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Horse Nutrition • Horses are nonruminant herbivores that naturally spend 60-75% of their day grazing. • Typically they ingest approximately 2% of their body weight (dry matter basis) per day while grazing Main Nutrients • • • • • Water Energy Proteins Minerals Vitamins • With domestication new alterations in feed, feed times, and methods have changed. • Starch cereals • Protein concenetrates • Dried forages • Confined more of the time in stalls • Smaller pastures • Fed 1-2 times per day • Resulting in about 40% of time eating Horses should have access to clean, fresh water at all times. A mature horse drinks on average 12-15 gallons a day. This will vary with the activity and temperature of the environment. For example: Summer-more Winter-less Important note: Hot, exhausted horses should wait 30 minutes before drinking water after heavy exercise. They are however, allowed to consume hay during this cooling down period. -Also owners should be aware that horses that consume more grains will need more water intake Nutrient requirements vary for your horse? •Measures in digestible energy (DE) and fed in kilocalories •Stage of Production •Maintenance •Work •Lactation •Pregnancy •Early growth •Age •Mature Size •Environment •Activity Level Equine Digestive System stomach small intestine cecum large colon descending colon esophagus foregut hindgut •Mouth to anus = 100ft rectum Equine Digestive System stomach small intestine cecum large colon descending colon esophagus foregut hindgut •Mouth, esophagus, stomach = 3-4 feet •Stomach Capacity = 8-15 quarts rectum Equine Digestive System stomach small intestine cecum large colon descending colon esophagus foregut hindgut rectum •Small intestine = 50-70 feet long •Small intestine capacity = 48 quarts (40-50L) Equine Digestive System stomach small intestine cecum large colon descending colon esophagus foregut hindgut rectum •Large intestine = 20 feet long •Large intestine capacity = 130 quarts (100L) Equine Digestive System stomach small intestine cecum large colon descending colon esophagus foregut hindgut rectum •Mouth breaks down food –increases surface area for enzyme action in the small intestine Breaks down structural carbohydrates for bacterial fermentation in the large intestine •Wets feed with saliva--3 gallons per day- lubricates esophagus Equine Digestive System stomach small intestine cecum large colon descending colon esophagus foregut hindgut rectum •Stomach has 10% of the digestive system capacity •2-18 hours retention 2 regions: fundus and pylorus •Therefore horses are constant grazers Equine Digestive System stomach small intestine cecum large colon descending colon esophagus foregut hindgut rectum •In the small intestine we: break down carbohydrates to glucose, proteins to amino acids, fats to free fatty acids, and add bicarbonate. Large Intestine • Large volume capacity (100L) • Very slow transit time 50-63 hours • Responsible for 50% of metabolizable energy • Absorbs ~80L of water a day • B vitamins are produced by the bacteria and absorbed DIGESTION •Total process = 65 hours •2-8 hours in the stomach •2-8 hours in small intestine •50-63 hours in large intestine • Adjusted feeding based on an activity level. Maintenance feed levels can be based per 100 lb of weight (1-2%). Supplemental feeding over maintenance should be based on the level and duration of work. CTVT p.367 • Page 366 CTVT COMMON FEEDSTUFF % DM Mcal/# % Protein Alfalfa 90 .94 18 Brome 89 .80 11 Orchard 88 .85 11 Straw 91 .70 4 Oats 89 1.3 12 Corn 88 1.5 9 Formulated diet for a horse ~5% fat 7-12% protein ~ 80% carbohydrates (major source of energy) Grass and hays foundation for feed Proteins (CP) expresses as %DM • Proteins convert the carbon chain of amino acids to intermediary acids and some to glucose. • Used in replacement and building of tissues • Can be expensive source of energy But can contribute to the demands of energy % DEPENDS ON ENERGY STATE OF INDIVIDUAL Fats Fats can aid in energy demands following hydrolysis to glycerol and fatty acids. Which can be converted to glucose and the fatty acid chain is broken down thru Beta oxidation in the mitochondria which will yield ATP and coenzyme A requiring tissue oxygen Not recommended to exceed 20% of total diet or 30% concentrate. Decreases palatability and results in loose stools Carbohydrates • Carb digestion and fermentation yield mostly glucose acetic, propionic, and butyric volatile fatty acids. • Comprise primary energy sources for many tissues. VITAMINS •Vitamin A--from green grass and green hay •A horse that grazes 4-6 weeks can build up 3-6 month supply of Vit A in the liver. Gestation and growing horses require more •Vitamin D--from forage •Vitamin E--from forage •Functions as a cellular antioxidant in conjunction with Vitamin A, needed for normal immune function. •Deficiency: equine degenerative myeloencephalopathy and equine motor neuron disease. (neurological disorders) •Vitamin K--from forage SALT should be fed free choice MINERALS •Calcium- building blocks of the skeletal system •-major source from roughage •Average horse (500kg) will require ~20g a day •Phosphorus-major source from grains Average horse (500kg) will require ~14g a day •We want the calcium to phosphorus ratio at 1.1:1 to 6:1 Selenium Trace element needed to aid in antioxidant defense Closely involved with activity of Vitamin E Deficiencies: pale weak muscles and yellowing of the depot fat “white muscle disease” (in foals) Pregnant mares need to receive adequate amounts in their diet Highly toxic : skin, coat, hoof abnormalities Salt Blocks contain trace-mineralized salts (microminerals) needed as supplements, when they are not available in the horses diet. Sodium is principal determinant of the osmolarity of extracellular fluid- i.e volume Types of feed • Roughages- grasses, legumes(hay) -relatively low in energy >18% crude fiber Foundation of equine feeding program • Concentrates- cereal grain that may or may not have supplemented protein, minerals and vitamins -often used as a supplement if forage is insufficient (always introduce and change slowly) do not exceed 50:50 concentrate to roughage • Complete feeds- typically a mix of roughage and concentrate- (80% roughage to 20% concentrate) -feed is grinded down to a formulated pellet. All in one for and owner -risks of colic, choking, and wood chewing, coporophagy Chopped hay Pulp Flaked corn Pellets Bran Crimped oats/Sugar beets/Micronized flaked barley/Sweet feed Round bale of hay Avg. wt: tons Square Bale of Hay Avg. weight: 60 lbs This is called a flake of hay. A flake can weigh from 1.5 – 5 lbs. Quality of hay • Free of mold • Soft and pliable to touch • Leafy with fine stems • Pleasant, fragrant aroma • Bright green, not brown or yellow • Grasses that are not maintained well can result in decrease of %CP to less then 10% Dry Matter Intake • Most maintenance horses (this means pasture raised horses, not working horses) can be fed with hay: 1.5 to 1.8 lbs hay/100lbs (BW/Day) • Work increases the need for water, electrolytes (sodium, potassium, chloride and calcium) and energy. Fiber aids in : GI activity Colonic blood flow Colonic mucosal cell growth and absorption Oats Corn (cracked or crushed) Wheat Sweet Feed Pelleted Feed • http://horsevideolibrary.purinamills.c om/ The Hays Make sure you check the quality Quality • Forage quality varies greatly by soil quality, species of grass, season of the year, rainfall, overgrazing, pasture rotation, weed control and the presence of toxic weeds • Laboratory analysis of forage for moisture, energy, protein, fiber and microminerals and micronutrients is fundamental in assessing roughage nutrient control • Hay analysis is performed at little or not cost by regional agriculture extension services Coastal Bermuda Hay Bales Sudan Grass Hay Johnson Grass Hay Prairie Hay CTVT p.367 The End! Critical Care Nutrition Critical care nutrition • Enterally or parenterally nutrition is sometimes required in critical patients. Nutritional support aids in quicker recovery time. • Horses can go 24-72 hours without food with little systemic effects. Unless stressed, the food deprivation has a greater effect Enteral nutrition • “If the gut works, use it” • Less expensive and more natural for patient. • Somewhat easier to administer • Support of organ function, improves organ blood flow, improves immune function, and helps patient gain weight Continued • Comprised of normal feed, slurry diets, and liquid diets. • Contains fiber to help with gastrointestinal activity, colonic blood flow, and mucosal cell growth and absorption • Vitamins • Minerals • Essential amino acids Tubes • Nasogastric tube • Eosophagostomy tube • Pelleted food should be a complete feed. 1kg:6L water- given slowly at 6-8L /feeding -harder to administer, use large bore NG tube • Liquid- formulas- easier - human and equine -ensure, vital HN, osmolite **Introduce all gradually and over a couple of days** Parenteral Nutrition • Used when GI tract is obstructed, dysfunctions, damaged, or painful • Formulations are made of protein in the form of amino acids, carbohydrates in the form of dextrose, and lipids in the form of long chain fatty acids. • **Should be introduced slowly and increases over time** Complications Mechanical – catheter related problems i.e. occlusion, disconnection, breakage, thrombophlebitis Metabolic- solution mixtures, hyperglycemia and decreases in plasma electrolytes, plus more Septic- techs must make sure to use antiseptic techniques when placing catheters. • Both EN and PN are viable sources of nutrition in critical patient • Proper nursing care and aseptic techniques are essential Davies,Z Introduction to Horse Nutrition. 2009. Wiley-Blackwell. Ames, Iowa. Frape, D. Equine Nutrition and Feeding. 3rd Edition. 2004. Blackwell, Ames Iowa. Pilliner, S. Horse Nutrition and Feeding. 2nd Edition. 2009. Wiley-Blackwell. Ames, Iowa. Reed.S.et.al. Equine Internal Medicine. 2009. Elsevier/Saunders. St. Louis, MO. Reeder, D. et.al. AAEVT’s Equine Manual for Veterinary Technicians.2009. Wiley-Blackwell. Ames, Iowa