The Riboflavin Content of Milk as Influenced by Diet

Abstract

Summary Experiments with cows, involving 460 determinations made over a period of 9 1 2 months, showed clearly that the riboflavin content of milk can be influenced only to a limited extent by the diet. When cows were transferred from pasture to a ration of natural feeds selected to be very low in riboflavin its content in the milk decreased about 25 per cent. Increasing the riboflavin intake 30 to 50 per cent by feeding a molasses-yeast byproduct caused only a temporary increase in the concentration of riboflavin in the milk. A winter ration consisting of good quality hay, acid grass silage and a grain mixture maintained the milk riboflavin at the pasture level. Goats fed a riboflavin-free purified diet continued to secrete large amounts of riboflavin in the milk, indicating this factor is not a dietary essential for lactation in the goat. No consistent difference was observed in the milk yield or the riboflavin concentration when the purified diet was supplemented with a molasses-yeast byproduct supplying riboflavin. Likewise, no advantage in milk secreted was noted between a thiamin-deficient purified diet and one adequate in it and other factors of the B-complex. The data from both cows and goats indicate that there is an inverse relation between the milk yield and the riboflavin concentration of the milk.