RATING ASSESSMENT OF FOREIGN AND DOMESTIC BREEDING BULLS USED WITHIN THE YAROSLAVL BREED LIVESTOCK BY REPRODUCTIVE CHARACTERISTICS OF DAUGHTERS
The article presents the results of rating assessment of foreign and domestic breeding bulls of Yaroslavl breed according to reproductive characteristics in the conditions of the northwestern zone of the Russian Federation. The aim of the study is to compare bulls of domestic and foreign selection, used on the breeding stock of the Yaroslavl breed, according to the reproductive characteristics of their daughters. The research was carried out on the basis of the rating developed in SZNIIMLPH. 415 daughters of seven domestic sires and five bulls of foreign selection were studied. Breading bulls with at least five daughters were selected for the formed database. To carry out the study, the method of rating assessment of bulls was used according to the complex of daughters’ reproduction signs. The method of rating assessment based on a set of features is to calculate the average rating of a bull for all the studied features. As a result of calculating the rating assessment of bulls according to the complex of daughters’ reproduction signs. in the population of the Yaroslavl breed, it was found that the bull of domestic selection Lornet 1026, which took the first position in the rating, has daughters with high early maturity, and its seed is quite active, as evidenced by the low index of insemination. At the same time, the daughters of this bull have the longest service period of 126 days. The daughters of a domestic breeding bull Nylon 1056 showed optimal performance for all the traits under study. The first place in the ranking of foreign bred bulls belongs to Rethyrement 11720463. His daughters have a high maturity - the age of the first fruitful insemination is 15.2 months; the age of first calving is 24 months, the optimal service period is 88.4 days, which is as close as possible to the norm of 90 days, insemination index was 1.4.