The Influence of the Cow's Diet on the Fat-soluble Vitamins of Winter Milk

IN the early stages of research on vitamins Funk [1913] advanced the sug- gestion that the secretion of these factors in the milk was controlled by their presence in the food of the lactating animals. Subsequent investigations have proved this conjecture to be true. McCollum, Simmonds and Pitz [1916], working with rats, found that the development of the young was greatly influenced by the presence or absence of vitamin A or B in the diet of the nursing mothers. Hart, Steenbock and Ellis [1920], Dutcher and co-workers [1920], and Hess, Hunger and Supplee [1920] demonstrated that the anti- scorbutic potency of cow's milk depended on the antiscorbutic character of the diet of the cow, whilst Hughes, Fitch and Cave [1921], and Kennedy and Dutcher [1922] were responsible for proving that the vitamin A or B content of the milk was similarly influenced by the diet of the animals. The last of these investigators introduced vitamin A into the cows' ration in the form of alfalfa hay and corn silage. We [Drummond et al., 1923, 1924] were able to confirm the observations of previous workers in this field, showing that by restricting the vitamin A content of the diet of the stall-fed. cow a correspond- ing diminution of the vitamin takes place in the. butter-fat. This fall in the vitamin A potency was shown by us to be rectified by the introduction of cod-liver oil into the deficient winter ration of the cows.