Rebecca L. Remillard, DVM, PhD, DACVN, is the Founder and President of Veterinary Nutritional Consultations, Inc. in Hollister, North Carolina, USA.

Contributors xvi Preface xix Section I The Horse 1 Animal Assessment 3 1 Feeding Horses: Back to Evolution 5Rebecca L. Remillard 1.1 Introduction 5 1.2 The Evolution of Equus 6 1.2.1 Environmental Changes 6 1.2.2 Musculoskeletal System Changes in Response to Predation on the Open Plains 7 1.2.3 Alimentary System Changes in Response to a Changing Food Supply 8 1.3 Equine Nutrient Requirements vs. Recommendations 10 References 13 2 Nutritional Assessment of the Horse 15Shannon Pratt Phillips and Meri Stratton- Phelps 2.1 Introduction 15 2.2 Obtaining a History 16 2.3 Physical Examination 16 2.3.1 Determining Body Weight 17 2.3.2 Estimating Body Composition 19 2.3.3 Body Condition Scoring 21 2.4 Changes in Body Weight 22 2.4.1 Etiology of Weight Loss 24 2.4.2 Weight Gain in Adult Horses 26 2.5 Laboratory Tests 26 2.5.1 Weight Loss or Low Body Condition Score 26 2.5.2 Weight Gain or High Body Condition Score 27 2.5.3 Mineral and Vitamin Imbalances 27 References 30 3 The Horse: Host 33Veronique Julliand, Sarah L. Ralston, and Rebecca L. Remillard 3.1 Introduction 33 3.2 Oral Cavity 34 3.3 Stomach 38 3.4 Small Intestine, Pancreas, and Liver 40 3.5 Cecum and Large Colon 43 3.6 Small Colon, Rectum, and Defecation 46 References 47 4 The Horse: Microbiome 51Veronique Julliand and J. Scott Weese 4.1 Introduction 51 4.2 Microbiota in Adult Healthy Horses 52 4.3 Microbiota in Healthy Foals and Young Horses 54 4.4 The Role of the Microbiota 55 4.4.1 Nourishment 55 4.4.2 Disease 57 4.5 Exogenous Impacts on and Manipulation of the Microbiome 58 4.5.1 Diet 58 4.5.2 Probiotics 59 4.5.3 Prebiotics 60 4.5.4 Drugs 60 4.5.5 Other Factors 61 4.5.6 Fecal Microbial Transplantation 61 4.6 Assessment of the Microbiota and Microbiome 61 4.6.1 Sampling Sites and Types 62 4.6.2 Sample Handling 62 4.6.3 Testing Methods 62 4.7 Summary 63 References 63 Section II The Diet 69 Nutrient Metabolism 71 5 Water 73Jonathan M. Naylor 5.1 Water as a Nutrient 73 5.2 Body Water Content 74 5.3 Water Requirement 74 5.4 Water Deficiency 76 5.5 Watering Devices 77 5.6 Sources of Water 78 5.7 Water Quality 79 5.8 Water as Habitat for Disease Vectors and Insects 82 References 83 6 Energy 86Richard Godbee and Robert Coleman 6.1 The Concept of Energy 86 6.2 Dietary Energy 89 6.2.1 Dietary Carbohydrates 89 6.2.2 Dietary Fats 91 6.3 Horse Energy Requirements 93 6.3.1 Cold Weather Care 95 6.3.2 Hot Weather Care 96 References 97 7 Protein 100Patricia Graham- Thiers 7.1 Function and Composition 100 7.2 Dietary Protein 101 7.2.1 Protein Digestion 101 7.2.2 Protein Quality 102 7.2.3 Ideal Protein 104 7.2.4 Protein Supplements 104 7.2.5 Non- Protein Nitrogen Sources 105 7.2.6 Protein Imbalance 105 7.3 Horse Protein Requirements by Life Stage 106 7.3.1 Maintenance 106 7.3.2 Growth 108 7.3.3 Gestation 108 7.3.4 Lactation 108 7.3.5 Work 109 References 110 8 Minerals 113Ashley Fowler, Mieke Brummer- Holder, and Laurie A. Lawrence 8.1 Introduction 113 8.2 Macrominerals 114 8.2.1 Calcium 115 8.2.2 Phosphorus 121 8.2.3 Magnesium 122 8.2.4 Sodium, Potassium, and Chlorine 124 8.2.5 Sulfur 126 8.3 Microminerals 127 8.3.1 Selenium 127 8.3.2 Iodine 131 8.3.3 Copper 133 8.3.4 Zinc 135 8.3.5 Iron 136 8.4 Other Minerals of Interest 138 References 140 9 Vitamins 148Sarah Dodd, Sarah K. Abood, and Jacqueline M. Parr 9.1 Introduction 148 9.1.1 Sources 149 9.1.2 Requirements 149 9.1.3 Deficiencies and Toxicities 151 9.1.4 Summary 153 9.2 Fat- Soluble Vitamins 154 9.2.1 Vitamin A 154 9.2.2 Vitamin d 157 9.2.3 Vitamin E 159 9.2.4 Vitamin K 161 9.3 Water- Soluble Vitamins 163 9.3.1 Thiamine (B1) 163 9.3.2 Riboflavin (B2) 164 9.3.3 Niacin (B3) 165 9.3.4 Pantothenic Acid (B5) and Pyridoxine (B6) 165 9.3.5 Biotin (B7) 166 9.3.6 Folate (B9) 167 9.3.7 Cobalamin (B12) 168 9.3.8 Vitamin c 168 References 169 Ration Assessment 175 10 Ration Assessment and Farm Investigations 177Rebecca L. Remillard and Sarah L. Ralston 10.1 Introduction 177 10.2 Farm Investigation 177 10.2.1 Animal Assessment 178 10.2.2 Ration Assessment 178 10.2.3 Water 182 10.2.4 Feeding Management Assessment 182 10.3 Ration Analysis 182 10.4 Ration Formulation 186 10.5 Reassessment 187 References 188 11 Forages 190Bridgett McIntosh 11.1 Introduction 190 11.2 Importance of Forages 190 11.3 Hay 192 11.3.1 Types of Hay 192 11.3.2 Forms of Hay 193 11.3.3 Hay Cuttings 195 11.3.4 Hay Grades and Relative Feed Value 195 11.3.5 Feeding Management of Hay 196 11.4 Pasture 200 11.4.1 Soil Testing and Fertility 201 11.4.2 Forage Selection 202 11.4.3 Nutritional Considerations in Pasture Plant Selection 203 11.4.4 Grazing Management 205 References 209 12 Toxic Plants 212Bryan Stegelmeier and T. Zane Davis 12.1 Introduction 212 12.2 Plants that Damage Dermal and Epithelial Tissues 213 12.2.1 Skin Photosensitization 213 12.2.2 Mechanical Injuries to Facial and Oral Tissues 218 12.2.3 Inflammation of the Hoof Laminae 218 12.3 Plants that Contain Gastrointestinal Toxins 220 12.4 Plants that Contain Hepatotoxins 223 12.5 Plants Containing Neurotoxins 227 12.6 Plants that Contain Muscle Toxins 235 12.7 Plants that are Toxic to the Urogenital System 238 References 241 13 Manufactured Feeds 244Erin Perry, Kathleen Crandell, Jeanne van der Veen, and Jesse M. Fenton 13.1 Introduction 244 13.2 Manufacturing Processes 244 13.2.1 Ingredients 245 13.2.2 Ingredient Processing 250 13.3 Palatability and Preference 254 13.4 Quality Control Measures 255 13.5 Package and Label 257 13.6 Equine Marketing Concepts 257 13.6.1 Specific Purpose 257 13.6.2 Price and Ingredients 258 13.6.3 Nutrients 258 13.6.4 Features and Benefits 258 13.7 Calculating Cost of Feeding 259 References 260 14 Dietary Supplements 264Donna M. Raditic 14.1 Introduction 264 14.2 Regulation of Supplements 264 14.3 Marketing of Supplements 265 14.3.1 Animal Food Additive 265 14.3.2 Dosage Forms 266 14.4 Evidence- Based Medicine 267 14.5 Musculoskeletal Diseases 268 14.6 Gastrointestinal Diseases 270 14.7 Behavior 272 14.8 Respiratory Diseases 272 14.9 Metabolic/Endocrine Diseases 273 References 274 15 USA Feed Regulations and Safety 279David A. Dzanis 15.1 Introduction 279 15.2 USA Regulatory Oversight 280 15.2.1 Food and Drug Administration Authority 280 15.2.2 State Authority 280 15.3 Basic Label Requirements 281 15.4 Labeling Claims 285 15.5 Special Products 287 15.5.1 Supplements 287 15.5.2 Medicated Feeds/Veterinary- Directed Feeds 287 15.6 Feed Safety 290 15.7 Enforcement 291 15.8 Reporting Problems with Horse Feed Products 292 15.9 Summary 293 References 293 Section III Feeding Management 295 Healthy Horses 297 16 Feeding and Drinking Behaviors 299Katherine A. Houpt and Rebecca L. Remillard 16.1 Introduction 299 16.2 Feeding Behaviors 299 16.2.1 Time Management 300 16.2.2 Pastured Horse Feeding Behaviors 301 16.2.3 Stabled Horse Feeding Behaviors 302 16.2.4 Food and Water Intake 303 16.2.5 Pica 303 16.3 Drinking Behavior 303 References 304 17 Feeding Adult and Senior Horses 307Géraldine Blanchard and Nettie R. Liburt 17.1 Introduction 307 17.2 Animal Assessment 308 17.3 Ration Assessment 312 17.4 Feeding Management 317 17.4.1 Maintenance of Weight and Condition 318 >6/ 9 318 17.4.1.2 Bcs