The Nutrition of the Newborn Dairy Calf. IV. The Minimum Riboflavin Requirement

Summary Nine male calves representing five dairy breeds were used to determine the minimum riboflavin requirement of the dairy calf up to 8 wk. of age. The basal riboflavin-deficient diet consisted of whole milk in which approximately 97 per cent of the riboflavin had been destroyed by photolysis. The photolyzed product contained an average of 0.04mg. of riboflavin per liter. This photolyzed milk was supplemented with vitamin A and the various levels of riboflavin studied. It was found that calves receiving 35 γ or less riboflavin per kilogram of body weight daily developed symptoms of riboflavin deficiency. The deficiency symptoms were more severe at the lower levels. The calves receiving 45 γ or more of riboflavin per kilogram body weight showed no symptoms that could be attributed to a deficiency of the vitamin. The data obtained indicate that the urinary excretion of riboflavin is a good index of the nutritional status of the calf as far as riboflavin is concerned. The data obtained indicate that the minimum daily riboflavin requirement of the male dairy calf up to 8 wk. of age is between 35 and 45 γ per kilogram of body weight.