MAMMALIAN CAROTENOIDS 



the carotene content of colostrum, ^ ^ ' and that the carotene content 

 of colostrum from one half of the udder milked before parturition was 

 the same as that from the other half milked just after parturition. ^ ' • ^ 



A drop occurs in the carotene plasma levels at parturition i « », 1 4 o, 1 4 1 

 (see Fig. 32) and thus there is no possible positive correlation between 

 plasma levels and colostral levels. ^^ Spielman, Thomas, Loosli, 

 Whiting, Norton and Turk^^*^ have, however, noted a correlation 

 between the carotene plasma values measured 18 days before par- 

 turition, and colostral levels ; this indicates that the storage of 

 carotenoids in the mammary gland is nroportional to the blood levels 

 operating during gestation. The importance of colostrum as a vehicle 

 for carotene (and vitamin A) in feeding of new born cows has been 

 well, illustrated by the work of Spielman, Loosli, Thomas, and Turk ^ * * 

 and of Wise, Caldwell, Parrish, Atkeson, and Hughes. ^ * ^ Spielman 

 et al. showed that newly born dairy calves maintained on a basal skim 

 milk (low carotene) diet, would not absorb carotene concentrates of 

 various types (crystalline carotene in oil, lucerne meal, etc.), but 

 scoured badly. Only after control of scours during the first week of 

 life by the daily administration of sulphathalidine was the carotene 

 reasonably well absorbed. Wise et al. have shown that on good quality 

 hay the blood carotene levels of calves do not increase until the animals 

 are at least six weeks old. It has further been noted that prepartum 

 milking of the dam considerably lowers the carotene levels of the calves 

 compared with those of calves whose dams were not so treated. ^ * * 



Some further points concerning carotenes in cows' milk ^hould be 

 mentioned before considering further the drop in plasma carotenoids 

 in the parturient cow. Cows' milk contains about half the concentra- 

 tion of carotenoids found in human milk, ^ * ^ but it should be em- 

 phasized that from the point of view of vitamin A activity the qualitative 

 inter-species differences result in the cows' milk being more potent 

 as a source of pro-vitamin A. The active carotene fraction represents 

 about 85 per cent, of total bovine milk* carotenoids ^ '^ '» ^ ^ ^ but only 

 25 per cent, of total human milk carotenoids. 



Berl and Peterson ^ * * have studied the carotene distribution during 

 butter making ; 10-14 per cent, remains in the skim milk, 89-94 per 

 cent, is transferred to the butter and only 0-8-2-0 per cent, remains in 

 the buttermilk. Kon, Mawson and Thompson ^^^ examined the 

 carotene content of the fat obtained from the different fractions pro- 

 duced during butter making and found that the carotene concentration 

 in separated milk fat and separated whey fat was many times greater 

 than in the fat of other fractions ; i.e., concentrations were highest in 

 the fractions containing the smallest fat globules. Cholesterol, but not 



241 



