Variability of hematological parameters in cows depending on their physiological status

Abstract

The object of the study was Holstein cows of the second-fourth milk secretion and first-calf cows of different production groups formed depending on the physiological status of the animals. The most pronounced hematological changes were observed in sexually mature cows during the first three months of milk secretion. After fawning, the number of erythrocytes, lymphocytes, and hemoglobin decreased. The concentration of bloodforming elements in the groups with a first-calf cow was significantly higher than in sexually mature cows. The level of erythrocytes and hemoglobin in first-calf cows reaches its maximum value at the beginning of milk secretion. Sexually mature cows after the first month of milk secretion were statistically significantly superior to first-calf cows at the beginning of milk secretion in terms of granulocyte content. Cows, in the first days of milk secretion, had the most fantastic range of variability in the scope of erythrocytes, leukocytes, and hemoglobin, which reflects the individual response of the body to significant changes in physiological status. At the same time, the first-calf cows at the beginning of milk secretion had the most stable level of these hematological indices. Dry cows, as a rule, occupied an intermediate position regarding the variability of the content of blood form elements. Thus, assessing the hematological profile of cows of different production groups helps specialists make targeted adjustments to rations and housing conditions, effectively manage genetic resources and obtain high profits.