Effect of Supplemental Zinc on Growth Performance, Nutrient Utilization and Trace Mineral Metabolism in Crossbred Calves

Fifteen crossbred calves (14 month, 226 kg) were used to determine effect of dietary concentration of Zn on performance, nutrient utilization and trace mineral metabolism. Treatments were: control (32.5 ppm Zn) and control supplemented with 35 and 70 ppm Zn through zinc sulphate. Calves were fed on concentrate and wheat straw based diet individually for a period of 180 days. A metabolism trial was conducted after 150 days of growth trial. Zinc supplementation did not affect (P>0.05), nutrient intake, body weight gain, nutrient digestibility and nitrogen balance. Cu, Fe and Mn intake and their balances were not influenced (P>0.05) by the levels of dietary Zn. Zinc retention was increased (P<0.05) as dietary level increased, but percent apparent absorption was decreased (P<0.01). The serum concentration of Zn, Cu, Fe and Mn were not affected by dietary Zn concentration. The results suggested that basal diet containing about 32.5 ppm Zn was adequate to support normal growth, nutrients digestibility and balances of minerals.