Effectiveness of breeding in the pedigree herd of Holstein breed

The selection and genetic parameters of fi rst-calf heifers (3470 heads), which were the daughters of 236 Holstein sires have been presented in the article. On average, there were at least 15 daughters per sire. The studies were carried out in the herd of Stupinskaya Niva LLC in the Moscow Region. The calculation of the selection and genetic parameters (heritability, variability, correlation, selection eff ect) was carried out using generally accepted algorithms of biometric analysis. The procedure for assessing the genetic parameters consisted of distributing phenotypic variances and covariances into genetic and non-genetic components. It was found that the coeffi cients of variability of milk fat and milk protein were 3–11 times lower than those of milk yield, milk fat and protein yield. The highest heritability coefficient (h²) was established for the mass fraction of fat in milk – 0.49, and the lowest – 0.36 for milk yield. The correlation between milk yield and the mass fraction of fat and protein in milk was negative and amounted to –0.48 and –0.21, respectively. The highest and most positive correlation was between milk yield and milk fat yield (+0.96), milk yield and milk protein yield (+0.99), and milk fat and protein yield (+0.95). It is necessary when selecting animals to take into account the yield of milk fat and protein, and use them as the main selection traits. The main attention should be paid to the selection and mating of sires with high breeding value since their contribution to genetic progress is significantly higher than that of the dams of cows.