ANSC 1st Edition Lecture 24Outline of Last Lecture I. Equine Digestive System, Forages, and Concentrate Feeds. Outline of Current Lecture II. Intake TablesIII. Concentrate Feeds: Proteina. Nutrient:Calorie RatiosIV. Concentrate Feeds: Mineralsa. Calcium:Phosphorous Ratiob. Other Important MineralsV. Concentrate Feeds: Vitaminsa. Vitamin B1b. BiotinVI. Mare and Foal Nutritiona. Body Condition ScoreVII. Types of Broodmaresa. Open or Maiden Mareb. Pregnant Maresc. Lactating MaresVIII. IX. Young Growing Horsesa. Foals and Weanlingsb. Yearlings, Long Yearlings, and Two Year OldsX. Working HorsesCurrent LectureHorse Nutrition and Feeding IIIntake TablesRelationship of Crude Fiber to Expected DE in Conventional and Fat Supplemented ConcentratesCrude fiber, % (feed tag) Approximate DE (Mcal/lb) DE (Mcal/lb) with 4-5% added fat (tag 7-8% fat)2 (= corn) 1.62 1.724 1.55 1.656 1.45 1.558 1.35 1.4510 (= oats) 1.25 1.35These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.12 1.15 1.25Typical Grain and Hay Intake Expressed as % BWIntake (% BW) Intake (% BW)Class of Horse Forage ConcentratesMature Idle 1.5 – 2.0 0.0 – 0.5Pregnant 1.0 – 1.5 0.5 – 1.0Lactating 1.0 – 2.0 1.0 – 2.0Weanling 0.5 – 1.0 1.5 – 3.0Yearling 1.0 – 1.5 1.0 – 2.0Light Work 1.0 – 2.0 0.5 – 1.0Moderate Work 1.0 – 2.0 0.75 – 1.5Intense Work 0.75 – 1.5 1.0 – 2.0Concentrate Feeds: Protein•act like a true monogastric during protein digestion•Protein quality is critical, particularly for growth-SBM bet source of essential AAs-CSM used, but not alone•Lysine first limiting AA-crystalline sources (synthetic) can be used•Urea can be tolerated-may meet N needs-microbial crude protein not successfully absorbed-will not become toxic, but cannot be utilizedDietary Crude Protein LevelsClass of Horse Range in Crude ProteinMature Idle 8-10%Performance/Riding 10-14% (14 much more likely)Lactation 14-16%Foals/Weanlings 16%Yearlings 14%Two Year Olds 12-14%You Can’t JUST Think About Protein Alone•Everything is relative to dietary energy provided•important to consider the nutrient:calorie ratios in the diet•Nutrient:calorie ratios are expressed as g/Mcal of DE•Nutrient:calorie ratios are important for protein, AAs (lysine), and mineralsNutrient:Calorie Ratios•ESPECIALLY CRUCIAL FOR YOUNG GROWING HORSES-to optimize growth-to minimize developmental orthopedic disease type problems-to meet requirements in reasonable amount of daily feedRecommended Nutrient:Calorie RatiosClass BW, lb DE, Mcal/d CP, g/d Ca, g/d CP:Mcal DECa:Mcal DEMature, idle horse1000 15 600 18.1 40 1.2Lactating 1000 25.8 1294 50.8 50 2.0Pregnant 1000 18 792 34.2 44 19Working Horses:Light 1000 18.8 750 22.9 40 1.2Moderate 1000 22.5 900 27.5 40 1.2Intense 1000 30 1201 36.6 40 1.2Growing Horses:Preweaning 300 13 715 29.1 55 2.3Weaning (6mo)475 17.3 867 36.2 50 2.1Yearling (12mo)715 21.3 956 34.1 45 1.6Nutrient:calorie ratio requirements of weanling horses in comparison to an oat grain/alfalfa diet Nutrient:Calorie Ratios (g/Mcal DE)Nutrient Provided by oats/alfalfa Required by weanlingProtein 49.2* 50.0Lysine 1.8* 2.1Calcium 1.7* 2.1Phosphorous 1.2 1.2*Less than required by weanlingConcentrate Feeds: Minerals*Supplemental Ca and P needed in more diets*•Ratio important:-minimum 1:1 Ca:P ratio-recommended 1.5:1 Ca:P ratio•many common feed ingredients have inverted Ca:P ratios (less than 1:1 Ca:P)•calcium carbonate or limestone used to add only Ca to the diet•dicalcium phosphate used to supplement Ca and PIngredients with Inverted Ca:P Ratio:Feed Ca, % P, % Ca:P RatioOats 08 .34 .24Corn .05 .27 .19SBM .35 .63 .56Wheat Midds .1 1.02 .1Oat Bran .13 1.13 .12Other Important Minerals for Horse Nutrition:Macrominerals:•Electrolytes supplemented to performance horses-Na, Cl, K-equine sweat is hypertonic (more concentrated than blood)Microminerals:•Cu, Zn, Mn important during growth/reproduction•Cu, Zn, Se important for maintaining effective disease resistanceConcentrate Feeds: VitaminsFat-Soluble Vitamins:•Vitamin A  added to diets at 1,000 – 2,500 IU/lb•Vitamin D  added to diets at 10% of A•Vitamin E  added to diets at 80 – 100 IU/lb-cannot be toxic•Vitamin K  synthesized through hindgut fermentationWater-Soluble Vitamins•B-complex vitamins  some synthesized in hindgut•Vitamin C  synthesized from glucoseVitamin B1 (Thiamin)•Actively involved in energy metabolism•influences appetite (Brewer’s Yeast)•helps lower blood lactate levels•normally synthesized in adequate amounts in the hind-gut of horse, but some hard working, heavily stressed horses may require additional Thiamin supplementationBiotin:•Supplementation 20 mg/day-long term supplementation may improve hoof health in 1/3 or more of horsesMare and Foal NutritionBody Condition Score:•subjective measurement of body fat reserves•used to assess energy status•body fat storage important to fuel physiological functions•1 = extremely thin•9 = extremely fat•same system used in beef cattleBody Condition Influences Reproductive Performance•at foaling: recommended BCS of 6•benefits of maintaining proper BCS:-cycle earlier-fewer cycles per conception (get pregnant quicker)-higher pregnancy rate-maintain pregnancy more easily-no benefits to BCS > 7Types of BroodmaresOpen or Maiden Mare:•feed to meet maintenance requirements•nutrition provided by medium-quality forages or combination or low-quality forage and concentrate•should enter breeding season at BCS 5 to 7Pregnant Mares:•60% of fetal growth happens in the last trimester•feed to meet maintenance requirements for the 1st 2 trimesters•gradually increase concentrate in diet when approaching 3rd trimester•carefully balance diet for protein and mineral needsLactating Mares:•early lactation: increase in energy, CP, and Ca requirements:-energy increases 90%-protein increases 120%•at foaling increase the concentrate portion of ration slowlyYoung Growing HorsesFoals and Weanlings:•creep feed recommended:-late lactation does not support all nutrient needs-nutrient requirements of foal differ from mare•creep rations:-assume low forage intake-should be palatable-high quality (14 – 16% CP)-higher nutrient:calorie ratio needed than the mare’s diet•weanlings have low forage consumptionDevelopmental Orthopedic