Племенная ценность по удою быков- производителей как фактор отбора по молочной продуктивности первотелок

Abstract

Studies have been conducted to identify the influence of the father's breeding value (BVF) in milk yield on the superiority of his daughters (BVY1l) over their peers on this trait, lactating in 2020 in the herds of the Leningrad region (n=3062). A positive correlation of BVF with the absolute milk yield of daughters and BVY1l was established, but this relationship is not high (+0,127 and +0,128). The sample is divided into three groups BVF by milk yield (from –410 to +1554 kg of milk): I – BVF milk yield of less than –100 kg («degraders») – 18,9 %; II – BVF milk yield of –100 to +99 kg («neutral») – 35,7 %; III – BVF milk yield of +100 kg or more («improvers») – 45,4 %. In terms of breeding value by milk yield, on average, the first heifers of group I lagged by –75±12 kg, group II – by –3±9 kg, and in group III the superiority was +41±9 kg. But at the same time, regardless of the level of BVF in all selection options, the number of daughters of bulls has both positive and negative value. So, in group I, 29,7 % of animals surpass their peers by +100 kg of milk or more, in group II, 32,8 % of such animals, and in group III, on the contrary, 32,5 % of the first heifers were inferior to their peers by –100 kg or more of milk. Thus, it can be stated that with an increase in BVF, an increase in BVY1l is observed. the descendants of the bull, that is, the official evaluation of the breeding bulls can be used as an animal selection tool to improve the breeding qualities of the herd.