The Influence of Breed, Feed, and Processing on the Riboflavin Content of Milk

Abstract

Expts. with 2 Holstein-Friesian and 2 Jersey cows over a lactation period of approx. 10 months showed that the milk of the Holstein cows contained on an average 34% less riboflavin than that of the Jersey cows. The Holstein cows, because of higher'' milk production, produced on an average aprox. 34% more riboflavin than the Jersey cows, thus demonstrating an inverse relation between milk yield per day and the ribo- flavin content. Supplementing a concentrate-dry roughage ration with substantial amts. of sunflower silage increased the riboflavin content of milk 36% (within 2 days), and the riboflavin content level was comparatively high for the remaining portion of lactation while the silage was fed. Stage of lactation, season, pregnancy, and oestrus had no discernible influence on the riboflavin content of milk. Colostrum milk contains about 3 times as much riboflavin as normal milk but loses approx. 30% of its riboflavin conc. within 24 hrs. after parturition of the cow. Neither pasteurization, homogenization, or storage for 24 hrs. at 40[degree] F in a dark refrigerator decreased the riboflavin content of milk.