Complex inherited disorders are often caused by a number of
different genes and are also influenced by environmental factors,
such as diet and exercise. The way in which these conditions
are inherited is not straight forward; hence the name complex
Where tests for these conditions are available, dogs are often
tested through grading systems, which rate to what degree the dog
is affected by the condition. Complex diseases can cause clinical
conditions that worry breeders the most, such as hip and elbow
dysplasia, and heart disease. These complex diseases are usually
seen across many different breeds and are also described in both
cross breeds and mixed breeds.
Which tests are relevant to your breed?
Before breeding, check whether any of the conditions mentioned
below may be relevant to your breed. Information on the tests that
are available and recommended can be found on our Breed Information
Centre, or by contacting your veterinary surgeon, breed club,
and/or your dog's breeder.
The results of dogs tested under any of the
BVA/KC health schemes are published on the Kennel Club's online
health resource Mate
Select and in the quarterly publication, The Breed Record
Supplement. Mate Select is free and easily searchable,
assisting breeders wishing to check on the health status of a
potential mate for their dog.
What tests are available for complex inherited disorders?
The Kennel Club, in conjunction with the British Veterinary
Association (BVA), currently run four clinical screening
It has been designed to address the problem of hip dysplasia.
The scheme evaluates radiographs that have been taken of an
individual dog's hips. Each hip is evaluated by two experts who
score nine anatomical features of the hip and score each hip out of
a total of 53. The two hip scores are then added together to give
an overall total hip score. So, a dog's hip score can range from 0
to 106, and the lower the hip scores the better the anatomy of the
In breeds where significant numbers of dogs have been through
the hip scheme, it is possible to calculate a breed mean hip score,
which gives a feel for the average score within that breed.
For additional information on considering hip score results when
breeding you may also wish to read the section below on estimated
It has been designed to address elbow dysplasia. Each dog is
assessed from radiographs that are taken of the dog's elbows. Each
elbow is graded on a scale of 0 to 3, by two specialists. The lower
the grade, the better the anatomy of the elbow. In this scheme, if
the dog has two different elbow grades, the higher of the two is
used as the dog's elbow grade.
has two lists, Schedule A and Schedule B. Schedule A contains
all of the known inherited eye diseases and the breeds that are
currently known to be affected by these conditions. Schedule B,
lists breeds and conditions where further investigation is urged.
Specialist panellists, appointed by the BVA, can examine any
individual dog for clinical signs of these diseases. Some of these
inherited eye diseases are not present from birth and breeders
especially are advised to have their breeding stock examined
throughout their dog's life.
View the schedule A or schedule B lists here.
MRI scans, scanned under BVA procedures, are reviewed by a panel
of BVA appointed neurologists and radiologists and graded by two
scrutineers. Grading is assigned according to the severity of the
CM and SM changes. As CM/SM is a progressive condition, scans
throughout the dog's lifetime are recommended, generally at years
1, 3-5, and over 5.
Procedure Notes, submission details and breeding advice are
available for all these schemes from the BVA Canine Health Schemes
(CHS) office, for more information, visit www.bva.co.uk/Canine-Health-Schemes/
Breed Clubs health screening schemes
In addition to the BVA/KC Health Screening Schemes, many breed
clubs support dog health and good breeding practices through their
own health improvement strategies and health screening programmes.
These programmes are organised by the breed club using specialist
veterinarians that they have identified. The results of these
screening programmes are collated and disseminated by the breed
To find contact details of your local breed club, please visit
our Breed Information
BAER Test Health Programme
(Brainstem Auditory Evoked Response) test (PDF) is used to
evaluate the hearing of a dog by detecting the electrical activity
of the brain in response to an auditory stimulus (usually clicks),
which is recorded and displayed on a computer screen. The test is a
reliable method for determining whether a dog is deaf and for
measuring the extent of its hearing loss. However, the test does
not measure the full range of canine hearing, only hearing in the
normal human range (some dogs will test as 'deaf' but can still
hear very high pitched noises).
Breeding advice for complex inherited disorders
Where health testing is recommended for your breed, it is
important that any potential breeding stock is tested prior to
mating. The results of these tests should be carefully considered
and used responsibly to produce healthy puppies. If any of the
BVA/KC health schemes are recommended in your breed, then once you
know the results for both the potential sire and dam, you may wish
to refer to the scheme specific advice found on the clickable links
above or from www.bva.co.uk/Canine-Health-Schemes/.
It is important to ensure that you also take into consideration
all health test results, the general health of each parent, the
inbreeding coefficient of the potential puppies that could be
produced, the temperament of the dogs and their conformation.
How complex inherited disorders are passed on to any progeny is
not straight forward and so you may wish to also consider the
results of any breeding dog's parents, grandparents, siblings and
Estimated Breeding Values
As mentioned above, complex disorders, such as hip and elbow
dysplasia are inherited in a complex way and the extent to which an
animal is affected is also influenced by their environment.
Estimated Breeding Values, or EBVs, are a resource that can be used
by breeders to assess the degree of risk to which an animal may
have inherited, and pass on, genes associated with a particular
Currently EBVs are available, via the Kennel Club's Mate Select, for hip and
elbow scores and are calculated using data from the BVA/KC hip and
elbow dysplasia screening schemes. EBVs are a more accurate way of
measuring a dog's genetic risk, than by using the scores from the
BVA/KC schemes alone. EBVs take into consideration a dog's hip or
elbow score, as well as the scores of all of their relatives. By
using this additional data, it excludes non-genetic or
You can currently find EBVs for hip scores for 15 breeds and
elbow scores for 5 breeds on the Kennel Club's Mate Select
resource, available at www.mateselect.org.uk.
EBVs are currently not available for all breeds. The
Kennel Club's ability to provide EBVs is based on complex
calculations, but is dependent on both:
- The proportion of dogs scored in a breed
- The spread of those scored dogs across each pedigree
Therefore, currently, EBVs are only available for breeds with a
large number and wide spread of tested dogs.
EBVs are available for the: Akita, Bearded Collie, Bernese
Mountain Dog, Border Collie, English Setter, Flat Coated Retriever,
German Shepherd Dog, Golden Retriever, Gordon Setter, Labrador
Retriever, Newfoundland, Rhodesian Ridgeback, Siberian Husky,
Tibetan Terrier and Rottweiler.
For further information on other health considerations to make
prior to breeding, please see our 'Breeding for Health'
information guide (PDF).