Ulceration of the anus in groups of pubertal male pigs
Steven McOrist, BVSc, PhD; Mark Williamson, BVSc, PhD, Diplomate ACVP
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Ulceration of the anus as a specific condition has not been reported widely in swine medicine. Sporadic occurrences were noted in groups of 40 to 200 sixteen- to 17-week-old entire male pigs on four separate finisher facilities with similar management. Cases on each facility rapidly rose from none to between 20% and 30% over 2 weeks, then stabilized. Gross lesions in early affected cases consisted of deep, punched-out cavity ulcers, commencing to one side of the anal sphincter. The ulcers initially had clean, well-circumscribed ulcer margins, with rolled edges and minimal obvious granulation. Affected pigs had fully developed secondary sex glands and firm dry feces. Deep ulcer tissue consisted of proliferative fibroplasia in vascular connective tissue. Bacteriologic culture and histologic Gram stains identified Streptococcus dysgalactiae and Clostridium perfringens within representative ulcers. Outbreaks occurred when aggressive and sexually active pubertal male pigs were housed in areas of poor water and excreta drainage. Anal ulceration lesions were clearly distinguishable from the more common conditions of anal prolapse or tail-biting lesions. Initial trauma to the anus due to homosexual behavior with a consequent mixed infection, including S dysgalactiae, in a softened ano-cutaneous environment, may be the cause for these unusual lesions.
Keywords: anus, ulceration, Streptococcus dysgalactiae
Cite as: McOrist S, Williamson M. Ulceration of the anus in groups of pubertal male pigs. J Swine Health Prod 2007;15(2):96-98.
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