Some Interrelationships between Vitamin E and Vitamin A in Holstein Calves

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Abstract
Thirty-six Holstein male calves, 64 days of age and partially depleted of their tocopherol and vitamin A stores, were fed in addition to a basal ration low in tocopherol and vitamin A, 1 of 3 levels of tocopheryl acetate, equivalent to 1, 5, or 25 mg of free tocopherol per lb live weight per day and 1 of 3 levels of vitamin A palmitate, equivalent to 10, 100, or 1000 /xg of vitamin A alcohol for a 4-week period. Upon completion of a 28-day tocopherol-vitamin A supplementation period, 1/2 of the calves were slaughtered and the other 18 calves were maintained on only the basal ration until plasma vitamin A decreased to 4.0 /xg/100 ml- Based on plasma and liver vitamin A concentrations at the termination of supplementation and on vitamin A depletion time, tocopherol resulted in an increase in utilization of vitamin A at the highest intake of vitamin A, decreases at the lowest intake of vitamin A and inappreciable change at the middle intake. Across all levels of tocopherol intake, the tocopherol concentration of the tissues decreased with increasing intake of vitamin A. This decrease was greater between the 10 and 100 /xg intake of vitamin A than between the 100 and 1000 jug intake. These results indicated a need to establish levels or ratios of intakes of vitamins A and E.