Equine Nutrition & Feeding

1. Equine Nutrition & Feeding

2. Time-Budgets Feral Horses • Select highest fiber, lowest protein content • 70% of its day foraging Stabled Horses • 10% of their day feeding • Meal fed

4. Mastication • Jaw sweeps 60,000 times/day when grazing • Saliva contains little, if any amylase

5. Left Side of Horse Right Side of Horse

6. Digestion is organ specific 8% Amino acids and fat digested and absorbed in small intestine Vitamins/minerals absorbed in small intestine Starch digestion occurs in the stomach and small intestines (Stomach: 15 min. Small intestine: 30-90 min.) 30% Fiber digestion occurs in the cecum/colon (48-72 hours) 62%

7. Stomach • 9-15 liters • Trickle feeders • Transit time <2 hr • Cardiac sphincter does not relax to allow regurgitation

8. Small Intestine • 30% of GIT, ~70 ft. long • ~contains 24 gallons • 3 Segments • Duodenum • Jejunum • Ileum • Starch digestion occurs in the stomach and small intestines • Amino acids and fat digested and absorbed in small intestine • Many Vitamins/minerals absorbed in small intestine • α-Amylase – low & varies widely between horses

9. Large Intestine Hindgut – 60% of digestive tract capacity • Cecum – • 25-35 liters • Large muscular mixing vat • Initiates fermentation • Begins protein degradation & B vitamin synthesis • Large Colon • 50-60 liters • Continuation & completion of microbial digestion, absorption of VFA, B vitamins • Conservation of electrolytes (Na, Cl, K), absorption of P • Small Colon • 18-19 liters • Primary function is to conserve water Fiber digesters most active pH of 6.2-6.8 Starch digesters prefer pH 5.2 – 6.0

10. Metabolized For Energy Volatile Fatty Acids Gas Wasted Energy B-vitamins & Vit. K Protein and Amino Acids? Microbial Fermentation Microbe Fibrous & Non-Fibrous Carbohydrate

11. Aspects of The Foal GI Tract • Small digestive tract • The small intestine does not increase in length from 4 wks of age • Cecum not fully functional until 15-24 mo of age • The large intestine increases with age even up to 20 yrs

12. Carbohydrates

13. High Grain or High Fructans Decrease in fiber fermenting Organisms Increase in lactate producing organisms Significant decrease In pH Increase in VFA& Lactic Acid of Hindgut Very low pH Subclinical Acidosis Time Released Buffer Irritation & damage To intestinal mucosa Bacterial lyses Minimal decrease in pH Inhibition of fiber fermenting Organisms & lactate Utilizing organisms Off Feed Decreased fiber digestibility Colic Symptoms Stereotypic Behaviors Optimal VFA absorption Release of endotoxins Optimal Energy for Working & Breeding Horses Laminitis How Hindgut Acidosis Can Occur In Hindgut And How It Can Be Attenuated Pagan, J. 2007. Feedstuffs

14. Postprandial Cecal pH Change

15. Same DE in each sample, take a look at the amount of starch though! Corn 4.3# 2.71# Oats 5.0# 1.82#

16. Starch Comparisons (what’s low, what’s high)

17. Starch Digestion • Critical capacity for hydrolysable carbohydrate overload ~0.4% of BW • Maximizing starch digestion in small intestine • Properties of the starch granule • Grain processing • Plant cell walls • Transit time through the small intestine • Availability & concentration of enzymes Cuddeford, D. 1999; Harris et al. 1999

18. Comparison of Small Intestinal Starch Digestibility of Processed Corn Processing affects the site of starch digestion.

19. REMEMBER! “The number one cause of deaths from colic is from starch overload due to feeding mismanagement.” Dr. John Reagor, PhD Chief of Toxicology Texas Veterinary Medical Diagnostic Laboratory

20. Building a Horse Ration • Start with horse needs • Maximize forage • Add energy if needed • Add protein & minerals if needed • Consider adding vitamins & supplements • Consistency is key to good feeding practices Feed concentrate that makes-up the difference between nutrients needed & nutrients in roughage

21. 1. Know What & How Much Your Horse is Eating • Grain • Hay • Supplement • Pasture

22. 2. Know Your Horse & Provide Feed Based on: • Class • Weight • Body Condition Score • Stage of production • Age • Activity level • Growth

23. Adult (no work) Working Light exercise Moderate exercise Heavy exercise Very heavy exercise Stallions Pregnant Mares < 5 mo 5th, 6th, 7th, 8th, 9th, 10th, 11th mo Lactation 1st, 2nd, 3rd, 4th, 5th, 6th mo Growing 4, 6, 12 mo 18 mo Light exercise Moderate exercise 24 mo Light exercise Moderate exercise Heavy exercise Very heavy exercise Nutrient Requirement Varies With Class of Horse

24. 3. Feed According to Body Wt. • Feed intake usually expressed as • % of Body Weight • Lbs feed/100 lbs body weight • Free Choice • Forages • Provide fiber & energy • At least 1% of body weight (dm basis) • Concentrates • Provide energy • Supplements • Provide protein, minerals and vitamins

25. How Much Hay & Grain Should an 800 lb. Yearling Foal Receive? • Total Intake: • Forage Intake: • Concentrate Intake:

27. How Much Hay & Grain (800 lb. Yearling)? • Total Intake: 20 pounds • 800 x .02 = 16 pounds • 800 x .03 = 24 pounds • Forage Intake: 10 pounds • 800 x .01 = 8 pounds • 800 x .015 = 12 pounds • Concentrate: 10 pounds (20 total–10 forage) • 800 x .01 = 8 pounds • 800 x .02 = 16 pounds

28. 4. Know Your Forage • Forage quality depends on: • Pasture vs hay • Legume vs grass • Cool vs warm season species • Plant maturity • Growing conditions • Harvest conditions

29. Grass Bromegrass Orchardgrass Tall Fescue Timothy Grain Hay Oat Hay Wheat hay Straw Legume Alfalfa Birds Foot trefoil Clovers Lespedeza Forages are the FoundationPasture, Hay

30. 5. Maximize Pasture Production • Fertilize grasses • Overseed • Frostseed • Interseed • Rotationally graze • Control weeds • Avoid overgrazing • Correct stocking density

31. 6. Evaluate Hay Quality • Visually • Stage of Harvest • Leafiness • Color • Odor • Softness • Penalties

32. 7. Match Hay Quality to the Horse

33. 8. Evaluate Hay Substitutes • Handout: Hay Substitutes • Note: • Fed as sole part of diet? • Advantages and disadvantages • Special comments • Compare on cost per pound of Digestible Energy (DE)

34. Hay Substitutes • Hay cubes • Haylage • Beet pulp • Rice bran • Wheat barn • By-products from grain harvest • Straw • Complete Feed with >15%

35. Square Bales Barn or some kind of permanent structure Tarp with hay stacked off the ground Round Bales Barn Tarp Sleeves or bonnets Plastic wrap Net wrap Twine wrapped, outside 9. Control Loss by Method of Storing Hay

36. Round Bale, Hay Storage Losses Storage Conditions Approximate Dry Matter Losses, % Outside, on ground, without cover 13-30+ Outside, on ground, plastic or tarp cover 8-9 Outside, on drained surface, without cover 7-8 Outside, on ground, net wrapped 6-7 Outside, on ground, full plastic ‘sleeve’ 5-6 Outside, drained surface, plastic or tarp cover 5-6 Inside bale storage 5

37. 10. Control Hay Loss in Feeding

38. Control Hay Loss in Feeding • Use a container for hay • Hay feeder • Feed bunk • Hay net • Limit the amount of time to access round bales • Feeders should be no higher than shoulder level

39. 11. Feed by WeightNOT Volume • Weights vary by: • Feed type • Processing method • So, the amount of energy provided varies

40. Calculating Nutrients • 3-lb coffee can full of • 32 lb/bushel oats = 2 1/2 lbs • 34 lb/bushel oats = 4 lbs • corn or pellets = 5 lbs • Oats = 1.46 Mcal/lb • Corn = 1.76 Mcal/lb • 2.5 * 1.46 = 3.65 Mcal • 5 * 1.76 = 8.8 Mcal • Hay • Bale 40-130 lbs • 10 flakes/bale • Avg 4” flake alfalfa 5 lbs • Avg 4” flake grass 3 lbs • Alfalfa = 1.10 Mcal/lb • Grass = .99 Mcal/lb • 5 lbs * 1.10 = 5.5 Mcal • 3 lbs * .99 = 2.97 Mcal

41. Forage Isn’t Everything • Most do not have all the minerals &/or vitamins a horse requires. Four ways to add these. • Add 1 to 4 oz mineral or mineral/vitamin supplement per day or • Add 1 to 2 lbs ration balancer (mineral plus protein) per day or • Feed 5 to 7 lbs fortified grain per day or • Feed 12 – 14 lbs complete feed (forage & grain)

42. 12. Evaluate Your Mixed Feed • Relative quality of the ingredients • Amount of crude fiber & energy • Price – • Cost/pound • Cost/pound of nutrient • Grain Intake Comparison

43. Oats variable crimped vs. whole Corn cracked, steam rolled Barley Sorghum & wheat less than 30% rolled, cracked, flaked, Energy Sources - Grains

44. Fat/Fatty Acids • No gall bladder • Horses can be safely fed up to 20% fat in the total diet • Energy from fat is 90% utilizable • Often used to supplement calories for hard-working horses and hard keepers • Reduction in DM intake & bowel weight • Calmer temperament

45. Protein • Muscle & bone growth, milk production, fetal growth, normal metabolism • Requirements can be met with good quality hay or pasture forage • Low requirements for maintenance • Quality = amino acid balance • Very important for young horses • Lysine, methionine, tryptophan most limiting for growth & milk production

46. Minerals • Content in the diet • Determined by soil & water • Quality of feed & proportion of grain to hay • Macro-minerals • Ca & P - quality forages usually provide adequate amount • This ratio is very important: 1.5:1 to 2:1 • Grains are rich in P and low in Ca • NaCl (Salt) • Salt block will meet many horse’s needs • If horses sweat a lot - need salt in the ration • Trace Minerals • Look for iron, zinc, copper, selenium

47. Minerals • Macro-minerals • Ca & P - quality forages usually provide adequate amount • This ratio is very important: 1.5:1 to 2:1 • Grains are rich in P and low in Ca • NaCl (Salt) • Salt block will meet many horse’s needs • If horses sweat a lot - need salt in the ration • Trace Minerals • Look for iron, zinc, copper, selenium

48. A guide to the recommended concentrations of trace elements in the diet, mg/kg dry matter. (Modified fromthe NRC 2007). These will need to be adjusted to suit individual circumstances, growth rate and appetite etc.

49. Vitamins Fat soluble: • stored in body - A, D, E, K • Toxicity’s can occur if fed in excess Water soluble: • must be continuously supplied • B-complex; niacin, thiamin, riboflavin • High quality fresh forages = maintenance for mature horses • Hay is poor in Vit A, supplement Vit A in the ration • Exposure to sunlight provides Vit D • Supplement Vitamin E

50. Guide to recommended levels of Fat-soluble vitamins (need to be adjusted according to individualcircumstances).