Temporal changes in metabolites of prostanoids in milk of heifers after intramammary infusion of Escherichia coli organisms.

A study was conducted to characterize the changes in the concentrations of three metabolites of prostanoids in the milk of a) heifers (n = 14; control) inoculated with Escherichia coli (E. coli) organisms into the udder and b) in heifers (n = 10; treatment) vaccinated with E. coli bacterin and treated similar to control heifers. Milk samples were obtained from the challenged quarter and analyzed for the concentrations of stable metabolites of thromboxane A2 (TXB2), prostacyclin (PCM) and prostaglandin E2 (PGEM) using radioimmunoassays. In control heifers milk TXB2 concentrations were significantly higher (P = 0.03) compared to treated heifers. Milk PCM concentrations increased significantly (P = 0.02) in control and treated heifers after the respective treatments, however, differences between the two groups were not significant. Milk PGEM concentrations also increased significantly (P = 0.02) in control and treated heifers after the respective treatments, and there were no differences between the two groups. Results of the present study suggest that, the prostanoids have a role in the pathophysiologic process of coliform mastitis.