Changes in live weight and protein parameters of blood in growing heifers and steers up to the age of 13 months

Abstract

The studies were conducted on bulls and heifers of Holsteinized black-breed. Two groups of 10 animals were formed in each group according to the analogy principle. In the first group, there were heifers and in the second group, there were steers. Feeding and growing conditions were the same. Blood for biochemical studies was taken at 1,3,6,9,12 and at 13 months of age. The live weight of the heifers and steers was monitored at the same time and we calculated the average daily gain. Total protein and albumin were determined by the colorimetric method. The number of globulins and the value of protein coefficient (albumin/globulins) were calculated by the calculation method. With increasing age of experimental animals, the level of total blood protein gradually increased. Thus, in heifers the concentration of total protein by 13 months of age increased by 9.3 g/l and amounted to 70.1±0.9 g/l. In steers, the increase was 11.3 g/l and amounted to 72.0±1.1 g/l. Comparing the indices of total protein between experimental animals it was found that during the experiment the level of total protein in blood was not significantly higher in steers. The amount of albumin in heifers from 1 to 13 months of age increased by 9.8 g/l, and in steers by 12.3 g/l. In all periods of the experiment, the level of albumin was higher in steers in relation to heifers. The level of globulins from 1 to 13 months of age in heifers and steers changed irregularly. There were no differences in this index between heifers and steers. The value of protein index increased with increasing age of heifers and steers. The live weight of the heifers at 13 months of age was 353.0±1.7 kg, and of the steers 377.7±2.1 kg.