Quality of milk monitoring during control cows milking in the Tyumen region breeding farms

The purpose of reseach is to monitor the quality of milk during control milking of cows in the farms of the Tyumen Region. Monitoring was carried out in the winter stall period of 2021 in two breeding farms on Holstein (n = 549) and black-and-white (n = 154) cows at the age of first lactation. In the average daily milk samples, the mass fractions of fat, protein, the content of urea, ketone bodies (acetone, beta-hydroxybutyrate) were determined. The results of a comprehensive analysis of milk made it possible to obtain information about the state of metabolism in the body of cows and the quality of their ration. In the Holstein herd during the milking period, an increased content of ketone bodies in the milk of some cows was observed (acetone – up to 0.33 mmol/L, beta-hydroxybutyrate – up to 0.23 mmol/L) and a shift in the equilibrium between the mass fraction of fat and protein towards increase in fat, which is a sign of intense metabolism and the mobilization of body fat reserves. In the first herd, an increased level of urea in milk was observed – 35.5–41.8 mg/dl. The ratio between the urea content and the total milk protein indicated that the ration of the first herd cows was not balanced in energy-protein ratio, and the main problem was an excess of protein digested in the rumen. In a herd of black-and-white breed, the level of ketone bodies in milk did not exceed critical limits (acetone – 0.13 mmol/L, beta-hydroxybutyrate – 0.08 mmol/L), and the average urea content during all lactation periods was normal (22.5–24.1 mg/dl), but the ratio between the mass fraction of milk protein and urea showed an excess of metabolic energy in the ration of cows after the 200th day of lactation. A comprehensive analysis of the quality of milk showed that in both herds it is necessary to adjust the feeding ration taking into account the physiological state of dairy cows.