Ulcerative Balanoposthitis and Vulvitis
(Pizzle disease, Knobrot, Peestersiekte)
Ulcerative balanoposthitis and vulvitis is characterized by ulceration and inflammation of the glans penis and the prepuce, as well as 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 is depressed.
The cause of ulcerative balanoposthitis and vulvitis is not clear. Mycoplasma mycoides mycoides has been isolated from affected sheep. Trueperella (Arcanobacterium) 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 may help prevent preputial adhesions. Tulathromycin has been used successfully. Recovered animals appear to have normal fertility.