Investigation of purulent vaginal discharge in cows, with particular reference to Haemophilus somnus

The relationship between vaginal discharge, site of inflammation in the reproductive tract and species of bacteria isolated was examined in cows that were either normal, subfertile, or had had an abnormal parturition. Microbiological and cytological examinations were performed on uterine swabs from 221 cows and cervical swabs from 107 cows. There were 167 subferitle cows, 144 of which had failed to conceive to 3 or more services (FTC) and 23 of which had not had a visible oestrus since calving (NVO). Metritis was diagnosed in 22% of the FTC cows, 48% of the NVO cows, and 12% of the cows with abnormal parturition. Fifty percent of cows with metritis had purulent vaginal discharge. However, only 25% of a total of 91 cows with vaginal discharge had metritis; the remainder had cervicitis. Fifty-four percent of subfertile cows had cervicitis without metritis. Mixed infection with aerobes and anaerobes was significantly correlated with uterine inflammation and was found in 20% of cows with metritis. The rate of isolation of H.somnus from inflamed uteruses (22%) and inflamed cervixes (39%) was significantly greater than the isolation rate from normal uteruses (8%) and cervixes (10%). No bacteria were isolated from 50% of inflamed uteruses and 37% of inflamed cervixes. The number of subfertile cows with or without metritis that subsequently conceived was not significantly different.