Assessment of reactive oxygen species and phagocytosis of milk leukocytes by alfa-tocopherol and enrofloxacin in bovine mastitis

The effect of enrofloxacin and alfa tocopherol on the capacity of bovine milk leukocytes to generate reactive oxygen species and phagocytic activity after stimulation with phorbol 12-myristate 13-acetate (PMA) for superoxide were studied in bovine clinical mastitis. Group I, consisting of 9 healthy cows, served as the control, whereas groups II and III each contained 9 cows with clinical mastitis on the basis of California Mastitis Test (CMT) positive reaction. Group II cows received 1500 mg of enrofloxacin for 5 days, while group III received 1500 mg of enrofloxacin for 3 days together with 2 injections of alfa-tocopherol and selenium on alternate days by parenteral route. The somatic cell count (SCC) reduced significantly (P<0.05) in group III cows, where recovery was 89%, whereas the SCC remained higher in group II cows, with a recovery rate of 78%. Superoxide radical generation in the isolated leukocytes of milk in group II and group III cows was significantly enhanced on day 3 post-treatment (PT). The phagocytic activity of the milk leukocyte was measured by acridine orange dye technique. Phagocytic activity increased significantly in group III cows to an extent of 44.13%, whereas such increase was 10% in group II cows. The phagocytic index (PI) also increased significantly in group III animals. However, a non-significant rise was observed in group II cows. In conclusion, the results of this study show that enrofloxacin and vitamin E have a beneficial effect on the functioning of the immune cells in bovine udders affected by intramammary infection.