The influence of breeding bulls on the growth rate of young black-and-white cattle

The article describes the influence of black-and-white bulls on the growth and development of young animals up to the age of six months. The study is conducted in the conditions of “Zarya” JSC (Molochnoye department, Vologda district) according to generally accepted methods. The author emphasizes that the formation of calves’ groups is carried out taking into account age, the amount of live weight at birth; all animals are in the same conditions of maintenance, feeding and raised according to the technology adopted in the farm. This makes it possible to identify differences in the growth rate of heifers in groups. Having studied the influence of the young animals’ linear affiliation on their live weight, we find significant differences in this indicator between the lines by the end of the dairy period - at the age of five and six months. The heifers belonging to the lines of Holstein origin Vis Back Ideal and Reflection Sovering have the greatest live weight. Having assessed the influence of repair heifers’ bulls-fathers, it is found that there are significant differences in the growth and development of their descendants. The daughters of different bulls develop differently during the dairy period. The animals with the highest growth rate and live weight differ from the producers of Kefir and Chest (Vis Back Ideal line). The daughters from bulls Victor (Montvik Chieftain line), Smartin (Reflection Sovering line) and (Orange Primus line) have the smallest weight by the end of breeding.