Congenital Deafness in Dogs
Congenital Deafness in dogs is when they are born with Deafness or, most commonly, suffer degeneration of the inner ear structure within the first few weeks after birth. This impairment to their hearing in either one ear (unilateral) or both ears (bilateral). It is generally caused by a genetic fault, although it can be the result of viral damage caused during the pregnancy before the puppy is born. This condition is usually associated with dogs with merle or piebald genes but is also associated with dogs with white coats and blue eyes.
Typically, this condition develops within the first weeks of a puppy being born, at which stage their ear canals are still closed. The much-needed blood supply to the cochlea is negatively impacted, resulting in nerve cells in the cochlea dying off, causing permanent Deafness.
Deafness in a dog is not a life-threatening disorder like some conditions such as renal disorders. It may not even be as painful as hip dysplasia, but Deafness puts your pet at risk from several hidden dangers. Deaf animals are at risk from motor vehicles or, in the wild, predators.
Deafness at birth can be congenital or from viral damage to the unborn puppy. A gene defect mainly causes inherited hearing disorders. The defect can be autosomal dominant, autosomal recessive, mitochondrial, sex-linked, or multiple genes related.
Congenital Deafness is generally seen in dogs with merle or piebald colour genes. It’s also associated with a white coat and blue eyes. The condition can impair hearing in one or both ears.
The most common causes of congenital Deafness in dogs are dead nerve cells of the cochlea and a permanently closed ear canal. This defect may be linked to one or more recessive, defective genes inherited from the parents.
Lack of Blood supply to the Cochlea and the Canal during the first few weeks of life can cause Deafness.
Deafness at birth may also be caused by developmental defects in the ear’s physiological apparatus and usually occurs in the first few weeks of fetal life. When the puppy is very young (below three weeks), you may not even know he has a hearing disorder.
White coats, piebald, and merle colours are primarily associated with Deafness at birth in dogs. Sometimes, they may be lacking entirely. The lack of pigment deficiency around the head hinders pigment cell growth in the dog’s inner ear. This causes the death of the nerve cells that are essential for hearing.
Commonly affected dog breeds include the Dalmatian, Australian Cattle Dog, Australian Stumpy Tail Cattle Dog, Bull Terrier and Bull Miniature, English Setter, Boston Terrier, English Cocker Spaniel, and many more. Oddly, some solid white dogs like the Spitz have no deafness problems.
Congenital Deafness in dogs has been noted in over 80 different breeds. Visit www.caninehearingtests.com for the complete list.
Because many deaf puppies get put down, it becomes essential to identify dogs affected by hereditary Deafness and remove them from the breeding pool.
Diagnosing Deafness in Dogs
Diagnosis of Deafness in dogs requires careful observation of how he responds to sound. Examples include the failure of noise to awaken him when he is sleeping or the dog failing to recognize or respond to a sound. Other signs of Deafness include unusual behaviour like confusion when verbal commands are given, unusual voice, excessive barking, hyperactivity, and lack of ear movement.
In young puppies being reared together, it may be more challenging to detect Deafness as the puppy under study may be likely to be aping the reactions of the others. When observed individually after an age when responses to sound are more predictable (3-4 weeks), detecting Deafness may be possible.
The response to smell, touch and visible objects must be differentiated from the response exhibited to sound. Because genetic tests for congenital Deafness in dogs are not available, the best hearing test for animals is BAER.
Brainstem Auditory Evoked Response (BAER) tests form an essential component of responsible breeding in animal breeds at high risk for congenital Deafness.
Although it involves a referral to a speciality vet practice, performing a Brainstem Auditory Evoked Response test is relatively simple. The patient animal “listens” for a click sound heard through special foam inserts placed in both ears. The results are picked by tiny electrodes inserted just under the scalp in electrical activity in the brain and auditory nerves. A relatively flat line indicates Deafness in either ear.
In white coats, merle colours, and piebald dogs, the un-pigmented skin in the dog’s inner ear causes atrophy in the nerve endings, and they die in the first few weeks of a dog’s life (weeks 1-3). That causes hearing impairment. Hereditary Deafness has no treatment.
In some cases, however, it can be prevented by not giving your pregnant dog any medication and getting regular check-ups. Congenital Deafness in dogs may be eliminated by removing identifiable carriers of the condition from the breeding program.
Before joining the breeding program, at-risk dog breeds should undergo the BAER test, and only those with two “good” ears should be included.
Deaf dogs don’t experience physical discomfort or pain due to hearing impairment. They do, however, need to have a caring, dedicated, and understanding owner. If your four-legged friend is deaf, there are several things you can do in terms of training and communication that will help your dog live a near-normal life.
Caring for a dog that is deaf in both ears may require more dedication from you. Training a hearing-impaired dog using hand signals must always be consistent to avoid confusing the pet. Such a dog is more likely to be easily startled, leading to biting. Deaf dogs may, therefore, not be suitable if you have young children as they may scare easily with the rapid child movements.
Deaf dogs will also require protection from certain physical dangers, such as passing motor vehicles and strange dogs. A deaf pet should always be on a leash when in an unenclosed area. It would help if you also were willing to learn a new way of communicating with your deaf dog. For example, you can use a vibrating collar to train your dog, or both of you can take training classes to learn hand signals.
With positive training, patience, and proper knowledge, owning a deaf dog need not be a challenge. It can be a rewarding experience as most dogs with hearing impairment cope well with their unique disability and are very trainable. When handled and trained well, they can even participate in dog sports.
The bottom line, dogs experiencing congenital Deafness are not very different from any other hearing dogs. They interact with other dogs; people, and they bark. They adapt well to their surroundings. All they need is help and understanding from you to adapt to their situation for a fruitful relationship.
Contact Details
Narelle Hammond (Baercom Technician)Sydney, NSW, Australia
Phone : +61419787375
Email : [email protected]