Copper Levels and Sources in Pre- and Post-calving Diets of First-Calf Cows

A study replicated over two years involving 197 first-calf cows compared reproductive performance, growth and health of calves and concentration of Cu in liver, colostrum, and milk. Three treatments were evaluated: control (no Cu but Mo and Fe added to hay diet); 200 mg Cu from CuSO4; and 100 mg Cu from AvailaCu® added daily. In 1998 a fourth treatment, 400 mg AvailaZn® was included with 100 mg AvailaCu®. Supplementation of Cu and/or Zn did not improve total pregnancy rate, or growth and health of calves. In 1998 cows fed only AvailaCu® conceived 10 days earlier compared to controls; however, in 1997 no differences in date of conception were found. Cu in colostrum and milk, and IgG levels in colostrum and calf serum were not improved by Cu supplementation