Effects of vitamin E on mammary and blood leukocyte function, with emphasis on chemotaxis, in periparturient dairy cows

Abstract

Objective - To determine the effect of vitamin E supplementation on the immune system of dairy cows Design - The following immune parameters were followed: production of chemotactic factors and superoxide by mammary macrophages and chemotactic responsiveness of blood neutrophils. Animals - 16 healthy Holstein dairy cows. Procedure - Dairy cows were assigned to 1 of 2 experimental groups: control (no vitamin E supplementation) and vitamin E supplemented Supplementation of vitamin E started 4 weeks before and continued up to 8 weeks after parturition, and included oral supplementation of vitamin E at the rate of 3,000 IU/cow/d In addition, the same group of cows received 1 injection of vitamin E (5,000 IU) 1 week prior to the expected date of parturition. Blood samples were collected weekly throughout the experimental period. Results - Vitamin E supplementation enhanced by 30 to 83% (P < 0.05) chemotactic responsiveness of blood neutrophils beginning 2 weeks before to 4 weeks after parturition, compared with controls There were no differences in production of superoxide or chemotactic factors by mammary macrophages between control and vitamin E-supplemented cows. Conclusions - Vitamin E supplementation prevents the periparturient inhibition of neutrophil chemotaxis It is unlikely that vitamin E affects directly the function of mammary macrophages.