Ascorbic Acid Requirement of Mature Horses

Abstract

Three mature geldings were fed pasture grass, a semi-purified diet with ascorbic acid and the semi-purified diet without ascorbic acid. The horses received the semi-purified diet without ascorbic acid for 6 months. The blood and plasma ascorbic acid levels during the feeding of the semi-purified diet without ascorbic acid were similar to that when the horses were receiving either pasture or the semi-purified diet with ascorbic acid. The average mg % ascorbic acid in the blood and plasma when pasture, and the semi-purified diet with and without ascorbic acid were fed were 0.48, 0.40 and 0.35; 0.39, 0.40 and 0.32, respectively. Corresponding values for daily urinary excretion were 63, 278 and 248, respectively.