Bull sires’ evaluation and influence on their daughters milk productivity

The purpose of the study is to evaluate the productive and biological indicators of Black-and-White cows of various origins in the herd of BMK LLC. Objectives: to study the indicators of milk productivity of first-calf heifers of different genotypes; evaluate sires by milk yield of daughters for 305 days of lactation in comparison with mothers; calculate the economic indicators of the use of daughters, estimated sires in the herd. Comprehensive studies were carried out in the herd of black-and-white cattle of BMK LLC in the Sverdlovsk Region in the period 2017-2020. The evaluation of sires was carried out according to the productivity of their daughters of the first lactation, having at least 20 lactating daughters in the herd. From the line of Vis Back Idial 933122 bulls were evaluated: Bosch 2733, Fennec 4241542328, Lan 66626709; from the line Reflection Sovering 198998, the bull Altadublin 8820742 was evaluated. It was found that the milk yield for 305 days of lactation in the daughters of the sire Fennec bull 4241542328 was 8815 ± 323.2 kg, the difference between the milk yield of daughters and the milk yield of their mothers was 705 kg (P ≤ 0.001), coefficient of variability - 17.9 %. And the bull Altadublin 8820742 turned out to be neutral in terms of milk yield for 305 days of lactation, while reducing the result of daughters by 35 kg compared to mothers. And the daughters of the bull Lana 666626709 have the most highly productive mothers with a milk yield of 8331 kg for 305 days of lactation. The mass fraction of fat in milk in the daughters of the bull Altadublin 8820742 is lower than in mothers by 0.09 %. And the mass fraction of fat in the daughters of bulls Bosch 2733, Fennec 4241542328, Lan 666626709 increased by 0.12; 0.02 and 0.11 %, respectively. Bulls Bosch 2733, Fennec 4241542328, Lan 666626709 are improvers in terms of the mass fraction of protein in milk, the indicator of daughters exceeded that of their mothers by 0.42; 0.40; 0.41 %, respectively, and the bull Altadublin 8820742 is neutral, since according to these indicators, mothers are inferior to their daughters by 0.03 %.