A survey on Clinical Factor Involved in the Pathogenesis of Canine Pyometra

Abstract

A total of 207 bitches of 24 breeds with pyometra were examined with the following results. The highest incidence, 30.3%, was found in the Spitz. The bitches ranged from 1 to 16 years old. The highest occurrence, 13.2%, was seen in the age group of 10 to 11 years. No bitches under 1 year old were affected.
Regular estrous cycles were repeated in 77.7% of the bitches. The interval between the last estrus and the onset of pyometra varied from under 1 month to 4 years mostly less than a month. Nulliparous bitches were affected with pyometra most frequently. There was a tendency for the occurrence of pyometra to decline with the increase in parity.
The interval between the last delivery and the onset of pyometra ranged from 20 days to 9 years with an average of 4 years. It was more than 5 years in about a half of the affected bitches. It was a characteristic finding that shortly before the onset of pyometra the highest copulation rate, 19.8%, was seen at the last estrus.
The results of this survey suggested that the primary important factor involved in the pathogenesis of canine pyometra might be uterine dysfunction under the normal ovarian control, but not the ovarian abnormality.