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 0.0846 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 =
10.25 Mcal DE
• Need 984 g – 423 g = 561 g CP
Balancing Horse Diets
• A = kg alfalfa hay, B = kg grain
• 10.25 Mcal = 1.75 Mcal/kg A + 2.45 Mcal/kg B
• 0.561 kg = 0.18 A + 0.089 B
• 1.75/0.18 = 9.72 multiplication factor for
equation 2
Simultaneous Equations
• 9.72 (0.18 A + 0.089 B) = 9.72 (0.561 kg)
• 1.75A + 0.865B = 5.45 kg new equation
Simultaneous Equations
• Subtract the new equation from 1st eq
• 1.75 Mcal/kg A + 2.45 Mcal/kg B = 10.25 Mcal
• 1.75A + 0.865B = 5.45 kg
new equation
• 0 + 1.59B = 4.8
• B = 4.8/1.59
• B = 3.02 kg grain
Simultaneous Equations
• Substitute 3.0 for B in either original eq
• 0.561 kg = 0.18 A + 0.089 B
• 0.561 kg = 0.18 A + 0.089 (3.0)
• 0.561 kg = 0.18 A + 0.27
• 0.561 – 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
24.6 Mcal
• Do the same for CP