Effect of Repeated Regrouping on Productivity and Physiological Parameters of Dairy Cows

The study examined the impact of social stress caused by repeated regrouping of cows of different breeds (Holstein, Red Steppe, and Simmental) on milk productivity and quality indicators (milk yield, fat, and protein content) as well as physiological parameters, including hormone levels (cortisol and adrenaline) and general blood parameters (white blood cell count, lymphocytes, red blood cells, and hemoglobin). It was found that the effect of social stress induced by repeated regrouping varied among breeds. Based on a comprehensive assessment of physiological stress biomarkers, Holstein cows were the most sensitive, showing a 48,87 % increase in adrenaline levels and a 15,37 % rise in hemoglobin concentration. Simmental cows also exhibited a significant increase in adrenaline levels (by 73,53 %), whereas Red Steppe cows demonstrated relative resistance, with only an 18,23 % elevation in cortisol levels. At the same time, regrouping had no significant effect on milk productivity or quality, and the observed deviations in physiological parameters remained within the normal range.