Merck Manual

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Professional Version

Ulcerative Balanoposthitis and Vulvitis in Sheep and Goats

(Pizzle Disease, Knobrot, Peestersiekte)


John WA Larsen

, BVSc, PhD, Faculty of Veterinary and Agricultural Sciences, University of Melbourne

Reviewed/Revised Nov 2020 | Modified Oct 2022
Topic Resources

Ulcerative balanoposthitis and vulvitis is characterized by ulceration and inflammation of the glans penis and the prepuce in males and the vulva of affected ewes. The first signs observed may be swelling and bleeding of the prepuce or vulva. On examination, ulcers are seen; these bleed readily when manipulated. In ewes, the ventral aspect of the tail (where it contacts the vulva) may be similarly affected. The condition may spread within a breeding flock to involve a considerable proportion of the animals. The pregnancy rate in affected flocks can be reduced due to a reluctance of severely affected rams to mate.

The cause of ulcerative balanoposthitis and vulvitis is not clear. Mycoplasma mycoides mycoides has been isolated from affected sheep. Trueperella pyogenes is frequently present. In some cases Histophilus ovis has been isolated. Viruses, such as ovine herpesvirus 2 or, in the case of goats, caprine herpesvirus 1 may be involved.

Affected rams should be removed from the flock and isolated. If practical, affected ewes should also be maintained separately. Rams should be treated with antimicrobials; ewes also respond well to antimicrobial treatment. Irrigation of the prepuce and the use of mild antiseptic creams may help prevent preputial adhesions. Tulathromycin has been used successfully. Recovered animals appear to have normal fertility. However, rams with severe preputial adhesions may be unable to completely extrude their penis, and these animals should be culled.

The disease is sufficiently infrequent that extensive surveillance is not warranted. However, if it occurs and goes undetected for some time, its effects on mating, and subsequent pregnancy rates, can be significant.

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