Summary: Deafness is a disorder in Border Collies that can result from a complex variety of issues. It can span anywhere from unilateral deafness or partial hearing loss to complete deafness either at birth or at some point later on in their life. Some of the main known causes of deafness are as follows, however there are likely more risk factors yet to be identified.

Excessive White: There are two known white spotting patterns in the breed that may pose some risk of deafness: piebald and whitehead. Excessive white, in all cases, poses a risk if the pigment deletion creating the white pattern also affects the inner ear of the dog. This lack of pigment causes a disruption to the function of the cells responsible for interpreting sound, leading to deafness. Any/all deafness from excessive white are present at birth and cannot come back later in life

Double Merle: Double merle is the colloquial term for a dog who has two copies of the merle gene which often causes birth defects such as deafness, blindness, and/or certain deformities when two copies are present. The combination of two copies of merle has the effect of large scale pigment deletion, working much like excessive white does to disrupt the cells in the inner ear that are responsible for interpreting sound. Merle is a readily testable gene and should be tested for in all breeding dogs, even if not visually merle.

Screening: BAER (Brainstem Auditory Evoked Response) screening is available at the age of 35 days and older. This screening can identify deafness-bilateral and unilateral, partial hearing loss, and is capable of monitoring progressive hearing loss over time. Experienced Veterinarians or Board Certified Veterinary Neurologists can use BAER testing to pass or fail dogs on record for OFA (hearing in both ears is only passable, unilateral or bilateral deafness is a fail). OFA does recommend seeing a Board Certified Veterinary Neurologist for BAER testing and to further evaluate any hearing loss.

Currently BAER testing can be difficult to find in some areas of the country, and/or expensive to evaluate, putting up some barriers for breeders and Border Collie owners to BAER test puppies/dogs.

Inheritance: Very complex, and can vary between breeds. The excessive white and merle genes (described above) are thought to affect inheritance of deafness.

As stated above, BAER testing can be a helpful tool going forward to evaluate hearing loss/deafness in Border Collies. It is currently the only tool to accurately test for hearing loss/deafness. It can be difficult to locate testing without traveling excessive distances.