DYNAMICS OF HORMONAL STATUS OF YOUNG SIMMENTAL BREED IN CONDITIONS OF VARIOUS HOUSING SYSTEMS

Abstract

The work is devoted to the study of the dynamics of the hormonal status of young cattle depending on the housing system. In this regard, the functional activity of the endocrine glands was studied: the adrenal cortex, pancreas, thyroid and genital glands. The content of cortisol, insulin, testosterone, thyroxine in the blood serum was determined during the periods: immediately after birth, at the daily age, after reaching 1, 2, 4, 6, 8, 12 and 18 months. It was found that the cortisol content in the blood of newborn calves (148.6–152.7 nmol/l) was the maximum. By the end of the first day, the level of this hormone decreased by an average of 7.07–17.62%. By 18 months, the cortisol content was in the range of 32.3–39.3 nmol/l. The bulls of the control group were more susceptible to the effect of adverse environmental factors. The highest level of thyroxine (169.2–173.4 nmol/l) was at birth. In subsequent periods, the thyroxine content decreased. Activation of the thyroid gland was noted at the age of 8 and 12 months. This is due to the period of puberty. The maximum values of insulin concentration in the blood were noted in daily bulls (1.28–1.83 mmol/l). Thus, in the control group, the insulin level increased by 38.64% compared to the data at birth, in groups 2 and 3, respectively, by 31.49 and 22.48%. At the age of one month, the level of pancreatic hormone, compared with baseline data, increased by an average of 3.87–5.30%, at the age of two months – by 2.27–8.66%. In subsequent age periods, the concentration of this hormone changed slightly. Relatively low testosterone levels were recorded in the first six months (0.47–1.32 nmol/l). At the age of 6, 8 and 12 months, the testosterone content increased to 2.97–3.34, 3.78–4.29 and 9.84–12.15 nmol/l, respectively. The highest testosterone content was found at the age of 18 months (13.24–15.48 nmol/l).