Сравнительная оценка голштинских быков-производителей разной селекции по продуктивным качествам дочерей

Abstract

Abstract. Purpose. Comparative assessment of productive qualities of cows-daughters of Holstein bulls-producers of different breeding. Methods. Milk productivity was assessed by the method of control milking, milk quality indicators – by the instrument method on the Lactan-1M device, reproductive qualities – by conventional methods. Results. The age of the first insemination influenced the age of the first fruitful insemination and the first calving. Earlier, calving took place for 6 to 9 months in heifers obtained from bulls of Russian and Dutch breeding – Alaska and Davis. The live weight of the repair heifers at the first insemination was almost the same. A higher live weight of the first insemination was in heifers-daughters of bulls Aurora and Relayble. Cows-daughters of bulls-producers of Aurora (Canadian breeding) and Alaska (domestic breeding) were distinguished by lower productivity. They had milk yields for 305 days of lactation and for the entire first lactation lower than the daughters of bulls-producers of Dutch and American breeding – Davis and Relayble. The productive longevity of cows-daughters of all evaluated bulls-producers is slightly more than one lactation 1.0 (Alaska bull) – 1.3 lactation (Aurora bull). According to MFF (mass fraction of fat) and MFP (mass fraction of protein) in milk, the milk of the daughters of the Davis producer bull of the Dutch selection was distinguished by the best indicators. Their MFF in milk was higher by 0.02–0.18 % and MFP by 0.19–0.22 %. The duration of the service period ranges from 101 days (Alaska) to 157 days (Davis). The coefficient of reproductive ability of cows in all groups of cows-daughters was below the optimal 0.95, which indicates problems with reproduction in groups of daughters of bulls of Holstein bulls of different breeding. The daughters of the Alaska bull of the domestic selection had the best CRC indicators (reproductive ability coefficient), and the lowest in the group of the daughters of the Dutch selection Davis bull. Scientific novelty. The scientific novelty of the work lies in the fact that a comprehensive assessment of the economic and useful qualities of the daughters of Holstein bulls of different breeding was carried out and their further use was determined.