Holoprosencephaly in Border Leicester lambs.

Holoprosencephaly in Border Leicester lambs is described. This defect is characterised by lack of the longitudinal cerebral fissure, fusion of the cerebral hemispheres and a single lateral ventricle. Facial defects are also associated with this condition. Results of a breeding experiment suggest that it is inherited in an autosomal recessive manner. Results from a survey indicate that the condition is widespread in Border Leicester sheep.