This is a relatively rare event in the mare compared to other species. It most often occurs within a few hours after foaling, but can occur up to a few days later. This is a very serious emergency as it can be associated with eversion and prolapse of the bladder, uterine rupture, intestinal prolapse, and rupture of the uterine artery.
If this occurs, the uterus must be placed into a plastic bag to prevent it becoming contaminated, and raised as high as possible to limit the amount of swelling that develops. Do not underestimate how heavy the uterus can be! To correct the prolapse it is necessary to prevent the mare from straining, with sedation, an epidural or a general anaesthetic. The uterus must be kept clean. Any tears must be repaired and bleeding brought under control. The placenta should be removed. The uterus is then replaced into position by gently kneading it, starting at the cervix and gradually working back in. It must then be filled with warm saline to fully invert the tips of the uterine horns; if they remain inverted, this encourages the mare to strain and she could re-prolapse. The uterus must then be encouraged to involute (shrink) with low doses of oxytocin. Ideally the mare should be hospitalised for close monitoring and ongoing treatment; once the prolapse is corrected, she must be treated as for a mare with metritis as well as being closely observed to ensure she does not re-prolapse.
