Prolapse of rectal or vaginal tissues usually occur sporadically in swine but when there is a common cause, can appear as an outbreak. Although seldom seen in nursing pigs, all other age groups are susceptible.
Prolapse of the rectum is most often the result of cold stress (piling for warmth), transport stress (piling in trucks), or from severe coughing. The prolapse may also be associated with severe enteritis from any cause, especially enteritis caused by salmonellosis or ascariasis in young pigs. Other causes of the enteritis can include intestinal mycosis following prolonged use of antibiotics or chemotherapeutic agents. The feeding of whey, brewer’s grains, or low fiber diets has preceded some outbreaks. Rectal prolapse can also occur as a result of severe coughing or straining caused by constipation, cystitis, vaginitis or urethral obstruction. Rectal stricture is a common sequel to prolapse of the rectum. The condition can be repaired surgically by amputation or, if the tissue is not overly traumatized, by replacement followed by use of a purse-string suture. “Rectal tubes” can also be used in repair of prolapses.
Prolapse of the vagina and/or rectum sometimes occurs as a consequence of flaccidity and relaxation of the birth canal in sows close to parturition. Prolapse of the vagina usually occurs first and is followed by prolapse of the rectum.
Zearalenone, a mycotoxin found in several feed grains, can cause vulvovaginal edema and irritation in prepuberal gilts or sows. Straining often leads to prolapse of the vagina and, perhaps, the rectum. Similar lesions can be caused by estrogenic substances in grains, certain pastures (including alfalfa) and therapeutic agents, and in products given to stimulate estrus. Genetic factors have been shown to contribute to prolapses of the vagina and uterus in some breeds.
When prolapse occurs in an outbreak situation, effort needs to be directed towards rapid identification of the triggering factor(s). Response to individual treatment of prolapse is poor with the exception of those cases identified within a few hours of their occurrence.