Influence of the oestrous cycle on experimental intrauterine E. coli infection in the sow

The influence of the oestrous cycle on the onset of endometritis in the sow was studied. Ten pubertal, unmated gilts of the Belgian Negative Landrace were used. Nine gilts were inoculated into the uterus by laparotomy with a suspension of an E. coli strain isolated from the uterus of a discharging sow from a herd having many problems with vaginal discharge and a lowered fertility. One gilt was as a control inoculated with 2 ml of a PBS-solution. All sows inoculated during dioestrus developed clinical symptoms, but only 1 of the 5 gilts inoculated at standing oestrus developed a vaginal discharge. These data confirm the hypothesis that the stage of the oestrous cycle has an important influence on the onset of endometritis. The resistance to E. coli infections was higher when the gilts were inoculated during oestrus.