EN
Physiological levels of zinc in the liver, spleen, pancreas, kidney, thymus, blood, plasma and serum were investigated in 25 slaughtered cattle during summer and winter seasons. The investigations were carried out by the method of activaiion analysis using incinerated samples irradiated with thermal neutrons. In the summer season the following zinc levels were found: the blood 0.24, p1asma 0.125, serum 0.126 mg per 100 ml and the liver 3.42 spleen, 2.32, pancreas 2.61, and kidney 1.9 mg per 100 g of the organ. In the winter season these values were as follows: the blood 0.20, plasma 0.123, serum 0.09 mg/100 ml; and the liver 2.85, spleen 2.02, pancreas 2.25 and kidney 1.9 mg per 100 g of the organ. In the summer season the zinc levels were usually higher.