Breed Health Tests

The Northern Bullmastiff Club

Why health screen a dog?

Since some diseases affecting dogs are inherited, dogs that share similar genes are more likely to share similar inherited conditions. Individuals in each breed share a significant amount of their genetic make-up and so certain breeds are more vulnerable to certain health conditions than others.

With the advances in science, breeders are now able to screen their breeding stock for various health problems before the dogs are bred from.
Testing all potential breeding stock, where relevant, allows breeders to select lower-risk dogs for breeding and to better understand the kind of genes a dog may pass on to its offspring, giving them the information required to avoid producing clinically affected puppies.
Making informed decisions from health test results enables breeders to adapt their breeding programmes and reduce the risk of the diseases appearing in future generations.

In some breeds certain tests are recommended by the UK Kennel Club prior to breeding, if the breeder is a member of the Kennel Club Assured Breeders Scheme, some tests are mandatory as a condition of being a member.
For Bullmastiffs the BVA/KC Hip Dysplasia Scheme is a mandatory requirement for Kennel Club Assured Breeders. All other breeders are strongly advised to use this scheme too.
It is also strongly recommended that both Kennel Club Assured Breeders and non-Kennel Club Assured Breeders should also use the BVA/KC Elbow Dysplasia Scheme.

On this page we list some of the health tests that are done by some breeders on their Bullmastiffs prior to breeding, with a brief overview of what is involved and links to some further information.

Hip dysplasia (abnormal development) is a condition where the hip joint does not develop correctly. As the dog gets older, abnormalities occur in the hip joints. These abnormalities include changes to the shape of the hip, ball and socket and the development of osteoarthritis (a common form of arthritis). The joint undergoes wear and tear and deteriorates, leading to a loss of function, this can cause varying degrees of pain, discomfort, stiffness and lameness.

Hip dysplasia is a complex inherited disorder, which is influenced by a number of different genes and by several environmental factors (e.g. diet, exercise or factors when in the womb before birth etc.). The way in which the condition is inherited is not straight forward and the disease is usually seen across many different breeds and is also found in both cross breeds and mixed breeds.

Changes to the hip joint will begin at a young age as the puppy starts to become more active and will get worse over time. These changes can lead to excessive wear and tear of the joint, causing one or both hip joints to become defective. At this stage the hip joint(s) may be painful and can have serious effects on the health, behaviour and welfare of the dog. The severity of hip dysplasia can vary from a poorly shaped hip joint with osteoarthritis, to a very deformed hip joint with advanced and very painful osteoarthritis. The severity of hip dysplasia cannot be accurately determined by a vet’s physical examination and the most reliable way of determining the health of a dog’s hips is by having them X-rayed under anaesthesia or heavy sedation and the X-ray sent off to be evaluated.

In the UK for evaluation we use The British Veterinary Association (BVA) and Kennel Club (KC) Hip scoring scheme which has been in operation since 1984 (other countries may have different schemes). The UK scheme screens animals for faults in the hip joints and is a guide for breeders to choose animals with the best hip joints for breeding. A dog’s X-rays are evaluated by a panel of BVA/KC scrutineers / experts who are part of the hip dysplasia scheme.

A hip score is a measure of evidence of hip dysplasia. Scores for each hip are added together to get an overall hip score for a dog. Each hip joint is assessed and the panel assign points based on nine aspects of each hip joint. The degree to which a dog is affected by hip dysplasia is represented by a score given to each hip, based on the 9 aspects that have been assessed on each side. This score ranges from zero to 106 (zero to 53 for each hip), the lower the score the better, with a score of zero representing the least degree of hip dysplasia and 53 representing the most.

The advice to breeders is to ideally breed only from dogs which score below the breed average. The earliest age that hip scoring can be performed is 12 months and there is no upper age limit. In addition to the vets fee for taking the X-ray there is also a fee that needs to be paid for the evaluation.

Owners should make an appointment with their vet who can take the required X-ray of the dog's hips (elbows can be done at the same time) and the resulting X-ray is then sent off to the BVA to be evaluated / scored, the results are sent back to the owner via the vet and are also published in the KC Breed Records Supplement, they will be printed on any new registration certificate issued for the dog and on the registration certificates of any future progeny of the dog. Results are also listed on the Kennel Club website.

Any individual thinking of using a stud dog or buying a puppy or can check to see if a particular sire or dam has been hip scored on the website if they know the correct KC registered name of the dog.

Link to KC Website to view a Hip or Elbow Score

For more in-depth information on hip dysplasia visit the British Veterinary Association (BVA) website

Link to BVA page for Hips

Download the Hip Dysplasia information PDF

Link to PDF for Hips

Visit the Kennel Club Website

Link to KC Website - Hip Dysplasia Health Scheme Page

Elbow dysplasia is a common inherited orthopaedic problem where the elbow joint does not develop correctly.
Elbow dysplasia includes a number of specific abnormalities or problems that affect different areas of the elbow joint. These cause problems by affecting the growth of the cartilage which forms the surface of the joint or the structures around it. As the dog matures, the joint undergoes wear and tear and deteriorates, leading to a loss of function. Even a small change in the shape of one part of the joint can have major consequences for the joint function, leading to varying degrees of pain, discomfort, stiffness and lameness (unable to walk correctly), osteoarthritis (a common form of arthritis), and serious effects on the health, behaviour and welfare of the dog.

Elbow dysplasia is another complex disorder controlled by a number of different genes and influenced by several environmental factors (e.g. diet, exercise or factors when in the womb before birth, etc.), making it very difficult to predict whether a dog will be affected. The disease is usually seen across many different breeds and it is generally accepted that this condition is more common in larger breeds, but can occur in any dog of any size, regardless of whether they are purebred or a mixed breed.

The severity of elbow dysplasia cannot be accurately determined by a vet’s physical examination. The most reliable way of determining the health of a dog’s elbows is by having your dog X-rayed under anaesthesia or heavy sedation, and then the x-ray sent off to be assessed by a specialist.

The British Veterinary Association (BVA) and Kennel Club (KC) Elbow scoring scheme has been in operation since 1998. A dog’s X-rays are graded by a panel of experts who are part of the elbow dysplasia scheme. Each elbow joint X-ray is assessed by two scrutineers who will agree the grading. The degree of elbow dysplasia present is indicated by a scale of 0 to 3 (0 being the best and 3 being the most severe). Only the highest grade of the two elbows is taken as the elbow grade for that dog.
The results are sent back to the owner via the vet and are also published in the KC Breed Records Supplement, they will be printed on any new registration certificate issued for the dog and on the registration certificates of any future progeny of the dog. Results are also listed on the Kennel Club website.

Any individual thinking of using a stud dog or buying a puppy or can check to see if a particular sire or dam has been elbow or hip scored on the website if they know the correct KC registered name of the dog.

Link to KC Website to view an Elbow or Hip Score

For more in-depth information on elbow dysplasia visit the British Veterinary Association (BVA) website

Link to BVA page for Elbows

Download the Elbow Dysplasia information PDF

Link to PDF for Elbows

Visit the Kennel Club Website

Link to KC Website - Elbow Dysplasia Health Scheme Page

BVA/KC/ISDS Eye Scheme

The Eye Scheme offers breeders the possibility of eye testing to screen for inherited eye disease in certain breeds. By screening breeding stock for these diseases, breeders can use the information to eliminate or reduce the frequency of eye disease being passed on to puppies.

At an eye testing session a Bullmastiff will have an assessment done by one of a specialist group of canine ophthalmologists (the Eye Panel) who will examine the dog to look for clinical signs of any inherited disease known to affect the breed. The test involves the dog having special drops placed on the eye to enable the specialist to see the back of the eye.
If no clinical signs are noted for these diseases, then the dog is declared ‘unaffected’; if signs consistent with one or more conditions are present, then the dog will be declared ‘affected’ for the relevant disease. A certificate is issued to the owner and the results are passed to the KC for inclusion in the tested dog’s registration database, published in the KC Breed Record Supplement and can be viewed online.

In some breeds, depending on the condition being checked for; prior to breeding, a dog may be required to undergo an eye examination annually due to the possibility of a disease developing gradually over several years.
Eye tests can be booked to be done with a canine ophthalmologists at multiple dog testing sessions organised by individual breed clubs to help reduce the cost to club members, they are also sometimes held at the large championship dog shows or you can book an appointment for a private session with a specialist vet. A fee is payable at the time of testing.

Heart conditions can be adult-onset or congenital heart diseases (present from early in life) and some breeders are now having their dogs heart tested prior to breeding. Heart testing has been done in other breeds for quite some time and "auscultation" heart testing sessions are sometimes arranged by their breed clubs.

Heart testing involves auscultation (listening to the heart for abnormalities with a stethoscope). For all breeds it may involve other diagnostic tools depending on the breed and the heart condition being screened for.
Other diagnostic tests include Doppler echocardiography (an ultrasound of the heart) and possibly electrocardiography (ECG). There have been official heart testing schemes available for some time in the UK. These schemes are specific to certain breeds in which congenital or acquired heart disease is prevalent.

Official heart testing should be carried out once the animal is twelve months old (ideally over eighteen months old in giant breeds). One heart test is normally adequate to exclude significant congenital heart disease, but in some breeds serial (usually annual) heart tests are required to exclude any adult-onset heart diseases for example - dilated cardiomyopathy (DCM).

For furter details please visit the following website

Link to the Veterinary Cardiovascular Society

Blood test for Hypothyroidism

Canine hypothyroidism (low thyroid hormones) can be an inherited trait.

As as in humans, hypothyroidism is caused by a deficiency of thyroid hormone, this can result in infertility, obesity, mental dullness, lack of energy and a range of behavioural problems. The dog's fur may become coarse and brittle and fall out and the skin may become hard and dark.

Reason for testing prior to mating :-

  • Females may have problems with their oestrous cycles, they may abort or give birth to weak, dying, or stillborn puppies and there may be problems with milk flow.
  • Males may have a low sperm count, lack libido, have shrunken testicles, or other infertility problems.

With the advances in animal genetic testing there are now companies that provide extensive ranges of genetic tests covering a large number of breeds and diseases or conditions which can provide reliable, accurate and precise results.

We are now noticing some Bullmastiff breeders in the UK are now DNA testing for the following:

Dominant PRA is an autosomal dominant trait and a form of Progressive Retinal Atrophy that affects English Mastiffs and Bullmastiffs. PRA is an eye disorder that causes the rod and cone cells to deteriorate over time, eventually leading to complete blindness. Dogs that are affected by this disorder often appear to have clinically normal eyes until around age 2-3 years old when the cells begin to die and vision loss increases. Some pups show signs of night-blindness by 6 weeks of age. By the age of 3-4 years most affected dogs are completely blind.

Canine Multifocal Retinopathy is an autosomal recessive eye disorder. The mutation causes raised lesions to form on the retina which alters the appearance of the eye but usually does not affect sight. The lesions may disappear, or may result in minor retinal folding. Symptoms of the mutation usually appear when a puppy is only a few months old, and generally do not worsen over time.

Degenerative Myelopathy is a progressive neurological disorder that affects the spinal cord of dogs. Dogs that have inherited two defective copies of the gene will experience a breakdown of the cells responsible for sending and receiving signals from the brain, resulting in neurological symptoms.

Cystinuria - crystal formation in the dogs urine, which in turn can lead to formation of cystine calculi (stones) in the kidney and/or the bladder.

Some Bullmastiffs carry a long haired gene in their DNA which produces dogs which as the name suggests are long haired / fluffy haired. This coat type is not a desired trait and is classed as a fault in the Bullmastiff breed standard, dogs carrying the long haired gene should not be mated to another carrier and any resulting offspring from a carrier parent should also be tested for the gene before breeding.

Although for Bullmastiffs there is not yet DNA test available for this condition, steps are being taken by one breeder to try to establish one.

At the moment there is an appeal for all Bullmastiff owners to have some blood drawn from their dog at the vets to help in research to develop a test. Once a test is developed it is hoped all Bullmastiff breeders will get their dogs tested before breeding them.

A short description regarding Cerebellar Ataxia can be found on our breed health page using this link Link to our breed health page

For further details on how you and your Bullmastiff can help in this study, please visit the dedicated facebook page and website.

Link to Facebook page

Link to website to download blood submission form and info for your Vet