ANTIOXIDANT STATUS OF DAIRY-COWS SUPPLEMENTED PREPARTUM WITH VITAMIN-E AND SELENIUM

Possible relationships among dietary antioxidants, oxidative status, a nd placental retention were investigated in periparturient dairy cows. During 6 wk prepartum, 16 cows each were given daily by capsule 1000 IU of vitamin E, 3 mg of Se, both vitamin E and Se, or neither (contro l). alpha-Tocopherol in serum and fast-acting antioxidants in plasma i ncreased, but, in red blood cells, thiobarbituric acid-reactive substa nces decreased during the last 6 wk before parturition in cows given v itamin E. These measurements were unaffected by supplementation of Se. Cows that had retained placenta greater than or equal to 12 h had low er fast-acting antioxidants in plasma and glutathione peroxidase in re d blood cells up to 2 wk before calving than did cows that shed fetal membranes in <12 h. Results suggest that inadequate dietary antioxidan ts may increase oxidative stress, production of lipid peroxides, and i ncidence of retained fetal membranes in dairy cows.