Preventing Postpartum Uterine Disease in Dairy Cattle Depends on Avoiding, Tolerating and Resisting Pathogenic Bacteria

Up to forty percent of dairy cows can develop metritis or endometritis when bacteria infect the uterus after parturition. However, it is unclear why other cows exposed to similar pathogens do not develop uterine disease. We suggest that resilient dairy cows prevent the development of uterine disease using the three complimentary defensive strategies of avoiding, tolerating and resisting infection with pathogenic bacteria. Avoidance maintains health by limiting the exposure to pathogens. Avoidance includes intrinsic behaviors to prevent exposure to pathogens or infected animals, perhaps signaled by the fetid odor of uterine disease. Tolerance improves health by limiting the tissue damage caused by the pathogen burden. Tolerance depends on controlling the tissue damage that pathogens cause in the endometrium by neutralizing bacterial toxins, enhancing tissue repair, and inducing adaptive metabolic responses. Resistance improves health by limiting the pathogen burden. Resistance relies on the immune system generating an inflammatory response in the endometrium to eliminate pathogenic bacteria. People who manage dairy cows can also help prevent uterine disease by using extended lactations, avoiding trauma to the genital tract, maintaining hygiene, and supplying appropriate nutrition during the transition period and after parturition to counter the metabolic stress of lactation. Developing new ways to prevent uterine disease depends on increasing our understanding of the mechanisms of avoidance, tolerance and resistance to pathogens in the postpartum uterus.