Breeding parameters of the main economically useful traits of milk productivity of black-and-white Ural type cows

Abstract

Currently first place in the number is a domestic black-motley breed, second place – Holstein. In the Sverdlovsk region, the Ural type of black-and-white cattle was created and officially registered in 2002 by crossing the breeding stock of the black-and-white breed of the Ural offspring with the Holstein bulls. In recent years, there has been a stable significant increase in milk productivity, as a result of which in five years the milk yield for the herd increased by 1388 kg of milk, and for full-aged cows by 1655 kg and reached 10257 kg. A significant increase in productivity was accompanied by a significant increase in the fat content in milk by 0.26% on average for the herd, and by 0.47% for first heifers. protein-Milk content has not changed much, but it is still not high enough. Over the past five years, there has been an increase in the variability of the main selectible trait – milk yield for both the first and third lactation. The selection boundaries for such an important quality indicator of milk as protein content have been slightly expanded. Coefficient of variability in protein content. The negative impact of milk yield on the level of fat content of the herd over the past more than 15 years has naturally changed from an average negative to an average positive in first-heifers, and in full-aged cows it has decreased from -0.17 to -0.08. The dependence of milk yield after the third calving on the results of the first lactation has decreased, but it is still quite significant, as evidenced by the corresponding correlation coefficient of 0.28. The increase in the correlation coefficient between the milk yield of mothers and daughters has almost doubled in ten years.