Mолочна продуктивність корів західного внутрішньопородного типу української чорно-рябої молочної породи в залежності від їх генетичної структури

Abstract

The analysis of milk productivity indicators of cows of the western inbred type of the Ukrainian black-spotted dairy breed was carried out, depending on the milk productivity level of their mothers. Certain features of the influence of maternal and paternal heredity on milk yield, milk fat content, reproductive capacity and duration of economic use of cows have been established. First-born cows, which come from mothers of the modal class (milk yield for 305 days of lactation in the range of 3411–5129 kg) and mothers from the group of plus variants (milk yield more than 5129 kg) prevailed in terms of the weight of peers from mothers from the group of minus variants (milk yield less than 3411 kg) by 20 % and 25 %, respectively. In the following age periods (second to fifth), due to the culling of low-yielding animals, the differences in milk yield between the cows of the experimental groups are evened out. The rate of elimination from the main herd of cows from plus-variant mothers is significantly higher than that of cows of other groups. By the fifth lactation, 91.2 % of the initial herd dropped out for various reasons, in other groups this figure was 63–67 %. Cows from the minus-variants group had the most fatty milk, the fat content in the milk during the first three lactations was 0.05–0.09 percent higher than that of other groups. The significant influence of the genotype of the parents on the level of milk yield for 305 days, the fat content in milk and the duration of the service period after the first calving in the whole herd, as well as on milk yield and the duration of the service period in the modal class and on the duration of the service period in the minus group were established