ABSTRACT:
The peripartum is characterized by immune and physiological changes in the mammary glands of cows, making them more susceptive to mastitis. This work aimed to evaluate the phagocytosis of Escherichia coli by phagocytes from blood and colostrum from healthy Holstein cows. Samples from 22 female, heifers and cows, were obtained during the first postpartum milking for evaluation of phagocytosis in glass cover slip, after stimulation with E. coli. The proportion of spreading blood phagocytes was higher when cells were stimulated with bacteria (p=0.003). However, the phagocytosis rate was low and similar to that observed when blood cells were unstimulated (p=0.299). Colostrum showed higher rates of spreading (p=0.000) and phagocytosis (p=0.001) when phagocytes were stimulated with E. coli. Comparing the results obtained for blood and colostrum, a higher proportion of not spreading phagocytes without bacteria inside, when stimulated (p=0.000) or not (p=0.002) with bacteria, was observed in blood. There was a higher spreading rate in colostrum when phagocytes were stimulated with E. coli (p=0.002). There was no difference in the percentage of phagocytosis in blood or colostrum samples incubated (p=0.478) or not (p=0.071) with bacteria. The results showed that E. coli influenced the activity of blood and colostrum phagocytes from Holstein cows in the immediate postpartum period, and will assist in the understanding of the immunological mechanisms that occurs in this period, considered as the most susceptible to infections in cows.
KEYWORDS:
peripartum; phagocytosis; bovine; colostrum