Influence of the origin of bulls on the indicators of the immunological activity of daughters and the realization of their genetic potential

The work was carried out on the basis of the breeding farm "Barybino" (Moscow region) in 2022 on two groups of daughters of bulls-producers of breeding from different countries. The first included daughters (n=15), bulls imported from Canada, the second - from the Netherlands (n=13). Milk productivity and reproductive qualities were assessed over two lactations. Biochemical parameters and IgG in the daughters of sires of different selections were studied in the second lactation. Biochemical parameters were determined on the device Hospitex Diagnostics "Screen Master", the quantitative content of IgG in blood serum - by ELISA. The purpose of the research is to study the influence of bulls-producers of foreign selection on the economic and biological indicators of daughters in the conditions of domestic production. As a result of research, based on the analysis of variance, the influence of the origin of sires on the content of albumin (p=0.038) and IgG (p=0.049), (p ≤ 0.05) was established. The indicator of the service period to the second lactation in group II decreased by 76 days (Р≤0.05) compared to the first lactation, while in group I it did not change significantly. The established data may indicate certain features of the adaptation of cows-daughters of bulls imported from Canada and the Netherlands.