Evaluation of the effectiveness of cows of Holstein breed

Abstract

According to the latest regulatory documents for conducting a breed inventory of breeding livestock for dairy cattle, all animals with Holstein blood of 75 % or higher are classified as Holstein breed. In the Sverdlovsk region, such animals consist of more than 75 % of the total dairy cattle population. The study of their effectiveness when used under the conditions of the Middle Urals is relevant and has both scientific and practical significance. The purpose of the work was to assess the efficiency of Holstein cows in the Middle Urals zone, taking into account the age dynamics in lactations. Productive longevity on average for the farm where the research was conducted was 2,45 lactations, i.e. the majority of animals did not survive to mature lactation. The highest milk yield indicators were for cows in their 3rd mature lactation. However, intensive rearing of replacement heifers, their early insemination and further intensive use to obtain high milk yields with increasing lactation duration leads to rapid wear and tear of the body. They culled out of the herd without reaching physiological maturity. As a result, there is a shortage of off spring, lifetime milk yield and a decrease in the efficiency of the industry. A low positive correlation was established between the duration of the period of open days and the frequency of insemination of cows in the fi rst 6 lactations, which ranged from 0,002 (2 lactation) to 0,12 (6 lactation). The highest milk production rate was in the 2nd lactation, and then it decreased. The optimal ratio of milk yield and live weight is a milk yield of 9800 kg of milk or more with a live weight of cows of 617 kg. The increase in milk yield with a simultaneous increase in live weight leads to a slight but decrease in this indicator.