Chronic Hypervitaminosis A in Holstein Male Calves

Abstract

Beginning at two and one-half months of age, daily vitamin A intakes from 62.5 through 16,000 μg per pound of live weight were fed to 28 calves for 12 wk. At intakes (estimated by regression) above 3,981 μg the ration consumed decreased and above 3,311 live weight gain decreased. Characteristic signs of hypervitaminosis A were observed in calves fed an 8,000 intake or above. Heart rate was elevated at intakes greater than 1,820 and cerebrospinal fluid (CSF) pressure decreased above 1,445. Vitamin A concentrations in plasma increased across all intakes and in liver up to an intake of 5,623, thereafter decreasing. Plasma ascorbic acid decreased across all intakes and tocopherol to 2,399, but thereafter increased slightly. The range of intakes above which increases or decreases were estimated to occur for serum protein fractions, inorganic phosphorus, and transaminase (GOT and GPT) and alkaline phosphatase activities and prothrombin time were from 1,000 through 4,365. At intakes exceeding 99, CSF protein fractions were affected. Liver, heart, and kidney weights per unit live weight increased above intakes of 1,995, 3,981, and 3,467. Metacarpal bones exhibited change in composition at intakes greater than 603. © 1964, American Dairy Science Association. All rights reserved.