Infl uence of some paratypical factors on the productive longevity of cows

Under current conditions of agricultural production, increasing milk productivity and extending the productive longevity of cows are the most important tasks. The purpose of the research was to determine the infl uence of some paratypic factors on the productive longevity of cows. The influence of the age of the first eff ective insemination and the duration of the period of open days on the productive longevity of cows of Black-and-White breed has been considered in thearticle. The studies were carried out at the training and research farm of the Federal State Budgetary Educational Institution of Higher Education “Northern Trans-Ural State Agrarian University”. For the research, a database of culling animals for the period from January 2019 to December 2021 was used. The object of the research were cows of Black-and-White breed that had one or more completed lactations. Groups were formed depending on the time of the first aff ective insemination and the duration of the open days period. The longevity of cows was calculated by counting the days of life in the period from the date of birth to the date of culling. The calculation of the duration of the productive period was carried out taking into account the dates of calving and the duration of each completed lactation by summing up all productive days. An analysis of the culling of animals from the herd was carried out. The main reasons for the culling of cows were limb diseases (24.7 %), mammary gland diseases (22.2 %) and gynecological diseases (21.3 %). The average age of eff ective insemination of animals was 15.5 months in the herd. It was found that the average longevity in the herd was 1815.7 days or 5.04 years, which in lactations consisted of 2.97. The longest productive longevity was observed in cows with the age of the fi rst eff ective insemination of 12–13 months. Therefore, the duration of the open days period should be kept at 90–120 days, in this case the lifetime productivity was 17277.9 kg of milk.