Rectal prolapse associated with a healed pelvic fracture in a pregnant free-ranging African black rhinoceros (Diceros bicornis). Part 2: surgery and necropsy.

The oedematous and traumatised protruding section of the rectal tissue of an adult free-ranging female African black rhinoceros (Diceros bicornis) was surgically amputated. Immediately before completion of surgery, the rhinoceros died of anaesthetic-related cardiac arrest. At necropsy a deformed pelvis and sacrum associated with a healed fracture of the left ileal wing were noted. New bone formation in and around the left ventral sacral foramina may have resulted in neuropathy of particularly the 3rd and 4th left ventral sacral nerves, which (in the horse) supply the majority of the nerve fibres innervating the caudal rectum and anus. The cause of the injury is not known, although back injuries, presumably sustained during mating by bulls, have been recorded in white rhinoceros. An encounter with elephants could also have been responsible for the injury in this case.