Comparative assessment of bulls for service on economically useful features of daughters

One of the main objectives of breeding is to increase the genetic potential of farm animal populations in dairy cattle breeding. Along with milk productivity of cows, an important factor promoting efficiency of animal husbandry is productive longevity and reproductive qualities of animals. For these purposes, we carried out a comparative assessment of stud bulls according to economically useful traits of their daughters. We found that the highest number of offspring belonged to the W.B. Aidial 1013415 line (32.3%) and the lowest number of cows belonged to the M. Chiftein 95679 line at 6.2%.Daughters of the Holstein lines bulls were characterized by higher milk yield in the first and third lactations, with the productivity of 7,8 – 9,6 thousand kilogram of milk, and higher fat content (3,91 and 4,03%). According to the parameters of productive longevity, we can point out daughters of the following bulls: Bonus 36 of the R. Sovering 198998 line with duration of economic use of 3,5 lactations and lifetime productivity of 21,7 thousand kg, Duplet 10101 of the A. Adema 30587 line (3,2 lactations and 22,2 thousand kg), and Muravei 413 of the S.T. Rokit 252803 line (3,3 lactations and 23,3 thousand kg). According to the number of live calves, we can distinguish daughters of the following bulls: Bonus 36 of the R. Sovering 198998 line (4.1 head), Duplet 10101 of the A. Adema 30587 line (3.8 head) and Muravei 413 of the S.T. Rokit 252803 line (3.6 head). Daughters of the same bulls produced the highest number of heifers – 2.3, 2.0 and 2.2 head, respectively. Taking into account the safety of young stock and the number of culls during the breeding period, only one first-calf heifer will be introduced into the main herd, which in turn will lead to the absence of the selection element in breeding work. Consequently, identification, selection and intensive use of improving bulls, whose daughters have high productive longevity and good reproductive qualities, is an extremely necessary selection method in the improvement of breeding cattle.