Riboflavin Content of Milk Collected in Different Months and Correlated with Other Constituents of the Milk

Abstract

Summary Riboflavin determinations were made on samples of milk collected at intervals from individual normal cows of different breeds and on different rations. The influences of season and individuality on flavin values were considered. The relationship of flavin content to the concentrations of the following constituents in the milk were tested: vitamin C, loss of C on 72 hours storage at 4° C, carotene, lecithin, fat, protein, phosphatase, leucocytes, mastitis streptococci, odd bacteria, lactose, and chlorine. The average flavin contents in March, April, and May were for Ayrshires 1.17 parts per million, for Holsteins 1.37, for Guernseys 1.53, and for Jerseys 1.73. Milk from cows between 15 days and 10 months after freshening, showed no significant difference in flavin content. The flavin content of milk was slightly higher in July after the cows had been pastured. The climate and ration were not the only important factors which caused variations in the flavin content of milk. The fat is the only constituent of milk for which an approach to a significant consistent relation to flavin was found. It is suggested that flavin may have a role in the production of milk fat.