Mares typically develop an odorless, grayish-white mucopurulent vulvar discharge of uterine origin. In some mares, the extent and severity of the inflammatory response are not readily assessable unless the reproductive tract is examined with the aid of a speculum. Whether or not the mare has outward clinical signs following infection, most will fail to conceive afterward. The infertility has been found to be short-lived, however, usually lasting only a few weeks. No long-term infertility problems have been reported in mares infected with Taylorella equigenitalis .
Abortion is a rare sequel to infection in the pregnant mare.
In two reported cases of abortion ascribed to Taylorella equigenitalis , the bacterium was recovered not only from the placenta, but also from several sites in the aborted fetus. Isolation of the Taylorella equigenitalis bacterium in culture long has been regarded as the only definitive means of establishing a diagnosis of CEM in the mare or confirmation of the carrier state in the stallion, reported Timoney. The sites usually sampled to culture for Taylorella equigenitalis in the mare include the uterus, cervix, clitoral sinuses, and clitoral fossa. He noted that care should be taken to use swabs that are small enough to sample the clitoral sinuses effectively. Swabbing of pregnant mares is restricted to sampling the clitoral sinuses and fossa.