Immune status of Holsteinized cows with different levels of milk productivity

Abstract

The aim of this work was to determine the immune status of Red Steppe cows with different levels of milk productivity and blood relationship across the upgrading breeds. The studies were conducted on a farm in the Omsk region. To determine the immune status of dairy cows, they were divided into three groups based on lifetime milk yield, productivity level, blood relationship across the upgrading breeds, pregnancy period, and health status. The first group consisted of the animals with low productivity (20,000–25,000 kg; n = 7), the second – with medium productivity (25,000–30,000 kg; n = 10), and the third – with high productivity (30,000 kg or more; n = 7). Statistical data processing was performed using one-way analysis of variance (ANOVA), as well as a special program for asses sing the effectiveness of immune responses using the normalized deviations method, which allowed for prompt diagnostics of impaired immunological reactivity of various immunocompetent cells and assessment of their functional state. The reliability of differences was determined using the Student's t-test with an error probability of p < 0.05. As a result of the conducted research, it was established that with an increase in Holstein blood (51% and higher), the resistance of the animal’s body decreases to a pronounced immunodeficiency without clinical manifestations. It turned out that the deviations identified in all individuals were associated with a disruption of the immune function of neutrophils. A decrease in the absolute concentration of neutrophils and lymphocytes was found in the group of low-yielding animals, compared with the group with average productivity by 16.5 and 16.0%, respectively, and when compared with the cows with high milk yield – by 20.5 and 21.5%. Also in this group, the concentration of T-lymphocytes was reduced by 39%, B-lymphocytes by 54% and cytoto xic T-lymphocytes by 52%. Holsteinized cows with Angler blood content of 50% or more had strong immunity with high lifetime milk yield.