Balancing Horse Diets All horses should be fed a minimum of 1% BW of forage per day Proper digestive function Prevents colic, laminitis Prevents behavioral problems

Balancing Horse Diets Horses at maintenance: Will eat approx. 2-3% BW per day May get all required Lysine, CP, and energy from forage

Balancing Horse Diets Some horses may need added grain and protein/Lysine Lactating mares Growing horses High exercise demands “Poor keepers”

Balancing Horse Diets Fat can be used to add energy Replaces starch Helps prevent colic and/or founder Max amount of fat = 10% of diet DM

Balancing Horse Diets Once we’ve provided 1% BW forage and suggested amount of fat Evaluate nutrients supplied Compare to requirements Balance the rest of the diet

Balancing Horse Diets Mature 500 kg gelding at moderate work Requirements: 24.6 Mcal DE 984 g CP

Balancing Horse Diets Feedstuffs: Grass hay (1.95 Mcal/kg DE, 8.46% CP) Alfalfa hay (1.75 Mcal/kg DE, 18% CP) Grain (2.45 Mcal/kg DE, 8.9% CP) Vegetable oil (9.2 Mcal/kg DE)

Balancing Horse Diets Energy Values of Feedstuffs: Use energy values specifically for horses Lower energy values than ruminants TDN, % ruminant x 0.88 = TDN, % horse

Balancing Horse Diets Feed 1% BW as grass hay 500 kg x 0.01 = 5 kg grass hay intake 5 kg x 1.95 Mcal/kg = 9.75 Mcal DE 5 kg x x 1,000 g/kg = 423 g CP Add 0.5 kg vegetable oil 0.5 kg x 9.2 Mcal/kg = 4.6 Mcal DE

Balancing Horse Diets Need 24.6 Mcal – 9.75 Mcal – 4.6 Mcal = Mcal DE Need 984 g – 423 g = 561 g CP

Balancing Horse Diets A = kg alfalfa hay, B = kg grain Mcal = 1.75 Mcal/kg A Mcal/kg B kg = 0.18 A B 1.75/0.18 = 9.72 multiplication factor for equation 2

Simultaneous Equations 9.72 (0.18 A B) = 9.72 (0.561 kg) 1.75A B = 5.45 kg new equation

Simultaneous Equations Subtract the new equation from 1st eq 1.75 Mcal/kg A Mcal/kg B = Mcal 1.75A B = 5.45 kg new equation B = 4.8 B = 4.8/1.59 B = 3.02 kg grain

Simultaneous Equations Substitute 3.0 for B in either original eq kg = 0.18 A B kg = 0.18 A (3.0) kg = 0.18 A – 0.27 = 0.18 A 0.29 = 0.18 A A = 0.29/0.18 = 1.61 kg alfalfa hay

Simultaneous Equations Our diet consists of: 5 kg grass hay 0.5 kg vegetable oil 3.02 kg grain 1.61 kg alfalfa hay

Simultaneous Equations Check our work: 5 kg grass hay x 1.95 Mcal/kg = 9.75 Mcal 0.5 kg vegetable oil x 9.2 Mcal/kg = 4.6 Mcal 3.02 kg grain x 2.45 Mcal/kg = 7.4 Mcal 1.61 kg alfalfa hay x 1.75 Mcal/kg = 2.82 Mcal Do the same for CP 24.6 Mcal