Assessment of Heavy Metals in Milk Produced by Black-and-White Holstein Cows from Moscow

Abstract

Milk must comply with quality standards for proper human nutrition. The purpose of this study was to conduct a comparative microbiological and elemental analysis of milk quality from Black-and-White Holstein cows. The studies were conducted on the basis of livestock farming in January-October 2019, Moscow region, Russian Federation. The experiment included 60 cows, divided into 3 groups of 20 animals of full age. All cows were kept under identical conditions. The first group consisted of purebred Black-and-White cows; the second group included Holstein half breeds; and the third group included the third generation of Holstein crossbreeds. 500 samples of milk were taken from animals of each group. The second group exceeded in content of zinc by 0.5 times (p≤0.05). The third group was recorded with lower manganese by 2 times (p≤0.001) while the first group by 0.5 times (p≤0.05) compering to the second group. Milk in groups 3 and 2 had a significant excess of iron and copper concentrations by 1.5-2.0 times (at p≤0.001), comparing to group 1. The milk in group 1 (purebred Black-and-White cows) exceeded TLV (threshold limit value) for lead (by 2.2 times) and cobalt (by 2.5 times). The milk in this group also had a higher cadmium content compering to the other two groups (by 1.3–2.7 times). Holstein crossbreeding helps to increase the concentration of cobalt, zinc and manganese. Lead and cadmium accumulate in the milk of purebred Black-and-White cows.