Content of sex and steroid hormones in blood serum of cows of Irmenskiy type in Novosibirsk Region

Abstract

There were carried out investigations on determining the hormonal status of cows of the Irmenskiy type with the annual milk production of 8000-10000 liters per cow. During the cows’ blood serum examination for the contents of major hormones (progesterone, estradiol, cortisol) affecting the reproductive function, a hormonal imbalance in the levels of progesterone and estradiol was revealed in 100% of cows. The results obtained were significantly different from the standard values according to the literature. The levels of progesterone and estradiol did not match the dynamics of physiological delivery flow and postnatal processes that has indicated the subinvolution of the uterus and ovarian hypofunction. The estradiol levels in the blood serums examined were extremely low during both delivery and 30-day period after delivery. In 30 days, the estradiol content corresponded to the average parameters of this physiological period. The dynamics of cortisol content in the blood serum was consistent with the known physiological laws for the period. The analysis of the delivery flow pattern and postnatal period in the cows examined showed that postnatal pathologies were observed in 88.5% of cows; the average service period was 169.6 days. The findings of investigations into the estradiol content in the cows’ blood serum during the delivery and the first few days after that and the progesterone content during the 15-20-day period before delivery and 1-2 after that could be a predictor of postnatal pathologies. The diagnostic criterion of the reproductive ability is a progesterone level by 45 to 60 days after delivery.