A note on the vitamin D content of cow's colostrum

IT is generally known that cow's colostrum is much richer in vitamin A and carotene than the later milk but, as far as we know, there is no information with regard to its vitamin D content.We were interested to see whether the changes in concentration of the antirachitic vitamin are similar to those of vitamin A and of its precursor.We therefore measured the antirachitic potencies of colostral fats obtained on successive days after calving and compared them with the activity of a normal sample of butter produced at the same time and under similar conditions of feeding.