Spontaneous vaginal rupture is a rarely seen condition of ewes, but in some seasons in the Crookwell district, CVH vets see (or hear about) a surprising number of cases across a range of sheep properties.
Spontaneous vaginal rupture occurs in heavily pregnant, usually multiparous (bearing twins or triplets) and overweight ewes in the last few weeks before lambing. The ewes are normally mature, averaging 3 to 6 years of age.
The process is dramatic and rapidly fatal. The ewe’s vagina suddenly tears, usually on the dorsal (top) part of the vagina, immediately providing a hole through which the intestines can escape. Severe bleeding accompanies the rupture with the ewe dying quickly, the prolapsed intestines visible.
Some cases document losses over 20% in individual flocks although the incidence is normally much lower. In one mob of very fat ewes in the Orange district seventy of the 320 ewes in the mob died of spontaneous vaginal rupture (Watt and Denham, Flock and Herd Case Notes).
Despite conjecture about a specific cause, the precise mechanism leading to the rupture is not known. There is no treatment - frequently the ewes are found dead – and euthanasia for welfare reasons is recommended.