Milk producing ability and reproductive qualities of the daughters of stud bulls whose semen was obtained using different methods

摘要

In the course of this research, parameters of the efficiency of sexed semen use were studied, as well as peculiarities of growth and development of the offspring, parameters of milk producing ability and reproductive qualities of daughters of stud bulls whose semen was sorted by sex and was obtained using traditional method. As a result, it was established that during the insemination of heifers with semen sorted by sex, the output of calves decreased by 22.9% compared with the normal semen, but the percentage of heifers increased by 37.6%. At the same time, fertilization rate of studied animals was 58.7%, the number of semen doses - 1.7. The best fertility was in the bull Parrah 343313777, it amounted to 74.0%. When using normal semen, the total fertilization rate of heifers was 75.4%, with semen dose rate of 1.3. When studying milk producing ability of the offspring, it was shown that the first lactation of daughters of stud bulls, whose semen was obtained by traditional method, exceeded milk yield of daughters of stud bulls, whose semen was sorted by sex, by 546.4 kg, while fat mass fraction in milk here was lower by 0.14%. Realization of genetic potential for milk yields during 1 and 2 lactations was higher among the stud bulls of second group and amounted to 56.5-58.7%, genetic potential realization of the stud bulls of first group was 45.9-53.5%. Reproductive qualities of the daughters of stud bulls of the compared groups are practically at the same level. Duration of indifference- and service periods for the daughters of bulls, whose semen was sorted by sex, turned out to be slightly longer in comparison with the herdmates of the second group by 1.4 and 1.3 days on average.