Feeding for Sound Growth

1. Feeding for Sound Growth • Major concern – Developmental Orthopedic Disease • Bone & joint disorders • Enlargements and deformities of: • Fetlocks, knees, hocks • Faster growing, earlier maturing, larger horses more susceptible

2. Nutritional Causes of DOD • 1. Fast growth rate, large body size • 2. Excess energy intake • 3. Slow growth followed by rapid growth • 4. Mineral imbalances • Low Ca, Low P, High P • Low Cu, Low Zn

3. Feeding Practices that Cause DOD • Grain inadequate in P, Cu, Zn when feeding alfalfa • Grain inadequate in lysine, Ca, P, Ca, Zn when feeding grass hay • Excessive amount grain • Over-feeding young horses in poor condition

4. Ca & P • Ratio important – 2:1 in diet • Adults < 6:1, growing < 3:1 • Bran – low Ca, high P (1:13) • Grains – low Ca, high P (1:5 to 1:10) • Hays – high Ca, low P (5:1 to 1.5:1)

5. Ca & P • Deficiency Ca and/or P can cause bone mobilization, developmental orthopedic disease • High P – interferes with Ca • High Ca – interferes with P, Zn

6. Cu & Zn • Critical for normal bone growth • Cu and/or Zn deficiency = DOD • Cu excess = death • Zn excess = Cu deficiency, DOD

7. Cu & Zn • Growing horses Cu = 150 mg/d or 25 ppm Zn = 450 mg/d or 75 ppm • Adults Cu = 150 mg/d or 15 ppm Zn = 450 mg/d or 45 ppm