THE INFLUENCE OF HEREDITY ON THE INDEXES OF COMPLETE BLOOD COUNT OF HOLSTEIN COWS AND HEIFERS WITH HYPERTHERMIA
Cows and heifers of the Holstein breed are characterized by different resistance to periodic hyperthermia lasting 6-8 hours. In animals of both physiological groups, there is a significant variation in the indicators of leukopoiesis and a more stable state of erythropoiesis (coefficients of variation 25-69 and 6-16 %, respectively). Cows have a decrease in the number of lymphocytes - up to 3.01±0.19 G/L and an increase in monocytes - up to 0.62±0.05 G/L (p<0.99) compared with heifers. Erythropoiesis of cows is characterized by the development of normochromic hyporegenerative anemia, which is manifested by a decrease in the number of erythrocytes, hemoglobin content and hematocrit in many animals. The volume of red blood cells did not change significantly. The heifers pedigree from the bulls of two lines (Reflection Sovereign and Vis Back Ideal) it did not affect the studied indicators of the complete blood count in hyperthermia.