EN
Effect of ketosis on the number and activity of leukocytes was investigated in 8 cows. The high level of ketone bodies in the blood was associated with a significant decrease in the total white blood cell count, neutrophils, and eosinophils, and insignificant decrease in lymphocytes. The number of monocytes was not changed. At the stage of ketosis, the neutrophil ability to NBT reduction was significantly lower, while the phagocytic index was slightly higher compared with the values during the time when the disease was not found.