In growing pigs, rectal strictures are sequelae of severely traumatized rectal prolapses (see Rectal Prolapse) or of infections that interfere with rectal blood supply. The former cause sporadic cases; the latter may be epidemic. One cause is Salmonella typhimurium infection (see Intestinal Salmonellosis in Pigs), which produces an ulcerative proctitis that heals in such a manner that normal function is not restored. The stricture is reportedly the result of fibrosis of the rectal tissue due to persistent ischemia caused by infection in an area of limited blood supply.
Several bloated pigs in varying stages of emaciation are generally seen in a group of growing pigs. Other clinical signs, including prior outbreaks of severe debilitating diarrhea, are common but not always reported. An index finger rarely can be passed into the rectum without considerable resistance.
At necropsy the colon is grossly distended, and the intestine is filled with gas and green feces. The predominant lesion is a narrowed rectal canal, due to annular fibrotic ulcers or rectal strictures found 2–5 cm cranial to the anus.
An epidemic of rectal strictures without prior rectal prolapses is indicative of S typhimurium infection. Culture of feces and regional lymph nodes usually yields S typhimurium. However, it is not possible to determine whether the lesion or the infection occurred first.
Treatment and Control
Early diagnosis and treatment of diarrhea is imperative for control. Good housing, management, and sanitation, with “all-in/all-out” movement of pigs is the best method to prevent further outbreaks. Surgery is not thought to be economically feasible.
Last full review/revision September 2013 by D. L. Hank Harris, DVM, PhD