Efficiency of milk production depending on the age of cows at first calving

Abstract

The article presents the materials of studying the influence of age and development of replacement heifers on milk production and further lifetime productivity of cows. The economic indicators of milk and lifetime productivity, duration of the use of cows for breeding purposes depending on the age of first calving and live weight were analyzed. The studies were carried out in 2009–2019 in the pedigree breeding unit of Irkutsk region. The indicators of productivity of cows of the black-andwhite breed of the Pre-Baikal type at different ages of first calving (22–28 months) were studied. The material of the work was the information database of animals from the breeding program Selex. Organizational, technological and economic research was carried out according to generally accepted methods. The ways of increasing milk and lifetime productivity of cows, increasing the profitability of dairy production on farms were determined. On the basis of the analysis, the optimal timing of calving and introducing first-calf heifers into the main herd in order to obtain profit was established 22 months from birth with a live weight of 530-540 kg. These cows showed the highest productivity during the first lactation, however, their lifetime productivity proved to be the lowest. The highest lifetime productivity was recorded in cows whose age at the first calving was 27 months; proceeds from sales of additional produce received by the farm amounted to 131191 rubles. It was found that cows whose first calving age was 28 months had a decrease in lifetime productivity (25382 kg/head), the cost of additional produce from these animals was 102577 rubles/head.