THE NUMBER OF SOMATIC CELLS IN MILK OF YAROSLAVL PUREBRED COWS DEPENDING ON MILK YIELD AND MILK-RETURN RATE

Abstract

Under modern market conditions in dairy cattle breeding not only quantity of products produced is of great importance, but also its quality, as well as the productive longevity of fixed assets, that is, cows. The number of somatic cells on the one hand is a criterion of milk quality and cow udder health, and on the other hand is a breeding sign. Scientists have found that the coefficient of heritability of the number of 133 somatic cells is 9-25%. Researchers from all countries conducted the study of many dairy breeds on this basis. Yaroslavl breed of cattle is insufficiently studied in this direction. The article describes the charac-teristics of t Yaroslavl breed first-calf cows including the number of somatic cells in milk and milk ejec-tion speed. In the studied population of Yaroslavl breed cows, milk yield is 4917±28 kg of milk, fat con-tent is 4.73±0.01% and protein - 3,28±0,01%, the rate of milk output – to 1.77±0.02 kg /min, daily milk yield in determining the rate of milk output was 19.8±0.1 kg. Тhe number of somatic cells in milk corre-sponds to GOST 31449 2013 and is 299,0±7.5 thousand/ml. The results of somatic cells studying in milk depending on milk yield and milk ejection speed are given in the article. It was established that the small-est number of somatic cells in milk (1,60-1,79 kg/min) was obtained in the group of highly productive first-calf cows with the productivity of more than 7000 kg of milk, as well as in the group with the average milk yield rate. The value of KSK is reduced with the growth of milk yield. The smallest number of somat-ic cells in milk was found in heifers with an average milk-return rate.