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Deafness in Bull Terriers


Bull Terriers along with many other breeds suffer with deafness, it is associated more with white dogs however coloured and even solid Bull Terriers can be affected. Dogs can either have deafness in one ear (partial deafness) known as unilateral deafness (or unis) or have deafness in both ears (totally deaf) known as bilateral deafness.

Deafness in the Bull Terrier is widely excepted by breeders and although it does state in the Bull Terrier Clubs code of conduct that deaf puppies should not be sold, testing for deafness is not endorsed.

Since the BAER test (more details below) has become more widely available more and more breeders are testing their breeding dogs and puppies, whilst this will not completely rid the bred of this condition it will help reduce the number of Bull Terriers with deafness.


Inside the dogs ear and how they hear

Their are four parts to a dogs ear, the ear flap, the ear canal, the middle ear and the inner ear.

The ear flap is made of cartilage, muscle and skin which captures sound waves and allows them to travel through the ear canal to the ear drum (tympanic membrane) which then vibrates.

The middle ear is the area behind the ear drum which contains the tympanic cavity. This is where the auditory tube, the the tympanic nerve, the vestibular window and the cochlea along with other parts are. Also within the middle ear are three small bones (the smallest bones in the body!), the malleus, the incus and the stapes. These bones transmit the air vibrations from the ear drum and tympanic cavity to the inner ear.


The inner ear is where the air vibrations are converted into nerve impulses, which when reaching the brain result in hearing. It is a labyrinth of fluid filed sacs, which are contained within an osseous labyrinth. The osseous parts of the inner ear are a shell shaped cochlea. This cochlea winds around a hollow core, containing the cochlea nerve. Within the cochlea are around 10,000 hair cells which respond to the air vibrations and stimulates the nerve cells to send messages to the brain, these hair cells are what the ear uses to change air vibrations to electrical signals that the brain then recognises as sound.



What causes Deafness and how is it inherited?

The cause of deafness is not yet fully understood, however it is believed to be caused by the loss blood supply to the cochlea and thus causing the degeneration of the hair cells contained in the cochlea. Without these hair cells their is no way the ear can change air vibrations into electrical signals which the brain recognises as sound, thus causing deafness.

The cause of the loss of blood supply is also unknown but is thought to be due to the absence of pigment producing cells in the blood vessels.

Again the mode of inheritance is not yet understood as two dogs with full hearing can still produce partial or fully deaf puppies. It is known however that by breeding a partially deaf or deaf bull terrier will increase the likeliness of deaf puppies, therefore it is advised not to breed from partial/fully deaf bull terriers.

The BAER test explained

The BAER (Brainstem Auditory Evoked Response) is the only way to certain that your dog can hear properly from both ears. In this test a computer is used to record the electrical activity of the brain's response to sound. stimulation. A sound stimuli, normally clicks, is passed through headphones placed over the dogs ears whilst recording electrodes are placed on the dogs heads.




Please click on the picture above of a Miniature Bull Terrier puppy having a BAER test carried out. Not sedated and not harmed in any way.

     You can also click on the picture above to see what a BAER hearing certificate should look like, this should be in your puppy pack or given when you buy a dog that has been BAER tested..



 (You will find more information on puppies being BAER tested at the bottom of this page)


Bull Terriers can be BAER tested from 5 weeks old until any age. This is a non invasive nor painful procedure so small puppies will not require sedation however an adult who won't sit still may require a light sedation. BAER testing is only required once in a Bull Terriers life and they will be certified either with normal hearing, unilateral deaf (deaf in one ear) or bilateral deaf (deaf in both ears).

You will be given a certificate to show the dog has had a BAER test which should be kept to show potential puppy buyers & given to the puppy buyer as part of your puppy pack. The breeder will have a certificate naming the entire litter with their results to keep on file.


Further information also on further tests to determine the amount of hearing a dog has.

This link gives overall information on BAER testing & more - Animal Health Trust Deafness Information

This link gives more information on BAER & more - Dermapet Hearing


Deaf Bull Terriers

Bull Terriers who are deaf in just one ear do not normally act in any different way to hearing bullies.

Bull Terriers who are completely deaf tend to learn as puppies to pick up other signals to recognise what is going on such as air/ground vibrations when a human enters the room etc, therefore do respond in similar ways to a hearing dog. Deaf bullies respond extremely well to training using hand signals, usually quicker than hearing dogs as they have no noise to distract them! Puppies should attend normal puppy training classes to socialise in the same way a hearing dog would.

The only extra training a deaf puppy requires is in being startled, this should be done slowly whilst a puppy so they do not become scared if woken by accident when sleeping.

Some people believe that deaf Bull Terrier puppies WILL become aggressive, I would like to note that their is NO medical research to back this up. I personally believe their is just as much chance of a hearing dog becoming aggressive as there is a chance a deaf dog becoming aggressive. 

Please follow the links for information on training using hand signals.


Deaf Dogs Information Website

Deaf Dogs Community Group


Author Debbie Wiles




(If you require more information on BAER hearing tests please contact Julia Freeman at The Animal Health trust julia.freeman@aht.org.uk) www.aht.org.uk

A litters hearing test being conducted by Julia Freeman at the Animal Health Trust in Newmarket


BAER Hearing Test On A Litter Of Puppies

On arrival Julia meets you and takes you to the test room where she sets up a puppy pen, (take some toys along with you). The puppies can eat, drink & toilet. Then play until they are tired, however long it takes.


They do eventually fall asleep one by one. There is no rush for this so just relax. No time limit is put on your appointment, Julia has all the time in the world for you and your litter and will work with your puppies plan for the day.


Whilst they are sleepy the test is carried out. The puppies are to tired to fidget so tend to sit still for the procedure which  takes just a few minutes on each ear.



In fact they usually just fall back to sleep in your arms. (Julia Freeman has never had to sedate a puppy for a hearing test).


Or they keep a close eye on what's going on!



Tired sleepy puppies stay snuggled in your arms during the test and this means a correct result can be obtained.


The BAER hearing test specialised computer set up.



Julia checking the puppies hearing.


Not best pleased at nap time being disturbed, but completely unharmed by the days events!




Back to nap time whilst the next puppy is tested. Once all puppies have been tested you will be issued with a certificate for each puppies test result and a litter sheet with all puppies and results printed for your own records.

For more information or to book an appointment for your litter (or adult dogs)

Please contact Julia Freeman at the Animal Health Trust julia.freeman@aht.org.uk

Animal Health Trust Deafness Information


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