Health and performance management systems should focus on early detection and subsequent prevention of physiological imbalances in dairy herds. Therefore, the need for constant monitoring of the state of health of cows of various physiological and technological groups, in particular markers of protein metabolism, is urgent. The content of total protein in blood serum of deep-bodied cows and heifers was established in the range of 58.3–102.7 g/l (77.2± 0.48 g/l). Disorders of its metabolism were diagnosed in 35.4% of animals, and in most of them (20.4%), mainly in heifers, it was manifested by hypoproteinemia. The optimal content of albumins was established in 81.2% of the studied herd with an average value of 41.1± 0.26%, including in 74.6% of dry cows and in 91.7% of heifers. Hypoalbuminemia was diagnosed in an average of 18.8% of animals, including in 25.4% of cows and in 8.3% of heifers. In dry cows, the pathology arose mainly as a result of the development of dystrophic processes in the liver in the previous lactation periods, in heifers, primarily due to a protein deficiency in the diet. In 72.2% of the studied animals, 40–10 days before the expected birth, there are no violations of the colloidal stability of coarsely dispersed proteins. In 14.1% of blood serum samples, the test was weakly positive (++), in 11.5% - positive (+++) and strongly positive (++++). In another 2.2% of cows, the formation of a dense clot of a milky white color in the test tube was ascertained already after 4–7 hours. after the reaction (the test is hyperpositive - +++++). Optimal values of urea metabolism in blood serum were established in 48.1% of dry cows and in 55.0% of heifers (3.53± 0.043 mmol/l; 1.82–6.80). A decrease in its content was diagnosed in 49.7 and 45.0% of animals, respectively. The metabolism of creatinine in blood serum was optimal in 94.8% of the examined dry cows and in 94.1% of the heifers, and its values were within the reference values. Hypercreatininemia was diagnosed in 5.4% of the studied animal population, which can probably be caused by the development of dystrophic processes in the glomeruli of the kidneys.
Key words: metabolism, diagnostics, proteins, albumins, urea, creatinine, liver, deep-bodied cows, heifers.