RGD uses the Human Disease Ontology (DO, https://disease-ontology.org/) for disease curation across species. RGD automatically downloads each new release of the ontology on a monthly basis. Some additional terms which are required for RGD's curation purposes but are not currently covered in the official version of DO have been added. As corresponding terms are added to DO, these custom terms are retired and the DO terms substituted in existing annotations and subsequently used for curation.
A congenital reproductive abnormality in white female offspring (heifers) in certain breeds of CATTLE, such as Belgian Blue and Shorthorn. The white color is inherited as a recessive trait which is associated with defects in the female reproductive tract (Muellerian system). These heifers are usually sterile.