The direction of the breeding process in a herd of Ayrshire breed cows in the conditions of the Vologda region

Abstract

The direction of the breeding process in herds and populations of dairy cattle breeds based on the actual indicators and variability of the trait is one of the main factors that allows to determine the effectiveness of breeding measures. As the initial material for the research there were taken the data of breeding records (n=681) of Ayrshire breed cows of the agricultural complex "Maysky" of the Vologda region. The number of cows was distributed by generations (195 cows with the first incomplete lactation, 177 cows with the first completed lactation, 130 cows for the second lactation, 179 cows for the third lactation and older). According to the research results, the superiority of the actual indicators for the live weight of heifers in animals of modern generation in early age periods was from 28 to 39 kg. Consequently, with each new generation, animals have better development indicators, as evidenced by the indicators of variation (variability) of the live weight of heifers in the early age periods of weak and moderate Cv = 5.3 to 10.6 %, depending on generation. The reduction of the age of the first insemination of heifers to 13.4 months (-2.2 months) and the first fruitful insemination to 14.0 months (-2.1 months) in animals from full-age to the first incomplete lactation was revealed. A targeted selection of cows was carried out in the herd according to the level of milk productivity of mothers after the first lactation - the selection efficiency was 977 kg of milk, according to the highest - 456 kg. The selection of breeding bulls was carried out according to the level of productivity of the breeding stock, however, it should be noted that the intensity of selection in cows for the incomplete first (10968 kg of milk) and first lactation (10635 kg of milk) is reduced compared to cows for the second lactation (11417 kg of milk). Consequently, in herds and populations of dairy cattle breeds, in order to achieve genetic progress in productivity in the next generation, it is necessary to determine the direction of the breeding process.