Ecology, Environment and Conservation Paper

THE DEPENDENCE OF PRODUCTIVITY AND ELEMENTAL STATUS OF DAIRY COWS ON THE LEVEL OF LEAD

Sergey Miroshnikov, Oleg Zavyalov, Alexey Frolov and Ivan Gorlov

Abstract

The purpose of this article was to study the relationship of lead content in hair and productivity and interior characteristics of dairy cows. The studies were performed on Holstein dairy cows in the farm “Gatchinskoe” of Leningrad Region and the “Agrofirm Industrial” of Orenburg Region (Russia). Depending on Pb concentration in hair, all cows were divided into six groups, including three groups in “Gatchinskoe” and “Agrofirm Industrial”: Groups I and IV up to 25 percentile, II and V - within 25-75 percentile, III and VI - above 75 percentile. Percentile intervals were calculated separately for each micropopulation. The elemental composition of biosubstrates was studiedaccording to 25 chemical elements using atomic emission and mass spectrometry (AES-ICP and MS-ICP). It was established that the increase in lead content in hair of cows of “Gatchinskoe” enterprise (Pb concentration 0.0245-0.247 μg / g) was accompanied by a decrease in daily productivity of cows by milk protein by 14% (P <0.05), milk fat by 24.7 % (P <0.05), daily milk yield by 24.6% (P <0.05). A similar analysis for animals “Agrofirm Industrial” (Pb concentration of 0.228-3 μg / g) did not reveal any statistically significant differences. Consideration of correlation relationships of toxic elements in hairand milk yield indicators revealed a significant relationship only of cadmium and daily production of milk protein (r = -0.58) and non-fat milk solids (r = -0.56) in “Agrofirm Industrial” and milk protein in “Gatchinskoe” (r = -0.44).An assessment of correlations between the concentrations of toxic and essential trace elements in animal hair according to individual groups- intervals of lead content revealed an increase in the number of reliable relationships with increasing lead concentration from 0.0245-0.0487 to 1.49-3.0 μg / g from 7 up to 15 respectively. It was concluded that further development of methods for noninvasive control of elemental metabolism is a prerequisite for creating a unified system of individual monitoring of highly productive animals.