The effectiveness of dairy cattle breeding largely depends on the intensity of use of breeding stock. At the same time, the factor of productive longevity of animals is of great importance, since it largely determines not only the economics of production, but also the effectiveness of improving the herd. The aim of the study was to study the influence of genetic and paratypical factors on the signs characterizing the duration of use of cows in the population of Holstein cattle of black-and-white breed in the conditions of breeding farms of the Vologda region. The study was conducted using a database of 15403 cows that were retired in 2021 and 2022. The influence of the studied factors on the signs of the duration of use was assessed on the basis of variance and correlation analysis. The reliable influence of genetic factors bull-father, the degree of blood in the Holstein breed, the age of the mother’s retirement in lactation; paratypical - the age of the 1st fruitful insemination and the 1st calving, milk yield for 305 days of the 1st lactation of the cow, milk yield for 305 days of the 1st and maximum lactation of the mother cows. Selective selection of breeding bulls based on the duration of productive use of daughters and cows, potential mothers of future heifers, by age in lactation will contribute to obtaining animals genetically predisposed to longer use. The results of the study can be used in breeding and breeding work to improve the population of Holstein cattle of the black-and-white breed.
Khromova et al. (Fri,) studied this question.