Effect of histamine on bovine milk fatty acids

Milk histamine content was monitored over the estrous cycle of several cows. Concentrations of histamine in the milk were maximal between days 0 and 1 and between days 4 and 7 of the estrous cycle. One quarter of a mammary gland of each of six cows was infused with 10 mg histamine free base. Milk samples were taken at 0, 4 and 10 hr, then analyzed for fatty acid composition. The 4-hr samples showed an increase in the proportion of short and medium length fatty acids, an increase in myristoleic, palmitoleic, oleic and linoleic acids and a decrease in stearic acid. The 10-hr samples showed a decrease in proportion of short and medium length fatty acids, a decrease in palmitic acid and an increase in stearic acid, while oleic acid and linoleic acid continued to increase from preinfusion. Linolenic acid showed no significant change during the experiment. Milk from one normal and one mastitic quarter of the mammary glands of several cows showed a significantly higher histamine content in mastitic milk than in normal milk.