maintenance of 1 kg barley, i.e. 9.2 MJ or 2200 kcal (Vermorel et al., 1984). H F U is calculated from specific digestion experiments on horses. To evaluate the net energy of barley for maintenance the following relationships are assumed: DE--0.82 GE; ME = 0.90 DE; N E = 0 . 7 8 ME. For practical rations, consisting of 75% forages and 25% concentrates, as a reference, the following relationships are accepted for the HFU system: DE = 0.67-0.83 GE; ME = 0.83-0.91 DE; NE = 0.63-0.80 ME.

282

Protein In most countries, the evaluation of the protein value of feedstuffs is expressed in terms of digestible crude protein (DXP), derived from the measurement of the apparent digestibility in the horse. However, evaluation as D X P does not discriminate between the amino acids and the non-protein nitrogen ( N P N ) fraction, the latter being absorbed as ammonia, which does not contribute to the protein requirement. Besides, D X P gives no information on the site of the absorption of nitrogen, i.e. in the small and in the large intestine. This is the reason why some authors recommend considering only the true protein fraction of the feeds and estimating the digestible {rue protein (DTP) (Wolter, 1975 ). But these systems do not account for protein degraded in the large intestine. Therefore, the H D X P system, as recommended in France, accounts for the protein, which is actually digested and absorbed in the small intestine, and for possible absorption of some amino acids in the hind gut. Thus determined H D X P values are recommended to be reduced by the following percentages (Jarrige and Tisserand, 1984): 10% for green forages; 15% for hay and dehydrated fodder; 30% for correctly-conserved grass silages. These corrections make allowance for the lower contribution of absorbable amino acids from roughages than from concentrates. However, none of the present systems considers the specific requirement of the horse for essential amino acids. NUTRIENT REQUIREMENTS

Energy requirement In horses, as for other livestock, total energy requirement is split between requirement for maintenance and for production, whatever it is. Apart from growth and reproduction (primarily pregnancy and lactation) horses have a significant specific requirement for muscular activity. Intensity of this activity is variable and ranges from riding~o racing and traction. TABLE III Energy requirementsfor maintenance (kJ

kg-1 WO.75) of horses

in variousenergysystems

DE

ME

NE

NRC (1978) . Loeweand Meyer (1974)

649 573

-

-

Vermorel et al. (1984)

586

502

351

283 Maintenance Maintenance requirements depend in a broader sense on the horse's personality and the environment in which it lives. Thus recommendations for energy requirements for maintenance may vary, as shown in Table III. Work Recent studies have evaluated the energy needs resulting from muscular work quite precisely. Not only the nature and importance of the work done are taken into account, but also the animals training and environment (Hintz, 1983). The amount of energy used during any physical activity depends on the muscular work intensity. For a moderate activity, e.g. a trotting speed of less than 300 m min-1, aerobic muscular fibers, mainly use glucose and long-chain fatty acids as energy sources. During a period of intense activity, the anaerobic muscular fibers, which contract rapidly, transform glucose into lactate, the accumulation of which in a muscle results in tiredness. Training increases the metabolization of fat reserves which are degraded into non-esterified fatty acids and diminishes the transformation of glucose into lactate. When the muscular effort required is brief and intense a diet rich in sugar and starch helps make glucose available in the muscles. In any case an excess of crude protein, which diminishes muscular work efficiency, must be avoided. For walking, energetic consumption is on average 1.5 J kg -~ bodyweight (W) for each horizontal meter and 29 J kg-1 W for each vertical meter. When speed increases, so does the amount of energy used. For pulling, requirement varies with speed, distance and the weight of the load to be pulled. Gestation During gestation the amount of energy stored in the uterus (foetus and annexes ) is about 4.2 MJ. Generally, the weight of conception products amounts to 10% of the mare's liveweight. It is, however, slightly higher, 12%, when mares weigh less than 400 kg. Since the foetal development takes place mainly during the last 4 months of gestation, it is recommended to add 1.5-3.6 MJ NE day- 1 during this period for a saddle mare and 2.1-5 MJ NE day -1 for more heavy breeds. Lactation Lactation requirement depends on milk composition and the quantity of milk produced. Mares' milk has a low energy content of 2.3-2.5 MJ k g - 1 owing to a very low fat content of 10-15 g kg -1. The corresponding allowance accounts for 3-4 MJ DE kg-1 milk. During a 5-6-month lactation period the mare produces an average of 10-30 kg milk daily with a maximum around the eighth week. This is an increase of 10% in comparison with the onset of lac-

284 tation. Milk production may be approximately estimated to be 3% of the saddle mare liveweight, 2.5% of heavy breeds and 5% of ponies. Growth Requirement for growth depends on the growth rate and the composition of liveweight gain. The foal's growth during the first weeks is very important. Thus the birth weight is about doubled within 1 month depending on the mare's milk production. From the third month on, the growth rate is reduced owing to a decrease in the mother's milk production, which is not completely compensated for by the intake of grass. At weaning the 5-6-month-old foal weighs 40-45% of its adult weight, i.e. 200-250 kg for a saddle horse and 300-400 kg for a heavy breed. At the age of 2 years, its weight is 70% of its adult weight, which is reached at the age of 3.5-5 years, depending on the frame. Fat content increases with age, whereas the protein content of the fat-free weight remains constant. Stallions during the mating season Semen production requires supplementary energy, depending on the intensity with which the animal is used. It is recommended to increase the allowances for draught, saddle and pure-bred stallions by 10, 15 and 20% at rest and 25, 30 and 35% during the mating season, respectively. Recommended energy allowances are shown in Table IV. Protein In horse nutrition, as for other species of domestic animals, protein plays an important role. Tissue renewal and the functioning of the organism call for a permanent supply of proteins and amino acids, to be met daily or in some cases, at least, in the longer term. Although amino acid supply is crucial, the requirement is mostly expressed as digested protein. No specific recommendations for essential amino acids are available. As for other animals, the factorial approach to requirement is common practice. Work The amount of protein used as a result of muscular work is not known exactly. It is probably low. The increased energy expenditure due to muscular work is not accompanied by a proportional increase in protein expenditure. Nitrogen loss by enhanced perspiration seems to be compensated for, by a surplus of protein in the diet, or by microbial degradation of unabsorbed protein. This surplus is often caused by feeding higher amounts of concentrates to cover enhanced energy requirement, without reducing the protein content of the concentrate. The surplus, however, might reduce the energetic efficiency of work.

285 TABLE IV Recommended energy allowances above maintenance for various performances and in various systems in horses Reference

Digestible energy~ N.R.C.

Work (kJ kg -1W h -i) Walking 2.1 Slow trotting 21.3 Fast trotting 52.3 Galloping/jumping 100 Gestation (kJ mare- 1day- 1) last 4 months 8860 Lactation 3310 (kJ kg -1 milk) Growth 5-9.5 (kJ g - 1W gain )

Net energy

Meyer

Pagan and Hintz

6.3 21.3 52.3 100

7.1-10.5 27.2 57.3 81.6

Vermorel et al. 8.6-14.2 20-40 b 52-80 c 59-92 d

Vermorel et al. 5.5-9.1 12.8-25.6b 33.1-51.5 c 37.8-58.8d

3200-3640 f

-

180-15780e 4440

4600-101004~ 2840

6.7-10.5

-

28.8-57.5 g

18.4-36.8g

aSources: NRC (1978); Loewe and Meyer (1974); Pagan and Hintz ( 1986); Vermorel et al. (1984). bLight work outside. CMedium work. dIntensive work outside. eSecond value refers to the last 4 months of gestation. fMargin according to variable k,. g400 kg W of the foal; gain of W=0.5 and 1 kg day -1, respectively. Higher values are recommended for racing horses.

Gestation and lactation A p r o t e i n - d e f i c i e n t diet d i m i n i s h e s fertility. T h e d e v e l o p m e n t of t h e foetus entails a n i m p o r t a n t p r o t e i n r e q u i r e m e n t in t h e t h i r d p a r t of gestation. T h e p r o t e i n a c c r e t i o n in t h e foetus a n d m a t e r n a l tissues has b e e n m e a s u r e d b y M e y e r a n d Ahlswede (1976). It a m o u n t s , for a m a r e of 500 kg W, to 1.3, 2, 2.2 a n d 2.8 kg d u r i n g M o n t h s 8, 9, 10 a n d 11 of gestation, respectively. H o w e v e r , the effects of t h o s e r e q u i r e m e n t s are m i n i m a l as far as p l a n n i n g is c o n c e r n e d , because a n a b o l i s m of p r e g n a n c y seems to be m o r e efficient t h a n of m u s c u l a r growth. T h e p r o t e i n c o n t e n t of m a r e s ' milk is relatively low a n d does n o t v a r y m u c h ( 2 0 - 2 5 g k g - 1 ) , e x c e p t d u r i n g t h e colostral phase. L a c t a t i o n r e q u i r e m e n t dep e n d s on milk o u t p u t , a l t h o u g h n o t i c e a b l e a m o u n t s of b o d y p r o t e i n reserves can be mobilized b y t h e m a r e to c o v e r her r e q u i r e m e n t for g e s t a t i o n a n d lactation. T h i s a p t i t u d e p e r m i t s some savings to be m a d e d u r i n g w i n t e r b u t n o t too m u c h a d v a n t a g e s h o u l d be t a k e n of it, because p r o l o n g e d n e g a t i v e - p r o t e i n b a l a n c e can r e d u c e t h e foal's weight a n d vitality at birth. T h e r e f o r e , recomm e n d e d n u t r i e n t allowances are usually c a l c u l a t e d to m a k e up for a l m o s t all

286

needs without using reserves. They take into account the quantities which go to the uterus and the udder and 45-55% efficiency of the use of amino acids by the pregnant or lactating mare.

Growth Protein requirements for growth vary with the importance of the liveweight gain, which contains about 22% of crude protein in the fat-free tissue. But, as the amount of fat in the gain increases with age, it diminishes for each kg weight gain as the animal becomes older. Accordingly, the requirement of DXP per kg liveweight gain diminishes with the age of the animals. Besides, a specific need for some essential amino acids must be taken in account. Stallions The protein requirement for semen production is negligible. Some authors however, propose an additional daily allowance of 200 g of digestible crude protein. Recommended allowance of protein for maintenance, pregnancy, lactation and growth is shown in Table V. No specific allowance is given for reproduction. Horse feeds Forages are traditionally used to feed horses. This herbivore is very sensitive to the quality of the herbage and in particular when the plant is at the growing stage. Grazed herbage at the pre-flowering stage of the grass allows a daily consumption of 90-100 kg whereas 2-3 weeks later at the flowering stage, consumption decreases to 50-60 kg. For grazing, horses prefer polyphyte meadows with 70-80% gramineae, TABLE V Protein allowances for horses Reference

Maintenance (g kg -~ W 0'75) Reproduction (mare) Pregnancy (g kg -1 W) Lactation (g kg - ~milk) Growth (g kg -1 W)

Digestible crude protein"

HDXP

N.R.C.

Jarrige and Tisserand a

3 0.18-0.20 32-45

Meyer 3

40-50 0.16-0.25

~Sources: N.R.C., (1978); Loewe and Meyer, (1974); Jarrige and Tisserand (1984). bHDXP = horse digestible crude protein.

b

2.8 0.17-0.37 40-55 0.37-0.44

287 10-15% leguminous plants and 5-10% other species. Coarse plants are little liked by horses and limit the fodder intake, which should be avoided. Whereas, unlike ruminants, horses can be given coarse pelleted, dehydrated forage without any problem, the use of badly-preserved hay, whitish or greyish, mouldy, or dirtied with earth results in colic and sometimes abortions. Feeding of wet or highly-lignified hay should be avoided as well. Silages can be used, but these must be very well preserved. Straw should be presented in racks. Alfalfa is especially recommended by some authors for stallions during the mating season. Although forage constitutes the basis of any diet, a concentrate, which can make up an important part of the diet of race horses, must be added. Cereals and oil meals or oil cakes can be used, often having been pressed or crushed and sometimes soaked and cooked. Oats and linseed cakes are often regarded as highly-recommended feeds for horses. Most of these recommendations are more a result of tradition than of scientific observation. Among other feeds, which can be given to horses, carrot and beet roots, industrial by-products, such as bran, beet pulp and, preferably dehydrated, brewery drafts can be used. Concerning the protein supply given to growing foals and brood mares by-products of animal origin should be used rather than proteaginous seeds. Poisonous plants must be avoided. These are, in meadows: buttercups, anemones, spurges, autumn crocuses and ragworts. Poisonous in hedges are fern, digitalis and deadly nightshade. Poisonous trees are false acacias, tuyas, yews and privets. CHANGES IN THE FUTURE After the big decrease in the number of horses owing to mechanization, particularly in Western Europe, it seems that the horse population in Europe may remain constant in the future. Maybe a slight increase in the number of saddle horses may be expected. Future research work should give us more information about the protein requirements of the horse, in particular concerning essential amino acids for growing foals, brood mares and perhaps stallions during the mating season. More information is needed about the energy expenditure of sporting animals. The percentage of concentrate and, to a certain extent, that of industrial byproducts, offered as compound feed may increase, to the detriment of forages.

REFERENCES Bickel, H., 1988. Feed evaluationand nutritional requirements.Introduction. Livest. Prod, Sci., 19: 211-216. Hintz, H.F., 1977. Nutrition of the Horse. In: J.W. Evans et al. (Editors), The Horse. Freeman, San Francisco.

288 Hintz, H.F., 1983. Nutritional requirements of the exercising horse. In: D.M. Snow, S.G.B. Peisson and R.J. Rase {Editors), Equine Exercise Physiology. Grante. Edition Cambridge, pp. 275-290. Jarrige, R. and Tisserand, J.L., 1984. M~tabolisme, besoins et alimentation azot~e du cheval. In: R. Jarrige and W. Martin-Rosset (Editors), Le Cheval, Reproduction, S$1ection, Alimentation, Exploitation. I.N.R.A., Paris, pp. 277-302. Laube, W., 1977. Das DDR-Futterbewertungssystem. VEB Dtsch. Landwirtsch. Verl. Berlin, 824 pp. Loewe, H. and Meyer, H., 1974. Pferdezucht und Pferdeftitterung. Ulmer, Stuttgart, 387 pp. Meyer, H. and Ahlswede, L., 1976. Ueber das intrauterine Wachstum und die K~rperzusammensetzung von Fohlen sowie den N§hrstoffbedafftragender Stuten. Ueber Tierernaehr., 4: 263-292. N.R.C., 1978. Nutrient requirements of domestic animals. No. 6. Nutrient requirement of horses, 4th edn., Washington DC. pp. 2-10. Pagan, J.D. and Hintz, H.F., 1986. Equine energetics. II. Energy expenditure in horses during submaximal exercise. J. Anim. Sci., 63: 822-830. Vermorel, M., Jarrige, R. and Martin-Rosset, W., 1984. Mdtabolisme et besoins Snerg~tiques du cheval, le syst~me des UFC. In: R. Jarrige and W. Martin-Rosset (Editors), Le Cheval, Reproduction, Sglection, Alimentation, Exploitation. I.N.R.A., Paris, pp. 239-276. Wolter, R., 1975. L'alimentation du Cheval. Vigot Frbres, Paris, 2nd edn., 177 pp.

Livestock Production Science, 19 (1988) 289-298

289

Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands

III. 3 . 2 . R a b b i t s

F. LEBAS

INTRODUCTION

Experimental work conducted in Europe and throughout the world during the last 15 years has allowed the definition of reliable recommendations to be used in feeding rabbits for meat production, under temperate European conditions. Several reviews of published literature have been made recently (Lang, 1981; Lebas, 1983; I.N.R.A., 1984). The feeding of rabbits has to take into account various special features of anatomy and feeding behaviour of this animal: (1) the digestive system with a relatively big stomach and the voluminous caecum where microbial digestion takes place; (2) the frequent intake (30-40 times a day) of small amounts of feed (2-8 g per meal) in a short time (4-6 min per meal) (Prud'hon et al., 1975). The traditional method of feeding rabbits for meat production was to rely on cereals, bran and forages which were fresh during the summer and dried during the winter. During this latter period, farmers also used fodder beet and carrots. Currently, this means of feeding is rapidly declining but it is still used for up to one third of the rabbits produced in France, for example. On intensive farms, which represent the major type of commercial production, rabbits are fed compound balanced diets. With this change in the feeding systems, which went along with the intensification of meat production, one has to pay attention to the bulkiness of the diet, besides the usual allowance for energy, protein and minerals. One should also keep in mind here, that the average transformation ratio of plant protein to animal protein by rabbits is 18% with fibrous materials, whereas this ratio is increased to 22% in the most efficient rabbitries. FEED EVALUATION

The energy value of feeds is usually evaluated as digestible (DE) or metabolizable (ME) energy, considering ME/DE equal to 0.94. Digestibility of feed is most likely to compare with that of pigs (Nehring et al., 1963 ). However, the results of digestibility experiments are somewhat conflicting. Some authors claim a reduced digestibility especially of crude fiber (Jentsch et al., 0301-6226/88/$03.50

© 1988 Elsevier Science Publishers B.V.

290 1963), compared to the digestibility in horses, whereas former experiments showed higher digestibility of organic matter at a high level of crude fibre (Axelsson, 1942). The conflicting results may stem from differences in cell-wall constituents. Within diets currently utilized, the low digestibility (10-30%) of cell-wall constituents associated with raw materials such as lucerne or straw, means that such materials only have a minor role in meeting energy requirements when compared with starch. On the other hand, cell-wall constituents from those plants that are only slightly lignified (usually young plants) have a considerably higher digestibility (30-60%) and their contribution to overall energy requirements may be 10-20% and up to 30% under the most favourable conditions. Some experimental efforts have been made to predict the digestible (or metabolizable) energy content of a diet from its chemical analysis (Battaglini and Grandi, 1984; De Blas and Santoma, 1984). In all cases, cell-wall constituents are the most explicative analysis for energy digestibility; for some researchers aciddetergent fibre (ADF) is the more suitable analysis but for others neutral detergent fibre (NDF) is better (Pagano-Toscano et al., 1985). At present, none of these equations is precise enough to be employed in practice. Therefore the DE content of rabbit feed is usually calculated by using the DE value estimated as for pig feedstuffs. According to Jentsch et al. (1963) digestible energy of rabbit feeds may be calculated as follows if digestible crude proteins (DXP), lipids (DXL), fiber (DXF) and nitrogen-free extract (NFE) (DXX) concentrations are known: DE (MJ kg -1) =21.95 D X P (kg kg -1) +39.62 D X L (kg kg -1) + 17.22 D X F ( kg kg- 1) + 17.39 D X X ( kg kg- 1) The protein value is based, in general, on crude protein and amino-acid content. Digestibility is generally assessed as the difference of nitrogen intake and nitrogen output in the hard pellets of the faeces. Thus, coprophagy of caecotrophe pellets is not prevented and the protein of these pellets is correctly considered as digestible. These pellets contain 350-450 g XP kg- 1DM, whereas unpalatable hard pellets contain between 100 and 200 g XP kg- 1 DM ( Proto, 1980). The digestibility of vegetable fat (e.g. soya bean oil) is comparable with data from pigs, although Nehring et al. (1963) show lower digestibility of fat in concentrates than for pigs. Pure animal fats have a lower DE content than fats of plant origin ( Maertens et al., 1985 ). NUTRIENT REQUIREMENTS Nutrient requirements and the recommendations of nutrient allowances may be distinguished for four categories of rabbits: (1) adult rabbits at mainte-

291 nance (males, non-reproducing does, those to be culled); (2) pregnant does (but not lactating); (3) lactating does (pregnant or not); (4) young rabbits between weaning ( around 1 month) and slaughter at about 2.5 months.

Energy The energy requirement of adult rabbits at maintenance varies according to different authors. Experiments in respiration chambers resulted in a daily maintenance requirement of 395 kJ DE kg- 1 WO.75 ( Schiirch, 1949 ). However, allowances for practical feeding at maintenance are much higher, e.g. 485 kJ and about 600 kJ DE kg -1 W °'75 according to Parigi-Bini and Xiccato (1986) and Jeroch (1986), respectively. The requirement for pregnant does is enhanced during the last 10 days before parturition by about 30%, but the spontaneous daily intake decreases during the same period by 10% (Lebas, 1979). Rabbits are generally fed ad libitum and regulation of intake is possible if dietary energy concentrations are between 9.2 and 13.0 MJ DE kg-1. With growing rabbits (0.5-2.5 kg W) as with lactating does (8 young suckled), the daily intake is 900-1000 kJ DE kg -1 W °75, i.e. about twice the maintenance requirement. Milk production of lactating does lasts about 30-50 days, with peak production during the third week. Does' milk is about two and half times more concentrated than cows' milk. The concentration varies considerably during the first week of lactation. In peak lactation, rabbit milk consists of about 260 g DM, 130 g protein, 90-100 g fat, 10 g lactose, 22 g minerals and 7.0-7.5 MJ energy per kg (Lebas, 1971). The amount of milk produced depends on the number of offspring. Forty to 50 g milk day- 1 kg- 1 W of the doe is a fair value and daily performance of 100-300 g is often achieved (Coates et al., 1964; Cowie, 1969; Lebas, 1971 ). Partial efficiency of utilization of metabolizable energy for milk production (kl) is about 0.6-0.7. Body reserves can only be mobilized marginally for milk production, owing to relatively small reserves (Lebas, 1971, 1973a). The composition of tissue accretion in growing rabbits is relatively high in protein and low in fat content, i.e. about 210 g protein, 35 g fat and 6.6 MJ energy per kg liveweight gain (LWG) ( Schiirch, 1949).

Dietary bulk In contrast to other farm animals, recommendations are given not only for crude fibre but also for indigestible crude fibre. This refers to the role of dietary bulk. Cell-wall constituents play an important role in providing bulk to the diet. Although the analytical technique is imprecise, assessment is generally satisfactorily achieved by the crude-fibre method. To ensure an adequate level of

292 bulk, a dietary crude fibre level of 13-14% appears sufficient for the young growing rabbit, if a minimum level of 10% indigestible crude fibre is allowed. For lactating does a slightly lower crude fibre level (10-11% ) is acceptable. The bulkiness of the diet and the physical form in which it is presented will influence the dietary energy value of the remainder of the diet: with bulkier feeds the associated increase in rate of passage of digesta may reduce the digestibility of other energy-yielding ingredients, however, without influencing apparent protein digestibility. Transit time increases with the size of particles, which contain the cell-wall constituents. A very fine grinding of raw materials, e.g. sieve holes of 1 mm diameter, may induce a disturbance of the digestive tract motility, specially with highly-digestible fibre sources (Pairet et al., 1986). However, grinding of diets with small ( 2 mm) or wide ( 7 mm) holes, in a commercial factory, failed to induce any digestibility variation or health disturbance in growing rabbits ( Lebas and Franck, 1986; Lebas et al., 1986). Protein and amino acids

The sensitivity of the rabbit to dietary protein quality, for a long time controversial, is now accepted. The most recent work has shown that 10 amino acids are essential and that an eleventh, glycine, is semi-essential (Adamson and Fisher, 1973). Following what is known with other species, it could be considered that tyrosine and cystine might partially replace phenylalanine and methionine, respectively. In fact the possibility of replacing one sulphur amino acid by the other has been confirmed although no work has been carried out on phenylalanine and tyrosine. Amino-acid requirements for the rabbit have only been studied in practice with respect to lysine, arginine and sulphur amino acids (methionine and cystine), and recently to threonine and tryptophan (Berchiche, 1985). When expressed as a percentage of the diet, lysine and sulphur amino-acid levels should be around 0.60-0.65% for each, while that for arginine should be more than 0.8%. There is a considerable difference for lysine and arginine between these optimum levels and those which have a negative influence. However, with sulphur amino acids the margin between optimum levels and excesses is small. Higher levels entail poor performance. Minimum levels of other essential amino acids have simply been calculated from diets which give satisfactory performance. When dietary protein provides all essential amino acids, dietary crude protein levels need only be 15-16% for growing rabbits. For breeding does, optimum levels of crude protein are between 17 and 18% with a balance of essential amino acids according to those for a young growing rabbit. Precise requirements for most of the essential amino acids in does are

293 not known, but recent work of Maertens and de Groote (1986) indicates a tendency for positive performance with a higher lysine concentration (5% of proteins) for breeding does in comparison with growing rabbits (4% of proteins ). An increase in dietary protein level, to 21%, will raise milk production but will reduce slightly the number of rabbits weaned. A lowering of dietary protein level from 16 to 13% will reduce weaning weight without any appreciable alteration to fertility. In addition, it is known that the feed intake of a diet balanced with respect to essential amino acids is always higher than that with a similar but unbalanced diet. If the overall quality of dietary protein is insufficient, daily DM intake is correspondingly reduced. All preliminary studies investigating classical non-protein nitrogen ( N P N ) sources (urea, ammonium salts) have proved unsuccessful. This has been confirmed for the Angora rabbit by Teleki et al. (1983), but according to recent work of Proto et al. (1987), N P N with a medium hydrolysis rate such as biuret, may be utilized by growing rabbits. This is to be confirmed before practical application can be recommended. Minerals and vitamins

Calcium and phosphorus requirements of growing rabbits are considerably lower than those of the lactating does. Significant amounts of minerals are excreted through milk: 7-8 g minerals daily at peak lactating, containing 1.5-2 g calcium. An excess (1.0%) or a lack (0.42% of the diet) of phosphorus induces a significant alteration of fertility (Lebas and Jouglar, 1984 ). The breeding doe is more tolerant to the calcium level of the diet, but the best range is 1.0-1.5%. Cheeke et al. (1985) showed that the calcium in ground limestone is of greater availability (81%) than the dicalcium phosphate or the calcium in alfalfa meal ( 54% for both). Phytate phosphorus of cereals, cereal by-products and soya bean meal is available for the rabbit ( Cheeke et al., 1985; Nelson et al., 1985). An imbalance in dietary levels of sodium, potassium and chloride may promote nephritis and reproductive problems, a risk which is particularly important with those plants, especially lucerne, that are grown with high levels of potassium-containing fertilizers. A growth-promoting effect of high dietary levels of copper ( 200 ppm) has occasionally been observed. The microflora within the digestive tract synthesizes important amounts of water-soluble vitamins, which the rabbit is able to utilize by ingesting caecotrophe pellets. In this way, requirements of all B-group vitamins and Vitamin C for maintenance and for an average production level may be met. On the other hand, very fast-growing animals will respond to supplements of Vitamins B1, B6 (1-2 ppm), B2 (6 ppm) and nicotinic acid (30-60 ppm) to the diet. Dietary levels of up to 1% Vitamin C will have no positive or negative effect

294 TABLE I Recommended nutrient levels in diets for various categories of rabbits reared intensively Dietary composition (assuming a dry matter content of 89% )

Units

Digestible energy Metabolizable energy Fat Crude fibre Indigestible crude fibre Crude protein Amino acids Lysine Sulphur amino acids Tryptophan Threonine Leucine Isoleucine Valine Histidine Arginine Phenylalanine plus tyrosine Minerals Calcium Phosphorus Sodium Potassium Chloride Magnesium Sulphur Trace elements Iron Copper Zinc Manganese Cobalt Iodine Fluorine Vitamins A D E K

MJ k g - 1 MJ kg -~ % % % %

B1 (thiamine) B2 (riboflavine) Panthothenic acid B6 (pyridoxine) B12 Niacin Folic acid Biotin

Fattening

10.4 10.6 3 14 11 16

Lactation

10.9 10.4 3 12 10 18.0

Gestation

10.4 10.0 3 14 12 16.0

% % % % % % % % % %

0.65 0.60 0.13 0.55 1.05 0.60 0.70 0.35 0.90 1.20

0.90 0.60 0.15 0.70 1.25 0.70 0.85 0.43 0.80 1.40

-

% % % % % % %

0.50 0.30 0.30 0.60 0.30 0.03 0.04

1.10 0.70 0.30 0.90 0.30 0.04 -

0.80 0.50 0.30 0.90 0.30 0.04

ppm ppm ppm ppm ppm ppm ppm IU kg-~ IU k g - ~ ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm

50 5 50 8.5 0.1 0.2 0.5 6000 900 50 0 2 6 20 2 0.01 50 5 0.2

100 5 70 2.5 0.1 0.2 12 000 900 50 2

0

-

Maintenance

9.2 8.9 3 15-16 13 13.0

10.4 10.0 3 14 11 17.0 0.75 0.60 0.15 0.60 1.20 0.65 0.80 0.40 0.90 1.25

-

-

50

All purpose

0.40 0.30

50

70 2.5

2.5

0.2

0.2

12 000 900 50 2 0 0 0 0 0

600 900 50 0 0 0 0 0 0

0

0

1.10 0.70 0.30 0.90 0.30 0.04 0.04 100 5 7O 8.5 0.1 0.2 0.5 10 000 900 50 2 2 4

20 2 0.01 50 5 0.2

295 on the growth performances. Studies on fat-soluble vitamins are less numerous, and required dietary levels have been obtained empirically. An excessive level of Vitamin D (above 2300 IU kg-1 diet) is associated with renal and aortic calcification and, therefore, a level of 2000 IU k g - 1 diet should never be exceeded. Harmful effects, mainly poor reproduction of the does and a high proportion of kits with hydrocephalus at birth have been described after addition of extra Vitamin A to the drinking water ( Cheeke, 1985 ). The growing rabbit is more tolerant than the breeding doe to vitamin excess.

Recommended nutrient levels Recommendations to cover the requirements are usually given in terms of dietary levels in the complete ration, as shown in Table I (I.N.R.A., 1984). Significant deviation from the recommended dietary level may have consequences on the performance and the health of the animals. This concerns above all the lack of bulk in the diet. However, increasing indigestible crude fibre above 12% worsens the feed-conversion ratio. Energy value of the feed below 9.2 M J DE kg-1 results in poor performance owing to limited intake capacity, although no change in health status of the animal will occur. With high-lucerne diets and coarse grinding, fatal compaction of the caecum content was observed (Auvergne et al., 1987). Table II shows the variations in performance to be expected if the levels of dietary protein or of certain essential amino acids are lower than those recommended in Table I. Lower performance levels need not necessarily be economically undesirable as long as dietary protein levels do not fall below 12-13%. TABLE II Consequences of a reduction in recommended dietary levels of protein by 1% or certain amino acids by 0.1% on the performance of fattening rabbits (4-12 weeks) Nutrient under consideration

Crude protein Methionine Lysine Arginine

Reduction of dietary level

1% 0.1% 0.1% 0.1%

Reduction in d a i l y liveweightg a i n

Increasein food conversion ratio

Absolute amounts (gday -1)

%

Absolute %

-3 -2 -5 -1.5

-8.5 -6 -14 -4.5

+0.1 +0.1 +0.1 +0.1

+3 +3 +3 +3

Dietary level belowwhich these relationships will not hold 12 0.4 0.4 0.5

296 PRACTICAL FEEDING

Under controlled conditions of rearing, dried and ground raw materials are used for rabbits and this allows formulation of balanced compound diets. Rabbits do not tolerate dust and therefore it is preferable to use pelleted diets. The ideal pellet size lies between 3- and 4-mm diameter and 8-10-mm length. It is important never to go beyond 5-mm diameter to avoid wastage (Table III). Intake of pellets is enhanced compared with the intake of meal, resulting in higher LWG and improved feed-conversion ratio (Table IV). If only meal is available for feeding rabbits it may be advisable to mix it with TABLE III Influence of pellet size on the performance of growing-finishingrabbits (5-12 weeks) Pellet diameter (mm)

Daily feed intake (g) Daily liveweight gain (g) Food-conversion ratio

2.5

5

7

117 32.4 3.7

122 33.7 3.7

131a 32.0 4.4

aThe apparent increase in food consumption was caused by feed wastage. TABLE IV The effect of form of presentation of feed on the performance of young growing rabbits Reference

Form of presentation

Daily feed intake (gDM)

Daily liveweight gain (g)

Feed-conversion ratio (g DM g- 1 LWG )

Lebas (1973b) a

Meal Pellet Meal Pellet Meal Mash (40% water) Pellet

82 94 79 85 102 78 104

29.7 36.0 20.7 22.9 26.5 27.9 33.1

2.76 2.61 3.82 3.71 3.85 2.80 3.14

King (1974) b Machin et al. (1980) c

Formulation of diets aMaize 55.8%, soya bean meal 25%, barley straw 15%, DL-methionine 0.2%, minerals/vitamins 4%. bFish meal 10%, grass meal 20%, wheat bran 40%, oats 12.5%, wheatings 17.5%, molasses at 1.5% was then added to pellets. CBarley 62%, soya bean meal 17.5%, barley straw 12.8%, molasses 5%, lysine 0.25%, methionine 0.05 %, minerals 0.93%. The trial was carried out at 25 ° C.

297

water at a ratio of 60-40%, but feeders must be kept scrupulously clean. Automatic valve-controlled watering systems are always preferable. For a rapid reproductive rate, all rabbits, with the exception of males, are fed on an ad libitum basis. If the rate is less intense, does are to be fed on a restricted basis from weaning to the end of the following pregnancy. The recommended level of feeding is usually 30-35 g of DM kg -1 body weight per day. Young growing rabbits are invariably fed on an ad libitum basis. When they are group fed, a single watering point is sufficient for 10-15 individuals. One feeder is sufficient for 10 individuals although two are often used to reduce any problems that may occur if one of them is blocked. The following daily feed intake per animal, kept in groups, is considered to be adequate for high performance: (1) young growing (4-12 weeks), 110-130 g; (2) lactating does with their litter (weaning at 4 weeks), 350-380 g; (3) adult at maintenance, 120 g; (4) 1-1.4 kg per doe, including offspring.

REFERENCES Adamson, I. and Fisher, H., 1973. Amino acid requirement of the growing rabbit: an estimate of quantitative needs. J. Nutrition (London), 103:1306-1310. Auvergne, A., Bouyssous, Th., Pairet, M., Ruckebusch, Y. and Candau, M., 1987. Nature de l'aliment, finesse de mouture et donn~es anatomo-fonctionnelles du tube digestif proximal du lapin. Reprod. Nutr. Dev., 27: 755-768. Axelsson, J., 1942. Digestive capacity of hens and rabbits. Arch. Kleintierzucht., 3: 81-97. Battaglini, M. and Grandi, A., 1984. Stima del valore nutritivo dei mangimi composti per conigli. 3rd World Rabbit Congress, Rome, Vol. 1, Associazone Nazionale Coniglicultori Italiani, pp. 252-264. Berchiche, M., 1985. Valorisation des prot$ines de la fSverole par le lapin en croissance. Th~se doctorat I.N.P. Toulouse, pp. 137. Cheeke, P.R., 1985. Vitamins, swallowing an unnecessary pill, or vitamins make strange bedfellows. J. Appl. Rabbit Res., 8: 101-103. Cheeke, P.R., Bronson, J., Robinson, K.L. and Patton, N.M., 1985. Availability of calcium, phosphorus and magnesium in rabbit feeds and mineral supplements. J. Appl. Rabbit Res., 8: 72-74. Coates, M.E., Gregory, M.E. and Thompson, S.Y., 1964. The composition of rabbit's milk. Br. J. Nutr., 18: 583-586. Cowie, A.T., 1969. Variations in the yield and composition of the milk during lactation in the rabbit and the galactopoietic effect of prolactin. J. Endocrinol., 44: 437-450. De Bias, C. and Santoma, G., 1984. Valor nutritivo de los alimentos. In: C. De Bias Beorlegui (Editor), Alimentaci6n del Conejo. Mundi Prensa, Madrid, pp. 59-66. I.N.R.A., 1984. L'alimentation des animaux monogastriques: porc, lapin, volailles. I.N.R.A., Paris, 282 p. Jentsch, W., Schiemann, R., Hoffmann, L. and Nehring, K., 1963. Die energetische Yerwertung der Futterstoffe, 2. Mitteilung: Die energetische Verwertung der Kraftfutterstoffe durch Kaninchen. Arch. Tierernaehr., 13: 133-145. Jeroch, H., 1986. Ftitterung des Kaninchen. In: H. Jeroch (Editor), Vademekum der Fiitterung. VEB G. Fischer Verl., Jena, 632 pp. King, J.O.L., 1974. The effects of pelleting rations with or without an antibiotic on the growth rate of rabbits. Vet. Rec., 94: 586-588.

298 Lang, J., 1981. The nutrition of the commercial rabbit. Part 1. Physiology, digestibility and nutrient requirements. Nutr. Abstr. Rev., 51: 197-225. Lebas, F., 1971. Composition chimique du lait de lapine. Evolution an cours de la traite et en fonction du stade de lactation. Ann. Zootech., 20: 185-191. Lebas, F., 1973a. Variations des r~serves corporelles de la lapine au cours d'un cycle de reproduction. In: I.T.A.V.I. (Editor), Journ~es de la Recherche Avicole et Cunicole, D~cembre 1973, Paris, pp. 59-61. Lebas, F., 1973b. Poseibilit~s d'alimentation du lapin en croissance avec des r~gimes pr~sent~s sous forme de farine. Ann. Zootech., 22: 249-251. Lebas, F., 1979. Efficacit~ de la digestion chez le lapin adulte. Effets du niveau d'alimentation et du stade de gestation. Ann. Biol. Anim. Biochem. Biophys., 19: 969-973. Lebas, F., 1983. Bases physiologiques du besoin prot~ique des lapins.Analyse critiquedes recommandations. Cuni-Sciences, 1: 16-27. Lebas, F. and Jouglar, J.Y., 1984. Apports alimentaires de calcium et de phosphore chez la lapine reproductrice. 3rd World Rabbit Congress, Rome VoL I, 461-466. Lebas, F. and Franck, T., 1986. Incidence du broyage sur la digestibilit~de quatre aliments chez le lapin.Reprod. Nutr. Ddv., 26: 235-236. Lebas, F.,Maitre, I.,Seroux, M. and Franck, T., 1986. Influence du broyage des mati~res premieres avant l'agglomdration de 2 aliments pour lapins,diff~rantpar leur taux de constituants membranaires:digestibilit~et performances de croissance.4e Journ~es Recherche Cunicole en France, Paris Ddc. 1986, Communication No. 9. Machin, D.H., Butcher, C., Owen, E., Bryant, M. and Owen, J.E., 1980. The effectsof dietary metabolizable energy concentration and physical form of the dieton the performances of growing rabbits. Second World Rabbit Congress, Barcelona, Vol. 2, 65-75. Maertens, L. and De Groote, G., 1986. The influence of the crude protein and lysine content in the diet of the breeding results of does. 3rd International Colloquy, The Rabbit as a Model Animal and a Breeding Object, Rostock, 11-13 September, 1986, Section If,pp. 90-97. Maertens, L., Huyghebaert, G. and De Groote, G., 1985. Digestibilityand digestibleenergy content of various fats for growing rabbits.Cuni-Sciences, 3: 7-14. Nehring, K., Hofmann, L., Schiemann, R. and Jentsch, W., 1963. Die energetische Verwertung der Futterstoffe.3. Die energetische Verwertung der Kraftfutterstoffedutch Schweine. Arch. Tierern~ihr.,13: 147-161. Nelson, T.S.,Daniels, L.B., Shriver,L.A. and Kirby, L.K., 1985. Hydrolysis of phytate phosphorus by young rabbits.Arkansas Farm Res., 34 (4): p.8. Pagano-Toscano, G., Benatti, G. and Zoccarato, I., 1985. Digeribilithdegli alimenti per conigli: confronto dei metodi Weende e Van Soest per la stima della frazione fibrosa.Coniglicoltura, 21 (1): 37-42. Pairet, M., Bouyssou, Th., Auvergne, A., Candau, M. and Ruckebusch, Y., 1986. Stimulation physicochimique d'origine alimentaire et motricit~ digestive chez le lapin. Reprod. Nutr. DSv., 26: 85-95. Parigi-Bini, R. and Xiccato, G., 1986. Utilizzazione dell'energia e della proteina digeribile nel coniglio in accrescimento. Coniglicoltura, 23 (4): 54-56. Proto, V., 1980. Alimentazione del coniglio da came. Coniglicoltura, 17(7): 17-32. Proto, V., Gioffr~, F., Di Franca, A. and Maiolino, A., 1987. L'utilizzazione di alcune fonti di azoto non proteico (NPN) neUa nutrizione del coniglio con ciecotrofia. Coniglicoltura, 24 (3): 45-51. Prud'hon, M., ChSrubin, M., Goussopoulos, J. and Caries, Y., 1975. Evolution, au cours de la croissance, des caract~ristiques de la consommation d'aliments solide et liquide du lapin domestique nourri ad libitum. Ann. Zootech., 24: 289-298. Schiirch, A., 1949. Die theoretischen Grundlagen der KaninchenfUtterung. Schweiz. Landwirtsch. Monatsch., 17 (2) : 3-27. Teleki, J., Szegedi, B. and Juhasz, B., 1983. Effect of feed mixtures and urea supplementation on the protein metabolism of angora rabbits. Allattenyesz. Takarman., 32: 165-169.

Livestock Production Science, 19 (1988) 299-354 Elsevier SciencePublishersB.V., Amsterdam-- Printed in The Netherlands

299

III. 4. Pigs and Poultry Y. HENRY, H. VOGTand P.E. ZOIOPOULOS

INTRODUCTION During the last decades there have been significant changes in the allocation of feed resources to pigs and poultry. Meat or egg production from non-ruminants is mainly based on the use of concentrates, with recent steady trends to a more diversified and economical feed supply, in order to lower the cost of production. This has resulted in the development of alternative feeds to cereals and common oil meals, with great fluctuations in composition and nutritive value, and t~ the use of industrial by-products and new processed feeds as energy and/or protein sources. Within this wide range of feeds, more fibrous feeds are being used, especially for pigs. Owing to the negative effect of fibre components on the availability of dietary nutrients (energy as well as protein and amino acids) there is an increasing need for a precise evaluation of the nutritive value of feedstuffs and of compound feeds. In order to meet the constraints of increasing productivity, there has been a trend to select and raise animals with a high level of performance for lean meat and egg production. More emphasis is then placed on protein and essential amino acids, to be supplied in greater amounts and in a more available form according to energy intake. The energy supply may nevertheless become critical through a limitation of voluntary feed intake for fast growing, lean animals. This is a problem of increasing relevance both for pigs and for chickens, especially in the case of excessive diet bulkiness (high fibrous feeds), owing to a limitation caused by physical factors related to gut fill. Similar limitations may occur when unpalatable substances, frequently associated with fibre, are present in the diet, as well as toxic and antinutritional substances. Therefore, the use of feed resources in non-ruminants implies a clear understanding of feed evaluation and nutrient requirements. This includes energy and protein as the major components of feeds, and it will be assumed that the other nutrients, i.e., minerals and vitamins, are not the limiting factors in the diet. Three parts will be considered: (1) nutritive value of feeds; (2) nutrient requirements; (3) future developments in the assessment of feed evaluation and nutrient requirements. The present situation of the systems in use in the European countries will be described in the Appendix. 0301-6226/88/$03.50

© 1988ElsevierSciencePublishers B.V.

300 NUTRITIVE VALUE OF FEEDS

Feed evaluation for non-ruminants is mainly based on the assessment of energy and protein (with essential amino acids), which are the 2 major quantitative components of the diet. However, a wide range of other nutrients are present, including minerals, trace elements and vitamins, although these are in low or minute amounts, and are generally provided in feed formulation at a relatively low cost.

Energy Former systems Until the 1960s energy evaluation of feeds in most European countries was based on the findings of Kellner (1913) on net energy for fat formation in fattening beef cattle. This resulted in the starch equivalent (SE) which was subsequently converted to fodder unit (FU) systems, usually equivalent to the energy value of 1 kg of barley. This concept was applied to pigs in the Scandinavian countries as the Scandinavian fodder unit (SFU), with appropriate adaptations to the digestibility coefficients. At the same time the total digestible nutrients (TDN) system, which corresponds to the total amount of digestible nutrients on an equicaloric basis, was developed and applied in some countries: as T D N in the U.K. (Evans, 1948); as "Gesammtn~ihrstofff' or GN in Germany (Lehmann, 1924). In France, a net energy system was derived by Leroy (1949), based on the calculation of metabolizable energy ( ME ) from TDN, its correction to net energy (NE) and conversion to a feed unit ("Unit~ Fourrag~re" or UF) equivalent to the energy value of 1 kg of barley. Since these systems were established from research data obtained on ruminants, there was a need to reconsider a specific energy evaluation procedure for pigs. This became possible with the development of direct calorimetric measurements of digestible energy (DE), metabolizable energy (ME) and net energy ( NE ) for fattening ( Schiemann et al., 1971 ) and growth ( Just, 1982a). In the case of poultry T D N (or GN; Lehmann, 1924) was also used in a first stage for the evaluation of feeds along with SE, SFU or total feeding value. In the 1950s "productive energy" values (Fraps and Carlyle, 1939, 1942) were the primary measures of energy value of poultry feedstuffs. Since the second half of the 1950s (Carpenter and Clegg, 1956; Hill, 1957; after the first proposal of Axelsson, 1939) there has been a general agreement on the use of metabolizable energy in the evaluation of poultry feedstuffs. A net energy system for fat formation is only used in some East European countries (Schiemann et al., 1971 ). Similarly, a method for calculating the net energy content of feedstuffs from determined ME values was described by de Groote (1974a).

301

Present systems for the energy evaluation of feeds for pigs and poultry Feed energy value for non-ruminants is expressed in any of the 3 main systems: DE, ME and NE. It is measured directly from calorimetric determinations (kJ or kcal), in the case of DE or ME, or more generally based on regression equations derived from digestible nutrients in the Weende analytical system (digestible crude protein, DXP; digestible fat, DXL; digestible crude fibre, DXF; digestible nitrogen free extract, DXX) or simply from crude nutrients (crude protein, XP; fat, XL; crude fibre, XF; nitrogen free extract, XX, or XP, XL; starch, S; sugar, Z). In this respect, a distinction is to be made between single feedstuffs and compound feeds, for which the ingredient composition may be unknown, so that the prediction of energy value is restricted to data on the crude chemical composition. The energy systems for non-ruminants have been presented in detail in several reviews; among these the most recent, for pigs, are from Henry and Pdrez (1982, 1983), Just (1982a), Morgan and Whittemore (1982), and, for poultry, from Farrell (1979), Fisher (1982) and Hartfiel (1983). A brief description of DE, ME and NE systems will be given, by considering for each of them the methods of measurement, the factors of variation (animal and dietary effects, level of feeding) and the mode of calculation. DE and ME systems. The DE value of feeds for pigs is simply measured in digestibility trials by total collection of faeces or by using feed markers along with faecal sampling. Digestibility trials with chickens are complicated by the voiding of mixed excrement (urine and faeces). An appropriate technique is to operate on chickens in order to form an artificial anus, whereby the faeces may be collected separately from the urine. Another technique is to determine the amount of uric acid in the mixed excrement and to calculate the total urinary nitrogen. As a consequence of these difficulties, DE values are not generally employed in poultry-feed formulation. The accurate measurement of ME requires methane losses to be taken into account in addition to urine, and this is only possible in a respiration chamber. In fact, losses of energy through methane in pigs are very low, especially in growing animals: they usually represent less than 0.5% of gross energy ( GE ), according to recent literature (Henry and Noblet, 1986). They are even lower in poultry. Although methane losses are likely to be higher in older animals, especially with diets containing a high level of fermentable carbohydrates, in practical conditions this source of energy loss is neglected, so that ME is simply determined by subtracting from DE the energy loss in urine. The urinary energy loss, mostly in the form of nitrogen, is closely dependent on the dietary protein level, and especially the amino acid balance (i.e. the level of the limiting essential amino acid). Therefore, for ME determination, it is necessary to standardize the level of nitrogen retention, for optimum pro-

302 tein utilization, for a given level of nitrogen retention, or for zero nitrogen balance. In pigs, ME is preferably measured under conditions of optimum protein and amino acid balance, in order to obtain a nitrogen retention of 0.50 or more according to apparently digested nitrogen in growing animals. With balanced diets ME represents a rather fixed proportion of DE: around 0.95. But in single feedstuffs ME: DE ratio is inversely related to protein level. In poultry, it is a common practice to correct ME data on the basis of nitrogen equilibrium (MEn), i.e., zero nitrogen retention (subtracting 8.22 kcal or 34.4 kJ per g of uric acid nitrogen), to correct for differences in nitrogen retention of the birds to which it is fed. Through these corrections for N-balance, protein-rich feedstuffs are underestimated and, on the other hand, energy yielding feedstuffs are overestimated. Therefore a correction on the basis of 0.33 of retained from digested nitrogen or 0.25 of retained from ingested nitrogen would be more realistic (Hartfiel, 1964; Hartfiel et al., 1970). The method in general use for measuring ME in feed ingredients with growing chicks was initiated at Cornell University in the 1950s (Hill and Anderson, 1958). ME measurements are also made with laying hens (to have birds with 0.33 digestible N retention), or with adult cocks (to have birds with no N gain or N loss). Farrell (1978) developed a rapid method for measuring a noncorrected apparent ME value with trained roosters. ME in poultry is expressed in apparent (AME) or true ( T M E ) value, by considering the endogenous losses of energy; AME in poultry is similar to ME in other animals and chapters. A rapid method for measuring T M E was developed by Sibbald (1976), using force-fed adult cockerels with a fixed amount of feed. T M E for poultry is the GE of the feed minus the GE of the excreta of food origin, i.e., a correction is made for endogenous energy. Because of the difficulty of its measurement the T M E method has not been adopted in the European countries. A new joint assay for the determination of AME and T M E was recommended by McNab and Fisher (1984). A new ME system for pigs based on negative corrections for the energy value of fermentable substances has been developed in the F.R.G. and is used as an energy unit (MJ) for expressing dietary recommendations (D.L.G., 1984). Animal effects, such as age, sex and genotype, have generally a small effect on DE or ME. In pigs, there is, however, some trend towards a slightly higher value with increasing age, probably owing to a better ability to digest fibre. This explains why DE and ME determinations with growing pigs are usually made within the liveweight range of 30-60 kg. DE and ME values in pigs are slightly decreased at a high level of feeding close to ad libitum. They depend, however, mainly on diet composition and especially on the fibre content, which exerts a linear depressive effect on total energy utilization at a rate which varies according to type of fibrous component. It is therefore a good predictor of the digestibility of energy (Henry, 1976; Pdrez et al., 1984). Conversely, in

303 poultry, dietary fibre may be considered as an inert diluent with no value for the birds ( Carr~ et al., 1984). Tables of the DE and ME values of feeds for pigs and poultry in the different countries are usually based on direct calorimetric measurements. In pigs, the experimentally determined DE values, which refer to a known feed composition, may be corrected for variable fibre content, within a given homogeneous class of feedstuffs for fibre composition, as suggested by Henry and P~rez (1982, 1983). Also in pigs, very few data on direct ME values of feeds are available, in the absence of well-defined experimental conditions with balanced diets for essential amino acids. Therefore, it has been suggested (I.N.R.A., 1984) that the directly measured DE values should be converted to ME, after taking into account an estimate of energy losses in urine for an optimum protein retention and in the form of methane. An alternative indirect approach may be used to predict DE and ME from digestible nutrients, according to the Weende proximate analysis. But, by doing so, the digestibility coefficients for the dietary nutrients are assumed as being constant irrespective of fibre level. Interactions between digestibility coefficients and fibre level are likely to occur in pigs, so that DE is determined more accurately from direct experimental values corrected for fibre content. On the other hand, the use of crude nutrients in the prediction equations only applies to a control of the energy value of compound feeds. Some equations are available for pigs as well as for poultry, as shown in the Appendix. For the calculation of ME value of single feedstuffs in poultry Janssen and Terpstra (1972) used formulae or correction factors for differences in the nutrient content of feedstuffs: a new common European Energy Table is now calculated on this basis (W.P.S.A., 1986).

The efficiency of M E utilization. The energy losses as extra heat during the transformation of ME to maintenance and animal products are based on the measurement of heat production or energy deposited from indirect calorimetry or on the comparative slaughter technique. They are both associated with the type of production ( animal effects) and with the chemical composition of the digested nutrients (dietary effects). (a) Type of production effects. ME is more efficiently converted by pigs for fat formation ( kf= O.74 ) than for protein deposition (/% = 0.56 ) (A.R.C., 1981 ). Similar values are reported for poultry (de Groote, 1974b): 0.70 to 0.84 for lipid deposition in adult birds and 0.37 to 0.84 in growing chicks; about 0.50 for protein deposition. The estimated efficiency of ME utilization for maintenance is 0.80 in pigs and 0.85 in poultry (adult cockerels, growing chicks and laying hens). It follows that the efficiency of ME utilization for growth (kg) is inversely related to the proportion of energy retained as protein. Therefore, the leaner the animal, the lower the value of/% which lies generally between 0.65 and 0.75

304 in growing pigs. In common practice, there is little fluctuation of ME utilization for growth (around 0.70) with varying energy partitioning for lean and fat 0.70-0.75. A similar range of efficiency (0.65-0.70) is noted for energy deposition in maternal and foetal tissues in the gestating sow, but the efficiency for foetal growth alone is much lower: 0.50 (Noblet and Etienne, 1986a,b,c ). In the lactating sow, the efficiency of conversion to milk secretion is between 0.70 and 0.75 (Noblet and Etienne, 1987a,c,d). In laying hens, ME is used with 0.60 efficiency for egg production and 0.80 for body energy gain ( de Groote, 1974b). (b) Plane of nutrition effects. According to the differential efficiencies of ME utilization for maintenance and types of production, the overall NE value of the diet is influenced by the level of feeding (ME/MEre) or the animal production level ( APL = ( NEro + NEg)/NE~ ). To obtain a single NE value for growing animals, it is therefore necessary to choose a given level of feeding, preferably close to ad libitum in high-performing pigs, as suggested by the Dutch workers (van der Honing et al., 1984). (c) Dietary effects. ME utilization is affected by the chemical composition of the absorbed nutrients to a greater or lesser extent depending on the type of production. ME from dietary fat is used efficiently by pigs for fat deposition: the corresponding efficiency is 0.90 compared to 0.73, 0.63 and 0.50 for digested nitrogen-free extract, crude fibre and crude protein, respectively, according to Schiemann et al. (1971). The superiority of fat over carbohydrates for energy deposition in growing pigs is well established. Similarly, in growing chicks, the efficiency values from carbohydrates and fat for lipid deposition are 0.75 and 0.84, respectively. On the other hand, the efficiency of utilization of ME from the digested fibrous substances is relatively low: about 0.60 of that corresponding to starch in pigs. It follows that the efficiency of ME utilization is negatively correlated with fibre content in the diet (Just et al., 1983a). Net energy systems. (a) NEF system. During the 1960s, following the original work of Kellner (1913), the research group of the Oskar Kellner Institute in Rostock (G.D.R.) proposed a new system based on the measurement of net energy for fat formation (NEF) in heavy castrated male pigs between 90 and 175 kg liveweight (NEFs) or adult cocks (NEFh), depositing a predominant proportion of fat in their body gain. After regression of retained energy on the amounts of digestible nutrients according to the Weende fractionation system, and the metabolic liveweight (W°75), to take into account the maintenance requirement, a prediction equation for NEF was derived (Schiemann et al., 1971; Hoffmann and Schiemann, 1980)

Pigs: N E F (kJ kg -1) =10.70 DXP+35.70 DXL+12.37 ( D X F + D X X ) ; Poultry: NEFh (kJ kg -1) =10.80 DXP+33.45 DXL+13.35 ( D X F + D X X ) , with digestible nutrients in g kg-1.

305 The main characteristic of this system is to provide a discrimination in the utilization of ME according to the type of nutrient, with the relative efficiencies of 1.0, 1.34 and 0.71 for digested carbohydrates, fat and protein, respectively. But it does not take into account the differential effects due to maintenance, type of production and differences in the level of feeding. (b) Danish net energy system for growth of pigs. In Denmark Just (1970) reported that energy concentration (ME kg-1 DM) accounted for the major part (90%) of the differences in net energy value (maintenance + growth) measured in growing pigs between 20 and 90 kg liveweight. A practical net energy system was then proposed (Just, 1975, 1982a), based on ME adjusted for differences in energy concentration, according to the following equation: N E (MJ kg -1 D M ) = 0 . 7 5 M E (MJ kg -~ D M ) - 1 . 8 8 ,

with ME being estimated from the contents of digestible nutrients (g kgDM) M E (MJ kg -~ D M ) =0.0215 D X P + O.0377 D X L + O.O173 ( D X F + D X X ) .

The net energy of 1 kg common barley (7.72 MJ kg -~ ) was defined as a feed unit (FE~). The constant term (1.88 MJ) in the prediction equation of NE indicates that for a given NE value feedstuffs with a high energy concentration, for instance containing a high amount of starch, are relatively better evaluated for production value than those containing a high proportion of fibre. On the other hand, no discrimination is made according to the type of nutrient, i.e., between ME from fat, protein and carbohydrates. Prediction of energy value in compound feeds For research or advisory purposes the energy value of diets can be estimated either from direct calorimetric measurements or with the aid of prediction equations based on digestible nutrients. In the control of compound feedingstuffs, however, when the actual composition of the feed mixtures is not known, prediction equations should essentially be based on chemical criteria. These include gross composition parameters or some fibrous components which take into account changes in energy digestibility in pigs, while in poultry the cell wall fraction is practically indigestible and may be considered as a diluting factor of the energy value (Carrd et al., 1984). Several regression equations based on chemical analyses have been suggested for the control of compound feeds, among which the most recent ones, expressed in DE or ME, are reported in the Appendix. Obviously, the error for predicting the energy value from crude nutrients is much higher than from digestible nutrients: according to Just et al. (1984), the corresponding coefficients of variation for pig diets were 5.0 and 0.8%, respectively, in the case of ME measurements. Therefore, these equations are only valid as a control of

306 the energy value of compound feeds within rather wide limits: the expected accuracy of predicted energy values from crude chemical composition is discussed in detail in the reviews of Fisher (1982) and Alderman (1985) for poultry and for pigs, respectively. In the U.K. (Morgan et al., 1987) and France ( Pdrez et al., 1984) the best predictors of DE or ME in mixed feeds were GE and neutral detergent fibre (NDF) as determined by Van Soest's procedure (Van Soest, 1963; Van Soest and Wine, 1967) ; this method of prediction was significantly better than that obtained from classical proximate composition including only crude fibre. Nevertheless, both effectiveness and precision of analytical techniques should be taken into consideration for choosing the most appropriate prediction equation. Within the E.E.C. committee of experts on "Straight and compound feeds", there has been an attempt since 1980 to establish a harmonized method for the calculation of the energy value of compound feeds. The working group for pigs, using pooled data from various trials in E.E.C. countries and Switzerland, proposed a prediction equation for consideration (see Appendix). For evaluation purposes in trade a minimum tolerance of 0.5 MJ was proposed. In poultry, the first equation based on crude nutrients was developed by Carpenter and Clegg (1956). Recently, in 1985, the Working Group of the European branches of W.P.S.A. proposed a new formula which has also been accepted by the E.E.C. for a control of the energy value in poultry feeds (see Appendix).

Comparison of energy values from different systems and conversion between units for pigs Since in poultry feed energy value is almost universally expressed in ME units, this problem only applies to pigs. Four different energy systems are used in practical pig feeding in European countries: DE, ME, which may be corrected for fermentable substances, NEF and Danish NE for growth. For the comparison of the available systems, two steps need to be considered, whether the comparison refers to single feeds or to least-cost formulated diets, in relation to production potential. The comparison of the energy value of single feeds in the different systems is given in Table I. The relative energy values are expressed in percentage of barley as a reference (and maize in the case of poultry). According to the way it is defined, DE does not provide any indication of the real energy value of the absorbed nutrients. Thus, it overestimates proteinrich feeds, and fibrous feeds to some extent, while the value of fat is underestimated. Similar shortcomings are found in ME except that it allows a better evaluation of protein-rich feedstuffs. As expected, correcting ME for bacterial fermentable substances (MEc.BFs) provides a lower relative value for highfibre feedstuffs. Among the NE systems, NEF provides a better evaluation of fat but an

1 2 . 5 8 12.60 9.84 8.90 1 0 . 2 6 10.26 I0.58 9.14 9.40 8.78 1 1 . 9 3 10.09 8.69 7.82 7.69 6.10

12.58 10.24 10.87 I0.58 9.61 12.12 9.28 7.90

13.55 12.44 15.67 10.80 14.29 13.71 32.72

13.63 13.04 16.49 9.70 13.61 13.50 31.35

14.34 13.79 17.56 11.16 15.47 14.00 31.35

12.28 13.74 13.53 11.05 13.51 10.60 9.35

ME3BFs (MJ)

12.27 13.86 13.42 11.08 13.52 11.00 7.73

ME ~ (MJ)

12.62 14.21 13.84 11.41 14.92 11.90 8.50

DE 2 (MJ)

Pigs

Energy value

9.23 6.93 7.52 6.91 8.97 9.19 6.66 5.84

9.09 8.27 11.40 6.01 8.09 9.75 31.32

8.77 9.92 9.50 8.08 8.58 7.10 6.13

NEF (MJ)

8.11 5.87 6.72 6.18 7.95 7.95 5.79 4.55

8.80 8.03 10.50 7.02 9.19 9.34 22.85

7.87 8.88 8.72 6.79 9.26 7.03 5.79

Danish NE (MJ)

5.13

11.05 10.22 15.19 9.97 II.83 8.36 29.30 37.65 11.44 6.86 7.70 8.39 -

11.92 13.95 12.98 10.82 9.33 5.90 6.51 lll.l 106.3 143.1 91.0 126.1 114.1 255.5

100 113.0 109.4 90.3 110.2 95.9 68.1

ME

99.7 102.5 81.1 8 3 . 5 86.1 8 8 . 6 83.8 8 6 . 2 76.1 7 8 . 3 96.0 9 8 . 8 73.5 7 5 . 6 62.6 6 4 . 4

113.6 109.3 139.1 88.4 122.6 110.9 248.4

100 112.6 109.7 90.4 118.2 100.6 72.9

Poultry 2 DE ME (MJ)

102.6 72.5 83.6 76.9 71.5 82.2 63.7 49.7

II0.3 101.3 127.6 94.4 116.4 111.6 266.4

100 111.9 110.2 90.0 110.0 86.3 76.1

MEcn~s

111.8 102.0 133.4 89.2 I16.8 118.7 290.3

100 112.8 110.8 86.3 117.7 89.3 73.6

Danish NE

105.2 103.0 79.0 74.6 85.7 85.4 78.8 78.5 102.3 I01.0 104.8 101.0 75.9 73.6 66.6 57.8

103.6 94.3 130.0 68.5 92.2 111.2 357.1

100 ll3.1 108.3 92.1 97.8 81.0 69.9

NEF

Relative values: pigs (Barley: 100)

92.7 85.7 127.4 83.6 99.2 70.1 245.8 315.9 96.0 57.6 64.6 70.4 43.0 -

100 117.0 108.9 90.8 78.3 49.5 54.6

Barley:100

36.8

79.2 73.3 108.9 71.5 84.8 59.9 210.0 269.9 82.0 49.2 55.2 60.1

85.5 100 93.1 77.6 66.9 42.3 46.7

Maize:100

Relative values: poultry

~Tables of composition according to I.N.R.A. (1984) and digestibility coefficients for pigs from D.L.G. (1984). 2European Table of energy values for Poultry feedstuffs, Beekbergen (W.P.S.A., 1986). :*ME corrected for Bacterial Fermentable Substances (BFS), as calculated in D.L.G. tables (1984). MEcBFs, NEF and Danish NE values were calculated with digestible nutrients obtained from I.N.R.A. composition data and DLG digestibility coefficients for similar feedstuffs.

Barley Maize Wheat Oats Soyabean meal (48% XP) Rapeseed meal Sunflower seed meal (30% XP, 25% XF) Peas Field beans Soya bean whole seeds Meat meal (35% XP) Fish meal Whey powder Tallow Soya bean oil Cassava meal Wheat bran Maize gluten feed Sugar cane molasses Beet pulp Citrus pulp Lucerne meal Soya bean hulls

Feedstuffs

Energy value of various feedstuffs for pigs in different systems and in comparison with poultry (kg as fed) 1

TABLE I

z~

308

underestimation of the value of protein-rich feeds. Therefore, this system is in favour of the inclusion of fat in combination with various protein replacement sources and fibrous feedstuffs, and a lower proportion of cereals, thus resulting in an increased complexity of least-cost formulated diets. The relative energy values of protein feeds are comparable in Danish NE and ME systems; in addition, the Danish NE gives a better evaluation of high-energy feeds, such as cereals, but this is due to starch content as opposed to fat in the NEF system. The relative merits of the available energy systems in least-cost formulation of balanced diets, according to price situation and energy density, have been described in some recent publications (Borggreve et al., 1975; Brette et al., 1986). According to the system used, the energy values for feeds of known composition are defined by directly determined values (DE, ME) or by a set of digestibility coefficients which are used in a prediction equation (NEF, Danish NE ). For converting from one energy unit to another the digestible nutrients could serve as a common link. While ME in mixed feeds is a rather constant proportion of DE (around 0.95-0.96), in single feedstuffs the conversion of DE to ME requires the protein content or protein-energy ratio to be taken into account. The average ME value of 1 kg of barley (85% DM) for pigs amounts to 12 MJ. The average correspondence between T D N and DE was established by Asplund and Harris (1969) and from Crampton et al. (1957) as the following: I kg T D N = 18.43 MJ DE.

Protein Basis of system Protein evaluation of feedstuffs in non-ruminants requires two successive steps to be considered: (i) the amino acid composition of feed protein by reference to the requirements; (ii) the digestibility and more generally the availability of protein and amino acids (AA). This topic has been developed recently in detail in some main reviews: for pigs, Fuller (1980), R~rat (1981), Low (1982), Darcy and R~rat (1983), Tanksley and Knabe (1984), Henry (1985a), Sauer and Ozimek (1986); for poultry, Fisher (1983), Larbier and Leclercq (1983), Boorman and Burgess (1986).

Amino acid composition o/protein in feedstuffs Tables of amino acid composition of feeds have been established in different countries. An example of the amino acid composition of the main feedstuffs for non-ruminants is reported in Table II. The contents of essential amino acids are expressed either as amounts in g per kg feed (or % ) or as a percentage of total protein (i.e. 16 g N, using 6.25 conversion factor from N to crude protein). In fact, the percentage of a given amino acid in protein is not always constant, and may decrease as protein content increases, owing to changes in

100 90 113 100 480

492 295 352 220 264 370 646 561 150 210

860 860 860 860 880

910 900 890 860 870 890 920 930 870 900

17.0 10.7 19.7 16.0 16.6 23.5 50.4 29.5 5.6 6.9

3.7 2.5 3.2 4.0 30.5 11.8 12.6 17.3 5.9 5.3 11.5 23.9 12.9 5.0 9.7

4.2 3.9 4.7 5.0 14.3 13.3 10.6 15.7 8.7 9.3 14.4 27.3 18.0 5.4 8.3

3.4 3.2 3.4 3.5 18.8 4.9 3.8 4.3 2.0 2.2 4.8 6.5 2.9 2.4 1.6

1.1 0.6 1.3 1.2 6.5 3.45 3.6 5.6 7.3 6.3 6.35 7.8 5.25 3.7 3.3

3.7 2.8 2.8 4.0 6.35 2.4 4.3 4.9 2.7 2.0 3.1 3.7 2.3 3.3 4.6

4.2 4.3 4.15 5.0 3.0 2.7 3.6 4.45 3.95 3.5 3.9 4.2 3.2 3.6 3.95

3.4 3.55 3.0 3.5 3.9 1.0 1.3 1.2 0.9 0.8 1.3 1.0 0.5 1.6 0.75

1.1 0.65 1.15 1.2 1.35

Lysine a ÷ b XP Wheat 1.45 ÷ 0.173 XP Maize 1.31 ÷ 0.159 XP Barley 1.67 ÷ 0.234 XP Peas 3.64 ÷ 0.595 XP Field beans 5.3 ÷ 0.467 XP 2Reference: I.N.R.A. (1984). :~Faecal digestibility (CVB-Veevoedertabel, 1984 ). 4European table of energy values for poultry feedstuffs, Beekbergen (W.P.S.A., 1986).

0.90 0.78 0.79 0.88 0.81 0.85 0.90 0.82 0.67 0.80

0.78 0.81 0.87 0.79 0.89

Xp 2

Poultry

0.58

0.93 0.86

0.85

0.72 0.67 0.77 0.92

0.88 0.85 0.69 0.86 0.70 0.90 0.88 0.80 0.73 0.85

0.70 0.84 0.81 0.75 0.87

Lysine :* X p 4

Digestibility coefficients

Threonine Tryptophan Pigs

Amino acid content (g/16 gN )

DM Protein Lysine I Methionine+ Threonine Tryptophan Lysine Methionine+ cystine cystine

Composition (g kg- 1)

1Prediction equations of lysine content (g kg ~) from crude protein (XP) content (g kg- ~) (I.N.R.A., 1984) (expressed as g kg- 1DM).

Barley Maize Wheat Oats Soya bean meal (48% XP) Peanut meal Sunflower meal Rapeseed meal Peas Field beans Soya beanwhole seeds Fishmeal Meat meal Wheat bran Maize gluten feed

Feedstuffs

A m i n o a c i d c o m p o s i t i o n o f s o m e r e p r e s e n t a t i v e ~ e ~ t u f f s i n p i g a n d p o u l t r y ~eding

TABLEII

¢.D

310

the distribution of the component protein fractions. Prediction equations are thus available for estimating amino acid content in feed from protein content (I.N.R.A., 1984). The ultimate step in protein evaluation of individual feedstuffs or of complete balanced diets is to assess the hierarchy of the successive limiting amino acids by reference to the corresponding requirements of the animals, expressed as a percentage of the diet or in relation to energy supply. Among the essential amino acids, the most limiting for pigs is generally lysine, owing to its low content in cereals. The secondary limiting amino acids are threonine, tryptophan or methionine, in an order which depends on the pattern of feed supply in comparison with the requirements.

Availability of protein and amino acids The apparently digestible crude protein (DXP) as measured from total faecal collection is a fairly good indicator of the overall protein quality at the digestive level. However, there are some shortcomings in the significance of faecal or total digestibility, especially for amino acids, since the modification of nitrogen residues by microflora in the hind gut ( ammonia absorption, bacterial protein) were shown to have little or no nutritional value to the pig (Zebrowska, 1973 ). Following pioneering work with poultry ( Payne et al., 1968) it was suggested that the appropriate way for evaluating availability of amino acids was to measure their digestibility at the end of the small intestine (ileal digestibility), using pigs fitted with simple or re-entrant cannulas to the ileum, or ileo-colic postvalvular fistulas. The development of ileo-rectal anastomosis in pigs according to a technique developed recently (Laplace et al., 1985), enabling a total collection of ileal digesta, should be promising for measurements on a routine basis. In poultry, the problem of eliminating bacterial influence in the hind gut is less crucial than in pigs, although caecestomized birds are used along with intact animals for amino acid digestibility measurements. In both cases amino acid digestibilities are expressed in apparent or true values, after correcting for endogenous losses. An alternative approach for evaluating AA availability in feedstuffs is based on growth assays, especially with growing chickens but also with pigs (Major and Batterham, 1981; Sato et al., 1987). The digestibility of crude protein and amino acids may be influenced by various dietary factors, such as the source of protein itself, fibre content, technological treatments and antinutritional factors, and to a lesser extent by animal-related factors, i.e., age, liveweight (Zoiopoulos et al., 1983; Just, 1986). In pigs, faecal digestibility of amino acids is generally higher than ileal digestibility, but great fluctuations in the difference between the two sites are observed ( from 2 to 14 points for total nitrogen). Furthermore, the differences

311

according to diets and protein sources are better revealed by measuring digestibility at the terminal ileum. At the present time, extensive tables of AA availability for pigs based on ileal measurements are not yet available. Before obtaining more precise and complete data with this procedure, two attempts have been made for estimating AA availability in feedstuffs for pigs. -In The Netherlands, tables of the content of faecal digestible amino acids have been established for lysine, methionine and cystine in a wide range of feedstuffs ( C.V.B., 1984). -In Denmark, an approximation of AA digestibility was suggested by multiplying the AA contents of a given feedstuff by the apparent digestibility of total protein, assuming that there is an overall relationship between protein digestibility and that of the different essential amino acids. These data are included in the Danish Tables of feed composition (Andersen and Just, 1983; Just et al., 1983b). In poultry, the apparent digestibility of lysine and threonine in common diets is around 0.85, compared with 0.80 for cystine and 0.90 for the other amino acids. In The Netherlands, in the booklet "Feeding values for poultry" (Janssen et al., 1979 ), tables of apparent digestibility values for 18 amino acids have been published and are often used in practice. NUTRIENT REQUIREMENTS

General remarks

Through increasing intensification there has been a trend toward more standardization in poultry and pig production with respect to genotypes, feeding regime, housing and environmental conditions, and marketing procedure. Nevertheless, large differences still exist between the European countries in the kind of production. This is especially the case for pigs, which are produced within a wide range of weight at slaughter: from light porkers (60 kg liveweight) in the U.K. to heavy pigs (145-160 kg) in Italy, through baconers in Denmark (90 kg), with the most common slaughter weight ranging between 100 and 110 kg. In poultry there is more uniformity in the type of broiler produced for meat, but, in addition, the increased contribution of secondary avian species brings a great variability in meat supply. Different ways are used to express nutrient requirements, either in amounts per day at a given liveweight and for a known level of productivity (litter size, egg production, liveweight and tissue gain), or as percentages of a diet of a standard energy value within a given liveweight interval. In fact, there is a lack of uniformity in the presentation of the requirements among the European countries, whether one considers production objectives (carcass weight and composition), the level of feeding (whether the animals are fed to appetite or

312

restricted), the categories of animals within the life cycle in connection with husbandry practices, or nutrient availability (protein and amino acids) in experimental diets. This makes it difficult to compare the requirements in the various countries on a common basis. The nutrient requirements of non-ruminants are essentially based on the results of feeding trials, taking into account appropriate criteria related to production objectives. In each country, they are derived from a wide range of data, not simply research data from the home country or region, but also from world literature. In addition, the factorial approach is being developed as more information is available on nutrient outputs and their rates of utilization for maintenance and production, but is not yet fully adequate for predicting the requirements with sufficient precision and reliability, except for minerals ( calcium, phosphorus) and to a limited extent for energy. Only recently new data have been collected which provide quantitative changes in energy deposition and its partition into protein and fat in relation to growth potential and composition of gain. In this respect significant progress has been made for nutrient recommendations for pigs in some countries, as in the U.K. (A.R.C., 1981), the G.D.R. and the F.R.G. (D.L.G., 1984), towards a better understanding of the variations in recommended allowances with production conditions. In the same way, the factorial approach has been applied recently to poultry, in the U.K. (Fisher, 1983) and the F.R.G. (Vogt, 1987b).

Energy

Until now a common practice in most European countries has been to restrict feed energy below ad libitum level, both in growing animals (to improve carcass leanness further in addition to the selection of lean genotypes) and in breeding stock (to spare energy for producing weaning piglets at a lower cost, especially during periods of low requirements as in pregnancy). Feed or energy recommendations are thus usually given in daily amounts of feed of a known energy value according to liveweight. However, with the more extensive use of rapidly-growing lean animals, specifications are limited to energy concentration.

Dietary energy concentration. Pigs require a relatively high energy concentration in their diets, especially after weaning (14-14.5 MJ DE kg -1) (energy concentration data in DE may be converted to ME by multiplying by 0.95) and during the growing and finishing phase (13-14 MJ DE kg-1), in order adequately to meet their energy requirement for fast lean tissue growth and to express an optimum feed-conversion efficiency. With breeding sows the energy density may be lowered to 12.5 or 12 MJ DE kg -1 during pregnancy, owing to a low energy requirement above maintenance, while during lactation the high

313 level of energy requirement for milk secretion demands a higher concentration (13 MJ DE kg-1 or more). The usually recommended range of energy density in a given country also depends on the energy value of the most common feed resources: for instance, in Northern Europe where barley is extensively used the standard energy concentration is kept down to 12.5 MJ DE or 12 MJ ME kg -1. Expressed in barley equivalent (12.5 MJ DE kg-1), the relative values of feed density are 1.12-1.16 in weaned piglets, decreasing to 1.04-1.12 in growing-finishing pigs, 1.0-1.04 and 0.96-1.0 in lactating and pregnant sows, respectively. When pigs are fed to appetite the optimum energy concentration for producing carcasses without excessive fatness depends on tissue growth characteristics. With conventional pigs exhibiting a high propensity to fatten the energy density should be restricted to keep carcass adiposity within acceptable limits (12.5 to 13 MJ DE kg-1), while lean-type animals are able to convert highly-concentrated feeds without adverse effect on carcass quality ( Henry, 1985b).

Amount of feed. The amount of feed or energy required by the pig according to the physiological status (growth, pregnancy, lactation) may be predicted in a first approximation by the factorial method from the components of energy requirements for maintenance and production, and from the rates of utilization of energy (ME) for each type of production as shown in Table III. In the case of growing animals, it is not possible to quantify precisely the energy requirements without knowing the expected rates of growth of the body components, either in terms of chemical constituents (daily retentions of protein and lipid) or of daily amounts of tissue deposited (lean and fat). The energy content of gain tends to increase during growth as a greater proportion of fat is deposited and the water associated with protein decreases. It is inversely related to muscle: fat ratio, so that the dietary-energy cost per unit of gain decreases following the genetic improvement of lean-tissue growth potential. Therefore, the composition of gain varies according to age, sex and genotype. For a given level of liveweight gain, the leaner the pig, the lower the amount of energy or feed required and the better the feed conversion ratio. Alternatively, the increase in both daily liveweight gain and lean-tissue content results in a sustained level of feed intake with a further improvement of feed efficiency. In European countries the practice of feed restriction according to a scale based on liveweight or age for maintaining a low rate of fat deposition in the carcass is still widespread. But the genetic improvement of lean genotypes allows a progressive increase in the daily feed supply to a level close to appetite, i.e., approximately to 3-3.5 times maintenance level, or 0.9-0.95 of ad libitum intake.

Milk production

Lactation

Uterine deposits Maternal deposits Maternal + uterine deposits

Gestation

Growth

Productions

k1=0.70-0.75 (av. 0.72)

/%= 0.40 kn = 0.75-0.80 kges t = 0.70-0.75

k s = 0.65-0.75 (av. 0.70)

kp=0.40-0.80 (av. 0.55) kf=0.70-0.80 (av. 0.75)

k~ = 0.80

Maintenance

Protein deposition Lipid deposition

Efficiency of ME utilization

Type of expenditure

420-460

Growingpig

19.0-21.0

Finishing pig

1.9-2.1

100 days gestation

Milk production (kg day -1 ) Amount of exported eJlergy (MJ day -~)

6-7 29.0-33.5

23.0-27.0

Multiparous sows

12.5-23.0

Maternal deposits ( M J kg - 1 gain )

12.5-17.0

Average 25-100 kg W

42 54

kJ ME g-~ deposit

460-480

Sow

5-6

Primiparous sows

Energy content of milk: 4.4-4.8 MJ k g - 1

0.420-0.500

70 days gestation

Uterine deposits ( MJ d a y - ~)

8.0-8.5

Piglet

Energy content of gain (MJ kg - ~)

1.8 1.3

kJ ME k J - ~deposited energy

460-630 (av. 500)

Piglet

Energy requirement (kJ ME k g - 1 W °'vS)

Mean level of expenditure

Factorial components of energy requirements in pigs (from Henry and Noblet, 1986; Noblet and Etienne, 1987d,c,b)

TABLE III

315

Poultry The specific feature of poultry feeding is that it is based on the flock as a unit, the requirement of which is the result of different requirements between individuals. Therefore energy concentration in feed is of importance under practical conditions: for details see the review of Leclercq (1986). In order to meet the energy requirement, the diet should contain a minimum energy concentration. Feed intake in birds is largely dependent on dietary energy content, although with high energy concentration they tend to exhibit a luxury feed consumption. During the rearing period the energy content of the diet should be on average 11.5 MJ MEn kg -1 for chicks and between 11 and 11.5 MJ MEn kg -1 for pullets. It should not be set below 10.8 and 10 MJ MEn kg -1 in chick and pullet diets, respectively. High energy rations may easily lead to too intensive growth. In order to limit growth rate it is common to restrict the level of feeding slightly during rearing pullets of laying breeds, while the intensity of feed restriction should be greater in meat-type pullets. With broiler chicks an increased energy content (with a constant energy: protein ratio) results in increased final weight and decreased feed intake, i.e. an improved final feed efficiency; the higher the energy content in feed, the fatter the broilers. Whereas a feed-energy content of 12.3 MJ MEn kg -1 is sufficient during the first days of life, the fattening rations should contain at least 12.75 MJ, and preferably 13 MJ MEn kg-1; the determining factor is the cost per energy unit. The diets for laying hens of light and medium breeds should contain between 10.5 and 12.5 MJ MEn kg-~: the optimum recommended level is within the range 11-11.5 MJ MEn kg -1 (10.5-11 towards the end of the laying period). Higher energy content may cause fatty livers and energy luxury consumption ( about 10-30 kJ h e n - 1d a y - 1per 0.4 MJ MEn k g - ~increased energy content). Laying rate is not influenced by feed-energy content, but egg weight is. With each 1 MJ MEn kg-1 increase in feed energy content the egg weight is raised on average by 0.5%, i.e., 0.3 g increase in a 60-g egg. Increasing feed energy content does of course allow an improved feed efficiency, but, owing to the mentioned energy luxury consumption, controlled feeding is recommended. With breeding hens of meat type, a feed energy content of 11-11.5 MJ MEn kg-~ is common, but here again restrictive feeding is absolutely necessary. The energy requirement per bird and per day can also be calculated by the factorial method. During the last decade a great number of equations have been proposed, taking into account mean body weight, liveweight change, egg output and environmental temperature.

Protein Protein requirements need first to be expressed in terms of essential amino acids (EAA). Protein level as such has a limited and variable significance since

316 it is adjusted to meet the requirement for the most limiting EAA, generally lysine. Therefore, the recommended protein level in the different instances is only indicative for the commonly used diets, and depends on the pattern of the combination of protein sources. Protein quality of the diet is thus defined by the percentage of lysine in the protein: generally 5.0% in growing pigs and lactating sows, and 4.5% in pregnant sows. Because of the relative constancy of the AA composition of deposited protein for a given physiological status, the amounts of recommended amino acids are derived through constant ratios to one of them as a reference (lysine) (A.R.C., 1981 ). In the same way, the AA requirements may be expressed in the form of "ideal protein" which reflects a constant pattern of EAA (70 g lysine kg-1) and an optimum balance between them. Supplementing practical diets with the limiting AA (lysine) in the free form allows a decrease in total protein content (one to two percent depending on the AA profile of the contributing protein sources), i.e. the lower the percentage of lysine in dietary protein (as with wheat versus maize ), the higher the amount of spared protein with supplementary lysine. Recommended levels of practically balanced protein after lysine supplementation have thus been suggested (I.N.R.A., 1984), as an intermediary step towards ideal protein to meet the requirements for both EAA and non-essential nitrogen. Protein and AA requirements in growing pigs vary according to the rates of deposition of body tissue components (lean, fat), depending on age, sex, genotype and level of feeding. In breeding stock they depend on the level of reproductive performance, as is the case for the yield of milk which is itself related to litter size in lactating sows. The increase in the potential for lean tissue growth is associated with a higher daily requirement for protein and EA. Since energy density of gain is lower in lean compared to fat animals, this results in even greater protein and AA requirements according to energy or in percentage of diet. For instance, in the special case of lysine, the factorial method suggested by Wiesemiiller (1984) permits the prediction of the daily requirement from liveweight (W, maintenance component) and daily retained protein (RP), according to the following equation Lysine (gday -1) =0.1 W°75 ( k g ) + R P (g)×0.074/0.6 This allows a correction of the daily recommended supply according to the level of daily gain. For 100 g increase in gain, the daily requirement for lysine is increased by 1.8 g, on the basis of 1 g lysine deposited (7.4% of deposited protein and 15% protein in gain) and a rate of 0.60 lysine deposited from total intake. In the absence of a precise correction for the requirements for the rate and composition of gain the recommended allowances for given categories of pigs should refer to the optimum level of performance, i.e. females in place of castrates for lean deposition during the growing-finishing phase. The requirements for protein and AA are most commonly given in total

317

amounts, so that the recommendations may differ between countries according to the characteristics of the reference diet used for collecting experimental data. Some attempts have been made to express the AA requirements in available form. In The Netherlands, specific recommendations are formulated for total digestible lysine, as well as methionine and cystine. In Denmark, the digestible amino acids included in the recommendations are simply estimated from the apparent digestibility of total protein.

Poultry The protein (IXP) for amino acid requirement, as in the case of energy, is dependent on the deposition (growth, egg) and maintenance requirement (a function of body weight). For one bird, it may be written in the following formula:

IXP=b. W-+

ADG'c (XP) kg

O'c (XP) k0

which may be simplified to IXP---b-W + a. (ADG,O) where: IXP =protein intake in g or amino acid intake in mg per hen and per day; b -- maintenance requirement per kg body weight; a-- requirement per g weight gain or per g egg output; W (liveweight) ( in kg), ADG (average daily gain) (g day- 1), c (XP) = content of protein in gain and eggs; O ( g h e n - 1 d a y - 1) _ egg output; kg and ko = the efficiencies of ME utilization for liveweight gain and egg production. In practice, the problem is not to feed one bird, but a flock of birds. For the requirement of a flock the "Reading flock response model" has been suggested (Curnow, 1973; Fisher et al., 1973). The essential feature of the model is to consider the response of an individual hen as a simple factorial model and then to derive the flock response as the integrated average of a large number of individual responses. Depending on the costs of single amino acids, the optimal amino acid supply for maximum performance may differ from that corresponding to maximum monetary profit. With adjustment of requirements according to these economic circumstances the optimum dose of amino acid can be determined by the following equation (Fisher, 1973; Fisher et al., 1983 ):

AAIopt =a O+b W+ x ~f a2a~ +b2a2w + 2ab'r'ao "aw where: AAIopt= AA dose which equates marginal costs and marginal income; a = A A (mg) per unit output, O; b = A A (mg) to maintain unit body weight, W; x = the deviation from the mean of a standard normal distribution which is exceeded with probability ak in one tail, _xbeing defined as above, k being the ratio of cost per mg AA or value per unit O; ao, aw = standard deviations of O and W; r = correlation between O and W. The factorial calculation of the amino acid requirement has mainly been applied for laying hens. Similar calculations have been developed for chicks,

318

pullets and broiler chicks, but to a minor extent (Fisher, 1983; Boorman and Burgess, 1986). The requirements of available amino acids for a flock of laying hens with an average body weight of 1.8 kg and an average laying rate of 50 g egg output per day have been calculated from the data of Fisher (1983). The amounts in mg hen -1 day-1 are the following: arginine, 647; histidine, 235; isoleucine, 584; leucine, 884; lysine, 830; methionine, 325; threonine, 484; tryptophan, 176; phenylalanine+tyrosine, 929; valine, 696. For calculating the necessary amino acid contents in the feed, the availability (or digestibility) figures and daily feed intake are to be taken into consideration.

Feed requirement per standard animal produced In order to facilitate the summing up of the nutrient requirements of the total pig population within a given country and to compare these with the available and needed feed resources, it is appropriate to define a standard animal which is representative of the 3 main categories of pigs contributing to the final production, i.e. breeding stock ( reproductive sows, boars and replacement gilts) for that part of nutrients required per pig produced annually per sow, post-weaning piglets ( 3-4 weeks of age to 25-30 kg liveweight on average) and growing-finishing pigs (25-30 to 100-110 kg liveweight on average). Attempts may be made, as a guideline, to estimate the total amount of feed required per standard pig produced and which is representative of the most common type of production in Europe. As shown in Table IV, to produce a 100TABLE IV

Total amount of feed per standard pig produced ~ Categories of pigs

Piglet

Growing-finishing Amount sow- 1 pig year- 1

Pre-starter Starter Standard energy density

14.6

14.6

Total amount per pig produced 2

Pregnancy Lactation 13.4

12.5

13.0

(MJ DE kg -1)

Liveweight interval (kg) Age interval (days) Avg daily gain (g) Feed conversion ratio Total feed intake (kg)

Energy intake (MJ DE) Protein intake (kg)

5-10 26-40 200-250

1.4 5.5

1.2

10-25 40-70 500-550 1.65

25-100 130-180 700-750 3.2

25 30.5

240

445 4.8 6.0

3200 40

130-180 300-400 880

140-180 320 1200

15 160 10

340 4540 56

1Amounts of feed and nutrients per standard pig slaughtered at 100 kg liveweight. 20n the basis of 17 pigs produced per sow and per year in the herd. Liveweight interval 1-100 kg.

319 TABLE V Energy and protein balance in broiler meat production

Input Breeding hens, meat type 12.7 kg chick and pullet feed 1 39.7 kg layer (inc. 10% males) feed1 Total per hen Total per chick2 Broiler 2.45 kg broiler feed3

ME (MJ kg -~)

XP (gkg -1)

Total ME (MJ)

Total Protein (g)

11.5 11.5

165 160

146 457

2096 6352

603 4.75

8448 66.5

13

225

Total Metabolizability ( % ) Gross energy Output Carcasses 4 1.058 kg oven-ready+ giblets Output X 100 Input

10.5

157

31.85

551.25

36.6 77 47.5

617.75

11.1

166

23.4

26.9

1Including losses and culls. 2127 chicks per hen. 31.4 kg WX 1.75 FE (1.36 kg WX 1.80 FE) =2.45 kg broiler feed. 43.2 kg W breeding hen + 0.475 kg W breeding male (10% of 4.75 kg) = 3.675 kg W total per hen: 127 (chicks per hen) = 0.029 kg W breeding hen/male per broiler + 1.400 kg W broiler = 1.429 kg W total per broiler × ~-~ (74% oven-ready + giblets) = 1.058 kg carcass (oven-ready + giblets). ME = Metabolizable energy; XP = crude protein content; FE = feed efficiency, i.e. amount of feed (kg) kg -1 liveweight (W) gain. kg pig at s l a u g h t e r requires o n average 350 kg b a r l e y equivalent, 17% o f which c o r r e s p o n d s to t h e p r o p o r t i o n o f feed n e c e s s a r y to m a i n t a i n t h e b r e e d i n g stock a n d to p r o d u c e e a c h pig at weaning. T h e a m o u n t of p r o t e i n n e c e s s a r y to produce a 100-kg pig is w i t h i n t h e range o f 50-60 kg. T h e p r o p o r t i o n of p r o t e i n f r o m cereals varies f r o m 50% or m o r e in c e r e a l - b a s e d diets to 10% or less w h e n b y - p r o d u c t s are t h e m a j o r c o n s t i t u e n t s of t h e diet, as in T h e N e t h e r l a n d s . T h e t o t a l efficiency values of e n e r g y a n d p r o t e i n utilization for broiler fatt e n i n g a n d egg p r o d u c t i o n o f laying h e n s o f light b r e e d s are given in T a b l e s V a n d VI, along w i t h feed i n t a k e d a t a p r o v i d e d in T a b l e VII.

320 TABLE VI Energy and protein balance in egg production

Input Breeding hens, light breeds 1.6 kg chick feed 6.2 kg pullet feed 1 36.5 kg layer (incl. 8% males) feed2 Total per hen Total per chick 3 Laying hens 1.6 kg chick feed 5.8 kg pullet feed 48.9 kg layer feed4

ME (MJ kg -1)

XP (g kg -1 )

Total ME (MJ)

Total Protein (g)

11.5 11.3 11.3

185 145 165

18.4 70.1 412.5

296 899 6023

501 6.3

7218 90

18.4 65.5 552.6

296 841 8068

642.8 75 857.1

9295

132

2395.4

11.5 11.3 11.3

185 145 165

Total Metabolizability (%) Gross energy Output Eggs 5 Carcasses6 (1.200 kg oven-ready + giblets )

6.5

118

11.4

175

Total Output X 100 Input

13.7

210

145.7

2605.4

17

28

1Including losses and culls, no restriction. 280 chicks per hen. 321-66 week--315 daysX 116 (110 g h e n + 6 g) g. 421-80 week = 420 days X 120 g X 0.97% livability (average during the year). 5325 eggs X 62.5 g egg weight = 20.3 kg egg mass output. 81.6 kg W breeding hen: 80 (chicks per hen) = 0.020 kg W breeding hen per laying hen + 1.692 kg W laying hen (1.8 kg W X 0.94% livability) = 1.712 kg W total per laying hen X ~ (70% oven-ready + giblets) = 1.200 kg carcass (oven-ready + giblets). FUTURE DEVELOPMENTS IN FEED EVALUATION AND NUTRIENT REQUIREMENTS IN NON-RUMINANTS

Future developments in feed evaluation Improvement of energy systems T h i s is a p r o b l e m o f i n c r e a s i n g r e l e v a n c e f o r p i g s . T a b l e s o f D E a n d p a r t i c ularly of ME values should be based more extensively on direct calorimetric

321 TABLE VII Feed intake of birds Adult birds

Laying hens light breeds medium breeds Breeding hens meat type dwarf type Turkey breeding hens Small body weight Large body weight Guinea fowl breeders Japanese quail hens light type meat type Peking duck breeders Muskovy duck breeders Geese breeders Growing birds Broiler Broiler Chick and pullets light breeds medium breeds meat type Turkey broilers Turkey ~ Turkey ~ Guinea fowl broilers Growing Jap. quails Growing pheasants Peking duck broilers Muskovy duck broilers ~ Muskovy duck broilers ~ Goslings Goslings

Egg output g ~ -1 day-1

MJ MEn kg- 1

Feed intake g ~ -1 day-1

40-60 40-60

11.25 11.25

105-125 115-135

30-50 40-60

11.25 11.25

145-165 120-130

40-60 40-65 20-40

12.1 12.1 11.9

140-160 220-245 90-110

9 10 40-70 30-70 50-110

11.25 11.25 10.9 11.7 10.5

23 30 220-265 150-185 300-420

Age (weeks)

kg/period

1-6 1-8

13.3 13.3

1-20 1-20 1-20 1-9 1-16 1-24 1-12 1-6 1-5 1-7 1-10 1-12 1-8 1-12

11.6/11.25 11.6/11.25 11.6/11.25 12.5/12.8 12.5/12.8 12.5/12.8 12.5 12.5 11.7 12 12.1 12.1 11.7 11.7

3 5 7.5 8 10 6 20 50 4.7 0.6 0.5 7.5 7.5 13 13 22

determinations along with suitable corrections for changes in composition characteristics for a given type of feed. In the case of ME, there is a need to standardize the mode of calculation and the use of correction factors according to variations in protein level and amino acid balance as well as for methane production in relation to the contribution of fermentable substances.

322 Besides DE and ME, which are clearly defined as a system, it is necessary to reconsider a net energy system which reflects the real value of balanced feeds for producing lean meat from pigs. This implies a better understanding of the variations of ME utilization and the specific needs for the different types of production and for maintenance according to genotype, physiological status, feeding conditions (level of feeding, fibre content and composition, protein level and amino acid balance ) and environmental factors (temperature, housing conditions and social environment). For the future the NEF system is likely to be less appropriate with further progress in selection for rapid leantissue growth. Nevertheless, for practical application, it has to be proved that net energy gives a significant advantage over ME for predicting the energy value of feeds in modern pig production. If so, a mode of calculation of a welldefined NE, i.e., for fast-growing lean-type pigs at a high level of feeding, has to be established from DE or ME or from digestible nutrients. In addition, differences in net energy utilization between the different categories of animals during growth or reproduction need to be established in order to correct the energy requirements expressed in the appropriate system according to the physiological status. This should allow a logical conversion from one energy system to another and would facilitate the comparison between systems and requirements from a given country to the others. A problem of growing importance with the use of diversified feedstuffs and complex diets is that of non-additivity in digestive and metabolic utilization. Digestive interactions between dietary components, i.e., between fibrous constituents and other nutrients (protein, lipid and soluble carbohydrates) need to be studied in more detail in relation to the effects of plane of feeding, by taking into account the end-products from fermentable substances in the hind gut and their metabolic use compared with the nutrients absorbed in the small intestine. For an accurate prediction of the energy value of single and compound feeds from dietary characteristics, either in crude or digestible amounts, it would be of great benefit to set up a new basis for nutrient partitioning in replacement of the traditional Weende method, by substituting for DXX with/more homogeneous fractions i.e., starch, sugar, and fibre constituents (cellulose, hemicellulose, lignin, pectins). This requires definite resolutions for revised biochemical procedure in feed analysis, especially for structural carbohydrates, with high enough precision and for large serial analyses. Following D.L.G. (1984) recommendations, Hoffmann and Schiemann (1985) already suggested an improvement in the assessment of the energy value (NEF) of pig feeds, by including the amount of fermentable substances in the prediction equation, in addition to digestible protein and fat, starch, mono- and disaccharides, and digestible pectins. On the other hand, it is necessary to predict more accurately the energy value of fats and the fat content of feedstuffs by considering their fatty acid pattern. It is expected that the development of in

323

vitro methods will bring some benefit for a rapid evaluation of the energy content of compound feeds for pigs and poultry.

Protein evaluation on the basis of amino acid availability For the future protein evaluation in pig and poultry feeds should be extended to a precise assessment of the availability of the different essential amino acids, through the measurement of apparent and/or true digestibility of protein and amino acids at the end of the small intestine for pigs and the use of caecestomized birds. The methodological constraints of ileal digesta collection or sampling from cannulated pigs could be avoided with the use of the ileo-rectal anastomosis technique, which allows total ileal excreta collection in digestibility crates for rapid routine measurement of ileal protein and amino acid digestibilities. A significant progress in this methodological procedure is to be expected, in order to provide a standardized technique adapted to large series of determinations. The measurement of ileal digestibility of protein and amino acids, especially for lysine, methionine and cystine, threonine and tryptophan, which are likely to be the most limiting in current feeding practice, preferably after correcting for endogenous losses, will allow: (i) a survey of amino acid availability within a wide range of novel feed ingredients; (ii) the assessment of the effects of technological treatments as a means of improving the nutritional value of potentially-available feed resources; (iii) the study of dietary digestive interactions between protein and fibre as well as, fat and antinutritional substances. The development of indirect in vitro techniques should also be explored for a rapid evaluation of protein quality in feeds by reference to ileal procedure. Future prospects for determining nutrient requirements Factorial estimation of the requirements according to performance level and production factors Energy as well as protein and amino acid requirements will have to be determined essentially on the basis of the factorial approach in relation to the level of performance (liveweight gain and tissue composition of gain, litter size, weight change during pregnancy and lactation, milk yield) and production conditions ( slaughter weight and carcass quality, climatic environment). Future recommendations for amino acids will preferably be given on an availability basis (ileal digestibility). In any case it is necessary to correct the requirements according to the rates of nutrient or tissue deposition instead of simply considering mean recommendations for an optimum level of performance. The adequacy of the factorial approach will be controlled by feeding tests. Consequently, more elaborate methods need to be applied in feeding and balance trials for estimating tissue and nutrient deposition, in order to relate production response (lean and fat tissue gain, maternal tissue changes, milk

324

production) to nutrient input in quantitative terms. The in vivo appraisal of body composition, especially in pigs, will bring a positive contribution to the assessment of initial lean and fat content according to liveweight and thus facilitate the use of comparative slaughter techniques along with balance trials.

A need for new criteria in the assessment of protein and amino acid requirements The concept of "ideal protein" for growth in pigs, which is simply based on a constant amino acid composition of deposited protein, thus resulting in fixed ratios between essential amino acids and lysine as a reference, should be reconsidered in relation to the differential metabolic fate of essential amino acids. The amino acid balance will have to be modulated according to protein turnover rate ( synthesis, degradation) and amino acid catabolism (oxidation) to complement the observations which have been restricted until now to protein and amino acid accretion. Specific problems related to future developments in feed resources In connection with the increasing use of supplementary industrial amino acids ( lysine, methionine, and in the near future tryptophan and threonine), one may expect a significant saving of dietary protein through the improvement of amino acid balance. This is in favour of more research effort towards a better understanding of the sparing effect of the amino acid balance on energy utilization, and consequently on feed energy value, in relation to protein level as evidenced by recent findings (Noblet et al., 1987 ). In addition to protein and energy saving, the stimulatory effect of improved amino acid balance on voluntary feed intake should provide maximum benefit from high performing animals for lean meat production in conjunction with possible growth manipulations and use of biosubstances. On the other hand, besides covering the dietary needs in the appropriate way, more attention should be given in the future to decreasing the excretion of nutrients (nitrogen, phosphorus) with the aim of avoiding soil contamination. CONCLUSION

With the rapidly increasing intensification of pig and poultry production during recent decades, and the subsequent steady improvement of feed conversion efficiency in meat and egg outputs, there has been significant progress in the evaluation of energy and protein in single feedstuffs and complete feeds for both non-ruminant groups, pigs and poultry. Feed-energy evaluation in pigs is characterized by diverse systems in use including digestible energy, metabolizable energy and net energy for fat formation or for growth, along with various ways of calculating the energy value within each system, either from direct calorimetric measurements with correction factors for differences in

325 chemical composition or, most commonly, from digestible nutrients. In contrast to pigs, energy evaluation in poultry is uniformly based on metabolizable energy, which is usually corrected to zero nitrogen retention. In both pigs and poultry, with the advancement of knowledge in feed composition and nutrient utilization, the prediction of energy value has gained in accuracy, and allows a good adjustment of feed supply to the requirements when there are unavoidable changes in feedstuff characteristics. Still the problem remains of developing the most adequate energy system, especially for pigs, which can closely predict production performance. More research is needed to produce an additional improvement, for instance by considering the use of a net energy system for growth and lean meat production. An improved nutrient fractionation system is needed to replace the traditional Weende procedure and the so-called digestible nutrients. This will enable the identification of the appropriate digestible nutrients according to the digestion site in the prediction equations by taking into account digestive interactions between fibrous components and the other nutrients. It might appear surprising that less progress has been made in protein evaluation on an availability basis than in evaluating energy. Despite a good knowledge of the amino acid composition of protein in feedstuffs, protein evaluation is still restricted in most countries to apparent protein digestibility, and dietary supply is generally based on crude amounts of protein and amino acids. For the near future there is an urgent need to encourage systematic measurements of digestible amino acid at the ileal site for pigs, or the use of caecectomized birds, whenever possible with a standardized procedure, in order to set up extensive tables taking into account quality changes between, as well as within, feedstuffs, depending on technological treatments. Nutrient recommendations for non-ruminants have been mainly produced up to now for an average level of performance on the basis of feeding trials. For the future, further expected improvement of production capabilities will im duce a widening of animal performance and this will necessitate diversification of the recommended allowances according to production conditions. The im creasing use of the factorial approach for predicting nutrient requirements, based on a quantitative appraisal of requirement components and the rates of nutrient utilization, will provide a means for a better adaptation of feed supply to animal performance and production objectives. This will also allow more uniformity in the presentation of the systems in use in the different European countries for predicting feed energy and protein value as well as nutrient requirements. REFERENCES Alderman,G., 1985.Prediction of the energyvalueofcompoundfeeds.In: W. Haresignand D.J.A. Cole (Editors), Recent Advancesin AnimalNutrition, Butterworths, London,pp. 3-52.

326 Alexiev, A. and Stojanov, V., 1984. Feeding standards for pigs (Bulgarian). In: Feeding Standards for Farm Animals and Tables of Feeding Value of Feedstuffs, Zemirdat, Sofia, pp. 90-109. Andersen, P.E. and Just, A., 1983. Tabeller over foderstoffers Sammensaetning m.m. Kvaeg-Svin. Det Kgl. danske Landhusholdningsselskab., Copenhagen, Denmark, 102 pp. A.R.C., 1981. The Nutrient Requirements of Pigs. Commonwealth Agric. Bureaux, London, 307 pp. Asplund, J.M. and Harris, L.E., 1969. Metabolizable energy values for nutrient requirements for swine. Feedstuffs, 41 (14): 38-39. Axelsson, J., 1939. The general nutritive value (energy value) of poultry feed. Proc. 7th World's Poult. Congr. and Exposition, Cleveland, OH, 165 pp. Beyer, N., Chudy, A., Hoffmann, L., Jentsch, W., Laube, W., Nehring, K. and Schiemann, R., 1986. DDR-Futterwertungssystem. 5. Auflage, VEB Deutscher Landwirtschaftsverlag, Berlin, 328 pp. Bolduan, G., Herrmann, U., Jung, H. and Kracht, W., 1984. Schweinefiitterung. Eine Fiitterungslehre ffir Schweineproduzenten. VEB Deutscher Landwirtschaftsverlag, Berlin. 159 pp. Boorman, K.N. and Burgess, A.D., 1986. Responses to amino acids. In: C. Fisher and K.N. Boorman (Editors), Nutrient requirements of poultry and Nutritional Research. 19th Poult. Sci. Symp., Butterworths, London, pp. 99-123. Borggreve, G.J., Van Kempen, G.J.M., Cornelissen, J.P. and Grimbergen, A.H.M., 1975. The net energy content of pig feeds according to the Rostock formula. The value of starch in the feed. Z. Tierphysiol. Tierern~ihr. Futtermittelkd., 34: 199-204. Breirem, K., 1986. Fornormer. In: K. Singsaas (Editor), Heje Lommehandbok for jordbrudere, skogbrukere, meierister og hagabrukere, Steensballe's Forlag, N ° 94, pp. 188-194. Brette, C., Duquenne, G., Henry, Y., Jacquot, L., Palisse-Roussel, M., Pdrez, J.M., Sauvant, D. and Theillaud, Vdronique, 1986. Influence du choix du syst~me dnergdtique sur les rdsultats de la formulation des aliments pour les porcs en croissance, Journ. Rech. Porcine France, 18: 91102. Burlacu, G., 1983. Valoarea nutriva a nutreturilor si normale de hrana la animale, Ceres, Bucharest, 34 pp. Burlacu, G., 1985. Metabolismul energetie la animalele de ferma, Ceres, Bucharest, 355 pp. Carpenter, K.J. and Clegg, K.M., 1956. The metabolizable energy of poultry feedingstuffs in relation to their chemical composition. J. Nutr., 47: 449-460. Carrd, B., Prdvotel, B. and Leclercq, B., 1984. Cell wall content as a predictor of metabolizable energy value of poultry feedingstuffs. Br. Poult. Sci., 25: 561-572. Chudy, A. and Schiemann, R., 1971. Energetische Verwertung von Futterstoffen beim Hiihn. In: R. Schiemann, K. Nehring, L. Hoffmann, W. Jentsch, and A. Chudy (Editors), Energetische Futterbewertung und Energienormen. VEB Dtsch. Landwirtschaft. Verlag, Berlin, pp. 168-202. Consorzio del Suino Pesante Italiano. Statuto e regolamento per la produzione del Suino Pesante Italiano. Reggio Emilia, 26 pp. Crampton, E.W., Lloyd, L.E. and McKay, V.G., 1957. The caloric value of TDN. J. Anim. Sci., 16: 541-545. C.S.N. (Ceskolovenska Statni Norma: Czechoslovak State Standard), 1982. Vyzina Hodnota Krmiv (Nutritive value of feeds). CSN 467093. C.S.N. 1984. Potreba Zivin pro2-Iospodarska Zuirata (Nutrient requirements for farm animals). CSN 467070. Curnow, R.N., 1973. A smooth population response curve based on an abrupt threshold and plateau model for individuals. Biometrics, 29: 1-10. C.V.B. (Centraal Veevoederbureau), 1983a. Veevoedertabel. Gegevens over voederwaarde, verteerbaarheid en samenstelling. C.V.B., Lelystad, The Netherlands, pp. C1-C 11. C.V.B., 1983b. Voedernormen voor de Landbouwhuisdieren en Voederwaarde van Veevoeders. C.V.B., Lelystad, The Netherlands, 36 pp.

327 C.V.B., 1984. Voorlopige tabel verteerbare aminozuren in veevoedergrondstoffen voor varkens. C.V.B., Lelystad, The Netherlands, 18 pp. Darcy, B. and R~rat, A., 1983. Protein digestion and absorption of the hydrolysis product in the small intestine of the pig. In: M. Arnal, R. Pion and D. Bonin (Editors), Proc. 4th Int. Symp. Protein Metabolism and Nutrition. Les Colloques de rI.N.R.A., N ° 16, Vol. I, Clermont-Ferrand, pp. 233-244. D.D.R.-Bedarfsnormen, 1984. Das DDR Futterbewertungssystem. V.E.B., Dtsch. Landw.-Verlag, Berlin. De Groote, G., 1974a. A comparison of a new net energy system with the metabolisable energy system in broiler diet formulation, performance and profitability. Br. Poult. Sci., 15: 75-95. De Groote, G., 1974b. Utilisation of metabolisable energy. In: T.R. Morris and B.M. Freeman (Editors), Energy Requirements of Poultry. 9th Poult. Sci. Symp., Br. Poult. Sci. Ltd., pp. 113-133. D.L.G. (Deutsche Landwirtschafts-Gesellschaft), 1984. DLG-Futterwerttabellen ftir Schweine. DLG-Verlag, Frankfurt-am-Main, 82 pp. Dokumentationstelle der Universi~t Hohenheim, 1986. N~hrstoff-Mineralstoff- und Aminosatirentabelle zur Gefltigelftitterung. In: J. Petersen (Editor), Jahrbuch ftir die Gefltigelwirtschaff 1987. Ulmer, Stuttgart, pp. 113-119. Eriksson, S. and Hartfiel, W., 1967. ~lber den N-Ausgleich bei der Bestimmung der umsetzbaren Energie von Futtermitteln fiir Htihner. Arch. Gefltigelkd., 21: 45-50. Eriksson, S., Sanne, S. and Thomke, S., 1976. Fodermedels tabeller och utfodringsrekommendationer. 2a upp., LTs, Forlag. Evans, R.E., 1948. Rations for Livestock. Bull. N°48, H.M.S.O., London. F.A.G. (Forschungsanstalt Grangeneuve), 1983. Energie digestible pour aliments compos~s pores, Grangeneuve, Posieux, Circulaire 23.12.83. Farrell, D.J., 1978. Rapid determination of metabolizable energy of foods using cockerels. Br. Poult. Sci., 19: 303-308. Farrell, D.J., 1979. Energy systems for pigs and poultry: a review. J. Aust. Inst. Agric. Sci., 45: 21-34. Fisher, C., 1982. Energy evaluation of poultry rations. In: W. Haresign (Editor), Recent Advances in Animal Nutrition. Butterworths, London, pp. 113-139. Fisher, C., 1983. The physiological basis of the amino acid requirements of poultry. In: M. Arnal, R. Pion and D. Bonin (Editors), Proc. 4th Int. Symp. Protein Metabolism and Nutrition. Les colloques de I'I.N.R.A., N ° 16, Vol. I, Clermont-Ferrand, pp. 385-404. Fisher, C., Morris, T.R. and Jennings, R.C., 1973. A model for the description and prediction of the response of laying hens to amino acid intake. Br. Poult. Sci., 14: 469-484. Fraps, G.S. and Carlyle, E.C., 1939. The utilization of the energy of feed by growing chickens. Tex. Agric. Exp. Bull., 571, 44 pp. Fraps, G.S. and Carlyle,E.C., 1942. Productive energy of some feeds and foods as measured by gains of energy by growing chickens, Tex. Agric. Exp. Bull., 625, 51 pp. Fuller, M.F., 1980. Protein and amino acid nutrition of the pig. Proc. Nutr. Soc., 39: 193-203. Ftinfte Verordnung zur Anderung der Futtermittelverordnung von 2, Januar 1987. Bundesgesetzblatt, Jahrgeng 1987, Teil I, No. 3, pp. 94-113, Bundesanzeiger Verlagsges-m.b.H., Bonn, 15 (33) : 395-419. Hiirtel, H., Schneider, W., Seibold, R. and Lantsch, H.J., 1977. Beziehungen der N-korrigierten umsetzbaren Energie und den N~ihrstoffgehalten der Futters beim Htihn. Arch. Gefliigelkd., 41: 152-181. Hartfiel, W., 1964. Fragen zur Energiebewertung von Futtermitteln im Tierversuch. Kraftfutter, 47: 670-672. Hartfiel, W., 1983. Energieeumsetzungen. In: A. Mehner and W. Hartfiel (Editors), Handbuch der Gefliigelphysiologie, VEB Gustav Fischer Verlag, Jena, pp. 662-690.

328 Hartfiel, W., Eriksson, S. and Aldermann, M., 1970. N-Korrektur und Ermittlung der umsetzbaren Energie yon Futterstoffen fiir die Gefl0gelern~ihrung. Arch. GeflOgelkd., 34: 221-224. Henry, Y., 1976. Prediction of energy value of feeds for swine from fiber content. Proc. 1st Int. Symp. Feed Composition, Animal Nutrient Requirements and Computerization of Diets. Utah State Univ., Logan; pp. 270-281. Henry, Y., 1985a. Dietary factors involved in feed intake regulation in growing pigs: a review. Livest. Prod. Sci., 12: 339-354. Henry, Y., 1985b. Principles of protein evaluation in pig feeding. World. Rev. Anita. Prod., 21: 47-59. Henry, Y. and Pdrez, J.M., 1982. Les systhmes d'dvaluation de l'dnergie dans l'alimentation du porc. Les Dossiers de l'I~levage, 5 (1): 51-66; 49-64. Henry, Y. and Pdrez, J.M., 1983. Les syst~mes d'dvaluation de l'dnergie dans l'alimentation du porc. Les Dossiers de l'Elevage, 5(2): 49-64. Henry, Y. and Noblet, J., 1986. Alimentation dnergdtique. In: J.M. Pdrez, P. Mornet and A. Rerat (Editors), Le Porc et son dlevage, Bases scientifiques et techniques. Maloine, Paris, pp. 233-260. Hill, F.W., 1957. Metabolizable Energy Values of Feedstuffs for Poultry and their Use in Formulation of Rations. Proc. Cornell Nutr. Conf., 22 pp. Hill, F.W. and Anderson, D.L., 1958. Comparison of metabolizable energy and productive energy determinations with growing chicks. J. Nutr., 64: 587-603. Hoffmann, L., 1983a. Grundlagenerkenntnisse zur Ableitung des Energiebedarfs fiir wachsende Tiere nach der faktoriellen Methode. Tag-Ber. Akad. Landwirtsch. Wiss., DDR. Berlin, 217: 69-97. Hoffmann, M., 1983b. Tierfiitterung, VEB-Dtsch-Landwirtschaftverlag, Berlin, 320 pp. Hoffmann, L. and Schiemann, R., 1980. Von der Kalorie zum Joule: Neue GrSszenbeziehungen bei Messungen des Energieeumsatzes und bei der Berechnung yon Kenzahlen der energetischen Futterbewertung. Arch. Tiererniihr., 30: 733-742. Hoffmann, L. and Schiemann, R., 1985. Zur Weiterentwicklung der energetischen Futterbewertung. Arch. Tierern~hr., 35: 439-460. Hoffmann, L. and Wiesemiiller, W., 1981. Neue Energie-Protein- und Aminosa'urenbedarfsnormen fiir Mastschweine und mRnnliche Jungschweine for die Zucht. Tierzucht, 35: 222-224. I.N.R.A., 1984. L'alimentation des animaux monogastriques (porc, lapin, volailles). I.N.R.A., Paris, 282 pp. Janssen, W.M.M.A. and Terpstra, K., 1972. Feeding values for poultry. 27 pp. Janssen, W.M.M.A., Terpstra, K., Beeking, F.F.E. and Bisalsky, A.J.M., 1979. Feeding Values for Poultry, 2nd edn., Spelderholt Mededeling 303, Veevoedertabel, 59 pp. Jeroch, H. and Hoffmann, L., 1983. Energie-, Protein- und Aminosaiirenbedarfsnormen ftir Hennen der Legerichtung (Legehybroden) und Mastrichtung (Broilerhennen). Tierzucht, 37: 396-399. Just, A., 1970. The energy value of balanced feed rations for growing pigs determined by different methods. Beretn. Forsoegslab., No. 381, Copenhagen, 212 pp. Just, A., 1975. Feed evaluation in pigs. World Rev. Anita. Prod., 11: 18-30. Just, A., 1982a. The net energy value of balanced diets for growing pigs. Livest. Prod. Sci., 8: 541555. Just, A., 1982b. The net energy value of crude fat for growth in pigs. Livest. Prod. Sci., 9: 501-509. Just, A., 1986. Evaluation of Energy and Protein for Pigs. VIth World Congress of Animal Feeding, Madrid. Just, A., Fernandez, J.A. and JSrgensen, H., 1983a. The net energy value of diets for growth in pigs in relation to the fermentative processes in the digestive tract and the site of absorption of the nutrients. Livest. Prod. Sci., 10: 171-186. Just, A., J~irgensen, H., Fernandez, J.A., Bech-Andersen, S. and Engaard Hansen, N., 1983b. The

329

chemical composition, digestibility, energy and protein value of different feedstuffs for pigs. 556. Beretning fra Statens Husdyrbrugsforsog., Copenhagen, Denmark, 99 pp. Just, A., JSrgensen, H. and Fernandez, J.A., 1984. Prediction of metabolizable energy for pigs on the basis of crude nutrients in the feeds. Livest. Prod. Sci., 11: 105-128. Kalaissakis, P., 1982. Applied Farm Animal Feeding (2nd edn.), 625 pp. (in Greek). Kalashnikov, A.P. and Kleimenov, N.I., 1985. Norm i raciony kormlenija selbskochozjajstvenich sivotnych (Nutrient requirements and rations for feeding farm animals), Agropromizdat, Moskva, pp. 121-158. Kellner, 0., 1913. The scientific feeding of animals. MacMillan Co., New York. Kirchgessner, M. and Roth, F.X., 1983. Sch~itzgleichungen zur Ermittlung des Energetischen Futterwertes von Mischfuttermitteln Mr Schweine. Z. Tierphysiol. Tierern~ihr. Futtermittelkd., 50: 270-275. Laplace, J.P., Darcy-Vrillon, B. and Picard, M., 1985. Evaluation de la disponibilitd des acides aminds: choix raisonn~ d'une m~thode. Journ. Rech. Porcine France, 17: 353-370. Larbier, M. and Leclercq, B., 1983. Evaluation des prot~ines et de l'~nergie dans les aliments des volailles. Die Versorgung yon wachsenden Schweinen und Gefli~gel mit Protein und Energie. Tagungsbericht, ETH, Z~irich, pp. 30-88. Leclercq, B., 1986. Energy requirements of avian species. In: C. Fisher and K.N. Boorman (Editors), Nutrient Requirements of Poultry and Nutritional Research. 19th Poult. Sci. Syrup., Butterworths, London, pp. 125-139. Lehmann, F., 1924. Uber Futterwert und Fiitterung in der Gefliigelhaltung. Kalender Rir Gefliigelz[ichter auf das Jahr 1925, 27: 212-223. Leroy, A.M., 1949. Normes pour l'alimentation dnergStique. V~me Congr~s Internat. Zootechnie, Paris. Low, A.G., 1982. Digestibility and availability of amino acids from feedingstuffs for pigs: a review. Livest. Prod. Sci., 9: 511-520. Major, E.J. and Batterham, E.S., 1981. Availability oflysine in protein concentrates as determined by the slope-ratio with chicks and comparisons with rat, pig and chemical assays. Br. J. Nutr., 46: 513-519. McNab, J.M. and Fisher, C., 1984. An assay for true and apparent metabolizable energy. Proc. 17th World's Poult. Congress and Exhibition, Helsinki, Finland, pp. 374-376. MSllgaard, H., 1929. Fiitterungslehre des Milchviehs, M.T.H. Schaper, Hannover. Morgan, C.A. and Whittemore, C.T., 1982. Energy evaluation of feeds and compounded diets for pigs. A review. Anim. Feed Sci. Technol., 7: 387-410. Morgan, C.A., Whittemore, C.T., Phillips, P. and Crooks, P., 1987. The prediction of energy value of compounded pig foods from chemical analysis, Anita. Feed Sci. Technol., 17: 81-107. Nehring, K., 1969. Investigations on the scientific basis for the use of net energy for fattening as a measure of feed value. In: K. Blaxter, J, Kielanowski and G. Thorbek (Editors), E.A.A.P. Pub. N ° 12, Oriel Press, Newcastle, pp. 5-20. Nehring, K., Beyer, M. and Hoffmann, B., 1972. Futtermittel Tabellenwerk. VEB Dtsch. Landwirtschaftsverlag, Berlin, 452 pp. Noblet, J. and Etienne, M., 1987a. Utilization of energy during pregnancy and lactation in swine. In: P.W. Moe, H.F. Tyrrell and P.J. Reynolds {Editors), E.A.A.P. Publ. No. 32, Rowman and Littlefields Publishers, Totowa, pp. 302-305. Noblet, J. and Etienne, M., 1987b. Metabolic utilization of energy and maintenance requirements in pregnant sows. Livest. Prod. Sci., 16: 243-257. Noblet, J. and Etienne, M., 1987c. D~penses et besoins ~nergdtiques de la truie au cours du cycle de reproduction. Journ. Rech. Porcine France, 19: 197-202. Noblet, J. and Etienne, M., 1987d. Metabolic utilization of energy and maintenance requirements in lactating sows. J. Anita. Sci., 64: 774-781.

330 Noblet, J., Henry, Y. and Dubois, S., 1987. Effect of protein and lysine levels in the diet on body gain composition and energy utilization in growing pigs. J. Anita. Sci., 65: 717-726. N.R.C. (National Research Council), 1979. Nutrient requirements of swine. Natl. Acad. Sci., Washington, DC, 52 pp. Oslage, H.J., 1985. Ergebnisse aus Schweinespezialberatung und Erzeugergemeinschaften. Schweine, Report 85, BM. Landwirtschaftkammer, Schleswig-Holstein, nr. 367. Payne, W.L., Combs, G.F., Kiffer, R.R. and Snyder, D.G., 1968. Investigation of protein quality ileal recovery of amino acids. Federation Proceedings, 27:1199-1203. P~rez, J.M., Ramihone, R. and Henry, Y., 1984. Prediction de la valeur ~nerg~tique des aliments compos~s destines au porc: ~tude exp~rimentale. I.N.R.A., Paris, 95 pp. P.W.N., 1985. Tabele Kladu chemicznago i wartosci pokarmowej pasz larojowych (Tables of chemical composition and nutritive value of feedstuffs), P.W.N., Warsaw. P.W.R.I.L., 1985. Normy zwienia zwierzst gospodarskich (Feeding Standards of farm animals), P.W.R.I.L., Warsaw. R~rat, A., 1981. Digestion and absorption of nutrients in the pig. Some new data concerning protein and carbohydrates. World Rev. Nutr. Diet., 37: 229-287. Sato, H., Kobayashi, T., Jones, R.W. and Easter, R.A., 1987. Thyptophan availability of some feedstuffs determined by pig growth assay. J. Anim. Sci., 64: 191-200. Sauer, W. an_dOzimek, L., 1986. Digestibility of amino acids in swine: results and their practical applications. A review. Livest. Prod. Sci., 15: 367-388. Schiemann, R., Nehring, K., Hoffmann, L., Jentsch, W. and Chudy, A., 1971. Energetische Futterbewertung und Energienormen. VEB. Deutscher Landwirtschaftsverlag, Berlin, 344 pp. Schulz, E., 1985. Ableitung der Energie- und Proteinversorgung von Schweinen w~_hrend der Mast und einige konsequenzen fiir die Rationgestaltung. Lohmann Information, Cuxhaven, 5 pp. Schiirch, A. and Bickel, H., 1986. Die Ern~hrung der Landwirtschaftlichen Nutztiere. Landwirtschaftliches Handbtichlein zum Wirz-kalender. Verlag Wirz. Aarau, pp. 75-116. Sibbald, J.R., 1976. A bioassay for true metabolizable energy in feedingstuffs. Poult. Sci., 55: 303-308. Sibbald, J.R., Czarnicki, J., Slinger, S.J. and Ashton, G.C., 1963. The prediction of the metabolizable energy content of poultry feedingstuffs from a knowledge of their chemical composition. Poult. Sci., 42: 486-492. Simonsson, A., 1985. N~iringsrekommendationer till swin. Sveriges Lantbruksuniversitet, Report No. 63, Uppsala, 21 pp. SundstSl, F., Hongslo, T., Herstad, O. and Raastad, N., 1986. Forverditabell for Kraftfor M.M., Oslo. Tanksley, T.D. Jr. and Knabe, D.A., 1984. Ileal digestibilities of amino acid in pig feeds and their use in formulating diets. In: W. Haresign and D.J.A. Cole (Editors), Recent Advances in Animal Nutrition. Butterworth, London, pp. 75-95. Titus, H.W., 1961. The Scientific Feeding of Chickens. 4th edn. Danville, IL, The Interstate. Van der Honing, Y., Jongbloed, A.W., Wieman, B.J. and Van Es, A.J.H., 1984. Verslag van de studie naar benutting van beschikbare energie van rantsoenen overwegend bestaande uit granen of bijprodukten door snelgroeiende mestvarkens. Rapport No 164, IVVO, Lelystad, The Netherlands, 23 pp. Van Soest, P.J., 1963. Use of detergents in the analysis of fibrous feeds. 1. Preparation of fiber residues of low nitrogen content. 2. A rapid method for the determination of fiber and lignin. J. Assoc. Off. Agric. Chem., 46: 825-829; 829-835. Van Soest, P.J. and Wine, R.H., 1967. Use of detergente in the analysis of fibrous feeds. 4. Determination of plant cell-wall constituents. J. Assoc. Off. Chem., 50: 50-55. Vogt, H., 1986. Report of the 17th Meeting of the Working group N ° 2 of the European Federation of W.P.S.A. Nutrition. W.P.S.A. Journal, 42, N°2, 289-190. -

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Appendix A. Pigs

GENERAL

The available energy systems (DE, ME, NE for fattening or for growth) are used in practical conditions for pigs in the different European countries with specific adaptations according to the method of calculation (digestible nutrients, prediction equation, energy unit) and feed characteristics (composition, digestibility coefficients). The inventory of the available systems for energy and protein evaluation is listed in Table AI. Nutrient recommendations are given in amounts per kg of standard feed of known energy value or in amounts per day on liveweight (W) basis, occasionally with specific corrections according to production performance (W gain, net gain during pregnancy, milk yield or litter size). With regard to essential amino acids (EAA), lysine is chosen as a reference, the requirements for the other EAA most likely to be limiting (threonine, tryptophan, methionine plus cystine) are derived from known ratios of EAA to lysine. Tables AII-AIV provide comparative protein and lysine recommendations in different European countries for piglets and growing-finishing pigs, pregnant and lactating sows, on the basis of a standard diet of a given energy value. Prediction equations of the energy value of mixed feeds from digestible nutrients, when they are known, or simply from crude chemical composition, are given in Tables AV and AVI. A brief description of the available feed-evaluation systems and feeding recommendations is given for the different countries with references.

TDN OFU, EFs UNp OFU OFU

(k)EFs

NEF NEF NEF

MJ MJ SFUN ry MJ

NKF NKF Danish

NEF ¢ NEF ¢

NKz

MJ MJ MJ kcal, SFU

EW EW FEB kcal MJ

Rostock eqn., dig. nut. Rostock eqn., dig. nut.

Crude nut. Dig. nut. Dig. nut. Dig. nut. as in F.R.G. Rostock eqn., dig. nut. Rostock eqn. dig. nut. Rostock eqn., dig. nut. Rostock eqn., dig. nut.

Rostock eqn., dig. nut

Rostock eqn., dig. nut. Rostock eqn., dig. nut. Dig. nut. Direct measurement (DE) Dig. nut. (Rostock eqn.), correction BFS d

Mode of measurement or calculation

+ + + + + + + + + + + + + + +

+ + + + +

+

+ +

+ + +

+ + +

+ + + + +

+

+ + +

+

+ + +

Digestible AA

DXP

Ideal protein (growth)

Faecal dig. Faecal dig. Calculation from dig. XP

Mode of measurement or calculation

dBacterial Fermentable Substances.

aNEF: Net energy for fattening: Rostock equation using digestible nutrients (dig. nut.). NKF: Netto kalorie fiir Fett (M~llgaard, 1929). blW=8.78 MJ kg -1 (2100 kcal); 1 FEB= 7.72 MJ kg -1 (1845 kcal); 1 EFs= 14.65 kJ NEF8 (3.5 kcal); 1 ry=barley equivalent; 1 UNp= 1 EFt, OFU = Oat feed unit. cUsing Dutch tables.

+ +

+

+ +

+

+ +

+ + +

Portugal Spain Switzerland Sweden Norway Finland Austria Yugoslavia G.D.R. Hungary Czechoslovakia Poland Romania Bulgaria U.S.S.R.

+ +

+

+ + + +

+

NEF ¢ NEF ¢ Danish NEI~

Energyb unit XP Total AA

NE a

DE

ME

Protein

Energy

U.K. Ireland Greece Italy

The Netherlands Belgium Denmark France F.R.G.

Country

Energy- and protein-evaluation systems in use for pigs in European countries

TABLE A I

b~

C~

60 50-90 60-100 60-80 60-120 60-100

35-100 30 25-60 20-40 35-60 35-60

NL DK F FRG GDR USA DK UK F FRG GDR USA

15-35 20 15-50 15-35 20-35

8-15

Specific liveweight (W) or W interval (kg)

NL DK UK GDR USA

NL DK UK F FRG GDR USA

NL UK F FRG GDR USA

Country ~

130

112 b 150 140

140

170 173

160

156d

180

180 190 195

2OO

210 220 212

110

125-135

120

130-140 140-155

160

150-170

160

150-170 160-190

190

150

7.8 7.0 7.0 6.5 5.7

min. 8.0 8.7 7.0 6.1

min. 8.0

11.0 9.5 7.0

10.0

12.5 12.5 10.3 9.5 7.9

11.0

12.0 14.0 14.0 11.3 13.0 9.5

Total

XP

DXP

Lysine

Protein

1 FE, 13.0 M J DE 13.4 M J DE (12.7 MJ ME) 12.0 MJ ME 0.62 kEF8 (900 g DM kg -1) 14.2 M J DE

1.3 EW 1 FE~ 13.4 M J DE (12.7 MJ ME) 12.0 MJ ME 0.60 kEFs (900 g DM kg -1) 14.2 MJ DE 6.8 7.0-8.0

6.5-7.3

1.03-1.07 EW 1 FE~ 13.0 MJ DE 0.62 kEF~ (900 g DM kg -1) 14.1 MJ DE

1.0-1.1 EW 1 FE. 13 MJ DE 14 M J DE (13.3 MJ ME) 12.0 MJ ME 0.62 kEF~ (900 g DM kg -~) 14.1 M J DE

1.1 EW 13 MJ DE 14.5 MJ DE (14.0 MJ ME) 12.0 MJ ME 0.61 kEFs (900 g DM kg -1) 14.6 MJ DE

8.9 8.0-9.0

8.10

Dig.

Energy content of standard feed k g - 1

aNL, The Netherlands; DK, Denmark; UK, United Kingdom; F, France; FRG, Federal Republic of Germany; GDR, German Democratic Republic; USA (N.R.C., 1979). bGenerally under feed restriction: feeding scale in European countries: 700-750 g ADG between 20 and 100 kg W; in U.S.A., ad libitum feeding. CNL, faecal digestibility; DK, calculated from protein digestibility. dIdeal protein.

Finisher b

Starting 25-30 kg W

Growe~ Sta~ing 15 kg W

Starter (10-20 kg W)

Piglet Pre-sterter ( 5-10 kg W)

Categories of pigs

Comparison of nutrient recommendations for growing pigs in some European countries (g kg- I standard feed)

T A B L E AII

5~

c~

1 2 1 2 1

F.R.G.

2.0 2.35 2.2 f 2.6 1.8 216

250 300 165 200

150 200 200-260 300-400 min. 180 min. 145 300

120

125 e

120

120 120 90-110 8.6 10 (11-12) d 11 13 10 12 7.7

18 22

Total

8-11 12-16

Dig.

XP

XP

DXP

A m o u n t d a y - 1 (g)

gkg -~ feed

A m o u n t d a y -~ (g) DXP

Lysine

Protein

al, 12 firstweeks (or total pregnancy); 2, last 4 weeks. bFaecal digestibility. ¢Computed from protein digestibility. dWithin parentheses, revised recommendations. e4.5% lysine in protein. qVIultiparoussows: for primiparous sows, 1:2.0;2:2.6.

U.S.A.

G.D.R.

U.K. France

Denmark

1a 2a 1 2 1 1

T h e Netheflands

2.5 3.0 2.0-2.4 3.2-3.8 2.0 2.5

State of Standard gestation feed (kgday -I)

Country

Comparison of n u t r i e n t r e c o m m e n d a t i o n s for p r e g n a n t sows in some E u r o p e a n countries

T A B L E A III

4.2

5.0

(4.5)d 5.5

4.3 4.0

min. 7.2 7.5

Total

3.5-4.5 c

5.9 b

Dig.

g k g - 1 feed

14.2 M J D E

0.55 K E F s kg -1 D M

12.5 M J M E

12.5 M J D E

1 FEs

0.97 E W

Energy c o n t e n t of s t a n d a r d feed kg -1

f~

10 _+1 10 -{-1 10 10 +_1 10 +_1 10 _+1

The Netherlands

"1% W of the sow + 0.4 kg per piglet. bFaecal digestibility. CThird week of lactation. dComputed from protein digestibility. ePrimiparous: 700 g day- i. f5.0% lysine in protein.

U.S.A.

G.D.R.

F.R.G.

U.K. France

Denmark

Litter size (no. piglets)

Country

5.6-6.1 0.4 a 6.0 c 0.4 5.25 5.5 0.3 5.1 0.4 5.35 0.36 5.5

Standard feed

715

800 75

825 800 e

730-800

640 60 665 45

660

780

130

150

145-160 ~

155 145

130 130

40 4 40 2.8 31.9

33 33

Total

34

39

Dig.

XP

XP

DXP

Amount day- 1 (g)

g kg-I feed

Amount day-1 (g)

DXP

Lysine

Protein

Comparison of nutrient recommendations for lactating multiparous sows in some European countries

TABLE A IV

5.8

7.5

7.5-8.2

6.3 6.0

min. 7.5

Total

g kg- l feed

1 FE~

6.5 d

14.2 MJ DE (13.4 MJ ME)

0.58 kEFs

12.5 MJ ME

12.5 MJ DE 13.0 MJ D E

0.97 EW

5.9 b

Dig.

Energy content of standard feed kg- 1

c~ c.~ ¢91

336 TABLE A V Prediction equations of energyvalue of singleor mixedfeeds(MJ kg- 1feed)from digestiblenutrients (g kg- 1feed)for pigs Energy Regressioncoefficients system DXP DXL DE ME

0.0242 0.021 0.0215

0.0394 0.0374 0.0377

References DXF

DXX

0.0184 0.0144 0.0173

0.0170 0.0171 0.0173

Hoffmannand Schiemann(1980) Hoffmannand Schiemann(1980) Just {1982)

ENERGY SYSTEMS

Digestible energy (DE) systems used in France, U.K., Ireland, Greece, Italy, Spain, Portugal, Switzerland, Poland, Hungary and Bulgaria Nutritive value France. There is no official energy system for practical use in pig feeding and the choice of the available systems is open. The DE values obtained from direct calorimetric measurements on a wide range of feedstuffs have been used to set up tables of feed composition and nutritive value in I.N.R.A. (1984), along with estimated ME values from DE according to DXP.

ME {MJ kg -1) =0.99 DE (MJ kg -1) - 0 . 2 9 DXP (g) The tabulated values are expressed in kcal kg- 1. For some feedstuffs, prediction equations are provided for correcting the DE value from crude-fibre content. In practice, the E system is used along with the NEF system as applied in the Dutch tables (CVB, 1983), which are based on the NEF system, with the first equation proposed by the Rostock group (Nehring, 1969).

U.K. and Ireland. For feeding pigs preference is given to the DE system, which was chosen by A.R.C. (1981) for expressing feed-energy value and energy requirements (MJ kg- 1). Greece. There is no official energy system for practical use and the choice of the available systems is open. However, the system most commonly used is the one based on DE. In this respect DE in MJ is predicted from tabulated proximate-composition data using the following equation proposed by Schiemann et al. (1971): DE (MJ kg- 1) __0.0242 DXP+ 0.039 DXL + 0.0184 DXF+ 0.017 D X X

5.75 5.62 5.53 5.74

Constant

0.0066 0.0040 0.0028 0.0021 0.0203 0.0180

XP

Regression coefficients

0.0252 0.0315

XL

*CV means coefficient of variation in %.

ME

DE

Energy system

-0.0178 -0.0149

XF

-0.0162 -0.0163

XX 0.68 0.69 0.70 0.69

GE -0.016 -0.016 -0.016 -0.017

NDF -0.035 -0.0223 -0.034 -0.024

ASH 0.27 0.34 0.25 0.33 (5.0) 0.54 (3.7)

RSD (CV*, %)

Prediction equations of energy value of compound feeds (MJ k g - 1) from crude chemical composition (g k g - 1) for pigs

TABLE A VI

0.887 0.956 0.893 0.960 0.76 0.8

R2

Pdrez et al. (1984) Morgan et al. (1987) P~rez et al. (1984) Morgan et al. (1987) Just et al. (1984) E.A.A.P. Working Group: provisional equation

References

338 with DXP, DXL, DXF and D X X in g kg- 1.

Italy. Both DE and ME (in kcal) are used, with a preference for DE. The conversion from DE to ME, for mixed feeds or for single feedstuffs, by taking into account crude-protein content, according to N.R.C. (1979) is: ME=DE (0.96-0.202 XP). In compound feeds, DE values are estimated from different available equations (Morgan and Whittemore, 1982; Kirchgessner and Roth, 1983; P~rez et al., 1984). Spain and Portugal. In Spain, there are no official recommendations on energy and protein evaluation, feed composition and feeding standards. In most cases DE is used as an energy unit (I.N.R.A., 1981, 1984 and A.R.C. tables and recommendations), but other systems like the Dutch system and the corresponding tables (C.V.B., 1983)are also utilized in practice. Committees have been appointed to advise on which system to adopt. In Portugal, the position for pigs is similar to that in Spain. Switzerland. The energy value for pigs is expressed in DE (MJ kg- 1). For complete rations based on concentrates, DE is calculated from proximate analysis of nutrients DE (MJ kg- 1) = 0.0190 X P ÷ 0.0335 X L - 0.0212 X F ÷ 0.0166 X X where XP, XL, XF and XX are given as g kg-1. This calculation is restricted to rations with ~<6% XL and ~<8% XF in the dry ration as fed. For rations with > 6% XL the factor 0.0335 is raised to 0.035. The equation is based on about 1400 digestibility experiments carried out by the Institute of Animal Sciences, Ziirich, the F.A.G., Grangeneuve and the Research Stations of the Swiss Agricultural Cooperatives (F.A.G., 1983; Wenk and Landis, 1985).

Poland. Energy evaluation is still made in Oat Feed Units, and in addition in DE, ME and NEF using Rostock equations (Hoffmann and Schiemann, 1980). Tables of feed composition are available, with the amino contents of feedstuffs (P.W.N., 1985). Hungary. The new energy systems in use in pig feeding, starting in 1986, are DE and ME, calculated from the digestible nutrients, according to the prediction equations of the Rostock group (Schiemann et al., 1971; Hoffmann and Schiemann, 1980). DEs (MJ kg -1 DM) = 0.0242 DXP ÷ 0.0394 DXL + 0.0194 DXF+ 0.0170 D X X

339 ME~ (MJ kg -~ DM) = 0.0210 D X P + 0.0374 DXL + 0.0144 DXF+ 0.0171 D X X with the digestible nutrients expressed as g kg-~ DM. Bulgaria. Energy value for pigs is expressed in one of the 3 following systems: (1) starch equivalent: feed or Oat Feed Unit (OFU)= 0.6 SE; (2) DE and ME calculated with the Rostock equations (Schiemann et al., 1971). 1 0 F U = 11.9 MJ DE or 11.5 MJ ME. Retirements France. Average nutrient recommendations derived from feeding trials are given for optimum production performance, i.e. for lean-meat production, with leantype females as a reference, under moderate feed restriction (90-95% of ad libitum intake): 700-750 g average daily gain (ADG) between 25 and 100 kg W. Minimal requirements are suggested for reproductive sows during pregnancy (30 kg net gain) and lactation (10 piglets per litter). U.K. and Ireland. Energy requirements are calculated according to the factorial method. (1) Growth. Maintenance: MEm (MJ)=0.719 W °63 or DEm (MJ)=0.749 W o.63,with W in kg. Production estimated from deposited protein and fat energy: with kv-- 0.56 and kf=0.74. Voluntary DE intake (MJ): 2.621 W °'63, i.e. 3.5 times maintenance or 50 (1 - e-°°24° w). Scale of feeding: 0.8-0.9 ad libitum at 30 and 90 kg W, respectively. (2) Pregnancy and lactation. Maintenance: DE (MJ)= 0.461 W 0.75. Energy deposited in products of conception and maternal tissues, for a low and high net gain in pregnancy: 20 and 40 kg, respectively, at 120, 140 and 160 kg W at mating. Correction for ambient temperature. Lactation: 140-200 kg W at parturition. Weaning age: 21-35 and 56 days. 8.4 MJ DE (8.0 MJ ME) kg -1 milk. Body weight loss: 0.18 kg day -1 with 48.7 MJ DE (46.4 MJ ME) kg-'. Greece. Mean recommendations (Kassalaikis, 1982) are given in daily amounts (MJ DE, DXP, lysine, methionine plus cystine) according to W for piglets, growing pigs, pregnant (beginning, end) and lactating sows (10 piglets per litter). Italy. Nutrient recommendations are adapted to the type of production, according to slaughter weight: meat-type pigs at 100-110 kg W, heavy pigs at 145-160 kg W. Official legislation (Consorzio del Suino Pesanto Italiano) is

340 available for feeds producing heavy pigs (characteristics and level of incorporation of ingredients in diets).

Switzerland. Feeding recommendations (Schfirch and Bickel, 1986) are given in daily amounts (DE, DM, DXP, lysine and methionine plus cystine) for pregn a n t sows (up to and after 12 weeks), lactating sows (depending on weaning age: 3-4 or 5-7 weeks), piglets and growing-finishing pigs, for given W and average daily gain.

Poland. Tables of nutrient requirements are revised at irregular intervals for the different classes of pigs (PWRL). Bulgaria. Feeding standards (Alexiev and Stojanov, 1984) are given in amounts per day and per kg feed with each of the three energy units and in total crude protein and amino acids.

References FRANCE

C.V.Ba., 1983 I.N.R.A., 1984. Nehring, K., 1969. U.K. AND I R E L A N D

A.R.C., 1981. GREECE

Kalaissakis, P., 1982. Schiemann, R. et al., 1971 ITALY

Consozio del Suino Pesante Italiano. Kirchgessner, M. and Roth, F.X., 1983. Morgan, C.A. and Whittemore, C.T., 1982. P~rez, J.M. et al., 1984. Scipioni, R., 1986 (personalcommunication). SPAIN AND P O R T U G A L

A.R.C., 1981. C.V.B., 1983a. I.M.R.A., 1984. SWITZERLAND

F.A.G., 1983. Schiirch, A. and Bickel, H., 1986. Wenk, C. and Landis, J., 1985. POLAND

Hoffmann, L. and Schiemann, R., 1980. P.W.N., 1985 P.W.R.I.L., 1985.

341 HUNGARY Hoffmann, L. and Schiemann, R., 1980. Schiemann, R. et al., 1971. BULGARIA Schiemann, R. et al., 1971 Alexiev, A. and Stojanov, V., 1984.

Metabolizable energy (ME) systems used in France, F.R.G., Sweden, Austria, Yugoslavia, Hungary, Czechoslovakia, Bulgaria and U.S.S.R. Information for France, Hungary and Bulgaria given under the heading of DE systems. Nutritive value F.R.G. A new energy system for pigs has been officially adopted since 1984 on the basis of ME, with two corrections applied to fermentable substances and sugar. Bacterial fermentable substances (BFS) are computed in the following manner: BFS = D X X + D X F - (starch + sugar). (1) Single feeds. ME is expressed in MJ kg-1 and calculated from digestible nutrients for single feeds according to Hoffmann and Schiemann (1980). Correction factor for BFS, above 100 g kg -1 DM, is based on 0.6 efficiency of utilization of ME from apparently digested fermentable substances compared to starch, i.e. -0.4, the value of the DXX coefficient. Correction for sugar (Z) is based on a lower GE content compared to XX. M E (MJ kg -1 DM) =0.021 DXP+O.0374 DXL+O.O144 D X F +0.0171 DXX-O.O014 Z - 0.0068 ( B F S - 100) with digestible and crude nutrients in g kg-1 DM, correction for sugar above 80 g kg-1 DM. (2) Compound feeds. In compound feeds, ME value is computed by using the prediction equation of Kirchgessner and Roth (1983) from crude chemical composition: M E (MJ kg -1) =0.0218 X P + 0.0314 X L + 0.0171 S + 0.0169 Z + 0.0081 O R - 0.0066 A D F RSD=0.27 (2.0%) S, Starch; OR, organic residue ( O M - ( X P + X L + S + Z + A D F ) ) In the absence of ADF content the equation is: M E (MJ kg -1) =0.0223 X P + 0.0341 X L + 0.017 S +0.0168 Z+0.0074 OR-0.0109 X F

342

RSD = 0.28 (2.1%), with O R = O M - ( X P + X L + S + Z + X F ) . This equation has officially been used for control of compound feeds for pigs since 1987. Sweden. The energy value for pigs is presently expressed in ME (MJ) and calculated according to the following equation, the same as that used for ruminants in the NKF system (MSllgaard, 1929), but with specific digestibility coefficients for pigs: M E (MJ kg- 1) = a D X P + b D X L + 0.0147 D X F + 0.0168 D X X

with: a--0.0193 in concentrates, including fish and meat meal; 0.0197 in milk and dairy products; 0.0184 in forages, b = 0.0348 in grains; 0.0369 in oil seeds; 0.0390 in feeds of animal origin; 0.0327 in silages and other forages; digestible nutrients are measured in g kg - 1. A new feed energy-evaluation system and revised feeding standards are under consideration in Scandinavian countries (Sweden, Norway, Finland). Austria. The energy-evaluation system is changing from GN (Gesamtn~ihrstoff) to ME, which is estimated according to D.L.G. (1984). Likewise, feeding recommendations are those defined by D.L.G. Yugoslavia. ME is used as the energy system: computed with the G.D.R.-Rostock equation (Schiemann et al., 1971). Czechoslovakia. The TDN system is still used for expressing the energy value of feeds. Starting in 1989 the ME system will be introduced (CSN, 1982) calculation from digestible nutrients according to the Rostock equation (Hoffmann and Schiemann, 1980). U.S.S.R. Feed evaluation is expressed in oats unit (OFU) along with ME (MJ): 1 0 F U = 11.1 MJ ME. Requirements F.R.G: Energy requirements (IME) are calculated factorially through partitioning between maintenance and production (D.L.G., 1984; Oslage, 1985; Schulz, 1985). Energy: Intake of ME (MJ) = MEre + RPE/k~ + RFE/kf; maintenance: MEre (MJ)=0.719 W °63 1.10 (A.R.C., 1981); energy retained as protein (RPE): kv = 0.54; energy retained as fat (RFE): kf= 0.70. RPE and RFE are given by tables according to W and ADG for a given W. Tables of recommendations (amounts per day) are available for the different

343

categories of pigs: adjustment according to litter size for lactating sows; amounts of ME, XP and lysine to growing pigs according to W and ADG; mean recommendations for 700 g ADG between 20 and 100 kg W. Sweden. Amount per day (MJ ME) or per kg feed of a given energy value (Simonsson, 1983). Pregnant sows: the recommended energy supply (MJ ME day-1) is a function of W at mating (120-160 kg), net gain during gestation (20 and 40 kg, with a difference of 4.1 MJ ME day- 1), climatic environment (18-20 ° C vs. 13-15 ° C, with a difference of 3.9-4.9 MJ day- 1between 120 and 160 kg W, respectively). Lactating sows: 36 MJ ME + 4.8 MJ per piglet, i.e. 84 MJ ME for 10 piglets, or 3.0 kg feed+ 0.4 kg per piglet for feed with 12 MJ ME kg -1. Piglets (8-25 kg) and growing-finishing pigs (25-110 kg day-1 or kg-1 feed) according to a feeding scale during growing-fattening (energy content of feed, 12.2-12.4 MJ ME kg-1). Austria. A legal regulation for minimum standards in pig feeding has been established by the Department of Agriculture and Forestry (Bundegetzblatt, 1987). Yugoslavia. Tabulated feeding standards (per kg air dry feed mixture) are provided for pregnant sows, lactating sows, gilts and boars, weaning piglets (5-25 kg W) and growing-finishing pigs (25-100 kg W) (Zivkovic and Zlatic, personal communication). Czechoslovakia. Tables of feed composition and nutritive value, and feeding standards for pigs, are available and revised at irregular intervals. The latest feeding standards were established in 1984 (C.S.N., 1984): amounts per day and per kg feed (DM, TDN, crude protein, lysine, methionine, threonine and tryptophan) for breeding sows (pregnant, lactating with 8, 10 or 12 piglets per litter), growing and breeding boars, piglets (5-7 and 7-15 kg W) and growing-fattening pigs (15-35, 35-65 and 65-115 kg W). U.S.S.R. Feed evaluation is expressed in oats unit (OFU) along with ME (MJ): 1 0 F U = 11.1 MJ ME. Feeding standards (OFU, ME, XP, DXP, along with essential amino acids lysine and methionine plus cystine) are given in amounts per day or per kg air dry feed (14% moisture). Tabulated recommendations (Kalashnikov and Kleimonov, 1985) are available for: boars (150-350 kg W); pregnant gilts and sows (120-240 kg W and above, with specific allowances during the last 30 days of gestation); lactating sows, according to age at weaning (26-60 days, mean recommendations for 10 piglets in the litter, below or above 2 years of age; per piglet, + 4.2 MJ ME, _+54 g XP, + 2.3 g lysine), piglets up to 20 kg W; growing-finishing pigs (feed-

344

ing scales between 40 and 120 kg W, corresponding to average daily gain of 550, 650 and 800 g, amounts per kg feed in the W intervals 40-70 and 70-120 kg). Amounts of energy, protein and lysine per year are also given.

References F.R.G. Bundesgesetzblatt, 1987. DLG - Futterwerttabellen fiir Schweine, 1984. Hoffmann, L. and Schiemann, R., 1980. Kirchgessner, M. and Roth, F.X., 1983. Oslage, H.J., 1985. Schulz, E., 1985. SWEDEN MSllgaard, H., 1929. Simonsson, A., 1985. AUSTRIA

Bundesgesetzblatt Mr die Republik Osterreich. 1985. D.L.G., 1984. YUGOSLAVIA Schiemann, R. et al., 1971. Zivkovic, S. and Zlatic H., (personal communication, 1986). CZECHOSLOVAKIA C.S.N., 1982. C.S.N., 1984. Hoffmann, L. and Schiemann, R., 1980. Somecek, K. (personal communication, 1986). U.S.S.R. Kalashnikov, A.P. and Kleimenov, N.I., 1985.

Net energy (NE) systems used in The Netherlands, Belgium, Denmark, France, Italy, Spain, Portugal, Sweden, Norway, Finland, G.D.R. and Romania Information for France, Italy, Spain and Portugal given under the heading of DE systems. Information for Sweden given under the heading of ME systems.

Nutritive value The Netherlands. Energy evaluation for pigs is based on the Rostock NEF system by using the first prediction equation reported by Nehring (1969), in which crude fibre was given a lower coefficient than XX, instead of a common coefficient for both as in the final equation:

345 N E F (MJ kg -~) =0.01041 DXP+O.03607 D X L

+ 0.00627 D X F + 0.01267 D X X with DXP, DXL, DXF and DXX in g kg -1. The net energy value (NE) is expressed in feed units (EW). The energy unit amounts to 8.78 MJ kg- 1 (2100 kcal), i.e. the energy value of a common mixed feed based on barley. The energy value is computed from Dutch feed-composition data and the corresponding digestibility coefficients (C.V.B., 1983a). For some classes of feedstuffs, such as tapioca meal, wheat by-products, maize by-products and molasses, specific equations are given for predicting NE and DXP. Belgium and Luxemburg. Similar to The Netherlands. Denmark. The net energy system for growing pigs which was developed by Just (1975, 1982a) has been applied officially in Denmark since 1975. The net energy value is obtained after correcting ME which is itself calculated from digestible nutrients, by using tabulated proximate composition data and digestibility coefficients, in the following manner: M E (MJ kg -~ DM)=0.0215 D X P ÷O.0377 D X L +O.0173 (DXF + DXX)

with DXP, DXL and (DXF + DXX) in g kg-1 DM. N E (MJ kg -~ DM) =0.75 M E (MJ kg -1 D M ) - 1.88

NE is converted to feed unit (FEz) which is equivalent to the NE value of 1 kg of barley (85% DM), i.e. 7.72 MJ kg -1 (or 1845 kcal kg-1). Norway. The energy system for pigs is a modification of the Kellner NK~system (MSllgaard, 1929), the same as that used for cattle, but with digestibility coefficients directly measured on pigs. Energy unit used: Scandinavian fodder unit (SFUN)based on the net energy of 1 kg of barley with 85% DM. Calculation of energy value: N K F (MJ kg- 1) = 0.00937 D X P + b D X L + 0.0987 D X F + 0.02384 D X X

with b=0.02092 in grains and 0.02384 in oilseeds and feeds of animal origin. NKF value is corrected by value number (W): cereals, 0.95; bran, 0.90; feeds of animal origin: 1.00. Finland. The calculation of energy value for pigs is the same as that used in Denmark (Just, 1975), by using specific tables of feed composition and digestibility coefficients. The feed unit (ry) is the NE value of 1 kg of barley (60 kg hl-1): 8.26 MJ NE kg -1 as fed (86% DM) versus 7.72 MJ NE kg -~ (85% DM)

346

in Denmark. The calculated FU values are thus 6-7% lower than those corresponding to the original Danish tables. G.D.R. The Rostock system (Schiemann et al., 1971; Hoffmann and Schiemann, 1980) was developed in G.D.R. and is used in practice for pigs (Nehring et al., 1972; Beyer et al., 1986). NEFs (kJ kg- 1) = 10.7 D X P + 35.8 DXL + 12.4 (DXF + DXX) with digestible nutrients expressed as g k g - 1. Corrections are applied in the following cases: digestible disaccharides (sucrose, lactose) -0.63 kJ g-1; digestible monosaccharides (glucose) - 1.26 kJ g-1; digestible milkprotein + 4.19 kJ g-1; digestible milkfat-4.19 kJ g-1. The energy value is expressed in a specific unit: 1 E F t = 14.65 kJ NEFs, or 1 KEFs = 0.01465 NEFs. Romania. The Rostock system (Schiemann et al., 1971; Hoffmann and Schiemann, 1980) is applied for pigs and the NEFs value is converted directly to a specific feed unit (UNp which is equivalent to 1 EFs in G.D.R.), according to the following equation: UNp kg- 1= 0.00073 D X P + 0.00244 DXL + 0.00085 (DXF + DXX) with the digestible nutrients given in g kg - 1. Corrections kg- 1: sugar, - 0.043 UNp; milk fat, - 0.286 UNp; milk protein, +0.286 UNp; 1 UNp= 14.65 MJ EFs. ME value may be calculated directly from the digestible nutrients in the Rostock system: ME (MJ kg- 1) _- 0.02135 D X P + 0.03739 DXL +0.01440 DXF+O.O1708 D X X with digestible nutrients in g k g - 1 In feedstuffs with high fibre content (green forages or silage), 10% deduction is made from the calculated value (loss of energy as methane from fermentations in the hind gut). Requirements The Netherlands. Nutrient recommendations (amounts day-1 or kg-1 feed) are given for the different categories of pigs (C.V.B., 1983b). Pregnant sows: 20% increase in feed allowance during the last 4 weeks of pregnancy. Correction for environmental temperature: + 100 g extra feed (0.97 EW kg -1) per I°C below 18°C.

347

Lactating sows (160-210 kg W). Basis for feed supply (0.97 EW kg-1): 1% of liveweight of sow + 0.4 kg per piglet. Growing-finishing pigs: feeding scale according to W and mean ADG between 35 and 110 kg W (650, 700 and 750 g day- 1) on the basis of 3.10 kg feed kg-1 gain (feed energy value: 1.03 EW kg-1).

Belgium and Luxemburg. Similar to The Netherlands. Denmark. Average recommendations have been derived from feeding trials: they are expressed in daily amounts of FE~, DXP, digestible amino acids (lysine, methionine plus cystine, threonine) according to W (Anderson and Just, 1983; Just et al., 1983). Norway. See References. Finland. Based on practical feeding trials, the recommendations for fattening pigs are comparable to those applied in Denmark, although higher during the growing phase and lower during the finishing period. G.D.R. The requirements are estimated factorially (Hoffmann, 1983b; Boldman et al., 1984; Beyer et al., 1986). (1) In growing pigs, maintenance: 279 kJ NEF~ kg -1 W 0.75. Energy allowance (EFt) kg- 1W gain according to W and W gain from the data of Hoffmann and Wiesem~iller (1981). The calculation of energy requirement according to the factorial approach is described in Hoffmann (1983a). Tables provide daily amounts of energy (kEFs) according to W and ADG. (2) In sows, recommendations for pregnant sows are differentiated according to parity (gilts, multiparous sows), stage of pregnancy (up to 84 days, 85-115 days). For lactating sows, different recommendations are given depending on parity and litter size: primiparous gilts and multiparous sows, with 8.5 and 10 piglets per litter, respectively: per extra piglet, 0.17 kEF~. Romania. Daily amounts of ME (MJ), NE (MJ), UNp, DXP (g), lysine and methionine plus cystine, (1) for pregnant sows (first 85 days and last 30 days) and lactating sows (10 piglets per litter, 4-week lactation), according to W; (2) for growing-finishing pigs, according to W and expected average daily gain at a given W (Burlacu, 1983, 1985). References THE NETHERLANDS C.V.B. (Centraal Veevoederbureau), 1983a. C.V.B., 1983b. C.V.B., 1984.

348 Nehring, K., 1969. BELGIUM AND LUXEMBURG

Similar to the Netherlands. DENMARK

Andersen, P.E. and Just, A., 1983. Just, A., 1975. Just et al., 1983. Just, A., 1982a. NORWAY

Breirem, K., 1986. MSllgaard, H., 1929 G.D.R.

Beyer et al., 1986. Bolduan et al., 1984. Hoffmann, M., 1983. Hoffmann, L. and Schiemann, R., 1980. Hoffmann, L. and Weisemuller,W., 1981. Nehring et al., 1972. Schiemann, R., et al., 1971. ROMANIA

Burlacu, 1983. Burlacu, 1985. Hoffmann, L. and Schiemann, R., 1980. Schiemann, R. et al., 1971. PROTEIN SYSTEMS

The total amino acids (TAA) system, along with crude protein (XP), used in all European countries The digestible protein (DXP) system is used concurrently in several countries: U.K., F.R.G., The Netherlands, Denmark, Italy, Greece, Switzerland, Finland, Austria, G.D.R. and U.S.S.R.

U.K. and Ireland. Net protein requirement including maintenance and production is Nm (g)=0.15 kg W o.75. For growing pigs, the requirements are expressed on the basis of "ideal protein" (70 g lysine kg-1), with the following essential amino acids to lysine ratios: lysine/methionine plus cystine = 0.5; lysine/threonine = 0.6; lysine/tryptophan = 0.15. For sows, m i n i m u m requirements for pregnancy. Lactation: based on milk yield (57 g protein k g - 1); efficiency of utilization of DXP: 0.70. Maintenance: 0.45 g D X P k g - 1 W. Protein digestibility in standard diet: 0.80. F.R.G. and Austria. As for energy, protein requirements are calculated factorially through partitioning between maintenance and production.

349

IXP (g day -1) = (IXPm + R P ) / N P U Maintenance: IXPm-- from 16.2 g day -1 at 20 kg W to 30.6 g day -1 at 100 kg W. Retained protein (RP) day- 1 and NPU (net protein utilization for maintenance and protein deposition) values are tabulated. The requirements for essential amino acids (lysine, methionine plus cystine, threonine and tryptophan) are derived from protein, on the basis of 5.0% lysine in protein for growing pigs and the following ratios: lysine/methionine plus cystine, 0.6; lysine/threonine, 0.6; lysine/tryptophan, 0.2. The standard feed is a barley-soybean meal combination with 0.8 apparent digestibility value. Crude-protein recommendations are converted to DXP on that basis.

France. Protein and amino-acid recommendations are given in total amounts for a standard maize-soybean meal diet with 0.87 digestibility of crude protein. The ratios of essential amino acids to lysine for growing pigs are the following: lysine/methionine plus cystine, 0.6; lysine/threonine, 0.6; lysine/tryptophan, 0.18. Italy. In addition to total and digestible crude protein, and total amino acids, protein evaluation may be expressed in digestible lysine. Sweden. Crude protein and amino acids (lysine, methionine plus cystine, threonine, tryptophan, isoleucine) in g per MJ ME or per kg feed of a given energy content, for the different classes of pigs and W intervals. Finland. Protein requirements are expressed in DXP. G.D.R. As for energy, protein and amino-acid requirements are estimated factorially. (1) In growing pigs, protein and lysine requirements are calculated from maintenance, deposited protein and lysine content of deposited protein, i.e. 7.4 g per 100 g protein (Wiesemiiller, 1984). Tables provide daily amounts of DXP, lysine, methionine plus cystine according to W and ADG. (2) In sows, for pregnant sows, according to parity and stage of pregnancy (up to 84 days, 85-115 days). For lactating sows according to parity and litter size: primiparous gilts (8.5 piglets per litter) and multiparous sows (10 piglets per litter); per extra piglet, 45 g DXP with 2.7 g digestible lysine.

350

Systems based on available amino acids (AAA) used in The Netherlands and Denmark The Netherlands. Amino-acid availability for pigs is expressed in faecal digestibility. Tables are available, which give digestible values for lysine, methionine and cystine in a whole set of feedstuffs (C.V.B., 1984). Denmark. Amino-acid digestibility values are computed by multiplying the amino-acid content of feedstuffs by the apparent digestibility of crude protein. Tables have been derived which provide the calculated contents of digestible amino acids for a given feedstuff, along with digestible protein. References C.V.B., 1984

For references see those given under the heading of energy systems. Acknowledgements The followingcorrespondents and colleagues are sincerely acknowledgedfor providing the specific information, documents and references for their own countries: J. Leibetseder, Austria; N. Todorov, Bulgaria and U.S.S.R.; K. Simecek, Czechoslovakia; A. Just, Denmark; M. Tuori, Finland; H.J. Oslage and D. G~ideken,F.R.G., W. Wiesemtiller, G.D.R.; J. Gundel, Hungary; R. Scipioni, Italy; F. Sundstol, Norway; L. Buraczewska, Poland; G. Burlacu, Rumania; J. C. De Blas, Spain; S. Thomke and A. Simonsson, Sweden; H. Bickel, Switzerland; Y. van der Honing, The Netherlands; G. Alderman, U.K.; H. Zlatic, Yugoslavia.

Appendix B. Poultry General

Energy value of feedstuffs for poultry is (with the exception of two countries) expressed in metabolizable energy (ME) nearly everywhere. However, some modifications of ME assessment are used in various countries. Seven equations to predict ME from crude chemical composition and digestible nutrients are shown in Table A VII. Frequently the researchers who have developedthese equations are quoted under the heading "Nutritive value". Requirements

In contrast to the large farm animals, ruminants and pigs, energy and protein requirements are formulated for flocks instead of individual animals. Re-

351 TABLE A VII

Equations used for ME prediction in different European countries (equations converted to kJ: nutrients: g k g - ~ feed) ME (kJ k g - 1) M E , (kJ kg 1) M E , (kJ kg 1) ME (kJ kg -1) ME (kJ kg -~) M E , (kJ kg -~) MEn (kJ kg -~)

= 2 2 2 + 159 (XP+2.25 X L + 1.1 S + Z ) = 14.74XP + 32.87 XL + 17.17 S + 14.86 Z =15.51 XP+34.31 X L + 16.69 S + 13.01 Z = 16.08 D X P + 39.06 D X L 1+8.79 D X F + 17.58 DXX 2 = 17.84 D X P + 39.78 D X L + 17.71 ( D X F + D X X ) = 19.3 DXP3 + 34.8 D X L 4 + 14.7 DXF + 16.7 DXX = 18.34 D X P + 3 8 . 7 7 D X L + 17.29 ( D X F + D X X )

(Carpenter and Clegg, 1956) (Sibbald et al., 1963) (W.P.S.A. equation, 1985) (E.E.C.) (Titus, 1961) (Chudy and Schiemann, 1971) (Eriksson et al., 1976) (Hiirtel et al., 1977)

~39.73 for fish and meat meals, 38.56 for milk and milk products. 216.75 for beans and oil plants, 15.91 for alfalfa meal and dehydrated grass, 15.49 for sugar and animal products. :~18.4 for forages, 19.3 for concentrates incl. fish and meat meal, 19.7 for milk, dairy products. 432.7 for silages and other forages, 34.8 for grass, 36.9 for oilseeds, 39.0 for feeds of animal origin.

quirements are therefore normally given as nutrients per kg of feed. Extensive recommendations on required nutrient density for various production stages of starters, broilers and laying hens are tabulated, e.g. by Vogt (1988). Also data for a factorial approach of energy and protein requirements are available (Vogt, 1987b). The energy requirement varies considerably according to body composition, individual activity, housing system, feather cover and ambient temperature.

Energy requirement (MEn) Energy requirement for maintenance, (1) broilers, 420 kJ per W o.75, range: 300-510 kJ per W o.70; (2) laying hens, light weight, white eggs: 490 kJ per W o.70;heavy weight, brown eggs: 460 kJ per W 0.75;range: 314-717 kJ per W o.75. Energy requirements for production, (1) broilers, NE content of body mass is 6-12 kJ g- 1, efficiency of ME utilization for protein (k~) is 0.41-0.64 and for fat (kf) 0.70-0.94; (2) laying hens, NE content of 1 g egg is 6.7 kJ, efficiency of ME for egg production is 0.7.

Energy requirement (NEF) Energy requirement for maintenance, laying hens on floor, 356 kJ NEFh per W 0.75; laying hens in cages, 341 kJ NEFh per W 0.75. Energy requirement for production, 8.375 kJ NEFh per 1 g egg output.

Protein requirement Protein requirements also vary considerably partly for the reasons quoted for energy requirements. Protein requirement for maintenance, (1) broilers, 1.6 g protein per 1 kg W; (2) laying hens, 2.2-3.5 g protein per W o.75 Protein requirement for production, (1) broilers, protein content of 1 g body weight (without feathers) is 0.18 g and of 1 g feather is 0.82 g, efficiency of utilization of XP for protein production decreases with the age from 0.67 to

352 0.60; (2) laying hens, protein content of I g egg is 0.1125 g, efficiency of utilization of XP for protein production is 0.45.

References Jeroch, H. and Hoffmann,L., 1983. Vogt, H., 1987. Vogt, H., 1988. ENERGY SYSTEMS

Metabolizable energy (ME) system used in Bulgaria, Czechoslovakia, Denmark, Greece, Ireland, Spain, Sweden, U.S.S.R., Turkey and Poland Nutritive value In Bulgaria (Alexiev and Stoianov, 1984) until 1975, ME was calculated using the equation of Titus (1961), since 1975 the Chudy and Schiemann (1971) equation has been preferred. In Czechoslovakia the equation of Titus (1961), in the U.S.S.R. (Kalashnikova and Klejmenova, 1985), the equation of Chudy and Schiemann (1971) and in Turkey the equation of Carpenter and Clegg (1956) are used for calculating the ME values of the diets. The formula in parentheses of the equation of Carpenter and Clegg (1956) was used in F.R.G. for many years (DLG-German Agricultural Society since 1972, Federal Ministry of Agriculture since 1979) for the control of the energy content of poultry compound feeds (as "Energiemesszahl" or "Energiezahl Gefliigel", EZG). ("Energy index poultry").

References Alexiev,A. and Stoianov,V., 1984. Carpenter, K.J. and Clegg,K.M., 1956. Chudy, A. and Schiemann,R., 1971. Kalashnikova,AP. and Klejmenova,N.I. (Editors), 1985. Titus, H.W., 1961. Personal communications,1987 from: V. Peter, Czechoslovakia;H. Vogt, Federal Republic of Germany;J. CastelloLlobet, Spain; A. Hatzipanagiotori,Greece;M.F. Maguire,Ireland; S.A. Svensson,S. Thomke and K. Elwinger,Sweden;M. Zincirliogly,Turkey;J. Ziolecki,Poland.

Metabolizable energy, N-retention = 0 (MEn) system used in Austria, Belgium, Cyprus, Denmark, F.R.G., Finland (since 1982), France (only adult chicks), Hungary, Luxemburg, Norway (since 1986), Sweden, Switzerland, The Netherlands, U.K. (A.R. C.) and Yugoslavia Nutritive value In Austria and Yugoslavia the equation of Sibbald et al. (1963) is used for calculating the ME value in the rations. In F.R.G. the ME content of rations and single feedstuffs is calculated with the equation of Sibbald et al. (1963) and H~irtel et al. (1977). In Sweden, the same equation containing digestible nutrients is applied for pigs and poultry. In The Netherlands, for the calcula-

353 tion of the ME value of single feedstuffs, J a n s s e n and Terpstra (1972) developed a special system: they use equations of corrections or correction factors for differences in the nutrient content of feedstuffs; a new common European Energy table was calculated on this basis by W.P.S.A. The use of the new W.P.S.A. Equation (1985) or E.E.C.-Equation (Directive 86/542-/E.E.C. of 09.04.86) has started in Denmark (01.02.1987), F.R.G. (03.01.1987), Switzerland, Turkey, U.K. (1987) and is under discussion in Austria.

References A.R.C. (Agricultural Research Council), 1975. F~infte Verordnung zur ~.nderung der Futtermittelverordnung vom 2. Januar 1987. H~irtel et al., 1977. Janssen, W.M.M.A. and Terpstra, K., 1972. Jeroch, H. and Hoffmann, L., 1983. Leclercq et al., 1984. Sibbald et al., 1963. W.P.S.A. equation, 1985. W.P.S.A., 1986. Personal communications, 1987 from: A. Wallig, Austria; G. de Groote, Belgium; H.P. Guler, Switzerland; K. Charalambous, Cyprus; A. Larsen, Denmark; G. Baroesa, Hungary; E. Wagner, Luxemburg; O. Herstad, Norway; W.M.M.A. Janssen, The Netherlands; S.A. Svensson, S. Thomke and K. Elwinger, Sweden; T. Kiiskinen, Finland; J. Stekar and F. Locniskar, Yugoslavia.

Remarks The N-corrected metabolizable energy (MEn) system, corrected to 0.30-0.40 nitrogen retention is in use in France (Leclercq et al., 1984) (chicks up to 21 days: 0.40 N-retention; pullets and layers after 21 days: 0.30 N-retention) and in Italy (the French system). Until 1985 the Norwegians corrected the M E values to 0.33 N-retention. In Sweden for direct determination of M E a correction to 0.33 N-retention is used (Eriksson and Hartfiel, 1967).

References Eriksson, S. and Hartfiel, W., 1967. I.N.R.A., 1984. Personal communications, 1987 from: G. Giordani, Italy; O. Herstad, Norway.

Net energy for fat formation (NEF) system used in G.D.R. and in Romania Nutritive value In the G.D.R. the equation of Chudy and Schiemann (1971) is applied.

NEFh (kJ kg-1) = 10.8 D X P + 33.5 DXL + 13.4 (DXF + DXX) with digestible nutrients expressed as g kg - 1.

354

The energy value is expressed in a specific "Energetische Futtereinheit (Energy feed unit: EFh)

1 EFh = 14.65 kJ NEFh = 0.74 DXP+ 2.28 DXL+ 0.91 (DXF+ DXX) Corrections are applied in the following cases: digestible disaccharides: - 0.63 kJ g-1 or -0.043 EFh; digestible monosaccharides: -1.26 kJ g-1 or -0.086 EFh; digestible milk protein: +4.19 kJ g-1 or +0.286 EFh; digestible milk fat: - 4 . 1 9 kJ g-~ or -0.286 EFh. In Romania the feed unit used (Unitablitor nutritive) UNa is equivalent to 1 EFh in the G.D.R.

References Chudy, A. and Schiemann, R., 1971. PROTEIN SYSTEMS

The crude protein (XP) system used in all European countries except The Netherlands In addition, digestible protein is sometimes used in Belgium, Bulgaria, F.R.G., G.D.R., Hungary, Norway and Switzerland. In The Netherlands only the amino acids are considered for protein evaluation of poultry feeds. In Denmark protein evaluation is based on crude protein, plus methionine, cystine and lysine. In addition, standard energy-protein ratios are recommended in Czechoslovakia, Denmark, G.D.R. and the U.S.S.R.

Amino acids Almost all European countries use both protein and total amino acids; only in The Netherlands, Belgium and Luxemburg are available amino acids used in addition. The amino acids methionine, methionine plus cystine and lysine are included in official or semi-official requirements or recommendations in 16 of the 24 consulted countries. In 10 countries tryptophan, arginine and threonine are also given and the remaining amino acids in 2 to 7 countries. Acknowledgements The following colleagues are acknowledged for providing the information from their countries: A. Walling, Austria; G. de Groote, Belgium; N. Todorov, Bulgaria (also for the information from the U.S.S.R.); K. Charalambous, Cyprus; V. Peter, Czechoslovakia; A. Larsen, Denmark; T. Kiiskinen, Finland; H. Vogt, F.R.G.; B. Leclercq, France; H. Jeroch, G.D.R.; A. Hatzipanagiotou, Greece; G. Baroesai, Hungary; M.F. Maguire, Ireland; G. Giordani, Italy; E. Wagner, Luxemburg; O. Herstad, Norway; J. Ziolecki, Poland; J. Castello Llobet, Spain; K. Elwinger, Sweden; H.P. Guler, Switzerland; W.M.M.A. Janssen, The Netherlands; M. Zincirlioglu, Turkey; C. Fisher, U.K.; J. Stekar and F. Locniskar, Yugoslavia.

Livestock ProductionScience, 19 (1988) 355-367

355

Elsevier SciencePublishers B.V., Amsterdam-- Printed in The Netherlands

III. 5. F u r - B e a r i n g Animals

ANNE-HELENE TAUSON

INTRODUCTION The mink (Mustela vison), the blue fox (Alopex lagopus) and the silver fox ( Vulpes fulva) are the main species in fur-animal production. Being carnivorous animals, these species are generally raised on diets based on by-products of animal origin, e.g. offal from the fishing industry and from abattoirs. By using products of less processing value to other domestic animals, fur-animal production is complementary to conventional animal production. The digestive tract of fur-bearing animals is very short, the length of the intestine being only 4 times the body length in mink and foxes. The rate of passage of feed through the digestive tract is rapid, especially in the mink, where it usually ranges from 1 to 4 h. In the fox, the first defecation takes place 6-8 h after feeding, and digestion is considered to be completed after 24-30 h ( P~reldik, 1975 ). Thus, the digestion in fur-bearing animals is not adapted to feedstuffs high in fibre content, and microbial digestion is of little importance. Moreover, because of a rapid kit growth rate, the concentration of nutrients should be high in order to meet the nutrient requirements. The digestibility and energy content of feedstuffs used for fur-bearing animals are evaluated in digestibility trials. The short digestive tract of the mink means that relatively short collection periods are sufficient. In the Nordic countries, digestibility trials with mink are carried out mainly by quantitative methods, with collection periods lasting 3-4 days (Glem Hansen and Jorgensen, 1977; Skrede, 1978a). The digestibility of the experimental feedstuff in a diet is evaluated by regression analysis. A few digestibility trials have also been carried out by the acid-insoluble ash method ( Kiiskinen, 1981 ). In Chapter II.2 (Lee, 1988), various classes of feedstuffs are considered of which only those with a high protein content and low fibre content, and preferably those with a high energy density in dry matter (DM), are useful in furanimal nutrition. Table I contains some examples of such feedstuffs, their apparent nutrient digestibility for mink and their metabolizable energy (ME) content. The data are adapted from N.J.F. (1985).

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© 1988Elsevier SciencePublishersB.V.

356 TABLE I Feedstuffs for fur-bearing animals; apparent digestibility and ME (MJ kg -1 DM) for mink (adapted from N.J.F., 1985) Apparent digestibility ( % ) Protein

Fat

90 90 90 90

92 92 92 92

16.74 17.70 20.23 21.97

89 84 79 72

92 92 90 88

15.24 12.52 11.30 9.42

Filleting scrap from herring 5-8% fat > 8% fat

85 85

92 92

19.26 22.36

Slaughter offal, cattle Rumen Mixed soft offal, 10% fat Liver

85 83 92

73 72 85

22.00 17.59 18.40

Slaughter offal, swine Throats Hide Backbone Cracklings

85 92 55 90

87 94 94 85

23.48 27.25 15.35 18.76

Poultry waste Mixed chicken offal Whole laying hens Blood

76 60 90

85 85

20.31 17.61 15.25

87 82

88 88

16.85 16.11

75 65 55 60 91 78 85 86

75 75 75 89 54 54

24 14 73

11.40 10.43 9.45 12.25 16.77 9.72 12.15 15.13

79 79 69 69 72 72 77 70

74 74 55 55 90 90

43 73 52 66 47 52 79 75

8.74 12.93 9.63 11.58 10.01 10.69 12.95 12.20

Whole fish Cod Industrial fish, < 5% fat Industrial fish, 5-8% fat Industrial fish, > 8% fat Offal from lean fish Low bone content, 3% ash Medium bone content, 5% ash High bone content, 7% ash Very high bone content, 9% ash

Dried protein feedstuffs Fish meal, low temperature Fish meal, fur animal quality Meat-and-bone meal Careful drying Normal drying Severe drying Feather meal, hydrolyzed Blood meal Soya bean meal Soya protein concentrate Potato protein Carbohydrate-rich feedstuffs Wheat Wheat, gelatinized Barley Barley, gelatinized Oats Oats, gelatinized Potatoes, cooked Potato mash powder Fat-rich feedstuffs Soy oil Fish oil Lard Tallow

96 94 85 70

Carbohydrate

85

ME

38.18 37.39 35.80 30.21

357 FEED EVALUATION

General The general approach to evaluation of feedstuffs, described in Section III.1 (Bickel, 1988) of this chapter, applies also to fur-bearing animals. Metabolizable energy ( ME ) is the energy unit most used for expressing energy allowances for fur-bearing animals. About 72-85% of the gross energy (GE) of fur-animal diets and feedstuffs is metabolized (National Research Council, 1982 ). The ME content of a feedstuff or diet can be calculated from chemical composition data and nutrient digestibility by use of ME coefficients. The following values are used per gram of digestible nutrient: protein 18.83 kJ (4.5 kcal); fat 38.93 kJ (9.3 kcal, Finland, Norway, Sweden); 39.76 kJ (9.5 kcal, Denmark);carbohydrates 17.16 kJ (4.1 kcal, Finland, Norway, Sweden ); 17.58 kJ ( 4.2 kcal, Denmark).

Fat Fat is a major source of energy in rations for fur-bearing animals. It also provides the essential fatty acids, linoleic acid, linolenic acid and arachidonic acid, and is a carrier for fat-soluble vitamins. Fat is deposited in large amounts in the body mainly as subcutaneous fat, the amount of which may be about 0.5 kg in mink at pelting. Other fat depot sites are the region around the kidneys and around the intestine. Fat digestibility is influenced by chain length of the predominating fatty acids in it and also by degree of unsaturation. The level of some minerals in the ration can also affect fat digestibility. In general, unsaturated fatty acids are highly digestible and saturated fatty acids have lower digestibility, but in both cases there is a fairly wide variation in digestibility depending on the source of the fatty acids (Table II ). Increased levels of different calcium salts may impair fat digestibility. The digestibility of lard was decreased by 2-5 units when the amount of CaHPO4, Ca3 (PO4) 2, CaC03 or bone meal was elevated from 3 to 9 g animal-1 day-1 (Ahman, 1976). Hydrogenation of fish oil in order to prevent rancidity occurring has a detrimental effect on fat digestibility. When capelin oil was hydrogenated to different melting points, the fat digestibility declined with increasing melting point of the fat (Table II; Austreng et al., 1979).

Carbohydrates The carbohydrates represent a very diverse group of nutrients regarding chemical composition. Although no actual requirement exists, carbohydrates

358 T A B L E II Apparent digestibility (%) in mink of total lipids and individual fatty acids of various origin (adapted from Ahman, 1976, and Austreng et al., 1979) Cattle tallow 1

Lard 1 Soya bean Cod liver Capelin Hydrogenated capelin oil oil 2 oil 2 oil 2 of different melting points 2 21°C

Totallipids Fatty acid 3 14:0 16:0 16:1 18:0 18:1 18:2 18:2÷20:0 18:3 20:1 20:5 22:0 22:1 22:6

33°C

41°C

69

85

96

94

94

91

84

67

88 62 98 41 85 97

94 90 98 58 90 95

95 94 97

87 90 93 88 95

96 89 91 77 94

95 85 85 77 90

93 76 82 70 78

88 50 59 46 53

99 100 -

75

85 99 100 99 100

61

48 92 96 96 -

43 83 84 91 -

97 100 99 97 100

97 100 99

1Data from ~,hman (1976). 2Data from Austreng et al. (1979). 3Number of carbon atoms: number of double bonds.

are widely used in diets for fur-bearing animals. For nursing kits lactose is of great importance, and for weaned kits and adult animals mono- and disaccharides and starch are the major carbohydrate sources. Crude fibre is almost indigestible, and the amount of fibre in the diet may affect the consistency of faeces. Mono- and disaccharides are highly digestible. For adult animals, however, the ability to digest lactose is decreased and only very limited amounts of lactose can be used. Untreated starch is poorly digested by mink, but the digestibility can be improved by heat treatment in order to gelatinize the starch. Completely gelatinized starch can be almost 100% digestible, depending on the origin of the starch. Since purified starch is seldom fed, the digestibility of the total carbohydrate fraction or of the nitrogen-free extract (NFE) fraction is of greater interest. In experiments on the digestibility of the carbohydrates of barley, maize, oats and wheat it was significantly improved by cooking. The carbohydrate digestibility was most improved in maize and wheat (69% and 75% digestibility, respectively, after cooking (Jorgensen and Glem Hansen, 1973 ) ). Compounds like pentosans and fibre are almost indigestible and may, if fed in excess, be disadvantageous for overall digestion. Some data on carbo-

359 hydrate digestibility are presented in Table I. Fineness of grinding is another factor that affects the digestibility of carbohydrates in cereals. The finer the grinding, the higher the digestibility of the carbohydrate fraction of the cereals ( Glem Hansen and S~rensen, 1981 ). Foxes digest carbohydrates far mo]~e efficiently than mink, at least from 8 to 10 weeks of age. Therefore uncooked cereals can be used in rations for foxes.

Protein

The digestibility of protein is of great importance in feedstuff evaluation. It may vary considerably between different protein sources and as an effect of processing. For fish products with low bone content the protein digestibility is usually very high. With increasing ash content, however, the digestibility decreases and Skrede (1978a) found the following linear relationship between ash content in DM and apparent protein digestibility (DXP) for 38-week-old standard male mink: y = 9 7 . 9 - 0.595x; r = 0.997"**, where y = percent DXP and x = ash content in DM. In fish meal protein digestibility is also highly dependent on the ash content. However, bone protein from fish products is considerably more digestible for mink than is bone protein from cattle or swine ( see Table I). For the blue fox, however, protein digestibility of meat-and-bone meal is about 80%. Processing may also influence the protein availability, and reduced protein digestibility due to heat damage may occur (see Table I). In vegetable protein feedstuffs, N-digestibility varies with source and treatment. Some examples are given in Table I. In recent years, investigations into the digestibility of amino acids for mink have started. Some of the results indicate that the digestibilities of the amino acids in cod fillet are very high, and there were only minor differences between the amino acids. In raw filleting scrap, on the other hand, the digestibilities of all the amino acids except tryptophan were significantly lower than in cod fillet, and the digestibilities varied considerably between the amino acids. In meat-and-bone meal the amino-acid digestibilities were widely dispersed and, on average, very low. The poorest digestibility was found for cystin, the digestibility of which ranged from 20 to 33% depending on the protein level fed. Thus it seems that amino-acid digestibilities do not diverge much from Ndigestibility in highly-digestible feedstuffs, but can be very dispersed in feedstuffs of low N-digestibilities ( Skrede, 1979a, b). A few amino-acid digestibility trials have been carried out on blue fox, and the results suggest that feedstuffs with poor digestibility are better utilized by the fox than by the mink ( Skrede et al., 1980).

360 ENERGY AND NUTRIENT REQUIREMENTS

Standards Feeding standards for fur-bearing animals have been worked out by the National Research Council (National Research Council, 1982 ) and by the Scandinavian Association of Agricultural Scientists (N.J.F., 1985; Rimesl~tten, 1964a). The N.R.C. standards are minimum requirement standards for practical purposes, intended to achieve normal growth rate, reproduction, production and health, b u t with no consideration given to safety margins. The N.J.F. standards are standards for practical purposes. Variation in chemical composition of feedstuffs, differences in genetic capacity between breeds of animals and the effect of climate and housing system have therefore been considered when evaluating the requirements for different nutrients. Using rations with a chemical composition within the ranges of the N.J.F. standards should thus guarantee normal production. The N.J.F. standards are used in all the Nordic countries, b u t with some modifications from country to country.

Energy Data regarding the energy requirement of fur-bearing animals are mainly based on production experiments. The M E requirement for maintenance (MEre) is dependent on factors such as the activity of the animals and ambient temperature. Investigations into the MEre requirement of mink suggest a conTABLE III MEm requirement of mink Stage of life/sex

Experimental technique

Growth Growth1 Growth2 Adult

Slaughter Slaughter Slaughter Respiration chamber, +20°C Adult Balance studies, restricted activity Adult, male Production experiments Adult, female Production experiments 1Beginning of July. 2August pelting.

MEm daily

Reference

618.6 kJ kg-°734 628 kJ kg- 1 712-732 kJ kg- 1

Harper et al., 1978 Enggaard Hansen et al., 1981 Enggaard Hansen et al., 1981

527 kJ kg-°'75

Glem Hansen and Chwalibog, 1980

540-712kJ kg-1

P~reldik and Titova, 1950

1000-1264 kJ

Rimesl~tten, 1964b

770-795 kJ

Rimesl~tten, 1964b

361 siderably higher maintenance-energy requirement t h a n for other domestic animals. Some results are quoted in Table III. The energy requirement for regulation of body temperature is of great importance for mink because the animals are exposed to a wide variation in ambient temperature. At temperatures ranging from + 22 to - 3 ° C it was shown t h a t the heat production increased linearly at the rate of 12.1 kJ kg -°75 per °C reduction in temperature (Glem H a n s e n and Chwalibog, 1980). An increase in daily intake of digestible energy (DE) of more t h a n 25% in experiments where the cage size was approximately doubled (Farrell and Wood, 1968a, b) indicates t h a t a considerable a m o u n t of the total additional energy is used for muscular activity. The energy requirement for gestation is considered to be very low in mink. The moderate rise in energy requirement towards the end of gestation is often compensated for by decreased activity in the female. In lactation, the energy requirement is related to litter size and age of offspring, and calculations by Glem H a n s e n (1981) suggest an average requirement of about 57 kJ kit -1 d a y - 1 for the first 24 days of lactation. Rimesl~tten's (1964b) data have been used when formulating the N.J.F. energy allowances which are presented in Table IV. Practical experience confirms t h a t these allowances are well suited to the animals' requirements. The energy requirements of the silver and the blue fox are less well-known t h a n those of the mink, and vary with seasonal changes in body weight of the adult silver fox (Table V; Rimesl~tten, 1978). Assuming an energy allowance TABLE IV Energy allowances for mink (kJ ME animal-~ day-1) recommended by N.J.F. (Rimesl~tten, 1964b ) Adult mink

December-February March-May 1-15 June 16-30 June 1-15 July 16-31 July 1-15 August 16-31 August September October November

Kits

Males

Females

1170 1090 1090 1090 1050 1050 1050 1050 1130 1340 1300

880 840 840 840 840 840 800 800 920 1000 960

Males 1000 1300 1510 1550 1590 1590 1380

Females 750 960 1090 1130 1170 1170 960

Average 290 670 880 1130 1300 1340 1380 1380 1170

~Supplementation for lactating females: 1-2 weeks of lactation, 40-80 kJ kit- 1day- ~;3-4 weeks of lactation, 130-210 kJ kit -~ day-1.

362 TABLE V Average body weight and daily energy allowances (kJ ME) for adult and growing silver foxes1 (Rimesl~tten, 1978) Month/age

Adults December January February March April May June July August September October November Kits 3 2-3 Months 3-4 Months 4-5 Months 5-6 Months 6-7 Months 7-8 Months

Body weight (kg) Males

Females

6.7 6.7 6.5 6.0 5.7 5.5 5.4 5.5 5.6 5.8 6.2 6.6

5.5 5.5 5.4 5.2 (5.0) 2 (4.8) 2 4.6 4.6 4.7 4.8 5.1 5.4

Daily energy consumption (kJ) Kits

1.80 3.00 4.10 5.00 5.75 6.O0

Males

Females

2340 2180 1930 1800 1880 2130 2300 2390 2510 3680 2760 2640

2050 1970 1800 1670 1760 1970 2130 2180 2260 2300 2430 2340

Kits

1880 2470 2635 2760 2340 2O5O

1Energy consumption of adults calculated on data from silver fox and blue fox and may therefore diverge from the requirement of the silver fox for some periods. 2Barren females. 3Kit liveweights at the beginning of each month. for t h e l a c t a t i n g silver fox female o f 2300 k J M E d a y - 1 , t h e e n e r g y r e q u i r e m e n t of t h e kits d u r i n g t h e first 8 weeks o f life c a n be c a l c u l a t e d a c c o r d i n g to t h e following linear regression b a s e d o n R i m e s l ~ t t e n ' s (1978) data: y= 1 2 2 5 x - 151; r = 0.99***, w h e r e y = daily e n e r g y r e q u i r e m e n t in k J a n d x = b o d y weight in kg. T h e p o s t - w e a n i n g e n e r g y r e q u i r e m e n t o f silver fox kits is q u o t e d in T a b l e V. F o r blue fox kits R i m e s l ~ t t e n (1976) suggests a n average e n e r g y r e q u i r e m e n t of a p p r o x i m a t e l y 80 k J g - 1 g r o w t h over t h e t o t a l g r o w t h period.

Energy density D i e t a r y e n e r g y d e n s i t y for m i n k can v a r y over a wide range b e t w e e n 4000 k J a n d 7000 k J o n a wet basis, c o r r e s p o n d i n g to a p p r o x i m a t e l y 15 0 0 0 - 1 9 000 k J k g - 1 D M , d e p e n d i n g m a i n l y o n D M a n d fat c o n t e n t . F o r diets o f good palatability t h e m a i n r e g u l a t i o n o f feed i n t a k e occurs o n a n e n e r g y basis. T h u s , m o r e

363

of a low density diet is consumed than of one of high energy density. Lactating females and their litters perform badly on low-density diets. Also, after weaning, in the period of rapid growth, a high energy density is preferable. In early lactation 16.0 MJ ME kg-1 DM seems sufficient to support normal kit growth rate, but when the kits start to consume feed the energy density should be increased to a m i n i m u m of 17.3 MJ ME kg -1 DM. However, no beneficial effect on kit or female performance has been found at energy density levels above 18.8 MJ ME kg-1 DM (Tauson, 1986). For silver foxes recommended minimum energy densities for kits older than 10-12 weeks are 12.6 MJ kg -1 DM, for adults 12.1 MJ kg -1 DM and for lactating females 14.6 MJ kg -1 DM (Rimesl~tten, 1978).

Fat and carbohydrate Diets for mink are generally high in fat content. The minimum requirement of fatty acids is not known, but N.R.C. (1982) suggests the minimum level of linoleic acid to be about 0.5% of DM for adult animals, and 1.5% for pregnant and lactating females and young growing kits. Using conventional feedstuffs for mink these levels are often exceeded, and cases of deficiency are rare. For the silver fox, the total minimum amount of the essential fatty acids (linoleic, linolenic and arachidonic acid) recommended by N.R.C. (1982) is 2-3 g animal- 1 day- 1. Carbohydrates are useful energy sources, but maximtim recommended carTABLE VI Fat and carbohydrate allowances for mink and blue foxes as recommended by N.J.F. (Rimesl~tten, 1964a) Period

Mink December-whelping Whelping-15 July 15 July-15 September 15 September-pelting Blue fox December-whelping Whelping-8 weeks of age of the kits 8-14 weeks of age of the kits 14 weeks of age of the kits-pelting

Percent ME from Fat

Carbohydrate

25-40 35-50 30-45 30-45

15-30 10-20 15-30 20-30

20-30

30-40

30-45

20-25

25-40

20-35

25-40

30-40

364 bohydrate levels can be fed to mink only after proper heat treatment of the cereals. Being rather low in energy density, carbohydrate-rich feedstuffs can be used to dilute highly-concentrated diets. The N.J.F. allowances regarding fat and carbohydrate are given in Table VI. Protein Determination of the minimum protein requirement for fur-bearing animals is very difficult owing to the animals' carnivorous nature. Low-protein diets are usually very unpalatable, and this often results in feed refusals. Data from N-balance studies are available, but problems with N-losses during collection often occur. Protein standards for fur-bearing animals are mainly based on data from production trials. The protein requirement is usually expressed as a percentage of ME in the diet. When expressing the nutrient requirement as a percentage of ME, animals consuming a lesser amount of a high-energy diet are supplied with the same amount of protein as animals consuming a larger ration of a low-energy diet. Even if this method is used to express protein allowances, a minimum amount of protein per animal per day ought to be stated for situations when the animals are fed restricted diets. As previously mentioned, strict minimum levels for the protein requirement of mink are not known. The standards used (Table VII) are based on experimental evidence, and also to some extent on observations in practice and on economical aspects. The N.R.C. (1982) value for maintenance is probably above the real minimum requirement but, on the other hand, mink rations so low or still lower in protein probably do not appear in practice because of low palatability. Owing to the high content of cystin in hair, the sulphur-containing amino acids are those most likely to be limiting in mink diets in the furring period. Maximum protein utilization has been found when the content of sulphurcontaining amino acids was 5.5 g/16 g N ( Glem Hansen, 1976), and based on this and on further research work it has been concluded that the maximum requirement for sulphur-containing amino acids occurs between 20-24 weeks of age, and that it amounts to 4.6-5.1% of the total protein fed (Glem Hansen, 1980). Other data largely support these results, but suggest the requirement of methionine and cystine to be 7.2 g/100 kJ ME from 1 September until pelting (Skrede, 1978b, 1981 ). For adult silver fox females, protein levels below 19-22% of DM were found detrimental to health and normal fur development. Before priming, protein levels of 13-16% of DM were supposed to be sufficient to maintain body weight. During lactation, however, protein levels lower than 25% of DM resulted in poor kit growth. Experiments with growing kits suggest that 28% protein in DM achieved normal growth between 50 and 161 days of age, but it was not sufficient for maximum N-retention. Between 162 and 259 days, 19-25%

365 TABLE VII The protein requirement of the mink and blue fox as recommended by National Research Council (1982) and N.J.F. (Rimesi~tten, 1964a) Standard

Mink N.R.C.

N.J.F.

Blue fox N.R.C.

N.J.F.

Stage of life/ period

Protein requirement g DXP/100 kJ

Percent of ME

Maintenance Gestation Lactation Early growth (9-13 weeks) Late growth (13-30 weeks ) Fur development (16-30 weeks) December-whelping Whelping-15 July 15 July- 15 September 15 September-pelting

1.1 1.9 2.1

20 35 40

1.9

35

1.6

30

1.9 2.2-2.61 2.2-2.6 2.2-2.6 1.9-2.4

35 40-50 40-50 40-50 35-45

Maintenance Gestation Lactation Early growth (7-16 weeks) Late growth and fur development (16 weeks-maturity) December-whelping Whelping-8 weeks of age of the kits 8-14 weeks of age of the kits 14 weeks of age of the kits-pelting

1.1 1.6 1.6

20 30 30

1.6

30

1.3

25 35-45 40-50 35-45 30-40

1Minimum 18 g DXP female -1 day -1. p r o t e i n in D M w a s c o n s i d e r e d to c o v e r t h e r e q u i r e m e n t for g r o w t h a n d fur d e v e l o p m e n t ( R i m e s l f i t t e n , 1978). F o r t h e b l u e fox t h e d i s c r e p a n c y b e t w e e n t h e N . J . F . ( R i m e s l f i t t e n , 1964a) a n d t h e N . R . C . (1982) p r o t e i n a l l o w a n c e s is c o n s i d e r a b l e , b u t t h e l a t t e r is m a i n l y b a s e d on e x t e n s i v e , m o r e r e c e n t w o r k b y R i m e s l f i t t e n (1976). T h e p r o t e i n levels r e c o m m e n d e d b y N . R . C . (1982) are t h e r e f o r e also a p p l i c a b l e for p r a c t i c a l feeding.

366 REFERENCES ]khman, G., 1976. Studier av fodermedlens n~iringsviirde och anv~indbarhet till mink. Del. II. Report No. 45, Department of Animal Husbandry, Swedish University of Agricultural Sciences, 153 pp. Austreng, E., Skrede, A. and Eldegaard, ]k., 1979. Effect of dietary source on the digestibility of fat and fatty acids in rainbow-trout and mink. Acta Agric. Scand., 29:119-126. Bickel, H., 1988. Feed evaluation and nutritional requirements. 1. Introduction. Livest. Prod. Sci., 19: 211-216. Enggaard Hansen, N., Glem Hansen, N. and Jorgensen, G., 1981. Energiomsaetningen hos mink vurderet ud fra slagteforsog. Scandinavian Association of Agricultural Scientists, Forssa, Finland, 15 pp. Farrell, D.J. and Wood, A.J., 1968a. The nutrition of the female mink (Mustela vison). I. The metabolic rate of the mink. Can. J. Zool., 46: 41-45. Farrell, D.J. and Wood, A.J., 1968b. The nutrition of the female mink (Mustela vison). II. The energy requirement for maintenance. Can. J. Zool., 46: 47-52. Glem Hansen, N., 1976. The requirement for sulphur containing amino acids for mink in the growth period. The First International Scientific Congress in Fur Animal Production, Helsinki, 17 pp. Glem Hansen, N., 1980. Minkens behov for protein gennem vaekstperioden. I. Dan. Pelsdyravl, 43: 219-221. Glem Hansen, N., 1981. Normer for minkens energiforsyning baseret pA de i produktionscyklus forekommende livsytringer. Post-graduate course in fur animal nutrition, Tune Landboskole, Denmark, 1981, 15 pp. Glem Hansen, N. and Chwalibog, A., 1980. Influence of dietary protein energy levels and environmental temperature on energy metabolism and energy requirement in adult mink. The Second International Scientific Congress in Fur Animal Nutrition, Vedbaek, Denmark, 10 pp. Glem Hansen, N. and Jorgensen, G., 1977. Fordejelighed of kemisk sammensaetning af fodermidler til mink. Dan. Pelsdyravl, 40: 251-252. Glem Hansen, N. and Serensen, P.B., 1981. Bor kornet finformales? Dan. Pelsdyravl, 44: 295-297. Harper, R.B., Travis, H.F. and Glinsky, M.S., 1978. Metabolizable energy requirement for maintenance and body composition of growing farm-raised male pastel mink (Mustela vison). J. Nutr., 108: 1937-1943. Jorgensen, N. and Glem Hansen, N., 1973. Kornarternes fordojelighed efter forskellig behandling. Forsogslaboratoriets Arbog, Afdelingen for forsog med pelsdyr, Kobenhavn, pp. 285-288. Kiiskinen, T., 1981. Sm~iltbarhetsfdrsSk reed proteinfodermedel, j~imfdrande av tvA olika metoder. Scandinavian Association of Agricultural Scientists, Forssa, Finland, 12 pp. Lee, J., 1988. Feedstuffs. 2. Forages. Livest. Prod. Sci., 19: 13-46. National Research Council, 1982. Nutrient requirements of mink and foxes. No. 7, Nat. Acad. Sci., Nat. Res. Council, 72 pp. N.J.F., 1985. Nordisk fodermedelstabell fdr piilsdjur, 1985. Scandinavian Association of Agricultural Scientists, 26 pp. Pdreldik, N., 1975. Feeding fur bearing animals. Vol. 1. English translation by Geti Saad. Agr. Res. Survey, U.S. Dept. Agric. and Nat. Sci. Found., Washington, DC, 219 pp. Pdreldik, M.N. and Titova, M.I., 1950. Experimental determination of feeding standards for adult breeding mink (cited by Aitken, F.C. in Feeding of Fur Bearing Animals. Commonwealth Agricultural Bureaux, Farnham Royal, Bucks., U.K). Rimesl~tten, H., 1964a. Normer for protein, fett og kullhydrater i foret til mink. Nord. Jordbrugsforsk., Suppl. II, pp. 483-486. Rimesl~tten, H., 1964b. Ener~ifgrbruket til mink og rev. Proc. Scandinavian Association of Agricultural Scientists' 12th cbngress, Helsinki, pp. 475-482.

367 Rimesl~tten, H., 1976. Experiments in feeding different levels of protein, fat and carbohydrates to blue foxes. The First International Congress in Fur Animal Production, Helsinki, 28 pp. Rimesl~tten, H., 1978. Solvrevens energibehov og forets sammensaetning. Scandinavian Association of Agricultural Scientists, Helsingor, Denmark, 30 pp. Skrede, A., 1978a. Utilization of fish and animal by-products in mink nutrition. III. Digestibility of diets based on different cod (Gadus morrhua) fractions in mink of different ages. Acta Agric. Scand., 28: 141-147. Skrede, A., 1978b. Utilization of fish and animal by-products in mink nutrition. I. Effect of source and level of protein on nitrogen balance, postweaning growth and characteristics of winter fur quality. Acta Agric. Scand., 28: 105-129. Skrede, A., 1979a. Utilization of fish and animal by-products in mink nutrition. IV. Fecal excretion and digestibility of nitrogen and amino acids by mink fed cod (Gadusmorrhua) fillet or meat-and-bone meal. Acta Agric. Scand., 29: 241-257. Skrede, A., 1979b. Utilization of fish and animal by products in mink nutrition. V. Content and digestibility of amino acids in cod (Gadus morrhua) by products. Acta Agric. Scand., 29: 353-362. Skrede, A., 1981. Normer for minkens protein {aminosyre) -forsyning. Post graduate course in fur animal nut.rition, Tune Landboskole, Denmark, 12 pp. Skrede, A., Krogdahl, A. and Austreng, E., 1980. Digestibility of amino acids in raw fish flesh and meat-and-bone meal for the chicken, fox, mink and rainbow trout. Z. Tierphysiol. Tierernaehr. Futtermittelkd., 43: 92-101. Tauson, A.-H., 1986. Olika energikoncentration i foder till digivande minkhonor och dess inverkan p~ valptillv~ixten. Scandinavian Association of Agricultural Scientists, Kuopio, Finland, 11 pp.

Livestock Production Science, 19 (1988) 369-374

369

Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands

III. 6. Farmed Atlantic Salmon and R a i n b o w Trout E. AUSTRENG, B. GRISDALE-HELLAND, S.J. HELLAND and T. STOREBAKKEN

INTRODUCTION

Intensive farming of anadromous rainbow trout and salmon is a new form of animal production which has developed rapidly in Europe during the last ten years. In Norway, for example, the production of salmon has increased from less than 5000 t in 1976 to ~ 45 000 t in 1986. This form of production is also expanding in other European countries. Consequently, considerable progress has been attained concerning feeds, feeding and production techniques. Fish differ from the other domestic animals in several ways. They live in water and move by swimming. They are poikilothermic; their body temperature varies according to the water temperature and, therefore, fish do not require energy for maintaining a constant body temperature. Atlantic salmon are anadromous; spawning and hatching take place in fresh water, but after they become smolts they are able to live in the saline sea, where they gain most of their weight. When sexually mature, the fish close the circle by returning to the river where they were born to spawn. Rainbow trout can also be anadromous or can live permanently in fresh water. The farming of anadromous rainbow trout and salmon consists of a freshwater period from hatching to smoltification, and a growing and finishing period in the sea. FEEDSTUFFS

In the Norwegian fish-farming industry, fish meal is the most important protein source in dry feed, while frozen or ensiled fish or fish-filleting offals are used in moist and wet diets. The most commonly used vegetable sources of protein and carbohydrate are soya bean meal and wheat, respectively. Capelin oil is generally used as the dietary source of fat. The quality and handling of the different ingredients strongly influence the nutritional and physical status of the diet. Polyunsaturated fish fats are very sensitive to oxidation unless stabilized with antioxidants. Rancid fat is toxic to fish and should not be fed. Dry feed should be stored under dry, dark and cool conditions in order to avoid rancidity and the loss of vitamins, such as Vitamin C. The thiamine content of the diet may also be reduced during stor0301-6226/88/$03.50

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370 age if thiaminase-rich fish products are used. Moist and wet diets are even more susceptible to damage during storage. The producer should also be aware of feedstuffs containing antinutritional factors ( Tacon and Jackson, 1985 ) FEEDING When considering the feeding programme of the fish, it is necessary to decide how much and how often the fish should be fed, and what method of feeding to use. If feeding by hand, the feeding level can be regulated to some extent according to appetite. Alternatively, the producer can follow a table and feed according to an anticipated growth rate. Tabulated feed requirements may be presented in several different ways. Most commonly, feed amounts are presented as a percentage of the biomass, and vary according to fish size and water temperature. With limited feeding the population growth rate decreases, and competition and aggressive behavior increase. Subsequently, this causes considerable differences in the individual growth rates and has effects on fish health (Storebakken and Austreng, 1987a, b). Overfeeding does not contribute to extra growth. In sea farms, the main problem with overfeeding is the drastic increase in local pollution (~,sg~rd, 1986). Overfeeding causes gill infections or irritation of the gills from the food particles, especially among small fish.

Frequency of feeding Our unpublished results indicate that Atlantic salmon fry and fingerlings grow best when they receive food every 5-10 min. Feeding every 20-30 min is sufficient for fish near the smolt stage, whereas larger fish require even less frequent feedings. Rainbow trout, having a considerably larger stomach than salmon, and therefore better storage capacity, can manage with somewhat fewer feedings. The required frequency of feeding, however, will be dependent on other factors such as water temperature (Brett, 1979). NUTRITIONALREQUIREMENTS

Energy Protein, fat and carbohydrate are used by salmonids to provide needed energy for basal metabolism, activity and production purposes. The energy requirement depends on several factors such as water temperature, activity and fish size ( Brett and Groves, 1979). However, other environmental factors such as oxygen content, salinity and pollution of the water also influence the energy requirement.

371 TABLE I Suggested levels of metabolizable energy derived from dietary proteins ( % )

Starter diet Growing diet Broodstock diet

Atlantic salmon

Rainbow trout

45-50 40-45 45-50

45-50 35-40 40-45

Protein

As with other animals, protein is required by fish to supply the amino acids needed for tissue-protein maintenance and growth. Surplus amino acids are deaminated and subsequently enter oxidative pathways to supplement the energy supply. The ammonia produced in the deamination process is detoxified by mammals and birds tlvrough the creation in the liver of urea, uric acid and other nitrogen-containing compounds. The production of these metabolites requires energy. In fish, however, a large proportion of the toxic nitrogen waste is released over the gills in the form of ammonia. Therefore, the efficiency of utilization of protein for energy is greater in fish than in birds and mammals. Salmonids are regarded as having a low tolerance of dietary carbohydrate, and thus a large proportion of the energy requirement has traditionally been supplied by surplus dietary protein. Because of this, it is customary to express the protein requirement as a percentage of the dietary metabolizable energy (ME). Suggested levels of protein in starter, growing and broodstock diets are shown in Table I. These requirements are dependent upon the quality of the protein in the diet, and were determined in experiments in which at least 75% of the protein was derived from animal sources. The efficiency of conversion of dietary protein and gross energy into edible carcass products by rainbow trout is approximately 35%, whereas whole-animal protein retention may be as high as 40-45% when feeding is optimal (Austreng, 1979; Storebakken and Austreng, 1987b). Fat

The requirements for essential fatty acids by salmonids are met by fatty acids from the linolenic (n-3) and linoleic (n-6) families. Diets for rainbow trout and coho salmon should contain a minimum of ~ 2.5% of these fatty acids (N.R.C., 1981). A definite upper limit for dietary fat has not been defined. Experiments with rainbow trout and salmon, however, have demonstrated improved growth and survival by increasing the fat content to 20-25% in dry diets (Austreng, 1976a, b; Andorsdottir and Austreng, 1985). It should be emphasized, however, that

372 the quality of dietary fat in these experiments was high. The fat consisted mainly of oils from marine fish with a high content of polyunsaturated fatty acids. The melting point of fat reflects the degree of saturation, and is important when considering the addition of fat to the diet. In an experiment with rainbow trout, the digestibility of individual fatty acids decreased rapidly when the melting point increased above 10 ° C (Austreng et al., 1979 ).

Carbohydrate Salmonids are carnivorous, feeding on fish, crustaceans and insects; carbohydrates are not a natural constituent of their diet. The glucose needed for metabolic purposes is, to a large extent, supplied by gluconeogenesis of amino acids. It may be beneficial, therefore, to use carbohydrates to 'spare' expensive dietary protein. The utilization of carbohydrates can be limited both at the level of digestion and, subsequently, at the tissue level, and varies according to the type of carbohydrate and the processing technique used. Digestion consists of acidic and enzymatic degradation of the complex carbohydrates into monosaccharides, which are subsequently absorbed. The efficiency of digestion decreases with increased molecular complexity of the carbohydrate. Phillips and Brockway (1956) reported the digestibilities of the following carbohydrates by trout: glucose: 99%; maltose: 93%; sucrose: 73%; lactose: 60%; cooked starch: 47%; raw starch: 38%. Metabolic intolerance of oral glucose loads has been reported by Phillips et al. (1948) and by Palmer and Ryman (1972). The former authors reported excessive mortality at the higher levels of carbohydrate feeding, and correlated this with excessive glycogen deposits in the liver. No specific requirement for carbohydrates in diets for salmonids has been proven. An upper limit of 12% digestible carbohydrate in dry diets has been suggested (Phillips et al., 1948), but higher amounts have been used in other experiments without negative effects on the health of rainbow trout (Austreng et al., 1977).

Vitamins and minerals Rainbow trout and salmon require the known water-soluble and fat-soluble vitamins ( Halver, 1985 ), although the specific requirements for fast-growing salmonids during the sea period have not been fully investigated. There is reason to believe that the dietary recommendations of these compounds may change substantially as improved research techniques more accurately reveal the physiological requirements. The mineral requirements for biological functions in fish are not well under-

373 s t o o d either. T h e s t u d y of t h e s e r e q u i r e m e n t s is c o m p l i c a t e d b y t h e v a r i e t y of tissues i n v o l v e d in t h e m i n e r a l exchange: kidneys; intestines; gills; oral a n d mucosal surfaces. A s u b s t a n t i a l p o r t i o n of t h e m i n e r a l n e e d s m a y be o b t a i n e d f r o m t h e water. C o n s e q u e n t l y , fish living in soft f r e s h w a t e r are c o n s i d e r a b l y m o r e d e p e n d e n t o n receiving s u p p l e m e n t a l m i n e r a l s t h a n are t h o s e in a m a r i n e environment. THE FUTURE As our e x p e r t i s e in t h e areas o f growth, r a t i o n f o r m u l a t i o n , feeding a n d care improve, we can e x p e c t b e t t e r g r o w t h p e r f o r m a n c e in t h e fish. G e n e t i c imp r o v e m e n t s will f u r t h e r a f f e c t g r o w t h r a t e s a n d various aspects o f m e t a b o l i s m ( G j e d r e m , 1983). C o n s e q u e n t l y , t h e r e q u i r e m e n t s for feed n u t r i e n t s will change. F u r t h e r m o r e , t h e availability, quality, price, a n d p r o c e s s i n g techniques of f e e d s t u f f s are likely to c h a n g e in t h e future. T h i s w a r r a n t s a continuous r e - e v a l u a t i o n of diet f o r m u l a t i o n , feeding p r a c t i c e s a n d feed resources.

REFERENCES Asgard, T., 1986. Forureining fr~ smoltanlegg - - fSrspill eller gjodsel - - eksempel. Norsk Fiskeoppdrett, 11 (7/8): 50-51. Andorsdottir, G. and Austreng, E., 1985. Fat levels in starter diet for Atlantic salmon (Salmo salar, L). Abst. "Fish Culture", 7th Conf. Eur. Soc. Comp. Physiol. Biochem., Barcelona, Spain. Austreng, E., 1976a. Fett og protein i f6r til laksefisk. I. Fettinnhold i torrf6r til laksunger (Salmo salar, L). Meld. Norg. LandbrHogsk., 55 (5), 16 pp. Austreng, E., 1976b. Fett og protein i f6r til laksefisk. II. Fettinnhold i torrf6r til regnbueaure (Salmo gairdneri, Richardson). Meld. Norg. LandbrHogsk., 55 (6), 14 pp. Austreng, E., 1979. Fett og protein i fSr til laksefisk. VI. Fordoyelighet og f6rutnyttelse hos regnbueaure ( Salmo gairdneri, Richardson) ved ulikt fettinnhold i f6ret. Meld. Norg. LandbrHogsk., 58 (6), 12 pp. Austreng, E., Risa, S., Edwards, D.J. and Hvidsten, H., 1977. Carbohydrate in rainbow trout diets. II. Influence of carbohydrate levels on chemical composition and feed utilization of fish from different families. Aquaculture, 11: 39-50. Austreng, E., Skrede, A. and Eldegard, A., 1979. Effect of dietary fat source on the digestibility of fat and fatty acids in rainbow trout and mink. Acta. Agric. Scand., 29: 119-126. Brett, J.R., 1979. Environmental factors and growth. In: W.S. Hoar, D.J. Randall and J.R. Brett (Editors), Bioenergetics and Growth. Fish Physiology, Vol. 8. Academic Press, New York, pp. 599-675. Brett, J.R. and Groves, T.D.D., 1979. Physiological energetics. In: W.S. Hoar, D.J. Randall and J .R. Brett (Editors), Bioenergetics and Growth. Fish Physiology, Vol. 8. Academic Press, New York, pp. 279-352. Gjedrem, T., 1983. Genetic variation in quantitative traits and selective breeding in fish and shellfish. Aquaculture, 33: 51-72. Halver, J.E., 1985. Recent advances in vitamin nutrition and metabolism in fish. In: C.B. Cowey, A.M. Mackie and J.G. Bell (Editors), Nutrition and Feeding in Fish. Academic Press, London, pp. 415-430.

374 N.R.C., 1981. Nutrient requirements of cold water fishes. National Research Council. Natl. Acad. Sci., Washington, 63 pp. Palmer, T.N. and Ryman, B.E., 1972. Studies on oral glucose intolerance in fish. J. Fish Biol., 4: 311-319. Phillips, A.M. and Brockway, D.R., 1956. The nutrition of trout. II. Protein and carbohydrates. Prog. Fish Cult., 18: 159-164. Phillips, A.M., Tunison, A.V. and Brockway, D.R., 1948. The utilization of carbohydrates by trout. FiSh Res. Bull., 11, 44 pp. Storebakken, T. and Austrengl E., 1987a. Ration level for salmonids. I. Growth, survival, body composition, and feed conversion in Atlantic salmon fry and fingerlings Aquaculture, 60: 189-206. Storebakken, T. and Austreng, E., 1987b. Ration level for salmonids. II. Growth, feed intake, protein digestibility, body composition and feed conversion in rainbow trout weighing 0.5-1.0 kg. Aquaculture, 60: 207-221. Tacon, A.G.P. and Jackson, A.J.,1985. Utilisation of conventional and unconventional protein sources in practical fish feeds. In: C.B. Cowey, A.M. Mackie and J.G.BeU (Editors), Nutrition and Feeding in Fish. Academic Press, London, pp. 119-146.

Livestock Production Science, 19 (1988) 375-388

375

Elsevier SciencePublishersB.V., Amsterdam-- Printed in The Netherlands

IV. A M E T H O D O L O G Y TO C O M P L E T E A NATIONAL FEED UTILISATION MATRIX USING EUROPEAN DATA K.P. PARRIS1and J.L. TISSERAND

INTRODUCTION In Europe, livestock product output is estimated to provide 50% of the annual value of the gross agricultural output. The daily per capita consumption of livestock products in Europe accounts for approximately 40% of the total food intake when expressed in energy value, and 65% when expressed in terms of protein. The feed necessary to support European livestock production requires the use of more than 70% of the total agricultural land area for pasture and feed crops, supplemented by imported feeds. These feed imports, for most countries in the region, account for the major share of total agricultural imports in value terms. In view of the significant role of livestock production in European agriculture, the prominence of livestock products in food consumption and also the importance of feed in agricultural trade, it is crucial for policy makers to have a clear understanding of the interrelationships in the feed-livestock economy. One way in which agricultural policy makers can assess changes in the feed-livestock economy is through the use of a feed-utilisation matrix (FUM). A FUM indicates, on a crop-year basis, the utilisation of all types of feed by different categories of livestock, and is usually shown, both in terms of product weight and in equivalents of energy and protein. A FUM time series is of immediate use to national policy makers as it provides a synthesis of how price and/or policy changes in the feed sector affect the livestock sector (or vice versa), in terms of variations in the level and price of livestock output and the composition and type of feeding practices. By constructing a quantitative model with the use of the FUM database, to replicate current conditions, it is also possible to simulate the impact of a single or set of price and/or policy changes on the feed-livestock economy. Thus, policy makers can assess the likely implications of various scenarios before implementing a particular policy or set of policies. In addition, the FUM database can assist policy makers interested 1This chapterrepresentsthe viewsof the author, whichare not necessarilythose of the O.E.C.D. or of member countries. The author wishes to thank those O.E.C.D. colleagueswho provided instructivecommentsduringthe preparationof this chapter,althoughthe usualdisclaimerapplies. 0301-6226/88/$03.50

© 1988ElsevierSciencePublishersB.V.

376 in short/medium/long-term issues by establishing a baseline for either trend analysis, projection studies or forecasting models of the feed-livestock economy. At present, as only three European countries publish annual FUM series, the study of feed-livestock relationships in the region is severely impeded by the inadequacy of the database for the whole region. This chapter provides a brief review of existing feed resource and utilisation data in Europe and also outlines a methodology to assist in the construction of a national FUM. A REVIEWOF EUROPEANFEED-RESOURCEAND UTILISATIONDATA European information and data on feed resources and utilisation, currently available, can be summarized in 3 main groups discussed in diminishing order of data comprehensiveness: feed-utilisation matrix (FUM) series; feedresource balances; unassembled feed information and data.

Feed-utilisation matrix (FUM) series At present, three European countries, Denmark, the F.R.G. and The Netherlands, publish complete annual FUM series. These FUMs show, at varying levels of disaggregation, the utilisation of feed between different classes of livestock in product weight and energy terms, and for Denmark only, in digestible crude-protein equivalent. France has also produced a FUM but the series was discontinued in 1977/78, while Belgium is currently engaged in a research project to construct a national FUM, but the results have yet to be published. The FUMs of Denmark, The Netherlands and the F.R.G., shown in Tables I-III for the crop year 1984/85, give some impression of the diversity of animalfeeding practices in Europe, but also differences in the structure of the national livestock inventory. As a point of comparison, during the following discussion, the figures in parentheses indicate the average for 1973-1975. Roughage feeds accounted for 75% (80%) of energy requirements in the F.R.G., 70% ( 76% ) in Denmark, 62% (78%) in The Netherlands. In energy terms the share of cereals in poultry (layers and broilers) rations was about 60% ( 75% ) in Denmark and in the F.R.G., while in The Netherlands the share of cereals was only 44% (62%). Concentrates, excluding cereals, provided over 85% (74%) of energy requirements in Dutch pig rations, but only 26% (17%) and 22% (18%) in the F.R.G. and Denmark, respectively. These trends show that in the space of only ten years, since 1973-1975, feeding practices have undergone considerable transformation. The major changes in animal feeding that have occurred, although in varying degrees for each country, include the increasing use of concentrates, relative to roughage feeds, in cattle rations and the declining share of cereals in the feeding of all categories of livestock. Declining cereal use in livestock diets has been compensated, to a large extent, by the growing

377

TABLE I Denmark: feed use by type of livestock, 1984/851 Horses

Wheat and rye Barley, oats, mixed grain and sorghum Maize Pulses, bran and other cereal products Soya meal Cottonseed meal Sunflower meal Rapeseed meal Copra meal Groundnut, linseed, palm kernel and other oilseed meals Lucerne, grass meal and grass pill Mash, draft and yeast Tapioca, guar, citrus meal and molasses Meat, bone and fish meal and fish silage Whole milk Skim/butter milk Skim milk powder Whey

Cattle

Product Feed 3 weight units (1000t) (million)

Digesti- Product Feed ble weight units crude (1000t) (million) protein ( 1000t )

--

--

--

42.0

42.0

Digesti- Product Feed Digestible weight units ble crude (1000t) (million) crude protein protein (1000t) ( 1000t ) 3,4

1 089.8

96.6

20.9 0.7

18.7 0.7

1.8 0.0

614.4 1.2

610.8 1.3

53.6 0.1

3 527.9 8.5

3 523.4 8.9

307.0 0.6

3.4 2.5

2.7 3.1 -2.5 ---

0.4 1.0 -0.8 ---

42.0 389.0 243.8 149.7 167.6 45.1

40.5 486.3 270.8 156.0 176.5 48.5

6.0 159.5 88.0 51.8 47.6 8.1

83.8 726.6

78.5 908.2

0.9

1.0

0.2

46.2

47.3

0.6 0.1

0.4 0.1

0.0 0.0

11.2 124.9

1.3

1.0

0.1

0.9

1.0 -1.0 ---

0.4 -0.2 ---

-2.4 ---

-6.9 ---

Fodder concentrates total Potatoes Beet residue andpulp Fodder beets Beet tops and silage Hay, grass, silage and green fodder Straw

Pigs

32.2 . --

.

8.9 5.5 5.5

9.3 5.8 5.9

11.2 297.9 -3.1 1.6 1.0

7.8

4.9

5.5

1.3

7.0 24.8

1.0 5.7

3.0 22.7

1.9 7.3

0.3 2.1

285.8

224.3

23.3

51.6

39.7

3.8

4.7 125.0 266.4 13.5 128.2

4.9 31.9 38.6 20.7 8.2

2.0 4.1 8.9 4.5 0.8

155.9 51.1 18.2 83.3

67.7 -11.6 3.9 7.8

2 240.4

476.2

5 992.7

817.5

27.9 10.0 2.7

1.3 0.3 0.1

4.9 .

.

.

--

--

135.7 --

--

352.5 11.9 1 301.6

.

136.5 90.2 15.9

--

-1.0 --

-0.0 --

2 124.3 212.4 7 827.9 1 302.5 4 043.2 321.5

17.0 53.6 54.6

--

280.0 22.4

47.4 5.6

5.7 0.1

19 354.6 3 276.0 1 249.2 312.3

396.2 7.4

--

Coarse fodder total

54.0

5.8

5 424.7

528.8

45.7

2.3

Fodder total

86.2

10.7

7 665.1

1 005.0

6 038.4

819.8

5.9

-30.1

-5.1

--

0.6 --

11984/85 covers crop year 1 July-30 June. Source is Danmarks Statistik, 1986, Table 7.17, pp. 106-107. ~Includes feed for fur animals and rabbits equal to in product weight (1000t) 6.9 wheat, 10.1 barley, 3.4 oats and 20.4 fish silage, a total of 30 900 feed units and 7800 tons of digestible crude protein. 3One Danish feed unit is equal to approximately 12.5 ME, MJ dry matter basis. For further details and clarification see Chapter III.2 (van der Honing and Alderman, 1988).

378 T A B L E I (continued)

Sheep

Wheat and rye Barley, oats, mixed grain and sorghum Maize Pulses, bran and other cereal products Soya meal Cottonseed meal Sunflower meal Rapeseed meal Copra meal Groundnut, linseed, palm kernel and other oilseed meals Lucerne, grass meal and grass pill Mash, draft and yeast Tapioca, guar, citrus m e a l a n d molasses Meat, bone and fish meal and fish silage Whole milk Skim/butter milk Skim milk powder Whey Fodder concentrates total Potatoes Beet residue and pulp Fodder beets Beet tops and silage Hay, grass, silage and green fodder Straw Coarse fodder total Fodder total

Poultry

Total livestock2

ProdFeed uct units weight (million) ( 1000t )

Digest- Product ible weight crude (1000t) protein ( lO00t )

Feed units (million)

--

--

--

227.1

227.1

20.4

5.7 --

5.3 --

0.5 --

75.6 75.3

74.2 79.3

1.2 1.4

1.0 1.8

8.9 131.4 . 7.3 . .

. .

. .

. .

0.1 0.6 . 0.1 . .

.

.

.

.

.

-.

.

.

.

.

. 0.3

. 0.3

--

--

-.

--

0.3

0.3

. . . .

. . . .

. . 20.5 .

. .

. . . . 8.7

56.1 8.4

. . 2.3

.

. 9.5 2.1 13.9 22.6

Feed units (million)

Digestible crude protein ( lOOOt)

1 369.0

1 369.0

121.3

6.6 4.9

4 261.2 85.7

4 248.6 90.2

371.0 5.6

7.9 164.2

1.0 53.9

7.6

2.5

. .

139.3 1 250.9 243.8 168.6 173.1 50.6

130.6 1 563.6 270.8 175.7 182.3 54.4

18.7 512.9 88.0 58.3 49.2 9.1

.

52.0

53.8

9.3

.

9.4

--

13.1

. . . .

40.6 . . . .

1.4 . . 0.1 .

. . -.

. .

0.8

24.2 147.7

15.2 32.2

2.1 7.8

10.1

1.0

351.8

275.1

28.2

50.0

22.8

199.4 125.0 625.8 25.4 1 429.8

221.6 31.9 90.7 38.9 91.5

98.2 4.1 20.7 8.4 8.6

626.3

113.9 136.5 2 214.5 7 870.2 4 043.2

8 936.1 27.9 222.4 1 308.5 321.5

1 421.5 1.3 17.3 53.8 54.6

3 339.0 320.0 5 539.3 14 475.4

403.8 7.6 538.4 1 959.9

--

--

. 5.9

--

Product weight (1000t)

5.9 .

0.1 . . . .

1.2 0.1 1.4 2.8

Digestible crude protein (lOOOt)

1.0

0.1

--

--

1.0 627.3

0.1 114.0

19 726.7 1 280.0

use of other concentrates, mainly imported, most notably of vegetable oilmeals, manioc and a variety of processing by-products such as maize-gluten feed and citrus pellets. A project is in progress at the Organisation for Economic Co-operation and

44 39 0 9

118 0 38 56 58 3

Pulses (incl. lupins) Vegetable oils and fats Alfalfa and grassmeal Manioc Oilseeds Sugar

By-products of Cereal milling Brewing Starch industry Potato industry

5 0 1 23 20 0 12

Wheat Rye Barley Oats Maize Sorghum Other cereals

37 32 0 10

114 0 27 52 79 3

5 0 1 20 21 0 10

689 6 0 6

453 0 109 2 149 0 7

379 1 479 0 118 0 12

Product weight (1000t)

Product weight (1000t)

Milk feed units 3 (million)

Pigs

Cattle

The Netherlands: feed use by type of livestock, 1984/851

TABLE II

586 5 0 6

440 1 78 1 972 0 7

394 1 465 0 124 0 11

Milk feed units (million)

26 0 0 0

13 3 1 144 7 0

186 0 4 0 187 45 0

Product weight (1000t)

Layers

22 0 0 0

13 10 1 132 10 0

194 0 4 0 196 46 0

Milk feed units ( million )

55 0 0 0

13 2 48 196 0 0

93 0 8 39 820 1 0

Product weight ( 1000t )

Broilers

47 0 0 0

13 6 34 180 0 0

97 0 8 33 864 1 0

Milk feed units (million)

8 0 0 0

1 0 15 5 13 0

11 0 0 6 17 0 1

Product weight (1000t)

7 0 0 0

1 0 11 4 17 0

12 0 0 6 18 0 1

Milk feed units (million)

Other livestock 2

822 45 0 15

598 5 212 2 549 79 11

674 2 492 68 1 162 46 25

Product weight (1000t)

Total

699 37 0 16

581 18 151 2 340 107 11

702 2 478 59 1 224 46 22

Milk feed units (million)

.

5 81 2 0 524 4 809

25 2 0 757 5 207 .

337 163 84 1 173 1 325 707

5

363 220 141 1 183 1 364 721

.

164 322 51 357 8 038 .

76

7 401 5 445 1 746 56

Product weight (1000t)

Product weight ( 1000t )

Milk feed units s (million)

Pigs

Cattle

537 362 58 143 7 761 .

75

6 297 3 441 1 696 55

Milk feed units ( million )

.

36 1 0 77 1 203

74

0 6 0 5 386 2

.

Product weight (1000t)

Layers

117 1 0 40 1 244

73

.

0 4 0 5 375 2

Milk feed units (million)

26 2 0 177 2 158 .

186

1 13 0 118 351 10

Product weight (1000t)

Broilers

84 2 0 23 2 052 .

183

1 9 0 117 341 9

Milk feed units (million)

1 0 0 12 141

11

0 5 1 11 15 6

Product weight ( 1000t )

5 0 0 7 136

11

0 4 0 10 14 6

Milk feed units ( million )

Other livestock 2

251 326 51 1381 17 347 59 913

352

371 645 146 1 761 3 863 795

Product weight (1000t)

Total

824 367 58 737 16 911 12 514

347

345 477 88 1 747 3 751 779

Milk feed units (million)

11984/1985 crop year 1 July-30 June. Source is Landbouw-Economisch Instituut, 1987, Tables 4b and 5b. 2Includes: horses, sheep, goats and other livestock. 3One Dutch milk feed unit (VEM) is equal to approximately 0.0115 ME, M J dry matter basis. For further details and clarification see Chapter III.2 (van der Honing and Alderman, 1988). 4Includes minerals, synthetic protein, vitamins, milk replacers and other concentrates. 5Includes fresh milk products, roots, tubers, hay, silage and grass. For 1984/1985 roughage feed is not allocated according to livestock type, however, previous years indicate that over 95% of roughage is consumed by cattle.

Animal and marine meal Animal and marine oils and fats Skimmed milk powder Whey powder Other concentrates 4 Total concentrates Total roughages5

Sugar beet pulp, dry Molasses Bagasse Maize-gluten feed Vegetable oilmeals Citrus pulp

TAB LE II ( continued )

c~ oo o

381 TABLE III F.R.G.: feed use by type of livestock, 1984/1985' (1000t grain units 2) Type of feed

Total feed

Horses

Cattle

Sheep a

Cereals 4 Potatoes 5 Roots and tubers 6 Forage, hay and green maize Straw Concentrates 7 Milk

16 636 370 2 865 24 040

130 . 34 514

3 010 . 2 194 23 174

162 . 30 125

4

323 12 026 1 642

33 42 --

266 5 857 1 225

Total

57 902

753

35 726

In the form of mixed feeds

15 112s

132

6 185

.

Goats

Pigs

Poultry

3 7

10 441 362 560 220

2 889 8 44 --

24 122 --

--3

-4 164 394

-1 841 20

463

17

16 141

4 802

--

--

5 328

3 179

'1984/1985 covers crop year 1 July-30 June. Source is Bundesministerium fiir Erniihrung, Landwirtschaft und Forsten, 1986, Table 12.1, p. 40. 2One German grain unit is equal to approximately 12.5 ME, MJ dry matter basis. For further details and clarification see Chapter III.2 (van der Honing and Alderman, 1988). 3Including feed for other livestock not elsewhere specified, but excluding household pets. 4Including rice for feed. 5Including potato waste. 6Feed roots and tubers, beet tops, dried sugar beet pulp. ~Bran, pulses, manioc, oilseed cake and meal, fish meal, meat meal, bone meal, dried green forage, molasses, processing by-products, corn-gluten feed, citrus and fruit pellets, vegetable and animal oils, yeast. 8Including mixed feeds for other livestock not elsewhere specified, but excluding household pets.

Development (O.E.C.D.) in Paris to complete FUMs for all O.E.C.D. member countries (the 24 signatories of the O.E.C.D. convention include: Australia, Austria, Belgium, Canada, Denmark, Finland, France, the F.R.G., Greece, Iceland, Ireland, Italy, Japan, Luxemburg, The Netherlands, New Zealand, Norway, Portugal, Spain, Sweden, Switzerland, Turkey, the U.K. and the U.S.A. Yugoslavia takes part in certain work of the O.E.C.D. ). This project involves the construction of national FUMs on an annual crop-year basis, showing feed utilisation in terms of product weight, metabolisable energy (ruminants) expressed in megajoules and crude protein expressed in tonnes. For each O.E.C.D. country the matrix defines a minimum of six livestock categories, and for most countries more than 25 different feed types. It is the objective of the study to produce FUMs similar to that shown for Denmark in Table I. The total feedutilisation matrix for each country is further sub-divided between feeds used in the compound-feed industry and those used on-farm. "On-farm" feed use is defined as feed grown and fed on-farm, straight feeds sold between farms, feed

382

used by non-sale feed compounders, such as large poultry enterprises, and imported straight feeds sold directly to farmers.

Feed-resource balances Feed-resource balances show the total quantities of various feeds used by all livestock over a year, but do not indicate the allocation between different categories of livestock. Such feed balances are often a residual calculation. For example, the national feed balance for barley is Feed b a r l e y - domestic production ÷ i m p o r t s - exports + stock changes -food, seed and other end u s e s - w a s t e Thus, because of the residual method of deriving feed use there is concern over the validity of such calculations, especially for those feeds with substantial non-feed uses. Of course, for certain products such as hay, the problem is not as acute, as nearly the entire product is consumed for feed, although a small quantity may be used for litter purposes. It is not uncommon, however, to find the calculation of feed use in such balances derived by determining total utilisation (from production, trade and stocks) and subtracting food, seed and other end uses, with the residual, if any, equal to waste, feed and statistical errors which are not usually subdivided. For the 12 member states of the E.E.C., through the use of questionnaires, the E.E.C. statistical service, EUROSTAT, has calculated feed-resource balances over the period 1970/71-1984/85, in units of product weight, barleyequivalent feed units and crude protein, with a further sub-division between feed of domestic and imported origin (see EUROSTAT, 1987). A study is currently under way at EUROSTAT to extend their feed-resource balances into FUMs for each E.E.C. country. In other parts of Europe, only Switzerland calculates a feed-resource balance, published annually (Secr6tariat des paysans suisses), which shows feeds produced domestically and imported in product-weight terms and converted to metabolisable energy in megajoules (MJ) and digestible crude protein.

Unassembled feed information and data The feed-data sources described so far provide an aggregate national view of feed utilisation or the feed-resource balance, but unfortunately the information exists for only a relatively few European countries. It is possible, however, to have some idea of a country's feed utilisation or at least feed-resource balance, from various unassembled sources of information and data, mostly available from government statistical bureaux, research establishments and trade associations of compound-feed manufacturers. These unassembled series of

383 data consist of the following elements: (1) national livestock inventory numbers; (2) area, yield and production of various fodder crops and pasture; (3) exports and imports of feeds; (4) compound-feedproduction data series, usually giving a list of the ingredients included and total compound-feed production by livestock category, although rarely revealing the utilisation of different feed types between various livestock categories; (5) technical coefficients of livestock nutritive needs including energy, protein and amino-acid requirements, also the nutritional composition of feed in terms of dry matter, crude fibre, energy, protein and amino-acid balance. For example, although at present the U.K. does not publish either an FUM series or a feed-resource balance, it is possible to gain some idea of feed utilisation in the U.K. from various unassembled data sources. "Agricultural Statistics", published annually by the Ministry of Agriculture, Fisheries and Food ( M.A.F.F. ), gives annual livestock numbers (disaggregated to include over 40 categories of llvestock), the area, yield and production of certain cultivated fodder crops and areas of grassland and rough grazing, while the Customs and Excise office publishes U.K. feed import/export statistics. In conjunction with U.K.A.S.T.A. (the trade association for U.K. feed manufacturers) M.A.F.F. publishes quarterly returns made by a representative sample of compound-feed manufacturers, constituting over 40% of total commercial production in Great Britain (Northern Ireland is excluded). The survey gives an estimate of the quantity of total raw materials used in compound-feed production (over 20 items are listed), the division of total production by livestock type, and the utilisation of ingredients by livestock type. M.A.F.F. also conducts a "Grain Fed to Livestock Survey", which reveals the quantity of grain (wheat, barley, maize, oats and other grains) fed to different types of livestock (cattle, pigs, poultry and other livestock). To convert livestock numbers and feeds into equivalent units of energy and protein the U.K., along with almost every country in Europe, has a rich body of scientific research that provides this information, for example the "Feed Composition, U.K. Tables of Feed Composition and Nutritive Values for Ruminants", published by M.A.F.F. For a review of the European technical literature covering livestock nutrient requirements and feed composition, the reader is referred to the other chapters of this book. Compound-feed production statistics are also available at the E.E.C. level through the annual "Feed and Food" published by the F.E.F.A.C., the European Feed Manufacturers Association, which represents the interests of the private European compound-feedindustry. Unfortunately, F.E.F.A.C. does not provide in its yearbook the utilisation of compound-feed ingredients by livestock category. This gap in the data remains a major impediment to the construction of national FUMs in Europe and it is difficult to understand why these statistics are rarely published at the aggregate national level. In Japan, for example, which also has a large private compound-feed manufacturing industry, the Ministry of Agriculture publishes the total annual feed-industry

384 utilisation of ingredients, showing the use of over 20 feed types by seven different categories of livestock (dairy cattle, beef cattle, calves, pigs, layers, broilers and other livestock). A METHODOLOGYTO CONSTRUCTA NATIONALFUM

General From this brief review of published European feed-livestock data it is evident that although only a few countries calculate an annual FUM, a variety of data, ranging from feed-resource balances to more unassembled series are available as raw material to assist in the construction of such a matrix. This section outlines a methodology to construct a national FUM. Although it does not cover every detail necessary for such a calculation, it describes the main procedures involved and highlights the major problems likely to be encountered with such a project. Establishing an FUM comprises three steps: (1) construction of a livestock inventory-to determine the number of a n i m ~ d over a crop year and also a calculation of their energy and protein requirements; (2) estimation of a feedresource balance to show the total quantity of feed consumed in terms of product weight and converted into energy and protein equivalents; (3) allocation of feeds between different types of livestock, the FUM, displayed in terms of product weight, energy and protein units. The most direct method of constructing a FUM is through the use of a national survey or questionnaire, similar to the annual census used to collect agricultural statistics in nearly all countries. However, the use of a questionnaire is not always possible, it may he more appropriate to use another approach to construct a FUM of the type that is explained here. In any case, even when FUM data can be constructed through a survey/questionnaire, the use of a FUM methodology of the type discussed above can be used to derive an alternative estimate of feed utilisation, the two sets of data are then compared and a composite or compromise set of results can be obtained.

Livestock inventory The construction of the livestock inventory aims to provide an estimate of the output side of the feed-utilisation matrix. Through calculation of the number of animals fed and slaug~ntered and still on feed over the duration of a crop year, multiplied by the annual energy/protein requirements of each class of animal, an estimate can be derived of total energy/protein requirements by livestock type. As most countries publish detailed livestock inventory statistics and animal nutrient-requirement tables, this calculation should not be too difficult. Care should be taken, however, when estimating the annual energy/pro-

385

tein requirements of livestock that have a reproduction cycle of less than a crop year, particularly poultry and pigs but also calves that are slaughtered before reaching 1 year old. It is also essential to ensure the proper classification of livestock to prevent any animal type from being inadvertently omitted or counted twice, for example to define replacement heifers properly as either calves or mature animals. A useful guide to livestock classification has recently been prepared by F.A.O., (1985). Feed-resource balance

A feed-resource balance, the input side of the FUM, involves estimating the quantities of feeds consumed by livestock over a crop year and converting from a fresh product-weight basis into equivalents of energy and protein. The units used to express energy and protein may either be the preferred national measures and/or those established internationally by I.N.F.I.C. (International Network of Feed Information Centres), which express metabolisable energy in MJ and crude protein in tonnes. Estimation of a feed balance, some of the difficulties associated with its calculation and the main sources of statistics have already been covered in this chapter. With regard to the time period, it is preferable to calculate the feed balance on a crop-year basis because feeds which are stored for winter feeding (e.g. hay, silage and grains ) can be assumed to be entirely consumed over a crop year. Using a calendar-year basis would involve the difficult calculation of determining, during the first part of winter up to the end of December, the extent of stored feeds already consumed by livestock. During the construction of a feed-resource balance it will frequently prove difficult to estimate the quantity of grazed roughage utilised by livestock, as commonly only data concerning the area of roughage are available in national statistics, and none for pasture yield or output. In Chapter II.2. (Lee ,1988), however, Lee does provide some useful information with respect to the yield of pasture across various European countries. However, if the area used for pasture is known, it is possible to calculate the potential quantity of pasture for grazing by assuming average yield values after taking into account the plant composition of the pasture, and by varying the annual yield of pasture in correlation with a similar roughage for which the annual yield variation may already be recorded, for example, fodder beets. Even so, this estimated potential supply of pasture cannot reasonably be assumed to approximate to the quantity of pasture consumed by grazing livestock. The use of pasture entails considerable losses, estimates suggest these may amount to 15-60% of the potential feed supply from pasture. Loss of pasture supply potential may occur because of understocking or land recorded for grazing but not actually used for the purpose, changes in the quality and quantity of pasture supply as a result of climatic variability and other environmental factors, and losses incurred dur-

386

ing grazing mainly from livestock trampling and also the spoiling of pasture from excreta. An alternative method of estimating the quantity of pasture consumed by livestock is through back calculation. Thus, by calculating total livestock energy requirements and the energy contribution of other feeds consumed by livestock, the residual may be reasonably assumed to equal the quantity of pasture utilised by livestock.

Allocation of feed consumed by livestock The allocation of feed, according to different classes of livestock, is the final procedure necessary to construct the FUM. Initially a check is important to verify that the estimated total livestock energy/protein requirements approximately equal the total quantity of feed actually consumed by livestock {also in energy/protein terms). While, in theory at least, it may be expected that the input and output side of the FUM should be approximately equal, in practice this may not always be the case. One problem may arise from using a standard energy value for each feed, regardless of the livestock type, as the utilisation of energy or protein in a particular feed will vary between cattle, pigs and poultry. Whilst it is preferable that individual energy/protein feed coefficients should be attached to every feed for each livestock type, based on the value for ruminants, in the absence of this data a standard energy/protein coefficient for all livestock is unlikely to generate an error larger than 5% in the FUM. It is also probable that when calculating the livestock protein requirements, while the estimate is correct for energy, the derived estimate may be 10-30% lower than the quantity of protein actually consumed. This error can occur because livestock farmers will usually ensure that their animals receive the correct energy requirements but feed protein excess to requirements, as an insurance against feeds which might be below normal protein content as well as to increase palatability. Of course, the allocation of feeds between different categories of livestock commences with utilising the information that already exists on feeding patterns. For some countries, as previously mentioned, unassembled data series exist on feed utilisation by livestock species for some feeds, especially those used by the compound-feed industry. To allocate feeds between different classes of livestock, for which no utilisation information exists, necessitates the use of a variety of procedures, of which the most important are given below: (1) The allocation of feeds on the basis of known feeding patterns. Horses, for example, are not normally fed silage, even though they will consume this feed. Working through the unallocated feeds in this way, through a process of elimination, makes the task of allocating the remaining feeds considerably easier. ( 2 ) The knowledge of local "experts", for information concerning a "typi-

387 cal" diet in their country for each animal category, may provide a very practical method of allocating feeds. Local expertise of animal-feeding practices to determine feed allocation by species might also be more useful if the country is divided into local production regions and feed intake and diet are measured on a quarterly basis. If quarterly/regional livestock inventory statistics are available, this building-block approach has the advantage of capturing weight changes of animals more precisely and it can reflect the effects of weather changes on feed intake and rather than using a theoretical national animal diet, will more accurately monitor the diversity of feeding practices in a country. (3) The allocation of feed, developed through the methods given in (1) and ( 2 ) above, can be cross-checked and adjusted against knowledge of the nutritional and physiological constraints of animal feeding. Thus the final feed composition derived for each class of livestock may be analysed in terms of whether it meets an animal's energy and protein requirements and also fulfils other criteria, such as the need for vitamins, minerals, amino acids and fatty acids. (4) In the case of poultry, pigs and dairy cows the estimated feed intake for these animals may be cross-checked with feed-conversion values which shows the quantity of feed necessary to produce a kg increase in egg production, liveweight gain or milk yield. This is perhaps also possible with beef cattle and sheep, although with greater difficulty. Knowledge of poultry, pig and dairy cow feed-conversion values is now widespread and may provide a reasonable indication of the accuracy of the FUM when expressed in terms of kg of feed per kg of livestock gain/egg weight/milk yield. Even for a country where feedconversion data do not exist, if the initial calculation of the FUM indicates a feed conversion for poultry, pigs and dairy cows considerably below (or in excess of) that in other countries (assuming similar conditions of production) then this may necessitate the re-examination of the FUM. CONCLUSION To summarize, using a combination of existing feed-utilisation data, knowledge of local feeding practices, the dietary needs and nutritional constraints of animals, plus animal feed-conversion efficiency information, it is possible to derive a national FUM. Inevitably the procedures to construct the FUM outlined here will contain various estimation errors, which are principally caused by a lack of understanding of animal nutrition and actual feeding practices in addition to inadequacies in primary data sources. Use of grazed roughage for feed is illustrative of the difficulties and errors associated with FUM calculations. Determination of the availability of grazed roughage for feed is extremely difficult, while it is also difficult to measure actual livestock intake of grazed roughage. Moreover, it should also be mentioned that the nutrient requirement for a particular class of livestock and the nutrient content of a particular feed may vary considerably between countries as already highlighted in

388

other chapters of this book, thus making it difficult to adopt internationally uniform national coefficients. While the task of constructing an FUM is complicated, and refinements and improvements can always be incorporated into the system of calculation, it is possible using the methodology outlined in this chapter to obtain a national FUM. Thus it is feasible to meet the central objective of developing FUMs, which is to enhance the understanding of feed-livestock interrelationships for the benefit of agricultural policy makers.

REFERENCES Bundesministerium ftir Ern~ihrung, Landwirtschaft und Forsten, 1986. Die Futterwirtschaft in der Bundesrepublik Deutschland 1986 (Wirtschaftsjahr 1984/85). Bonn, F.R.G. Danmarks Statistik, 1986. Landbrugsstatistik 1985 (Agricultural Statistics 1985), Copenhagen, Denmark. Eurostat, 1987, Feed Balance Sheet - Resources. Luxembourg, mimeo. F.A.O., 1985. Guidelines and recommendations regarding statistics on livestock numbers and livestock products in EEC member countries. F.A.O./Economic Commission for Europe, Geneva, Switzerland. Landbouw-Economisch Instituut, 1987. Jaarstatistiek van de Veevoeders 1983/84 en 1984/85. Den Haag, Netherlands. Lee, J., 1988. Feedstuffs. 2. Forages. Livest. Prod. Sci., 19: 13-46. M.A.F.F., Agricultural Statistics. Ministry of Agriculture, Fisheries and Food, London (annual publications). M.A.F.F., Feed Composition: U.K. Tables of Feed Composition and Nutritive Values for Ruminants. Ministry of Agriculture, Fisheries and Food, London (annual publications). Secretariat des paysans suisses, Swiss Agricultural Statistical Yearbook, Brugg, Switzerland (annual publications). Van der Honing, Y. and Alderman, G., 1988. Feed evaluation and nutritional requirements. 2. Ruminants. Livest. Prod. Sci., 19: 217-278.

Livestock Production Science, 19 (1988) 389-408 Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands

389

V. G E N E R A L S U M M A R Y F. DE BOER and H. BICKEL

INTRODUCTION

Food produced by farm livestock is renowned for its high quality, since it complements vegetable food to meet human nutritional needs in an almost ideal way. Livestock do this by a remarkable and complicated process of transforming feeds, which are almost exclusively of vegetable origin, into human food: milk, meat and eggs. Some aspects of livestock performance serve human beings in a different way, by providing for muscular activity, such as traction and riding, or for protection against adverse conditions as in wool, leather and fur. In controlling this process to earn their living, farmers have to make considerable efforts to match the feed input as accurately as possible, to the required food or product output. To accomplish this, knowledge of each of the three links in the chain (feed, transformation process, food) is essential. This is the reason for the long-standing and vigorous research effort in this area. In Table I some relevant features of these links in the chain are shown. The chemical characteristics of animal feed and human food quoted in this volume are the well-known chemical groupings originating from the Henneberg and Stohmann proximate-analysis system, which was developed at Weende in Germany in 1864. Although the terms used are identical, we now know that striking differences exist between the composition of protein, fat and other components in feedstuffs and in the food output from livestock. Moreover, TABLE I Relevant features of food production by livestock Animal feed

Losses by transformation processes in livestock

Human food

Protein Fat Carbohydrates (starch, fibre) Vitamins Minerals

Faeces, Urine, Digestive gases, Heat (maintenance, activity, nutrient transformation)

Protein Fat Carbohydrates (few)

0301-6226/88/$03.50

Vitamins Minerals

© 1988 Elsevier Science Publishers B.V.

390

i FEED

GE

DE

ME

,

, ,

~ i

/

I I

Milk 17 % NE ~ _ _Heat __ 5 %

18%

15%ane ,~,nance

(heat)

Met

ary losses

Faecal los~es

Fig. 1. Schemeof conversionlossesof feedsin livestock (dairy cow;24 kg milk). their levels vary in feedstuffs much more than in the resulting food output as milk, meat and eggs. Only fat content in meat varies considerably in food produced by livestock. Thus, the transformation process in livestock, ingestion of feed, digestion, metabolization and synthesis of food, evens out the wide variety in feed composition, so that the protein, fibre and other components are converted into fairly consistent, first-class food. The energy for this process ultimately has to be provided by the animal feed, resulting therefore, in considerable losses of energy in the transformation of animal feed into human food. In Fig. 1 this is illustrated as an example, in a simplified manner, for a dairy cow. Schemes for other kinds of livestock production such as meat, growth, eggs, muscular activity and wool will have the same characteristics, but the magnitude of the energy losses will vary considerably. FEEDSTUFFS There is a tremendous variability in the feedstuffs available for livestock feeding. Some are unacceptable or indigestible to human beings, e.g. grass, whilst others can be used for direct human consumption, e.g. cereals. Nevertheless, substantial amounts of cereals are destined for livestock feeding. This fact has resulted in some criticisms being made, in particular when populations elsewhere in the world suffer from famine. It is often suggested that cereals and other food should be taken out of livestock rations, thus saving biological transformation losses and releasing food for the starving peoples. Theoreti-

391 TABLE II Variability in DM and ME in feeds for ruminants (indicative)

Forages Cereals/other seeds By-products

DM (gkg -1)

Digestibility of OM (%)

Metabolizable energy (MJ kg-1DM)

150-900 800-950 100-900

35 -84 69-92 72-95

5.0 - 13.0 10.2-14.0 3.0-14.2

cally, the principle is sound, but its realization in practice meets often insoluble problems: the geographic dispersion of production and potential human consumption sites, the associated transportation problems, changes in production patterns caused by shifting prices, and the absence of buying power in the famine regions. Discussions on this topic have led some people to propose the elimination of the production of feed, including grasses, for livestock: they consider that soil which is serving that purpose, is under-utilized because of the energy losses illustrated in Fig. 1. Arithmetically, the statement is correct, when considering the gross energy (GE) of grass and the amount of food energy, produced by ruminants from it. However, this approach is unrealistic for two reasons: (1) in large areas, the soil is only suitable for the production of grass and no alternative use is possible; (2) grass, both in organic matter or grossenergy terms, has no food value to human beings at all. This is in contrast to cereals. Therefore, any food produced by the utilization of grass is a positive gain of food energy, instead of a loss of food production for mankind. In particular, ruminant animals act as primary food producers, in two steps, and therefore equal arable crops in this respect. Table I on Page 5 of Chapter I (de Boer and Bickel, 1988) illustrates the serious consequences when these facts are not taken into account. Feedstuffs in Chapter II.1 of this volume (de Boer, 1988), have been classified into 4 groups: forages; cereals and other seeds; by-products, both vegetable and animal; compound feeds. Numerous tables illustrate the wide range between and within these classes. This is caused by intrinsic as well as regional factors. Broad indicative data are shown in Table II.

Forages Within this class of feedstuffs, grass and conserved forages, silages and hay, play a dominant role. There are other non-gramineous forages or fodder crops such as maize, fodder beet and kale, and some crop by-products, maize stover, sugar-beet tops and leaves. The quantitative significance of these types of for-

392

age differs significantly in various areas of Europe. Using various data presented in Chapter II.2 (Lee, 1988), Table III gives indicative information on this variability. Table IV illustrates the point that the actual and potential yield of grassland areas differ markedly. Obvious reasons for this are climatic variations, in particular rainfall, and the availability of fertilizer, primarily nitrogen. Of course the climatic components cannot be altered, but better use of fertilizer might narrow the indicated gaps substantially. Except in some regions of West Europe, the potential yield of grassland seems to be about twice the present yield. Similarly, feed production from grassland may still be increased considerably by more efficient control of conservation losses. Data given by Lee (1988) in Chapter II.2, Table XIII on Page 32, indicate the scale of avoidable and unaTABLE III Relative significance of various forages in feed supply ~

Total forages3 Total feed supply Grass Grass silage and hay Annual fodder crops (maize silage included) Crop by-products

Western Europe 2

Other countries

U.S.S.R.

100

100

100

42 34

100 " 22 19

18 5

10 3

15 46

100 7 22

44 27

100 28 17

29 10

14 6

21 8

13 5

~Based on data from Lee (1988) in Chapter II.2, Tables II, III, VI, XI and X I I . 2Belgium, Denmark, France, F.R.G., Ireland, Luxemburg, The Netherlands, the U.K. 3The difference of the total of forages from 100 is covered by concentrates. TABLE IV Actual and potential dry matter (DM) production from grassland in Europe 1

Production (109 kg DM) Actual Potential Permanent pasture (108 ha) UAA3 (108 ha) Bovines (108 ) Other ruminants (108) (sheep and goats)

Western Europe 2

Other countries

U.S.S.R.

201 374

128 254

? ?

41 74 69

60 156 63

338 554 114

41

103

148

1Based on data from Lee (1988) in Chapter II.2, Tables III-V and F.A.O. (1985). 2As in Table III. 3UAA = Utilized Agricultural Area.

393 voidable losses in grass silage making. A reduction of nutrient losses of about 25% may be possible. Reductions in the losses associated with haymaking are not shown, mainly because in most of Europe, grass silage making is becoming more and more popular at the expense of haymaking. The chief reason for this shift is that nutrient losses in silage making are lower, in general, than in haymaking and a higher-value forage can be made and stored. Lee (1988) indicates in Chapter II.2 that in E.E.C. countries between 45 and 50 million hectares have only one type of forage production: grass. For the remainder of Europe (U.S.S.R. excluded), the relevant area is estimated to be about 55 Mha. In the U.S.S.R. this area was estimated to be 338 Mha (in 1975 ) as quoted in Table III (p. 19, Chapter II.2, Lee 1988). Combining these data with the production capacities referred to before results in the data in Table IV. Table IV shows, that of the European area which can produce food only through ruminant livestock, about 41% is concentrated in 8 countries in a narrow zone along the west coast of the European continent. The total actual dry matter (DM) yield (grass and its conserved products) is estimated to be about 57% higher in that area than in all the other countries of Europe together (U.S.S.R. excluded). T h a t gap is expected to remain even when maximum yields have been achieved at some time in the future. Therefore, for equivalent levels of livestock production, the proportion of forage in ruminant rations in the western zone of the European continent will always be greater than elsewhere in Europe. The relative importance of annual fodder crops has been shown in Table III. Lee (1988) indicates clearly (in Chapter II.2 ) that within this class of forages, the area of maize for silage has expanded considerably all over Europe, at the expense of root crops. There are indications also, that whole-crop silage from other cereals, wheat, barley and oats, is becoming more popular.

Cereals, pulses and oilseeds In recent years, livestock in Europe (U.S.S.R. excluded) has consumed about 275 million tons of cereals, as well as some 3 million tons of pulses. Together, these feeds supplied about 35% of the total feed-energy requirement for livestock, fed on the farm of origin, or as purchased compound feeds. Cereal consumption in animal husbandry in the U.S.S.R. recently increased from 70 to 105 Mt. For Europe as a whole, production and consumption of cereals rose, whereas production of pulses decreased. Cereal production and consumption by livestock increased earlier, and to a greater extent in Europe, than in the U.S.S.R., resulting in considerable differences in yield per hectare, as shown by Todorov (1988) (Chapter II.3 ). Simplifying Table IV on Page 55 results in Table V. Putting the highest cereal yield per hectare in Europe at 100, within any

394 TABLE V Relative yield of cereals per ha in various regions in Europe and U.S.S.R.

Barley Maize Wheat Oats Rye All

H2 L H L H L H L H L H L

NW/W 1

C

N

SE/E

M

100 79 78 33 100 75 100 71 92 63 100 78

95 57 100 11 77 45 93 48 100 34 82 41

71 53 84 22 72 41 78 56 80 43 61 43

75 47 94 46 54 39 25 23 33 27 63 51

61 15 77 14 40 15 35 12 50 12 56 16

U.S.S.R. 27 32 22 24 26 22

1NW/W, France, The Netherlands, Belgium, Luxemburg, Denmark, the U.K., Ireland; C, F.R.G., G.D.R., Poland, Czechoslovakia, Hungary, Switzerland, Austria; N, Sweden, Norway, Finland; SE/E, Bulgaria, Rumania, Yugoslavia, U.S.S.R.; M, Portugal, Spain, Italy, Greece, Albania. 2H= Highest yield; L = lowest yield. region of Europe, the highest and lowest yields are indicated in Table V. The differences are striking, and as Todorov (1988) correctly states (in Chapter II.3 ), cereal production potential is not yet exhausted. Accepting that climatic conditions, particularly rainfall, and geographical latitude, set unavoidable limits to closely approaching the highest possible yields, nevertheless, by classical improvements, such as optimal fertilization, and improving cultivation and harvesting methods, substantial increases in the yields of cereals seem possible. This seems achievable primarily in the Eastern, South-Eastern and the Mediterranean areas of Europe, as well as in some individual countries in other parts of Europe. Todorov (1988) (Chapter II.3) illustrates these expectations until the year 2000 in a series of graphs for Europe without the U.S.S.R., as well as including the U.S.S.R. These projections indicate a possible increase of cereal production of about 25% in the next decade in Europe, and about twice that in the U.S.S.R.

By-products Vegetable origin If forages and seeds (cereals and others) are considered to be primary feeds for livestock, by-products resulting from their processing might be termed "secondary feeds". T h e y become available not only at harvesting, e.g. straw, sugar-beet tops and leaves, b u t a significant proportion arise as by-products in human-food processing. The variety in h u m a n food, beverages included, is

395 amazing, as also is the variability in the resulting by-products. The differences in appearance and composition of blood meal, bran, molasses, oilmeals and straw illustrate this point very well. Some by-products are hardly considered as such any more, because their impact equals, or even sometimes surpasses, the significance of the initial goal of the food-production process. The chief examples of this phenomenon are the oilmeals from soya beans and sunflower seeds. On the other hand, some processing residues, which were traditionally considered wastes, have become by-products for livestock feeding. Such changes have been brought about mainly by a growing concern about the pollution aspects of the disposal of such wastes, which were traditionally dumped into rivers or into pits in the ground. Thus, in recent years, research efforts to estimate their use as livestock feeds have been intensified. Boucqud and Fiems (1988) show (in Chapter II.4) an extensive list of many of the newly-introduced by-products (Table VIII on Page 116). The quantities of by-products fed to livestock are difficult to estimate. They are subject to the influence of the terms of trade, politics and food-consumption patterns, which differ appreciably within countries and between years. As an example, there is no fixed partitioning of the cereal harvest into livestock feed and that used for the production of bread, alcohol and starch in all their various forms. For by-products of vegetable origin, Boucqu~ and Fiems (1988) present (in Chapter II.4) a series of flow diagrams, permitting calculation of the quantities of the various by-products from the food-production chain. By-products are classified on their origin, milling, starch production, alcohol production etc. Table VI shows the diversity of by-products which may originate from one cereal such as maize. Clearly, the present and future availability of by-products for animal feeding are linked with human-consumption patterns, size of populations and the associated food-production technology. The population in Europe and the U.S.S.R. is expected to grow, although its rate of growth is slowing down. In some countries, the size of the population is even starting to decrease. Nevertheless, an increase of population of roughly 80 million people is expected in Europe by the year 2000 (Probst, 1982). All these factors taken together, will result in larger quantities of by-products becoming available for feeding livestock. As Boucqu~ and Fiems (1988) state, there is a growing tendency, especially in Western Europe, to find alternative uses for agricultural products because of the surplus production of food. If such alternative utilization is to be realized, a new range of by-products may enter into feed rations for livestock. Crop by-products, such as straw and sugarbeet tops are available in large quantities, but their utilization in livestock feeding is limited and even decreasing (Lee, 1988; Sundstol, 1988). By-products from root crops are voluminous and therefore involve high transportation costs. Moreover, they are becoming available in smaller quantities because of

396 T A B L E VI Average amount of by-products resulting from maize processing for various food-production goals (kg by-product per 100 kg maize)1

Meal Alcohol Bran Grits Germ meal Maize oil Gluten feed Gluten meal and steep water Distillers' grains Distillers' solubles

Dry milling

Wet milling

Alcohol production

60 -21 (20-22) 9 (8-10) 8.5 1.5 --

65 (62-68) ---3.2 3 20

-37.5 w

----

4.5 ---

-20 (90% D M ) 32.5 (35% D M )

---

~Based on data from Boucqud and Fiems (1985) in Chapter II.4 Table II and Figs. 1 and 3.

the decreasing root-crop area (storage also presents problems for these products). Straw has a very low feeding value, because of its high fibre content. For more than 100 years, research workers have attempted to process straw into a feed with a higher feed value. Although alkali treatment, sometimes in combination with high temperature (steam) and pressure, produces a substantial increase in feeding value, only a small percentage of straw is upgraded in this way in Europe and the U.S.S.R. (Sundstol, 1988). Possibly modern biotechnology, by the manipulation of bacterial attack, may result in a more extensive utilization of the more than 560 million tons of straw and stover produced annually in the E.A.A.P. region.

Animal origin By-products of animal origin arise almost exclusively from 3 types of food production: milk, meat and fish. Each of the three foods is bound up with its own particular processing industry and each of these produce a large variety of by-products. Skim milk and whey, both fresh and as powder, meat and bonemeal, fat, tallow and fish meal are well-known examples. A common feature of the vast majority of these by-products is their high energy content and the high protein content, of good quality, in the dry matter as well as the absence of crude fibre. By-products of vegetable origin differ in these aspects markedly from by-products of animal origin, as is illustrated by Miller and de Boer (1988) in Tables I and II of Chapter II.6. Similar to the processing of vegetable food, wastes arise from the animal food-production process. One important waste in animal production, manure,

397 TABLE VII Percentage of liveweight, destined for the rendering industry after slaughter 1'2 Cows, heifers, bulls Sheep Pigs '~ Poultry 4

6-21 13 9-10 18-27

1Bones and trimmings from carcasses excluded. 2Data based on Miller and de Boer (1988) in Chapter II.6 Tables V-VIII. 3Piglets excluded. 4Hens and broilers.

has gained a special impact in some areas of Europe now. It becomes increasingly a threat to the environment. Extensive research and other actions are undertaken to control the problem. Miller and de Boer (1988) indicate in Chapter II.6 that using some types of manure, after proper processing, is possible. Even so, it is unlikely that this will help to solve the problem even marginally, if at all. This is in marked contrast with many wastes of vegetable origin. The availability of various types of by-products of animal origin varies greatly between countries and also between years. These fluctuations depend, as mentioned before, on terms of trade, consumption patterns and politics. Moreover, lack of statistical consistency in data collection in many countries means that a clear picture of real availability data is difficult to obtain. Miller and de Boer (1988) present in Chapter II.6 a series of tables with national production quantities of milk, slaughtered animals and fish, as well as some partitioning schemes for the processing of milk, as well as for slaughtered animals. In Table VII some of the scarcely available partitioning data for slaughtered animals are presented. Future availability of by-products of animal origin depends of course on the consumer's demand for food of that type. The increase of population, as quoted before (Probst, 1982 ), will mean that greater quantities of by-products of animal origin will become available, unless consumption patterns change dramatically. Such a change seems unlikely if milk and meat production are expected to rise by 13% and 25-32%, respectively (Probst, 1982) and fish catch by 18% (Chapter II.6) by the year 2000. New methods of process technology will, in a similar way to the situation for by-products of vegetable origin, lead to new types of by-products for livestock feeding also.

Compound feeds and additives From the beginning of this century, compound feeds have played an increasingly important role in livestock feeding. They represent a fourth class of feed-

398 stuffs in addition to forages, seeds and by-products. This is because compound feed ingredients are derived mainly from seeds and dry by-products. The mere fact of compounding leads to a levelling out of the marked differences in chemical composition and other feed characteristics of the feedstuffs referred to earlier. Moreover, deficiencies of minor substances such as minerals, trace elements and vitamins, which may very well occur when particular by-products or a large amount of one ingredient are used, are easily and elegantly avoided by adding these substances to the compound. The original properties of the raw materials are no longer recognizable, nor can they be recovered. The composition of compound feeds changes continuously and rapidly, depending on the fluctuation of marked prices of ingredients, but still maintaining their designed feeding value. Compound feed production in various European countries is shown in Table VIII. Despite the frequent changes in compound-feed ingredients, there are differences in the usage of raw materials in various classes of compound feeds. By-products, especially those with fairly high fibre levels, are mainly used in compound feeds for ruminants, whilst compound feeds for poultry hardly contain any of these. Pig feeds are intermediate in this respect, sow feeds in particular making use of fibrous by-products. Oilmeals are present in nearly all compound feeds. The proportion of cereals in compounds varies considerably, depending on the class of livestock and on national economic policies in the various European countries. This is reflected in Table IX. Apart from the minerals, trace elements and vitamins, already mentioned, compound feeds may contain a range of additives designed to affect positively the productivity and/or the health of livestock. Such additives are usually synthetic organic molecules alien to the animal's normal physiology. To avoid any risk of damage to livestock and consumer health, very strict conditions of approval for their use in livestock husbandry are observed all over the world. TABLE VIII Compoundfeedproductionin variousregionsin Europeand in U.S.S.R. 1 Region 2

106tons year- 1

Percentage

North West/West (NW/W) Central (C) Northern (N) South East/East (SE/E) Mediterranean (M) U.S.S.R. Total

54.6 37.9 6.9 11.8 31.6 70 213

25.7 17.8 3.2 5.5 14.8 33 100

1Data for variouscountriesreferto variousyearsas indicatedby Namuret al. (1988) in Chapter II.7, Table VII. 2See Table V.

399 TABLE IX Estimated proportion of cereals (%) in compound feeds in some countries1 Country

1983

1984

1985

1986

Belgium Denmark F.R.G. France Ireland Italy The Netherlands Portugal Spain U.K.

23 38 21 48 46 50 16 63 66 43

21 40 23 46 46 51 15 61 66 41

24 36 25 47 43 52 15 45 66 43

23 33 24 41 39 51 15 33 63 38

1Source,F.E.F.A.C., Brussels. Normally it takes 8-10 years to obtain approval for the use of a particular ingredient. Additives of this kind may be classified in 7 groups as shown by N a m u r et al. (1988) in Chapter II.7 on Page 204. The information on feedstuffs in Chapter II shows a somewhat fragmentary picture, because of incomplete and often inconsistent data from the different sources used. Nevertheless, despite these limitations, the authors managed, to assemble data, which illustrate the extremely variable feed-production levels in Europe, including the U.S.S.R. Animal-feed production capacities are also presented, showing t h a t feed production in the E.A.A.P. is still well below its technical potential. To quantify this situation more accurately, a uniform system of statistical data collection all over Europe is urgently needed. If that could be achieved, it would m a t c h the progress made so far in systems of feed evaluation, and for testing the nutrient requirements of livestock in Europe. In a strict sense, complete uniformity has not been achieved here either, but the foundations of the systems indeed are similar. In the following paragraphs the European position in this field is summarized. FEED EVALUATIONAND NUTRIENT REQUIREMENTS Feed is evaluated according to its fate in the transformation process to livestock product or use for traction and riding. The partitioning of feed energy, or its fate in the transformation process (as shown in Fig. 1) is not constant for the various feedstuffs. It varies depending on: (1) the particular feedstuff; (2) the livestock species utilizing it; (3) the type and level of production required. Thus, a particular feedstuff, which is not constant owing to varying climatic, soil or production conditions, has only one particular efficiency of utilization for one particular type of livestock production. Of course, such a

400 theoretical basis needs substantial simplification to make it applicable in livestock production. Bickel (1988) describes (in Chapter III. 1 ) the general approach to tackling this complex problem. The first step is always to determine the quantity of gross energy (GE), contained in the feedstuff. This can be done by bomb calorimetry, or by determining the chemical components by the Weende proximate-analysis system, and adding their respective energy contents together. Deducting the physiological energy losses in the transformation process, using either approach, enables the calculation of the levels of digestible energy (DE) and metabolizable energy (ME) in the feed. The relationship of ME to net energy (NE), the latter corresponding to the energy of the animal's product, is variable and difficult to determine in quantitative terms. In fact, any type of animal production, e.g. maintenance, lactation or growth of livestock has its own particular efficiency of utilization. Based on long-term research at many centres, average values for these parameters are now available and are used in prediction formulae linking feeding value and requirements together, as Bickel (1988) shows in Chapter III.1. Protein has a specific value within the total energy value of the feed. This is due to its nitrogen component. Protein requirements, being of vital importance in animal physiology, can be accounted for in a similar manner as that used for energy, as regards both feed evaluation and requirements. Ruminants

Remembering the tremendous variability in feedstuffs within and between various countries in Europe, it is not surprising that feed-energy evaluation and the assessment of nutrient requirements were tackled in very different ways. For ruminants, the German scientist Kellner (1905), developed a feedevaluation system based on the fat deposition in steers resulting from the feeding of 1 kg digestible starch. All other forms of production such as lactation, growth etc. were expressed in relation to the fat deposition and thus as starch equivalents (SE). Elsewhere in Europe, the fat deposition of barley or oats instead of starch was introduced as relative feed unit, called a 'fodder unit' (FU). The requirements of pigs and poultry initially were also expressed in SE units, although digestibility of nutrients differs widely between ruminants and non-ruminants. These systems proved, after several decades of research, to be unsatisfactory in accuracy for two main reasons: (1) applying the SE system not only for fat accretion but generally for growth, maintenance and lactation supposes equal or proportional efficiencies for all forms of production, which appears to be incorrect; (2) most forages were underevaluated in relation to concentrates. Thus, in many countries of Europe the SE-based systems have been replaced by energy systems based on the ME values of feeds and their associated effi-

401 ciency values. This revision was accomplished in the context of regional and national livestock-husbandry systems, resulting in a variety of units being chosen. Some systems base their calculation on the basic energy unit, the joule (J), or the megajoule ( M J ) . Others use the net energy content of 1 kg of barley as the unit to calculate the quotient and call it a feed unit (FU). Other countries have continued to express energy as calories ( 1 calorie = 4.184 J ). On the other hand, a few countries still adhere to modified M E or F U systems as conceived in the first decades of this century. In total, van der Honing and Alderman (1988) quote (in Chapter III.2) 19 feed-evaluation systems now in use or proposed in Europe, of which 13 are based on the M E concept. T h e y have produced a series of instructive tables (Tables III, IV, VI-VIII on Pages 225, 226, 229, 230, 232), showing the energy values of feedstuffs in different energy systems, as well as the energy requirements for defined levels of production in lactating cows and growing bulls. The M E requirement of a standardized lactating cow, according to the various systems, is shown in Table X. The data in Table X illustrate clearly that there is a remarkable similarity in requirements, when expressed in M J ME, despite the very different types of units chosen in various countries. The variation that exists between the systems is b o u n d up with differences in feed quality and feeding systems, which affect efficiency of energy utilization. Still, the data assembled by van der Honing and Alderman (1988), clearly mark a step forward towards a common energy feed unit. Such a feed unit is urgently needed as shown in Chapter IV, where Parris and Tisserand (1988) refer to O.E.C.D. and E.E.C. studies on this issue. TABLE X Indicative requirements of a lactating cow,weighing600 kg and producing daily 20 kg fat-corrected milk in various energy systems' Country

Denmark France3 F.R.G. G.D.R. The Netherlands Sweden Switzerland U.K. U.S.A. (used in Israel)

Name of unit

SFU UFL MJ NEL EFt VEM Mcal ME MJ NEL MJ ME Mcal NE

Requirement, expressed in: System's unit

MJ ME

12.0 ( 13.8 ) 98.9 8846 14 100 38.7 98.3 169 24.5

1582 ( 1642) 1652 1552 1622 162 1642 169 171

'Data based on van der Honing and Alderman in Chapter III,2.Table III and the Appendix. 2 M E calculated from N E assuming kl (efficiencyof utilizationof M E for lactation ) at 0.60. 3Data in parentheses based on revised energy system. I.N.R.A. (1987).

402 As with energy, in recent years the concepts for protein evaluation have been revised as a result of new research results. The old concept was, and in a number of countries still is, assessing the differences in crude protein (N ><6.25) ingested and excreted in the faeces. The greater the difference, the better the digestibility and feeding value of the protein. This system disregards almost entirely the central role of the microbial processes in the rumen, whose complexity has been increasingly understood as a result of modern and sophisticated research. Van der Honing and Alderman (1988) illustrate that clearly in Fig. 3 in Chapter III.2. Since 1977, 6 new protein-evaluation systems have been published. Table XII on Page 239 shows the common factors involved in these systems. Variability in some of the factors is still considerable, reflecting the need for more research to provide a better foundation for these protein systems. It is now generally accepted, that the protein present in the small intestine of a ruminant is a mixture of original feed protein and microbial protein. The latter, in fact, is resynthesized feed protein and incorporates non-protein nitrogen to some extent. Microbial protein comprises 50-70% of the total protein flow in the intestine. The wide range in the levels of microbial protein formation largely depends on the ration fed and the associated fermentation conditions in the animal's rumen. The different systems take these factors into account to varying degrees. As indicated before, considerable gaps still exist in our knowledge of the metabolisms of both energy and protein. That implies the introduction of "margins of safety" in nutrient requirements. Reducing these margins means more efficient feed utilization and consequently lower production costs. New technology may also help in this respect. The partitioning of energy utilization for various types of livestock production is controlled by complicated and inter-dependent processes, involving endocrinological, enzymatic and other features of intermediary metabolism. Changing these processes in a safe and physiologically appropriate manner may provide a new dimension in feed utilization. Promising results have been accomplished in this respect with somatotropin, an important physiological link in the biological chain of hormonal effects on energy partitioning. For all these reasons, future research should focus on such items as the quantitative information on processes in intermediary metabolism. Besides, reliable and rapid feed-analysis techniques are necessary. Non-ruminant herbivores; horses and rabbits

Non-ruminant herbivores such as horses and rabbits are fed mainly with roughage (Tisserand, 1988; Lebas, 1988). However, they utilize roughages less efficiently than ruminants do. Obviously this can be explained by anatomic differences of the digestive tract: non-ruminant herbivores have a relatively

403 small stomach but voluminous large intestine, which is populated by microorganisms. In contrast to ruminants, microbial digestion takes place after digestion and absorption of those nutrients, which are readily degraded by enzymes of the animal. Accordingly the yield of energy and nutrients from nonstarch polysaccharides (NSP) is much less in non-ruminant herbivores than in ruminants. However, it is higher than in pigs and poultry, because NSP are degraded in the caecum and colon of non-ruminant herbivores by microorganisms, producing volatile fatty acids, which are available for the animal as energy source. The microbial protein however, which forms an important source for ruminants, is virtually lost for horses as a nutrient. It is excreted with the faeces. Rabbits, however, make use of this valuable protein source by coprophagy. Feed value and feed requirement for non-ruminant herbivores are estimated in a similar way as for other animals. The energy value and requirement are mostly expressed by DE or ME. The G.D.R. uses net energy fat. In France, energy value and requirement are based on net energy for maintenance. Physical activity forms an important part of the horse's performance. To assess physical activity precisely for a factorial calculation of the requirement is difficult. Therefore it is usually expressed as a multiple of maintenance requirement, which might be sufficient for practical feeding programmes. A reliable evaluation of the protein value and protein requirement for horses is not yet available. Further research is needed to assess absorbable protein, as protein value and protein requirement, respectively. For rabbits, digestibility of protein, if coprophagy is not prevented, is a reliable measure to estimate the protein value of the feed and the protein requirement of the animal.

Pigs and poultry Some decades ago, feed-evaluation systems for pig and poultry feeds were based on starch equivalent (SE) and the fodder unit (FU), or alternatively on total digestible nutrients (TDN). Since then, calorimetric research with both pigs and poultry has yielded data resulting in the present energy systems for these classes of livestock. The Oskar Kellner Institute in Rostock (G.D.R.), developed a net energy (NE) evaluation system based on the energy deposited as fat in adult, castrated, male pigs and in adult cocks. In Denmark, an energy system was developed for pigs which uses a simple equation for converting ME to NE. However the majority of European countries are using DE or ME as a basis for feeding systems. For poultry, ME is used predominantly as the feed-evaluation parameter. As with ruminants, nearly every country's particular unit depends on the local feeding situation and livestock-production systems. Feed-evaluation systems are designed in principal for individual feedstuffs with their own particular digestibility and metabolizability values. Compound

404

feeds possess a fairly constant feeding value within a special feed type, in spite of the continually changing pattern of ingredients. Exceptionally high levels of fibrous feedstuffs in compound feeds may affect normal additivity and interaction of the separate ingredients. Therefore in the F.R.G. correction of the feeding value for microbial fermentation in the hind gut of non-absorbed structural carbohydrates is applied. Assessing the energy values of compound feeds through prediction equations for DE or ME is difficult to achieve. That approach could be improved if, for example, digestibility could be rapidly assessed in the laboratory. Developing in vitro techniques including near infra-red reflectance {NIR) may be of considerable importance here. For the time being, the feeding value of compound feeds is assessed by regressing ME or NE values on the gross chemical composition of the feed, except when the pattern of ingredients is disclosed by the manufacturer. The evaluation of the protein values of feedstuffs for pigs is traditionally based, in most countries, on digestible crude protein (DXP), but very often merely on crude protein (XP), as is the case for poultry feed. In both cases, however, the content of certain amino acids (AA), especially lysine and methionine plus cystine are stated. So far, this additional information is restricted to the total AA levels, whereas digestible or available contents of AA would be more useful. Such data, however, are scarce, and there is still discussion as to whether ileal or so called faecal (overall) digestibility is preferable. Tables with AA digestibility data are published in The Netherlands and Denmark. In the future evaluation of protein value based on available AA may be the best option. Nutrient requirements for pigs and poultry are often based empirically on national-feeding experiments, although in recent years attempts have been made to apply the factorial method, especially for pig feeding. The energy requirement expressed in MJ ME of an average sow, suckling 10 piglets per litter and weaning 21 piglets per year, and the average energy requirement of a fattening pig between 20 and 100 kg liveweight, with 700-750 g average liveweight gain, is shown in Table XI. Net energy requirements according to proposals from The Netherlands, G.D.R., U.S.S.R. and Denmark (EW, KEFs, OFU, FEs) are considered together with DE, ME and TDN requirements. Conversion factors, according to the specifications by Henry et al. (1988) in the Appendix of Chapter III.4, were applied. Table XI shows an amazing similarity of the requirement, independently of the systems. Poultry are normally fed ad libitum, as is often also the case for fattening pigs. Because they are generally kept in groups or flocks, energy requirements are expressed in terms of energy concentration in the dry matter. The energy and protein requirements for poultry, as applied in European countries is shown and discussed by Vogt (1987a) (see Chapter III.4). Protein requirements generally of poultry are expressed as XP with specification of lysine and methionine + cystine requirements. Sometimes other essential

405 TABLE XI Indicative requirementsof an averagebreeding sow and a fattening pig in variousenergysystemsI Name of unit (abbreviated)

DE (MJ) ME (MJ) EW (The Netherlands) KEF~ (G.D.R.) OFU (U.S.S.R.) TDN (kg) FEs (Denmark)

Requirement, expressed in: Unit

MJ ME average breeding sows

Unit

MJ ME fattening pig3

41.5 39.4 3.37 2.02 3.55 2.25 3.14

39.4 39.4 39.5 39.5 39.4 39.3 38.0

29.5 28.0 2.23 1.34 2.52 1.60 2.24

28.0 28.0 28.0 28.0 28.0 28.0 29.1

1Data based on Henry et al. (1988) in Chapter III.4 and Appendixwith tables. 2Mean daily amounts for an average sow with 10 piglets litter -1 and weaning 21 piglets year-~; 87% DM in feed, average efficiencyof ME conversionto NE 75%, ME/DE = 0.95.1 TDN = 18.4 MJ DE. ~Meandaily amounts for fattening pigs between 20 and 100 kg liveweight,700-750 g averagedaily gain, 2.2 kg feedday- 1on average,averageefficiencyof ME conversionto NE 70%, ME/DE = 0.95. 1 TDN= 18.4 MJ DE. amino acids (EAA) are also taken into account. For poultry a model for calculating the protein and AA requirements by the factorial method has been developed in the U.K. In conclusion, n u t r i e n t requirements of n o n - r u m i n a n t s should be assessed increasingly by the use of the factorial approach for both energy and AA requirements. In the future, the inclusion of synthetic AA in pig and poultry diets is expected to increase for two reasons: (1) to use the available feed protein sources more efficiently; (2) to decrease the problems of excessive excretion of nitrogen by livestock.

Fur-bearing animals and fish The choice of feeds for fur-bearing animals is very limited (Tauson, 1988, Chapter III.5 ). Their digestive tracts are very short and the rate of passage of ingested feeds is very high. Consequently, only feeds with a low fibre content are suitable for feeding to mink and foxes. Feeds of animal origin (fish byproducts, by-products from slaughter houses), and some vegetable feeds with high levels of high-quality protein, are most appropriate. Feedstuffs rich in easily-digestible carbohydrates may also be used, but they need cooking for mink and young foxes. Feeds are evaluated as in most other animal-production systems. The energy values of nutrients (GE, DE and M E ) are derived from proximate analyses

406 and digestion experiments. The AA composition of the proteins is critical. In recent years, experiments have focused on the assessment of the digestibility of AA. The energy requirements of fur-bearing animals are very much dependent on ambient temperatures. Thus, the ME requirements for maintenance of mink increase by nearly 53%, if ambient temperature decreases from 20 to - 3 ° C. Fish, primarily trout and salmon, need feeds similar to those for fur-bearing animals, i.e. protein-rich feeds, hardly-any fibre and a very restricted carbohydrate supply, because carbohydrates are not completely digested Austreng et al., 1988, Chapter III.6). Protein, together with high-quality fat represent the main energy sources for fish. Deamination implies a suboptimal utilization of proteins, but in contrast to mammals and birds, there is no energy cost to detoxicating ammonia, because it is voided straight into the surrounding water. Therefore, the energy value of protein for fish is greater than its value for mammals and birds. Concerning energy requirement, the striking fact has to be considered, that the fish is able to adapt its body temperature, and thus its feeding level and metabolism, to the ambient temperature of the water. Besides, considerable differences in physical activity influence the requirement. FEED UTILIZATIONIN EUROPE Although, in every country, statistics are available for livestock population, for its output, for areas for feed production and for other livestock husbandry items, their similarity is generally small. Therefore it is difficult, if at all possible, to collect an identical set of quantitative information in these fields from various countries in order to produce an international survey. Still, the growing interdependency of countries all over the world makes production of such uniform data more and more urgent for policy makers. Numerous data in this volume show that technical, qualitative data on assessing feed composition, on feed evaluation and on nutrient requirements of livestock are approaching an internationally uniform concept. If uniform quantitative information on feed utilization in Europe should become available a set of feed utilization matrices (FUMs) could be produced. An FUM shows, on a crop-year basis, the utilization of all types of feed by different categories of livestock, both in terms of product weight and in equivalents of energy and protein. So far only one country, Denmark, produces a complete FUM annually as shown in Table I in Chapter IV ( Parris and Tisserand, 1988 ). Some other countries (e.g. the F.R.G. and The Netherlands) do so in a limited manner. An O.E.C.D. project as well as an E.E.C. study are under way to produce FUMs for all member countries, similar to the Danish approach. Parris and Tisserand describe in Chapter IV the methodology to construct an FUM. This involves three steps: ( 1 ) construction of a livestock inventory, determination of the livestock fed in a crop year and calculation of their annual

407 energy (ME) and protein (XP) requirement; (2) estimation of feed-resource balance, showing the weight of feeds consumed as well as their energy and protein equivalent; (3) allocation of the feeds to different types of livestock, expressed in units of weight, energy and protein. Step one is probably rather simple, because livestock inventory statistics and nutrient-requirement data are generally available in all countries. Step two is more difficult, because estimation errors are unavoidable. Mostly feed-balance data are of a residual character. T h a t means t h a t total feed production, less all kinds of alternative utilization, e.g. h u m a n food, export, seeds and others, is supposed to be used as feedstuff. Thus, all inaccuracies in the estimation are assembled in the feed-balance part. A specific source of error is the estimation of the quantity of grazed roughage. Generally only the area of roughage is available in national statistics. Deriving yield and output requires considerable assumptions in calculating these data, which might not be realistic enough. Step three is also subject to some errors in estimation, such as applying standard-utilization coefficients for energy and protein utilization, regardless of the type of livestock production. However, this size of error will probably not exceed 5% as quoted in Chapter IV. It must be concluded t h a t the construction of an FUM, per country annually, involves a number of inaccuracies. Still, reaching t h a t goal would mean a substantial gain in valuable information on feed resources, compared with the present situation.

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408 Miller, E.L. and de Boer, F., 1988. Feedstuffs. 6. By-products of animal origin. Livest. Prod. Sci., 19: 159-195. Namur, A.P., Morel, J. and Bickel. H., 1988. Feedstuffs. 7. Compound animal feed and feed additives. Livest. Prod. Sci., 19: 197-209. Parris, K.P. and Tisserand, J.L., 1988. A methodology to complete a national feed utilisation matrix using European data. Livest. Prod. Sci., 19: 375-388. Probst, F.W., 1982. Appendix 2. In: R.D. Politiek and J.J. Bakker (Editors), Livestock Production in Europe, Perspectives and prospects, Elsevier, Amsterdam, pp. 307-336. Sundstol, F., 1988. Feedstuffs. 5. Straw and other fibrous by-products. Livest. Prod. Sci., 19: 137-158. Tauson, A.H., 1988. Feed evaluation and nutritional requirements. 5. Fur-bearing animals. Livest. Prod. Sci., 19: 355-367. Tisserand, J.L., 1988. Feed evaluation and nutritional requirements. 3. Non-ruminant herbivores; horses. Livest. Prod. Sci., 19: 279-288. Todorov, N.A., 1988. Feedstuffs. 3. Cereals, pulses and oilseeds. Livest. Prod. Sci., 19: 47-95. Van der Honing, Y. and Alderman, G., 1988. Feed evaluation and nutritional requirements. 2. Ruminants. Livest. Prod. Sci., 19: 217-278. Vogt, H., 1987. Energy and protein requirements for poultry. Recommendations in European countries. W.P.S.A. Journal, 43, in press.