Effect of inorganic and chelated zinc supplementation on the performance of cross bred calves

Cross bred calves (20; 1 m old of 32.3±0.74 kg BW) divided into four equal groups were fed either a basal diet containing 30 ppm Zn (T₀). T₀ supplemented with 80 ppm inorganic zinc (T₁), 80 (T₂) or 40 ppm (T₃) of chelated zinc respectively for 120 days. The average intake of DM, TDN and CP were similar. Animals in T₂ group showed significantly higher (P<0.05) growth than unsupplemented group. Zinc supplementation irrespective of its source and level, increased (P<0.05) ADG of cross bred calves, as compared with unsupplemented group. Overall feed: gain ratio was also lower (P<0.05) in zinc supplemented groups than in control group. Plasma zinc content of zinc supplemented calves increased sharply and it was higher (P<0.01) than control group. However, no significant difference was observed between the supplemented groups T₁, T₂ and T₃. Zinc supplementation over and above the basal dietary level (30 ppm), increased (P<0.05) the plasma insulin concentrations. However addition of zinc (80 ppm) in the chelated form increased blood superoxide dismutase (SOD) activity of calves significantly (P<0.05) than the group given inorganic zinc.