Anury in two Cairn terriers.

Congenital anury (taillessness) was observed in 2 Cairn Terriers. Fecal staining of the hind limbs was evident in both dogs. A mating of the affected dogs produced a litter of 2 apparently normal pups. The small litter size may have been attributable to lethal gene combinations similar to those described in mice. The radiographic appearance of the caudal and sacral vertebrae was atypical in both tailless dogs. Results of myelography and electrodiagnostic testing of anal sphincter function were normal in one of the dogs. One of the tailless dogs was euthanatized and was found to lack specific muscles and muscle parts responsible for normal defecation, which resulted in fecal staining of the hind limbs. Pedigree analysis revealed the tailless dogs to be closely related and slightly inbred, suggesting a hereditary etiologic factor for anury.