THE EFFECTIVENESS OF BIOLOGICALLY ACTIVE SUBSTANCES APPLICATION DURING THE DRY PERIOD IN UKRAINIAN BLACK-AND-WHITE DAIRY COWS

The article presents the results of studies on the effect of injection solutions on the course of calving and the postpartum period, indicators of reproductive capacity of cows, and milk yield per 100 days of lactation. Three groups of animals were formed for the study: a control group and two experimental groups, R1 and R2. Cows were selected into groups of 25 animals each by the estimated calving date. The solutions (group R1 – L-arginine, microelements in the form of nano-carboxylates Ge, Zn and vitamin B12; group R2 – L-arginine, sodium succinate, microelements in the form of nano-carboxylates Se, Zn, Mn, Cu and vitamin B12) were administered subcutaneously behind the shoulder blade, from 271 days of gestation, three days in a row at a dose of 20 ml. The results of the study showed that the animals in the experimental groups had a significantly shorter gestation period by 9.7 (P < 0.001) and 6.7 (P < 0.001) days, respectively, compared to the control group. It should also be noted that in animals administered R1, all calves were born alive, while in the control group there were three stillborn calves and in the experimental group R2 – two. A study of the time of placenta delivery showed that in the control group this process was the longest and lasted 9.4 hours, while in the experimental groups it was 2.9 and 3.6 hours shorter, respectively. Also, a positive effect of the drugs on the duration of lochia discharge was noted. In the experimental groups, this period was shorter by 1.6 (P < 0.001) and 2.4 (P < 0.001) days. The interval from calving to the resumption of the estrous cycle is an important indicator of reproductive performance in cows. In animals from experimental groups R1 and R2, this indicator was 7.9 (P < 0.05) and 13.6 (P < 0.001) days shorter than in the control group. In this regard, it can be assumed that the solutions affect the hypothalamic-pituitary system (HPS), which regulates hormone secretion by the pituitary gland and influences physiological processes in the animal ‘s body. A positive trend in groups R1 and R2 is also observed by the service period indicator. The difference between the control and experimental groups is 22.3 and 29.0 days, respectively.