BAER Hearing Testing in Dogs: What It Is, Which Breeds Need It, and How to Prepare

A deaf puppy sold without disclosure is a welfare failure — BAER testing is the only reliable way to confirm a dog's hearing status

Congenital deafness in dogs is more common than most casual observers realize. In breeds with white or merle coloring, the genes that produce those coat patterns can disrupt the development of the inner ear, leading to deafness that is present from birth. BAER testing is the only objective, definitive way to assess hearing in dogs, and it is an essential tool for breeders of at-risk breeds.

What Is BAER Testing?

BAER stands for Brainstem Auditory Evoked Response. It is an electrophysiological test that measures the brain's electrical response to sound. Unlike behavioral hearing tests (clapping, whistling behind the dog), BAER cannot be fooled — it directly measures neural activity.

The test involves:

1. Small electrodes placed on the dog's scalp (subcutaneous or surface)
2. A series of clicks delivered through earphones placed in the dog's ear canals
3. Computer measurement of the brain's electrical response to those clicks
4. Independent testing of each ear — this is critical, because a bilaterally deaf dog behaves differently from a unilaterally deaf dog

The test is painless, typically takes 5-15 minutes, requires no anesthesia in most dogs, and can be performed on puppies as young as 5-6 weeks of age once the ear canals open.

Unilateral vs. Bilateral Deafness

This distinction matters enormously in breeding programs:

Bilateral deafness — Deaf in both ears. The dog cannot hear at all. These dogs are typically easily identified by behavior — they sleep through loud noises, do not respond to their name, startle when touched unexpectedly.

Unilateral deafness — Deaf in one ear, normal hearing in the other. These dogs behave nearly identically to hearing dogs. They can be nearly impossible to identify through behavioral observation alone. They may not perform well in competitive events that require directional hearing, and they should not be bred because they can produce deaf offspring.

BAER is the only reliable way to identify unilaterally deaf dogs.

Genetics of Congenital Deafness

In most breeds, congenital deafness is associated with the piebald gene (S locus) and the merle gene (M locus). Dogs with extensive white coloring have reduced pigmentation in the inner ear — specifically, the melanocytes that form the stria vascularis of the cochlea are absent or deficient. Without these melanocytes, the cochlea does not develop properly, and hearing loss results.

This is why deafness is so prevalent in:

• White dogs (piebald genetics)
• Merle dogs (particularly double merle)
• Dogs with blue eyes (blue eyes are associated with reduced pigmentation)

The relationship is probabilistic, not certain. Many white or merle dogs hear perfectly. But the risk is significantly elevated, which is why testing is essential rather than optional.

Breeds That Should Be BAER Tested

Breeds with high deafness prevalence requiring BAER:

• Dalmatians — By far the most studied; up to 30% of all Dalmatians have some degree of deafness (8% bilateral, 22% unilateral in some studies)
• Australian Cattle Dogs (Blue Heelers) — High prevalence in merle and heavily white individuals
• Bull Terriers (white) — Significant deafness prevalence
• Collies (rough and smooth) — Especially merle individuals
• Shetland Sheepdogs — Especially merle
• Australian Shepherds — Especially merle and heavily white
• Border Collies — Merle individuals
• Boston Terriers
• Boxers (white)
• English Setters — White and heavily ticked
• Jack Russell Terriers
• Catahoula Leopard Dogs

Where to Get a BAER Test

BAER testing is performed by:

• Veterinary neurologists
• Veterinary teaching hospitals
• Some canine health clinics, particularly those organized by breed clubs

The OFA coordinates and maintains a database of BAER test results. Testing that is submitted to OFA becomes part of the dog's public health record and can be verified on ofa.org.

Cost typically ranges from $75-$200 depending on location and clinic type. Breed clubs often organize BAER testing clinics at national specialties at reduced rates.

BAER Testing in Breeding Programs

Recommendation: BAER test all puppies before placement in at-risk breeds. At minimum, BAER test all dogs intended for breeding.

Breeding decisions:

• Bilaterally deaf dogs should be spayed/neutered and placed as pets. They should not be bred.
• Unilaterally deaf dogs should not be bred — they are at higher genetic risk of producing deaf offspring.
• Only bilaterally hearing dogs (normal on both ears) should be included in breeding programs.

For Dalmatians specifically, the DPCA (Dalmatian Club of America) recommends BAER testing all puppies before sale, and the OFA maintains comprehensive statistics on Dalmatian BAER results by color and eye color.

Summary

BAER testing measures brainstem response to sound and is the definitive test for congenital deafness. It detects both bilateral (both ears deaf) and unilateral (one ear deaf) deafness — the latter is essentially impossible to identify behaviorally. Test all puppies in at-risk breeds at 5-6 weeks of age. Do not breed bilaterally or unilaterally deaf dogs. Submit results to OFA to contribute to breed health data. Selling a deaf puppy without disclosure is a serious welfare failure — BAER testing is the standard that prevents it.