Features of the amino acid composition of cow’s milk depending on the season

One of the key criteria for assessing the quality of milk is its protein-amino acid composition. The purpose of our study was the need to study the features of the amino acid (AA) composition of milk of highly productive cows depending on the season and to identify correlations between the indicated indicators of cows' milk. The data obtained show fairly close values (less than 9 % difference between the data for February and July) for the relative content of almost all replaceable ("synthesized") and essential ("non-synthesized") AA in cows' milk. The exception is the content of the relatively replaceable AA Arg and Cys (although the absolute values for the content of Cys in milk are extremely low and not reliable). Very strong (from 0.79 to 0.99) positive correlation coefficients were found between the content of AA in milk of cows in February (group 1) and the content of protein (both total and true), with the exception of the content of Cys and Arg (from 0 .62 to 0.63), which, in general, are also strong positive correlations. Correlations of all AKs with single (morning, evening) milk yields, as well as with daily milk yield, are negative: either moderate (from -0.37 to -0.46) or even strong (from -0.51 to -0.73) correlations. This is quite consistent with our assumption that an increase in milk yield leads to a decrease in the protein content (and, accordingly, AA) in cows' milk. Similar data, but with lower correlation values, are typical for group 2 (July). It is advisable to continue research in terms of expanding the indicators of the antioxidant status of milk in conjunction with the amino acid composition in order to clarify the mechanisms for the formation of high-quality livestock products.