Masculinisation of the external genitalia in ewes with clover disease.

Prolonged exposure of ewes to oestrogenic pasture resulted in partial fusion of the labia of the vulva and hypertrophy of the clitoris. Partial fusion of the labia was also seen in ewes which had grazed oestrogenic pastures on normal commercial properties, and was related to the amount of histological change in the cervix. This lesion may be useful as a screening test for previous exposure to oestrogenic pasture.