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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. (Am J Vet Res 1996;57:468–471)

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in American Journal of Veterinary Research