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Feeding Young Horses. Goal: Rapid growth with as few developmental and health problems as possible. Feeding Young Horses. Energy Protein-Amino acids – Lysine Minerals Macro – Ca, P Micro – Cu, Zn. Reaching Mature Size. First year most critical 90% of height, 65% of weight See table
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Feeding Young Horses • Goal: Rapid growth with as few developmental and health problems as possible
Feeding Young Horses • Energy • Protein-Amino acids – Lysine • Minerals • Macro – Ca, P • Micro – Cu, Zn
Reaching Mature Size • First year most critical • 90% of height, 65% of weight • See table • At moderate rate of growth: • Mature height = 2 to 3 y • Mature weight = 3 to 5 y
Protein & Energy for Young Horses • Weanlings • ADG = 1.4 to 1.9 lb • 2.8 to 2.9% total DMI
Protein & Energy for Young Horses • Yearlings • More moderate gains • ADG = 0.75 to 1.25 lb • After 1 yr, colts have 0.2 to 0.3 lb greater ADG than fillies
Protein & Energy for Young Horses • Two-year-olds • ADG = 0.25 lb (100 lb/year) • (May need more if in training)
Energy Requirements – Growing Horses • DEmaintenance + DEgain • DEm (kcal/kg BW/d) = 56.5X-0.145 • X = age in months
Energy Requirements – Growing Horses • DEmaintenance + DEgain • DEg (Mcal) = (1.99 + 1.21X – 0.021X2) x ADG • X = age in months • ADG = kg/day
Energy Requirements – Growing Horses • Weanling, 227 kg, 0.75 kg ADG, 4 mo • DEm • DEm (kcal/kg BW/d) = 56.5(4-0.145) • 56.5 x 0.8179 = 46 kcal/kg BW • 46 kcal/kg x 227 kg = 10,442 kcal • Or 10.4 Mcal DE
Energy Requirements – Growing Horses • DEgain • DEg (Mcal) = (1.99 + 1.21X – 0.021X2) x ADG • [1.99 + (1.21 x 4) – (0.021 x 16)] x 0.75 • 6.49 x 0.75 = 4.9 Mcal DE
Energy Requirements – Growing Horses • DEmaintenance + DEgain • 10.4 Mcal + 4.9 Mcal = 15.3 Mcal DE
Protein Requirements NRC, Lys:DE = 2 L.H. Breuer, 1998; Advances in Equine Nutrition I, KER
CP/Lys Requirements – Maintenance • Minimum: CP (g/d) = BW kg x 1.08 • Average: CP (g/d) = BW kg x 1.26 • Elevated: CP (g/d) = BW kg x 1.44 • Lysine (g/d) = CP (g/d) x 4.3%
CP/Lys Requirements – Maintenance • Total CP requirement = CPm + CPg • Growing horses: • CPm (g/d) = BW kg x 1.44
CP/Lys Requirements – Growth • CP (g/d) = (BW kg x 1.44) + ((ADG g x 0.20)/E)/0.79 • E = efficiency of protein use Protein in gain Protein digestibility
CP/Lys Requirements – Growth • E = efficiency of protein use • 50% for 4-6 mo old • 45% for 7-8 mo old • 40% for 9-10 mo old • 35% for 11 mo old • 30% for 12 mo old or older