A fresh look at vesicovaginal reflux in mares

VESICOVAGINAL reflux, more commonly referred to as urovagina or urine pooling, is a frustrating condition to deal with in horses intended for breeding. The long-term consequences of urine accumulation in the vaginal fornix include vaginitis, cervicitis and endometritis, which collectively lead to an environment within the genitourinary tract characterised by inflammation (Emberston 1990). This in turn reduces the ability of the mare to conceive or, following conception, maintain a pregnancy to full term, as chronic endometrial changes may lead to infection due to reduction in the efficacy of uterine defence mechanisms and therefore result in early embryonic death. In addition to this, urine is known to have a marked effect on the motility of spermatozoa such that they may be prevented from reaching the oviduct in the first place (Griggers and others 2001).

Diagnosis of the condition can be complicated by the lack of outward clinical signs, with vaginoscopy the only definitive method for confirming a build-up of urine within the vaginal vault. The picture is further complicated in a percentage of mares that only intermittently pool urine, although repeat examination during oestrus, when the tubular tract is under the influence of a high concentration of circulating oestrogen, is most likely to lead to positive confirmation of the condition (Woodie 2012 …