Miniature Bull Terrier Health

The Miniature Bull Terrier is a relatively healthy breed, however, as with all dogs, there are known inherited conditions which we need to be aware of in order to help safeguard the health of the breed. We do ask that people report any serious health conditions to the Breed Health Co-ordinator, in order for a record of problems to be collated and compared yearly which may help us pinpoint any new issues arising and assist us in keeping track of health problems.

The main conditions which currently affect the breed and for which we test are as follows

(Note the word ‘dog’ is used throughout but relates to both male and females)

Primary Lens Luxation (PLL)

This is a very serious and painful eye condition which was previously the major health issue affecting the breed but which is now well under control following collaboration between the MBTC, the Kennel Club and the Animal Health Trust (AHT) who worked tirelessly, fundraising and collecting DNA samples from affected animals, in order to enable the AHT to isolate the gene mutation responsible for this inherited condition. The DNA test to identify a dog’s status as ‘affected’ ‘carrier’ or ‘clear’ was launched in 2009 and this means that the PLL status of all puppies can be determined from the age of 5 weeks.

Two clear parents can only produce clear puppies – these puppies do not need to be tested as they are ‘clear by parentage’.

A ‘clear’ can be mated to a ‘carrier’ in which case all puppies must be tested and will subsequently be certified either ‘clear’ or ‘carrier’.

In theory an ‘affected’ could be mated to ‘clear’ – although these days this is unlikely to occur – in this case all puppies would be ‘carriers’ and would require a test and a certificate to prove it.

Under no circumstances should anyone breed from two ‘carriers’

The PLL DNA test is a once in a lifetime test and all breeding dogs should have evidence of their PLL status as should all puppies.

Patella Luxation

The patella, more commonly known as the knee-cap, can luxate (slip out of place) and this can be a painful condition for the dog. In severe cases an operation to fix the joint will be required. A competent vet can manipulate the dog’s legs to check for signs of slipping patella. Dogs should be checked for this condition after 12 months of age and again should any symptoms arise.

Heart Disease

There are a number of different heart conditions which can affect dogs, however, the main two known in the Miniature Bull Terrier are Mitral Valve Displaysia (MVD) and Aortic Stenosis (AS). It is recommended that all dog’s hearts are tested by a qualified Cardiologists at the age of 12 month by means of Auscultation which simply means the Cardiologist listens to the beating of the dogs heart through a stethoscope. For the pet owner, if they are advised their dog is free of murmur, then no further tests are needed. If a low grade murmur is detected, ie grade 1 or 2, the vet will probably advise testing on an annual basis but generally no further action would be needed as these low grade murmurs are unlikely to affect the dog through its life. If, however, the murmur is higher, the Cardiologist will recommend further testing with ECG or Doppler.

For all breeding stock, advice from the AHT/KC is that only dogs clear of murmur or with, at most, a grade 1 murmur, should be bred from. However, as part of the KC interbreeding scheme a miniature bull terrier can be mated if it has a grade 2 murmur as long as the These dogs/bitches should be tested annually and have a valid, current certificate prior to mating.

Some phrases explained:

Hereditary Heart Disease is one which is passed genetically from the parents but which may not be expressed as a disease in the puppy.

Congenital Heart Disease is one with which the puppy is born.

An Acquired Heart Disease is not present at birth but develops later. eg due to age.

Murmur is the sounds of turbulence when listing to the heart with a stethoscope which are created by the sounds of blood hitting the closed valves and can indicate the presence of heart disease.


Dogs can either be deaf in one ear (unilateral deafness) or deaf in both ears (bilateral deafness). It is difficult to notice deafness in young puppies as they tend to react to vibrations or follow their litter mates. A BAER (Brain stem Auditory Evoked Response) carried out by a specialist is the only way to know for certain. Small probes are placed on the puppy/dog’s head along with a headphone over the ear which emits a clicking noise, this is liked to a computer which records the brains response. This is a non-invasive test that does not cause any pain or harm to the puppy/dog. On some occasions adult dogs will need to be lightly sedated. This test can be carried out on puppies from 5 weeks old and any age after that. This test is only required once in the dog’s lifetime. A copy of the report from the specialist should be kept for proof.

Kidney Disease

The main Kidney Disease affecting the breed is FAMILIAL NETHROPATHwhich is screened for using the Urine Protein: Creatinine (UPC) test. The recommended or ‘standard’ result, at which a dog is NOT considered at risk, is a ratio of 0.5, however, on advice from the KC/AHT, Miniature Bull Terriers specify the lower, ‘safer’ ratio of 0.3. Any ratio above 0.5 should be investigated with further tests. It is recommended that the UPC Ratio test is carried out at the age of 12 months and then annually thereafter with all breeding dogs/bitches having a current, valid certificate prior to mating.


The urine protein:creatinine ratio is a simple test that measures how much protein is being lost through the kidneys, and determines if the loss poses a health risk for the pet. The test involves measuring the amount of protein and creatinine in a urine sample, and mathematically dividing the protein value by the creatinine value.


Creatinine is a by-product of muscle metabolism. Creatinine is excreted in urine at an approximately constant rate, which means it can be used as a standard for comparison for other substances that are also excreted in the urine.


Losing a small amount of protein through the kidneys may not be important if the kidneys are otherwise working well, however, if kidney function is compromised then even small amounts of urinary protein loss should be investigated.

Substantial protein loss through the kidneys is a concern because it means the kidneys are not working properly.



No .The protein:creatinineratio should be performed only on urine that is free of blood and inflammatory cells. The presence of blood and inflammation in urine may give a falsely high result for the protein: creatinine ratio, suggesting there is kidney disease when none is actually present.

Ideally, the urine for the test should be collected, mid stream and first thing in the morning, prior to eating.


This list is not a definitive list of all conditions which can affect the breed.

It is recommended that annual health checks are carried out to ensure good health is maintained throughout your dog’s life.

The Miniature Bull Terrier Club highly recommend that each of these hereditary problems are tested for prior to mating., they are in line with the Club’s Code of Ethics and the recommendations laid down by the KC’s Assured Breeder Scheme.

More detailed information on the above problems can be provided, please contact the Health Coordinator for further information, support or advice.

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