Disruption of the blood supply to the small colon following rectal prolapse and small colon intussusception in a mare.

A coliky and depressed four year old Arabian mare was examined three days after replacement of a rectal prolapse that had occurred during parturition. Fresh blood was present in the rectum and a septic peritonitis was diagnosed based upon the clinical pathological examination of the peritoneal fluid. At laparotomy the terminal 1.3 meters of small colon was found to be necrotic as a result of rupture of the terminal mesocolon and associated blood vessels. Based upon the poor prognosis the mare was euthanized. Rupture of the mesocolon was thought to be a sequel to the rectal prolapse. The anatomy predisposing the horse to these events is discussed.