[The effect of zinc on mineral, hematological and immunological indices in calves]

The aim of this work was to study the effect of zinc added to feed on some selected biochemical and haematological indices and its stimulatory action on immunity of calves during its physiological decrease. Investigations were carried out on 18 calves aged 20 days. Twelve calves were divided into 2 groups and they received 450 and 900 mg of Zn++ under the form of ZnSO4 x 7H2O. The following parameters were examined: serum and tissue concentrations of Zn, Cu, Fe and Ca, number of erythrocytes and leucocytes, Hb and Ht indices, leukogram with shifting blood picture to the left, percentage of NBT-positive neutrophils, ability of macrophages for spontaneous migration and serum carotene, vitamin A and gamma-globulin levels. Increased serum and liver zinc levels were found in experimental animals in comparison with a control group and the ability of macrophages for spontaneous migration was increased. Index of shifting the white blood cells to young forms and the percentage of NBT-positive neutrophils were variable. A significant increase in carotene, vitamin A and gamma-globulin levels was also observed.