Evaluation of milk productivity and longevity of the daughters of stud bulls whose semen was obtained using different methods
The use of sex-separated genetic material is considered one of the most innovative methods in countries with developed animal husbandry. To study the milk productivity of the daughters of sires whose sperm was obtained using different technologies, two groups of cows were formed according to the principle of analogue groups. As a result of the study, it was found that the milk yield of the daughters of sires, whose sperm was divided by sex (group I), for 305 days, both for the first and for the highest lactation, was lower by 124.5 and 159.1 kg, respectively, than that of their peers - daughters of sires whose sperm is obtained by traditional technology (group II). The content of fat in the milk of cows of group I for the first lactation was 0.05 %, and for the highest - 0.23 % more than that of peers of group II. The protein content in milk was also 0.02 % higher in group I cows. The realization of the genetic potential for milk yield for the first and highest lactation was higher in the offspring of sires, whose sperm was obtained using traditional technology, and amounted to 54.9-71.6 %. In terms of the mass fraction of fat, the opposite trend was observed: the descendants of bulls of group I had an IHP of 92.7-99.3 %, of group II - 85.1-87.3 %. Life expectancy and productive longevity were higher by 0.2 years and 0.15 lactations, and lifetime milk yield - by 704.5 kg in the daughters of producers obtained from sexed semen.