Vandegraaff R
Aust Vet J. 1976 Jan;52(1):21-3. doi: 10.1111/j.1751-0813.1976.tb05364.x.
Squamous-cell carcinoma of the vulva was observed in 3.1% of Merino ewes up to 3 years old. It is suggested that this high incidence of tumours was related to increased exposure of the perineal region to direct sunlight. It occurred in a group of sheep where short docking of tails and a radical surgical procedure to reduce cutaneous myiasis (Mules' operation) both led to greater exposure of the perineal region. The perineum was also subject to scarring from the operation and to application of organophosphate compounds to control cutaneous myiasis.
在3岁以下的美利奴母羊中，观察到3.1%患有外阴鳞状细胞癌。据推测，这种肿瘤的高发病率与会阴区域直接暴露于阳光下的增加有关。它发生在一组绵羊中，这些绵羊尾巴短截以及采用根治性手术减少皮肤蝇蛆病（穆尔斯手术）都导致会阴区域暴露更多。会阴还因手术而留下疤痕，并且为了控制皮肤蝇蛆病而应用有机磷化合物。
