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
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.
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
The BAER test
(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
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
(You will find
more information on puppies being BAER tested at the
bottom of this page)
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
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
This link gives more information
on BAER & more -
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.
Dogs Community Group
Author Debbie Wiles
NOTE: INFORMATION SUPPLIED ON
THIS PAGE IS FOR INFORMATION PURPOSES ONLY. IF YOU SUSPECT YOUR DOG HAS
ANY OF THE ABOVE SYMPTOMS OR PROBLEMS PLEASE SEEK THE ADVICE OF YOUR
(If you require more information on BAER hearing
tests please contact Julia Freeman at The Animal Health trust
litters hearing test being conducted by Julia Freeman at
the Animal Health Trust in Newmarket
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.
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