Immunohematological parameters in cows depending on the functional state of the liver and the stage of the production cycle
The study aimed to identify and quantify changes in immunohematological parameters in cows at different stages of the production cycle depending on the functional state of their liver, to develop diagnostic, therapeutic and preventive measures. The study was conducted on 274 cows: fresh (n = 60), lactating (n = 60), early (n = 87) and late dry cows (n = 67). The functional state of the liver was classified retrospectively into normal (NMP), stressed (SMP) and pathological profiles (PMP) based on the threshold values of aspartate aminotransferase, glutamate dehydrogenase, gamma-glutamyl transferase, alkaline phosphatase and total bilirubin levels in the blood serum. The immunohematological profile was assessed based on the white blood cell count, phagocytic activity (PA) values and the phagocytic index. In SMP animals, PA was reduced to 44.0% (with NMP 49.0%), and the leukocyte count in the blood was reduced to 7.65×10 9 /L (with NMP 9.34×10 9 /L). In fresh cows with PMP, the absolute leukocyte count in the blood decreased to 7.53×10 9 /L, and PA was 48.0%. Suppression of adaptive immunity and activation of the inflammatory response were typical for lactating animals with SMP and PMP: the relative content of lymphocytes in their blood decreased to 44.0% and 45.5%, respectively, while segmented neutrophils increased to 41.5% and 41.0%. In cows with SMP, suppression of adaptive immunity persisted in the early dry period: the relative content of lymphocytes in the blood was reduced to 44.0%, and that of segmented neutrophils increased to 43.0%, with a decrease in PA to 45.0%. For PMP animals during this period, an increase in the relative content of monocytes in the blood to 4.50% was typical. In the late dry period, in cows with SMP, a decrease in the relative content of eosinophils (to 4.0%) and monocytes (3.0%) was observed in the blood; with PMP, a decrease in the phagocytic activity of neutrophils and monocytes (to 38.0%) with an increase in the proportion of segmented neutrophils (to 35.0%). Thus, the white blood cell count and PA parameters in cows with SMP and PMP at different stages of the production cycle have a specific profile that distinguishes them from healthy animals, which must be taken into account when developing diagnostic, therapeutic, and preventive measures.