AnimAl nutrition Seventh Seventh Edition Edition AnimAl nutrition Seventh Edition A n P. McDonald R. A. Edwards J. F. D. Greenhalgh i C. A. Morgan L. A. Sinclair R. G. Wilkinson m P. McDonald A R. A. Edwards Animal Nutrition is a core text for undergraduates in Animal Science, Veterinary Science, Agriculture, l Biology and Biochemistry studying this subject. It also provides a standard reference text for agricultural J. F. D. Greenhalgh advisers, animal nutritionists and manufacturers of animal feeds. n The latest edition of this classic text continues to provide a clear and comprehensive introduction to the C. A. Morgan u science and practice of animal nutrition. The text is supported by key experimental evidence throughout. Quantitative aspects of the subject are clearly explained and illustrated by worked examples. Chapters t L. A. Sinclair that deal with the calculation of requirements include problems and solutions to aid student learning. Other r chapters include essay-type questions that students can use as a guide to revision. R. G. Wilkinson i t The new edition of Animal Nutrition has been completely updated and has been reorganised to i present the subject in six sections: o • the components of foods – carbohydrates, lipids, proteins, vitamins and minerals n • the digestion and metabolism of nutrients – how animals obtain and utilise nutrients from foods • quantifying the nutrients supplied by foods – digestibility, energy and protein values • the nutrient requirements of animals – maintenance and production M M • a description of the foods commonly given to animals – their nutrient content and factors o c r D affecting their use g o a n • the contribution of animal products to human nutrition – including effects on health and the n a environment l d S The Appendix provides comprehensive tables on the composition of foods and the latest feeding in standards for dairy and beef cattle, sheep, pigs and poultry, and horses. E c d l a w i r a P McDonald was formerly Head of the Department of Agricultural Biochemistry at the Edinburgh School rd W of Agriculture. R A Edwards was formerly Head of the Department of Animal Nutrition at the Edinburgh s School of Agriculture. J F D Greenhalgh is Emeritus Professor of Animal Production and Health at il k the University of Aberdeen. C A Morgan is an animal nutritionist at the Scottish Agricultural College, i G n r Edinburgh. L A Sinclair is Professor of Animal Science at Harper Adams University College. R G Wilkinson s e is Principal Lecturer in Ruminant Nutrition at Harper Adams University College o e n n h a l g h www.pearson-books.com Front cover image: © Getty Images CVR_MCDO4238_07_SE_CVR.indd 1 20/12/2010 15:00 ANIMAL NUTRITION We work with leading authors to develop the strongest educational materials in biology, bringing cutting-edge thinking and best learning practice to a global market. Under a range of well-known imprints, including Prentice Hall, we craft high-quality print and electronic publications which help readers to understand and apply their content, whether studying or at work. To find out more about the complete range of our publishing, please visit us on the World Wide Web at: www.pearsoned.co.uk ANIMAL NUTRITION SEVENTH EDITION P McDonald Formerly Reader in Agricultural Biochemistry, University of Edinburgh, and Head of the Department of Agricultural Biochemistry, Edinburgh School of Agriculture R A Edwards Formerly Head of the Department of Animal Nutrition, Edinburgh School of Agriculture J F D Greenhalgh Emeritus Professor of Animal Production and Health, University of Aberdeen C A Morgan Scottish Agricultural College L A Sinclair Harper Adams University College R G Wilkinson Harper Adams University College Contents Preface to the seventh edition xi Acknowledgements xii Part 1 THE COMPONENTS OF FOODS 1 1 The animal and its food 3 1.1 Water 4 1.2 Dry matter and its components 5 1.3 Analysis and characterisation of foods 5 Summary 14 Further reading 15 2 Carbohydrates 16 2.1 Classification of carbohydrates 16 2.2 Monosaccharides 18 2.3 Monosaccharide derivatives 20 2.4 Oligosaccharides 23 2.5 Polysaccharides 26 2.6 Lignin 30 Summary 30 Further reading 31 3 Lipids 32 3.1 Classification of lipids 32 3.2 Fats 33 3.3 Glycolipids 43 3.4 Phospholipids 44 3.5 Waxes 46 3.6 Steroids 47 3.7 Terpenes 50 Summary 51 Questions 51 Further reading 52 4 Proteins, nucleic acids and other nitrogenous compounds 53 4.1 Proteins 53 4.2 Amino acids 53 4.3 Peptides 59 4.4 Structure of proteins 60 4.5 Properties of proteins 61 4.6 Classification of proteins 61 4.7 Nucleic acids 63 v Contents 4.8 Other nitrogenous compounds 66 4.9 Nitrates 67 4.10Alkaloids 68 Summary 68 Further reading 69 5 Vitamins 70 5.1 Introduction 70 5.2 Fat-soluble vitamins 74 5.3 The vitamin B complex 87 5.4 Vitamin C 99 5.5 Hypervitaminosis 100 Summary 101 Further reading 102 6 Minerals 103 6.1 Functions of minerals 103 6.2 Natural and supplementary sources of minerals 107 6.3 Acid–base balance 110 6.4 Major elements 112 6.5 Trace elements 121 6.6 Other elements 135 Summary 136 Further reading 136 Part 2 THE DIGESTION AND METABOLISM OF NUTRIENTS 139 7 Enzymes 141 7.1 Classification of enzymes 142 7.2 Nature of enzymes 144 7.3 Mechanism of enzyme action 146 7.4 Specific nature of enzymes 148 7.5 Factors affecting enzyme activity 150 7.6 Nomenclature of enzymes 154 Summary 155 Further reading 155 8 Digestion 156 8.1 Digestion in monogastric mammals 156 8.2 Microbial digestion in ruminants and other herbivores 171 8.3 Alternative sites of microbial digestion 186 8.4 Nutrient digestion and the environment 188 Summary 189 Further reading 191 Historical reference 191 9 Metabolism 192 9.1 Energy metabolism 194 9.2 Protein synthesis 213 vi Contents 9.3 Fat synthesis 219 9.4 Carbohydrate synthesis 226 9.5 Control of metabolism 232 Summary 233 Further reading 234 Part 3 QUANTIFYING THE NUTRIENT CONTENT OF FOODS: DIGESTIBILITY, ENERGY AND PROTEIN VALUES 235 10 Evaluation of foods: digestibility 237 10.1 Measurement of digestibility 238 10.2 Validity of digestibility coefficients 243 10.3 Digestibility in different sections of the digestive tract 244 10.4 Factors affecting digestibility 247 10.5 Measurement of mineral availability 251 Summary 252 Questions 252 Further reading 253 11 Evaluation of foods: energy content of foods and energy partition within the animal 254 11.1 Demand for energy 254 11.2 Supply of energy 255 11.3 Animal calorimetry: methods for measuring heat production and energy retention 262 11.4 Utilisation of metabolisable energy 270 Summary 278 Questions 279 Further reading 280 12 Evaluation of foods: systems for expressing the energy value of foods 281 12.1 Energy systems and energy models 282 12.2 Energy systems for ruminants 283 12.3 Energy systems for pigs and poultry 295 12.4 Energy systems for horses 297 12.5 Predicting the energy value of foods 298 Summary 300 Questions 301 Further reading 301 Historical references 302 13 Evaluation of foods: protein 303 13.1 Crude protein 303 13.2 Digestible crude protein 305 13.3 Determination of endogenous nitrogen 306 13.4 Measures of protein quality for monogastric animals 308 13.5 Measures of food protein used in practice in the feeding of pigs and poultry 315 vii Contents 13.6 Measures of food protein used in practice in the feeding of horses 317 13.7 Measures of protein quality for ruminant animals 318 13.8 The UK metabolisable protein system 331 13.9 Feed into Milk 333 Summary 337 Questions 338 Further reading 339 Part 4 THE NUTRIENT REQUIREMENTS OF ANIMALS 341 14 Feeding standards for maintenance and growth 343 14.1 Nutrient requirements for maintenance 345 14.2 Nutrient requirements for growth 361 14.3 Nutrient requirements for wool production 373 14.4 Mineral and vitamin requirements for maintenance and growth 375 14.5 Nutritional control of growth 378 Summary 381 Questions 383 Further reading 383 Historical reference 383 15 Feeding standards for reproduction 384 15.1 Nutrition and the initiation of reproductive ability 385 15.2 Plane of nutrition, fertility and fecundity 387 15.3 Egg production in poultry 391 15.4 Nutrition and the growth of the foetus 395 Summary 402 Questions 403 Further reading 403 16 Lactation 405 16.1 Sources of milk constituents 406 16.2 Nutrient requirements of the lactating dairy cow 410 16.3 Nutrient requirements of the lactating goat 440 16.4 Nutrient requirements of the lactating ewe 444 16.5 Nutrient requirements of the lactating sow 449 16.6 Nutrient requirements of the lactating mare 453 Summary 457 Questions 458 Further reading 459 17 Voluntary intake of food 461 17.1 Food intake in monogastric animals 462 17.2 Food intake in ruminants 468 17.3 Food intake in horses 474 viii