“…In humans, peroxide values are correlated positively with age. 17,39,40 Because these vitamins, mainly vitamin E and b-carotene, are antioxidants, 11 it is believed that older dairy cows have significantly lower serum concentrations of fat-soluble vitamins because of increased oxidation of these compounds. In a recent study of dairy cows during the periparturient period, LeBlanc et al 5 found that serum bcarotene and vitamin A concentrations were not significantly affected by age.…”