The role of growth hormone and IFR-1 in the formation of leukocytic blood composition in the body of calves during cultivation

Abstract

Purpose: to evaluate the biological properties of growth hormones (GH, IGF-1) in the dairy and vegetable periods of growing Holsteinized Black-and-White heifers, determined by their ability to regulate the age-related variability of the leukocyte composition of the blood.Materials and methods. The work was carried out in the conditions of the SPK «Koelginskoe» named after V. I. Shundeeva I. N. (Chelyabinsk region) in 2019–2020 on heifers of Holsteinized Black-and-White breed during the dairy and vegetable growing periods. Animals up to 3 months of age were kept individually, and then in groups of 10 animals. Milk and milk replacer were used in the diet of animals only up to 3 months, and then they were transferred to a plant-based diet. When compiling the feeding ration on the farm, they were guided by the norms of the VIZh. The experimental group (n=10) was formed according to the principle of approximate analogues, heifers were included in its composition after a clinical examination, which was carried out later with each blood sampling. For laboratory studies, whole blood and blood serum were used. Blood sampling was performed at 1, 3, 6, 9, 12 and 13 months of age in the morning before feeding. The leukocyte composition of the blood, the concentration of growth hormone and IGF-1 were determined.Results. It was found that the total number of leukocytes in the bloodstream of heifers increases with age by 28.06% (p<0.05), which is accompanied by an increase in the percentage of eosinophils, segmented neutrophils and monocytes in the leukogram by 45.31; 5.70 and 50.00% (p< 0.05), a decrease in lymphocytes, rodshaped neutrophils by 5.69 and 43.39% (p<0.05). The level of STH by the end of the heifer rearing period decreases by 54.32% (p <0.05), and the insulin-like growth factor type 1, on the contrary, increases by 32 times (p<0.05). The values of the correlation coefficients in the statistical matrix of STG and IGF.