Dynamics of cortisol in calves against the background of the use of polymethylsiloxane polyhydrate as an anti-stress drug

Our core interest is the dynamics of cortisol in the period of delivery of calves when an environmentally safe drug polymethylsiloxane polyhydrate is being used. Experimental groups of calves received suspension of the drug at a dose of 0.1 g / kg, 0.3 and 0.5 g / kg of body weight. The cortisol level in the newborn calves was 7.12±0.06 mcg/DL, providing sufficient enzymatic activity. In calves of 5-day-old age, by the end of the colostrum period, the cortisol level significantly decreased, in the control group by 5.84 times, reaching 1.22±0.26 mcg/DL; in experimental groups 2, 3 and 4, respectively, by 6.3; 9.13 and 8.68 times (p≤0.05). When the calves reached the age of 15 days, the cortisol content in the calves in the control group was 0.10 mcg/DL; in groups 2, 3 and 4, respectively, it was 0.11; 0.12; and 0.14 mcg/DL. In comparison with the control group calves, the calves of experimental groups on the first 5 days of life, the drug at a dose of 0.1 g/kg of body weight contributed to a decrease in cortisol by 7.4%, at a dose of 0.3 g/kg-by 36.1%, at a dose of 0.5 g/kg-by 32.8%. While the drug was being used for 15 days, in groups 2, 3, and 4, the cortisol content was higher relatively to group 1 by 0.01 mcg/DL, 0.02 mcg/DL, and 0.04 mcg/DL, respectively. Therefore, for calves of 5-day-old age, the optimal cortisol concentration is 0.78-1.22 mcg/DL, for 15-day-old calves, respectively, 0.11-0.14 mcg / DL. We recommend that calves use a suspension of polymethylsiloxane polyhydrate at a dose of 0.3-0.5 g/kg of body weight on the first five days of life, followed by a dose of 0.1-0.3 mg/kg.