120 likes | 281 Views
Trace Mineral Requirements. Mineral Requirements. Given as concentration required in the total diet DM Includes all the ingredients the animal is consuming. Mineral Requirements. Sheep are more sensitive to Cu toxicity than are cattle or horses
E N D
Mineral Requirements • Given as concentration required in the total diet DM • Includes all the ingredients the animal is consuming
Mineral Requirements • Sheep are more sensitive to Cu toxicity than are cattle or horses • Do not feed a mineral supplement formulated for cattle or horses to sheep
Example Calculation • A cow is consuming: • 30 lbs of alfalfa/grass hay (90% DM; 7 ppm Cu) • 4 oz of commercial trace mineral mix (97% DM; 500 ppm Cu)
Calculate Cu Supply – Hay • Hay: 30 lbs x 0.90 = 27 lbs DM 27 lbs DM x 0.454 kg/lb = 12.26 kg DM 12.26 kg DM x 7 ppm (or 7 mg/kg) = 85.8 mg Cu from hay
Calculate Cu Supply – TM mix • Mineral mix: 4 oz x 0.97 = 3.9 oz DM 3.9 oz DM x 28 g/oz = 109.2 g DM 109.2 g DM /1,000 = 0.109 kg DM 0.109 kg x 500 ppm (or 500 mg/kg) = 54.5 mg Cu from mineral mix
Calculate Cu Supply – Total • Total Cu in the diet: 85.8 mg + 54.5 mg = 140.3 mg • Total DM intake by cow: 12.26 kg hay + 0.109 kg mineral mix = 12.37 kg • 140.3 mg Cu/12.37 kg DM intake = 11.3 mg/kg Cu (or 11.3 ppm Cu)
Evaluate Cu Supply • If “look at” Cu analysis of hay: 7 ppm vs. 10-15 ppm requirement Wrongly conclude DEFICIENT • If “look at” Cu on supplement tag: 500 ppm vs. 100 ppm maximum Wrongly conclude TOXIC