Сontent of carotene in blood serum of highly productive cows by periods of lactation and keeping methods as a criterion for assessing vitamin metabolism

Within the research topic No. FMGZ-2022-0003 studies were conducted on biochemical composition of highly productive lactating and dry cows’ blood. The studied cows were stable and loose housed. The research was carried out at the animal husbandry complex for loose housed cows with pipeline milking, the animal husbandry complex for loose cows with a milking parlor, the animal husbandry complex for loose cows with robotic milking. The research results were obtained during the production experience conducted on the basis of an agricultural enterprise in the Vologda region. The content of carotene in the blood of highly productive cows during the study was determined with different housing methods, from 0.47 mg% at the peak of lactation at a robotic content to 0.81 mg% at the decline of lactation at a loose managing. The maximum level of carotene in the blood serum of animals was observed at the beginning and the end of lactation in cows with loose housing and it was 1.36 and 1.41 mg%, respectively. The minimum level of carotene was recorded at the peak of lactation with robotic content and the dry period with loose and robotic housing and was 0.1 and 0.12 mg%, respectively. According to the housing methods minimal fluctuations in carotene from generally accepted physiological norms were noted with a stable managing system and range from 11% to 44%. The results of biochemical studies indicated a low dependence of carotene on the blood serum of cows from lactation stage. The established average values of carotene indices and their deviation from the reference values indicated violations of vitamin metabolism.