An analysis of the inheritance pattern of an adult-onset hearing loss in Border Collie dogs.

BACKGROUND

During routine diagnostic BAER testing of dogs of various breeds for private owners at the Western College of Veterinary Medicine in Saskatoon, it became evident that some individual dogs developed hearing loss as adults. Although inherited congenital deafness has been widely reported in dogs, this type of deafness had not.

FINDINGS

Special clinics were set up to screen working Border Collies at herding competitions. To determine the typical age that geriatric deafness might be expected, retired dogs were also recruited. Five of the 10 Border Collies 12 years of age or older had hearing loss (1 bilaterally deaf and 4 had reduced hearing). The adult onset deafness which exhibited in three families, did not usually occur until 5 years of age, too young to be geriatric deafness. This adult onset deafness fits an autosomal dominant pattern of inheritance. Several of these dogs had been BAER tested at younger ages with no sign of deafness. The deaf dogs were not associated with either gender. A survey was developed which was completed by the dog owners, that indicated that the hearing loss was gradual, not sudden. In addition, some family studies were conducted.

CONCLUSIONS

Dogs at 5 years of age were often in the prime of their herding careers and then did not respond appropriately to distant commands. This type of deafness is important to dog owners but is also a potential medical model for some forms of hearing loss in humans. This report also suggests that geriatric hearing loss is common in dogs older than 12 years.