The total accumulation of heavy metals in body in connection with the dairy productivity of cows.

Monitoring of health status and metabolism of dairy cows is essential for modern milk production. At the current level of productivity of dairy cows, in addition to essential elements, increasing attention must be paid to controlling the exchange of toxic elements, a significant number of which belong to the category of heavy metals. In this regard, the objective of our research was to study the relationship of pools of heavy metals in the body of dairy cows, evaluated according to hair composition and elemental composition of blood serum and milk productivity of animals. Assessment of trace element content in the samples was performed using inductively coupled plasma mass spectrometry (ICP-MS). Fat and protein content in milk was assessed by the FIL-IDF procedure. In order to assess the metabolic load of chemical elements in body of cows, the coefficient of total load C was calculated. It allowed us to divide all animals into three groups. Assessment of the content of 25 chemical elements in hair of cows revealed a general regularity of increase in average statistical values of concentrations of some elements with increasing load from 6.9 in group I to 10.7 in group II and 15.8 in group III. As C grew from 10.7 in group II to 15.8 in group III, the content of 20 chemical elements in the coat of animals from group III exceeded that in group II. Exceptions were only Ca, K, P, Se, and As. Thus, the productivity of dairy cows turned out to be interconnected not so much with the level of heavy metals (9 elements), but with a wider list of 20-23 chemical elements. Thus, the optimal course of metabolic processes in animal organism, coupled with the highest productivity, is possible when the internal environment of body is saturated with a certain amount of chemical elements. Accordingly, a lack or excess of these substances will be associated with a decrease in the efficiency of metabolism and animal productivity.