The Placental Transmission and Fetal Storage of Vitamin A and Carotene in the Bovine

Abstract

Four rations were fed to 29 Hol-stein and 4 Guernsey heifers during the last 60 days of their gestation periods. The rations were: wheat straw plus a concentrate mixture, a normal fitting ration of concentrates, hay and corn silage, a normal ration plus one million I. U. of carotene daily, and the normal ration plus one million I. U. of vitamin A daily. No significant differences were observed in the mean plasma carotene of the newborn calves from the 4 dietary groups. However, the plasma vitamin A of the newborn calves from the carotene supplemented cows was twice that of the normal group, while the vitamin A supplemented group showed a 4-fold increase. Carotenoids were present in significant amts. in the livers of all newborn calves and varied directly with the carotene content of the maternal prepartum diet. Addition of one million I. U. of vitamin A daily to the normal ration of pregnant cows resulted in an average total fetal liver storage of 97,177 I. U. of vitamin A. Evidence was obtained that the prepartum diet of the normal bovine influences markedly the vitamin A and carotene reserves of the newborn calf.