ВПЛИВ ОСНОВНИХ КОРТИКО-ВЕГЕТАТИВНИХ МЕХАНІЗМІВ РЕГУЛЯЦІЇ НА ВМІСТ ЦИНКУ В КРОВІ КОРІВ ЗАЛЕЖНО ВІД ПОРИ РОКУ

Abstract

The results of studies on the influence of the main characteristics of cortical processes on the content of Zinc in the blood of cows in summer and winter are presented. Experiments were conducted on cows of the Ukrainian black-and-white breed of the 2-3rd lactation. Types of higher nervous activity (HNA) were determined using the method of food conditioned reflexes by G.V. Parshutin and T.V. Ippolitov. The essence of this method consists in evaluating the animal’s motor reaction to the place of food reinforcement, the rate of development and processing of the conditioned motor-food reflex, the level of orientation response and external inhibition. To study conditioned reflex activity, 4 research groups were formed with 5 animals in each. The first group included animals of strong, well-balanced, mobile type of the HNA, in the second – strong balanced inert, in the third – strong unbalanced, and in the fourth – weak one. For our studies we used blood samples of animals obtained from the jugular vein. The iron content was determined in the whole blood by atomic absorption spectrophotometry in a flame mode. The research revealed that zinc content in the blood of cows of different types of higher nervous activity (HNA) did not exceed the physiological limits and was 14-20 μmol/l. It should be noted that in animals of strong types of HNA the content of zinc did not depend on the season, whereas in cows of the weak type of HNA its content in the blood in winter was significantly higher than in summer by 14.1% (p <0.01). The zinc content in the blood of cows of different autonomic nervous system (ANS) state did not depend on the season significantly. The content of zinc in cows of different types of HNA was slightly different. Only in cows of weak type of HNA its content was significantly lower in summer by 22.8% (p <0.001), while in winter, the content of this micronutrient in cows’ blood of SBI, SU and weak type of HNA was lower by 14.2% (p <0.001), 15.5% (p <0.001) and 19.6% (p <0.001), respectively. Only the strength of the cortical processes (η2x = 0.23; p <0.05) significantly influenced the micronutrient content in the cows’ blood in summer, while the influence of the balance and mobility (η2x = 0.03-0.17) were insignificant. In winter, the content of zinc was limited mostly by the mobility of the nerve processes (η2x = 0.72; p <0.001), however, the balance (η2x = 0.39; p <0.01) and strength (η2x = 0.25; p <0.05) significantly influenced the micronutrient content of cows blood as well. Thus, obtained data indicated the presence of cortical mechanisms for regulating the content of Zinc in the blood of cows. It was established significant influence of the main characteristics of cortical processes on the content of zinc in the blood of cows, while the ANS state of animals did not significantly limit the content of this micronutrient in the blood.