Increased pressure in the abdomen, straining and hormonally-induced loosening of pelvic tissues approaching calving time may predispose animals to vaginal prolapse. Increased intraabdominal is most commonly associated with advanced pregnancy or excess fatness. Partial, intermittent prolapse of the floor of the vagina may initially occur when affected animals lie down. Over time minor irritation and tissue injury may lead to further prolapse and then affected animals may start to strain and further exacerbate the condition. The urinary bladder and intestines may be trapped inside the prolapsed tissue. Prolapsed tissue is at increased risk of exposure, inflammation and trauma leading to congestion, oedema, drying and necrosis.
Because overfat and heavily pregnant animals are usually excluded from the export process, occurrence of vaginal prolapse will be rare.
A vaginal prolapse presents as a mass of tissue protruding from the vulva. Affected animals may be noticed with an arched back due to frequent straining. Vaginal prolapses are up to the size of a basketball, rounded, smooth and pink in the early stages, later becoming dry, hard and dark from congestion, sunburn, faecal staining and abrasions.
Differential diagnoses include rectal prolapse, which protrudes from the anus (and may occur concurrently), and uterine prolapse which occurs during or soon after calving. A prolapsed uterus will hang down further (to the level of the hocks), and is covered in caruncles (the lumps of tissue where the placenta was attached).
Treatment should not be delayed. Progressive swelling, drying and necrosis can make it difficult to replace. The urinary bladder and intestines may be trapped within the prolapse.
Replacing the prolapse is best done under caudal epidural anaesthesia to reduce straining. If glycerol or icing sugar are rubbed on the prolapse, oedematous swelling may be reduced making replacement easier. If the urinary bladder or intestines are present in the prolapse, manipulate these into the pelvis to make replacement of the prolapse easier. Insertion of a perivulvar Buhner's suture, leaving a 3 to 4 finger hole, will help prevent prolapse recurring. The suture will need removing when calving is imminent.
Avoid exporting fat, heavily pregnant cattle.