The Relationship of the Prepartum Diet to the Carotene and Vitamin A Content of Bovine Colostrum

Abstract

A study has been made of the relationship of the prepartum diet to the vitamin A and carotene content of bovine colostrum. Four different rations were fed to 29 Holstein and 4 Guernsey heifers during the last 60 days of their gestation periods. The rations were a low-carotene ration of wheat straw and a concentrate mixture; a standard dry-cow ration of concentrate, mixed hay and corn silage; the standard ration supplemented with one million I.U. of carotene daily; and the standard ration supplemented with one million I.U. of vitamin A daily. Colostrum from cows receiving the low-carotene ration contained significantly less vitamin A per gram of butterfat than did colostrum from cows receiving the standard dry-cow ration. The carotene content per gram of butterfat in the colostrum from the carotene-supplemented cows was significantly higher than that from the other groups, although the vitamin A content was not increased. Colostrum from cows receiving the vitamin A supplement contained an average of 687 μg. per 100 ml. or 164.5 μg. per gram of butterfat, while the colostrum from the standard dry-cow ration group contained only 374 μg. per 100 ml. or 91 μg. per gram of butterfat, showing that the vitamin A content of colostrum may be influenced by the prepartum diet. Regardless of the form of vitamin A in the ration, the ester form of vitamin A predominated in the colostrum. Highly significant positive correlations were found between the plasma carotene and vitamin A of the cows 18 days before calving and the carotene and vitamin A content of the colostrum. © 1947, American Dairy Science Association. All rights reserved.