摘要：In the Sverdlovsk region Holsteinized Black Pied cattle of the Ural type are bred which are represented by large, highly productive animals with a high genetic potential for productivity. Great importance is attached to the rearing replacement calves. The aim of the study was to study the dynamics of the live weight of replacement heifers from different seed bulls during rearing and its dependency on the age of the first insemination. The highest average daily weight gains were in the dairy period of heifers development, they ranged from 989 g for the daughters of the bull Thunderline to 1054 g for their peers from the bull Maximum. There were also high average daily gains during this period when rearing heifers from the bull Renigend. In the second period of rearing from 6 to 10 months of age there was a decrease in the average daily weight gain in all groups. Heifers from different seed bulls reach the required live weight for the first insemination at different ages. Maximum’s daughters, which had the weight of 399.4 kg at the age of 12.9 months. reached the required live weight most quickly. Their peers from other seed bulls reached the aforementioned live weight only at the age of 13.7 months.
