Abstract
The objective of this study was to evaluate the nutrition according to the milk metabolites and components during the seasonal dependence of the dairy cows. In the summer time, it was confirmed that significantly lower content of milk protein and fat (P < 0.001) and lower milk, protein, and fat yields (P < 0.001) occurred, compared to the autumn period. The content of milk lactose was not statistically significant (P > 0.5). The evaluation of nutrition according to protein in milk and milk urea in the summer period was confirmed in the 2nd group of milk samples which represented 53 % of the group’s higher content of milk urea, higher content of urinary nitrogen excretion, and a lower nitrogen utilization efficiency compared to the 1st group of milk samples. The autumn period was confirmed in the 2nd group of milk samples which represented 53 % of the group with higher milk yield and lower content of milk proteins and milk fat compared to the 1st group of milk samples. The evaluation of nutrition using the analysed content of milk urea and proteins in milk represents a suitable tool for evaluating the impact of malnutrition or overfeeding of energy and protein on milk production and other components.