7 male buffaloe calves were used to study the influence of addition of zinc oxide to the commonly fed rations for 90 days on their health and body weight gain. During the experimental period the calves received, for about one month a basal ration composed of green barseem, commercial con centrate mixture and wheat bran, then turned on diet composed of barseem hay, comercial concentrate mixutre and green corn. The calves were alloted into three groups. Group one received no supplemental zinc, while calves of group 1 and Il recveived 250 mg and 1000 mg zinc oxide plus the basal ration. During the experiment body weight gain of the calves was estimated, and blood was analysed for zinc, copper, manganese, calcium, phosphorus and magnesium levels. The following results were obtained:
1- The highest significant body weight gain was recorded
in the calves of Group III.
High dietary zinc supplementation depressed the serum copper levels while manganese levels, recorded. Also a strong positive correlation between serum zinc calcium levels was found.