Trace Mineral Requirements Beef CattleSheepHorses ElementReqmtMax.ReqmtMax.ReqmtMax. Co, ppm Cu, ppm I, ppm Fe, ppm501, Mn, ppm20-401, , Mo, ppmNA50.510NA Se, ppm Zn, ppm

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 kg/lb = kg DM 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 = g DM g DM /1,000 = kg DM 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 mg = mg Total DM intake by cow: kg hay kg mineral mix = kg mg Cu/12.37 kg DM intake = 11.3 mg/kg Cu (or 11.3 ppm Cu)

Trace Mineral Requirements Beef CattleSheepHorses ElementReqmtMax.ReqmtMax.ReqmtMax. Co, ppm Cu, ppm I, ppm Fe, ppm501, Mn, ppm20-401, , Mo, ppmNA50.510NA Se, ppm Zn, ppm

Evaluate Cu Supply If “look at” Cu analysis of hay: 7 ppm vs ppm requirement Wrongly conclude DEFICIENT If “look at” Cu on supplement tag: 500 ppm vs. 100 ppm maximum Wrongly conclude TOXIC