CAROTENOIDS 



Typical carotenoid plasma levels for new-born cattle of any breed 

 are 22-50 (i.g./100 ml. ^^^'^^^ but breed differences become obvious 

 within eight days of birth. ^ ^ ^ 



Colostrum and Milk 



As in the case of humans the colostrum of cows is very rich in 

 carotene, i o e, 1 1 o, 1 2 1, 1 3 3. 1 3 6 ^phe pre-nursing value of colostrum 

 is between 5-10 times higher than that of seventh-day milk when 

 calculated on the whole fluid, and three times higher when measured 

 on the fat basis. ^ ^ 9, 1 3 3 Dann^^^ had previously reported greater 

 differences between colostrum and late milk, and claimed that heifers 

 produced colostrum richer in (vitamin A) than did cows. Recently it 

 has been shown that the carotene content of the first successive 2 lb. 

 samples of colostrum increases considerably, ^ ^ ' that interruption 

 of milking increases the concentration of carotene in the milk but does 

 not alter the 3-day yield, ^ ^ « that vitamin E therapy has no effect on 



'22 18 14 10 



Days pre-parcum 



2 



2 6 W 14 



Days post-parcum 



Fig. 32. — Illustrating the drop in plasma carotene levels of cows at parturition. 

 {From Sutton, T. S., Kaeser. H. £., and Soldner, P. A. (1945) J. Dairy Sci., 28, 

 933.) 



240 



