ADAPTIVE REACTIONS OF COWS, DEPENDING ON THEIR FUNCTIONAL STATE, PHYSIOLOGICAL AND TECHNOLOGICAL LOADS
The state of cows’ adaptation was investigated under several physiological loads, such as: pregnancy, lactation, time after calving, at rest and under technological loads. Adaptive reactions were assessed by the degree of activity of the sympathoadrenal system (SAS), by the state of the nervous and cardiovascular systems of cows. The following were identified: secretory function, the amount and change in the concentration level of catecholamines, as well as the electrical activity of the skin; studies of the cardiovascular system were carried out by electrocardiography. An increase in the stress of the physiological regulation of the body of the female was revealed as it approached the next calving. Using selected gradations of sympathoadrenal system activation, periods of tension and their connection with the physiological state of animals were identified. It has been established that while maintaining the physiological optimum, only a part of the animals has the ability for long-term, stable productivity without depleting the body’s reserves. Several animals responded inadequately to the physiological loads (pregnancy, lactation): they develop a state of unstable adaptation - there is a significant activation of SAS and the stress of functional systems. Pregnancy in heifers is accompanied by a significant activation of SAS. The first-calf cows have calving, and a new-season period activates the SAS-work. After calving in the first-breed cows, the new pregnancy period activates their SAS. For 2-4 months of pregnancy, the number of animals with unstable adaptation and system’s stress increases. In general, the reaction of elder cows to lactation and pregnancy was less pronounced. However, that increased the number of animals with a decrease in the activity of SAS, which indicated the depletion of their system.