A survey of Pennsylvania dairy producers revealed that uterine infection was a major problem in reproductive management, second only to inefficient estrous detection. Cows with uterine infection in the early postpartum period generally have lower conception rates later during the breeding period. This effect would have been more severe if the herds were not participating in a routine herd health program whereby uterine infections and other postpartum reproductive problems were detected and treated early. Other studies confirm that even mild uterine infections adversely affect conception rates. A high percentage of cows have bacteria present in the uterus during the first two weeks after calving and may be considered to be infected.
Older cows tend to have more infections.
The natural process of uterine repair, termed involution, with all the associated physiological mechanisms is usually very effective in reducing the population of bacteria and inflammation in the uterus. The following is a list of factors that can contribute to a higher than usual rate of infection. Overconditioning at the time of calving has been related to a higher incidence of infections in some studies but not in others. However, it makes some sense that overconditioned cows might have poorer uterine muscle tone, fatigue earlier during the calving process, experience a higher incidence of difficult births and thus have a higher incidence of uterine infections than cows in good body condition. On the other hand, severely underconditioned cows appear to be more susceptible to infection than cows in proper condition.