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

116. Factors affecting Milk and Butterfat Secretion. II. The Colour of the Butterfat

“…Rep.W). However, Steenbock et al (5) found that although highly pigmented butters tend to possess a high vitamin activity the relationship was not constant and that the addition of cod-liver oil to the diet increased the vitamin-A activity out of all proportion to the colour; Golding et al (6) showed that the vitamin-A content of milk during the winter could be enhanced by cod-liver oil feeding. Sutton and Krauss (7) found that although the depth of colour of the butterfat for four breeds increased in the order Ayrshire, Holstein, Jersey, Guernsey, yet the vitamin-A activity of the Holstein and Guernsey butterfat was much greater than that of the Ayrshire and Jersey.…”

I. Reproduction and lactation

“…As far as amount is concerned McCay & Maynard(65) have re-examined the effect of feeding cod-liver oil, and have confirmed the original findings of Golding et oi. (66) and of Golding(67) that the milk-fat content is definitely reduced by feeding the oil and that the factor responsible is not present in the unsaponifiable portion. They had previously observed the formation of muscle lesions when herbivora were fed on the oil and so they discuss whether the factor responsible for the lesions can be identical with that causing the decrease in fat secretion.…”

The Nutritive Value of Fats, with Special Reference to Butter and Margarine

“…The authors do not mention the degree of unsaturation of the fats they used, but Table 5 shows that the fats which gave the poorest growth were the most unsaturated ones. It is clear that when highly unsaturated fats form the main source of fat ip the diet of calves they can be harmful, a fact which recalls the well-known deleterious effect on milk secretion of giving cod-liver oil, a highly unsaturated fat, to cows (Golding, Soames & Zilva, 1926;McCay & Maynard, 1935;Hilditch & Thompson, 1936). Much of the work which has just been discussed indicates that the unsaturated fats do not have the same ill effects on rats as on calves.…”