EFFECT OF ORAL SUPPLEMENT OF ZINC AND COPPER ON LAMENESS AND REPRODUCTIVE PERFORMANCE IN DAIRY CATTLE

The aim of this study was to evaluate the effects of oral supplements of zinc and copper on lameness and reproductive performance in dairy cattle. Performance indicators on a dairy farm are very different. In this study which was conducted on 40 Holstein cows at one of Amol's dairy farms, some of these indicators include lameness, abortion; retained placenta and open days were studied. 360 mg zinc and 125 mg copper were added to rations of daily 20 heads of cattle (case group) daily for one year. Control group was given same diet without the supplement. Regular and seasonal blood sampling were done and serum levels of zinc and copper were analyzed. The results suggested that lameness (p<0.01), retained placenta (p<0.05), open day (p<0.05) and abortion (p<0.05) were reduced significantly after treatment. There is a significant difference in these incidence, between case and control group (p<0.01). Due to the simultaneous increase in serum levels of copper and zinc with reduction the incidence of the disease, we conclude that the use of trace elements such as copper and zinc in improving reproductive performance and lameness were useful.