Comparative characteristics of the genetic potential of stud bulls of the black-and-white breed

The rational use of genetic material from high-quality stud bulls has great economic importance for animal husbandry, since the genetic progress of the breed, population and herds is mainly determined by the contribution of producers rated by the quality of offspring and recognized as improvers. A comprehensive assessment of the stud bulls of black-and-white breed was carried out in the leading farms of the Orel region in order to identify bulls-improvers with a valuable genotype. The experimental studies were done in LLC "Maslovo", Orel region, with a herd of black-and-white cows with Holstein blood from 62.5% to 89% in the first completed lactation. The assessment of the bulls by the quality of their offspring was made by comparing the dairy productivity of daughters with the milk productivity of herd mates and dams. The best productivity among the stud bulls of the R. Sovering line-had the daughters of the bull Blesk - 5075 kg and Magikan - 5039 kg. In the line of V.B. Aydial it was revealed that the daughters of the bulls of the Emir and Elf had the best productivity. When assessing the producing bulls by fat content, it was found that in the generation of the daughter of a peer of the production line bulls R. Sovereing, the best in fat content were the daughter of the bull Blesk - 3.79% and Magikan - 4.00%. In the line of V.B. Aydial, the best milk fat among peers was shown by the daughter of the bull Khan. By the protein content of dairy ox Magikan of the line R. Sovering and Elf of the line of V.B. Aydial occupy leading positions among the estimated bulls. A comprehensive assessment of the stud bulls showed that among the estimated stud bulls, the stud bulls Blesk (R. Sovering) and Emir (V.B. Aydial) can be used for improving the milk yield, milk yields of their daughters exceeded their herd mates by 101.5 and 277, and dams 1024 kg and 454 kg, respectively. Stud bulls Han (line V.B. Aydial) and Magikan (line R. Sovering) are the leaders in butterfat percentage. No protein leaders were detected.