Abstract
This article is devoted to the study of the influence of the genotype on the Holstein Frisian on economic longevity and the lifelong productivity of cows. Indicators of the productive longevity of 1017 purebred Holstein Frisian and cross-bred cows with a different share of genes by Holstein breed, who left the herd of Dairy cattle at Al-hiera project for 2009 and 2010 were studied. Also, the values and orientation of the correlation links of the economic longevity period with indices of lifetime productivity of experimental cows of different genotypes were determined. It was found that in experimental animals with an increase in the genotype share of genes in the Holstein breed, a positive trend was observed to increase milk yield per day of lactation, and a negative tendency to decrease the duration of productive use, lifelong dairy productivity, and economic efficiency. In all groups, a high positive correlation was found between the duration of use of cows and lifelong milk yield, the duration of use of cows and their lifelong yield of milk fat, as well as between lifetime milk yield and a lifetime yield of milk fat. The presence of a weak correlation between the indices of milk yield per day of lactation and longevity has been established. The yield of lactation for one day was positively associated with lifelong milk yield and the yield of milk fat: in the group of black-and-white cows and hybrids with Holstein blood, not more than 50.0%, the correlation was weak, and in high-blooded hybrids - average. The most significant effect of the genotype was on the variability of indicators of lifelong milk yield and milk fat production.