Deafness affects white coated dogs, but not all white coated dogs are deaf.
Approximately, 85 different dog breeds have been reported to be linked to congenital deafness, meaning that the breed carries the genetic material that causes a dog to be born deaf.
We could talk about the scientific mumbo jumbo of theoretical outcomes of two dogs carrying the recessive deafness gene, but who has time for that? To put it in a nutshell, we commonly see deafness in dogs with white pigmented skin.. However, this still leaves us to wonder, why are white coated dogs deaf?
What is Deafness?
Deafness is defined as a loss of hearing, caused by a delivery interruption of sound to the brain.
When sound waves reach you, they enter the canal of the ear and strike the eardrum. The eardrum vibrates like a big gong, causing the ear ossicles or middle ear bones to vibrate as well. The vibration reaches the fluid filled and spiral-shaped cochlea of the inner ear, creating waves.
All this commotion causes a pressure change and forces the cochlea’s hair cells to move. These hair cells are connected to the auditory (hearing) nerves that sparks a nerve impulse down the auditory pathway that connects to the brain.
Why are White Coated Dogs Often Deaf?
White coated dogs are often affected by deafness because they carry the piebald gene, which is demonstrated by their predominant white coat and often blue eyes. The piebald gene is a result of the absence of melanocytes, the cells which create pigment.
These melanocytes are the part a dog’s DNA that determines if he will have brown or black hair, blue or brown eyes, and so on and so forth. When a dog is born without the genetic material to create melanocyte cells, a white hair coat and sometimes blue eyes, are the result.
So, what does hair color have to do with hearing loss? Well, the ability to hear is made possible by a special layer of cells within the inner ear. This specialized layer of cells and the cells that determine hair color, come from the same stem cell source. Without this stem cell, the dog’s body won’t be able to make this specialized layer of hearing cells and will likely be white in coloration.
Which Dog Breeds Are Most Commonly Affected by White Hair Coat Related Deafness?
Approximately, 85 different dog breeds have been reported to be linked to congenital deafness. This means that the breed carries the genetic material to cause the dog to be born deaf.
However, the following breeds are most commonly deaf due to the piebald gene:
- English Bull Terriers (with white hair coat)
- Boxers (with white hair coat)
- English Settlers
Is the Piebald Gene The Only Clue To Canine Congenital Deafness?
No. Apart from the piebald gene, congenital deafness is also linked to the merle gene that causes a dog to have a merle colored coat and blue eyes.
To be noted, blue eyes are not a true eye color, but rather a lack of color producing pigment within the iris. The lack of pigment on the iris suggests a lack of pigment cells throughout the body, including the inner ear which makes hearing possible.
Dogs possessing the merle gene do not have the piebald gene, which allows them to have a colored hair coat.
Dog breeds that are commonly affected by the merle gene are the Old Sheepdog, Dappled Dachshund, Australian Shepherd and the Border Collie.
How to Test Canine Deafness
The only way to effectively test a dog’s hearing is through a r Brainstem Auditory Evoked Response test or a BAER test. A veterinary professional will attach electrodes to the skull and measure the electrical activity within the brain. The technician will make a series of clicks that are passed through headphones, placed on the pup’s ears. As stated previously, when a dog hears a sound, a connection is made by nerves to the brain. This ear to brain connection is the electro-activity that can be measured by the BAER test.
A series of waves will display on the BEAR test screen in a dog with perfect hearing, but little to no waves will appear in a deaf dog. BEAR tests can determine whether a dog is deaf in one (unilateral deafness) or both ears (bilateral deafness).
White coated dogs can carry the piebald gene that causes them to become deaf. Dog owners can determine if their dog is deaf as early as 6 months of age.
So, if you own a white coated dog that you suspect is deaf, talk to your veterinarian about performing a BEAR test and the next steps to helping your dog live a happy, normal life.
Bonus: learn how to train a deaf dog.