Elemental status and its changes in relation to the boundaries of the “physiological standard” in cows of the Holstein breed of different lactations
The paper presents data on the assessment of fluctuations in the exchange pools of chemical elements in the wool of Holstein cows in relation to the boundaries of the “physiological standard” in the context of lactations. The object of the study was Holstein cows of I, II, III and IV lactations. Wool was used as a biosubstrate to assess elemental status, which was selected from the upper part of the withers of cows during the milking period (20-40 days). Elemental analysis of samples was evaluated by AES-ICP and MS-ICP methods. As a result of the experiment, it was found that cows of I lactation showed minimal concentrations of a number of toxic elements (As, Hg, Cd, Sr). Animal IV lactations were ahead of animals I lactation in terms of accumulation of Zn in wool (P≤0.01), while they were inferior in accumulation of Cu (P≤0.05). The calculation of the Spearman’s correlation coefficients of the sum of toxic elements (As, Hg, Sr, Cd) with the concentrations of essential elements revealed a positive correlation for Mn (r = 0.49) and Se (r = 0.68), a negative correlation for Cu (r = -0.57) and Zn (r = -0.56). Interpretation of the elemental status of cows with respect to the boundaries of the “physiological standard” revealed an increase in the number of deviations from the standard as the duration of productive use increased from two to eleven.