Collielife

Health Testing in Dogs

Health testing in pedigree dogs generally takes two forms: clinical screening and genetic DNA testing. These tests provide different types of information and should be used together where appropriate.

Health testing cannot guarantee that every puppy will remain completely healthy, but it can help breeders understand potential risks and make more informed breeding decisions.

Clinical health screening

Clinical screening assesses a dog for physical signs or features associated with a particular condition at the time of examination.

Examples include:

Some clinical tests show whether a dog has visible signs of a condition at the time of testing. Others provide a score, grade or measurement that helps estimate the dog’s health or its risk of passing on an inherited problem.

A normal result does not always guarantee that a condition will never develop later, particularly where age, environment or several genes influence the disease.

Genetic DNA testing

A DNA test examines a specific gene or genetic variant associated with a particular inherited condition.

Most canine DNA tests require a simple mouth or cheek swab. Some tests may require a blood sample collected by a veterinary professional.

Depending on the condition and its mode of inheritance, a DNA result may describe a dog as:

Clear: The dog does not have the particular genetic variant covered by that test.

Carrier: The dog has one normal copy and one copy of the tested variant for an autosomal-recessive condition. A carrier will not usually develop that particular recessive condition but can pass the variant to its puppies.

Affected: For a straightforward autosomal-recessive condition, the dog has two copies of the tested variant.

At risk or increased risk: The dog has a genetic result associated with an increased likelihood of developing a condition, but the result may not predict with certainty whether symptoms will appear.

An affected or at-risk DNA result does not always mean that a dog currently has symptoms or will definitely develop them. This depends on the particular condition, how it is inherited and whether other genes or environmental factors are involved.

A DNA test only provides information about the particular genetic variant being tested. A dog described as clear for one condition may still be affected by, or carry genes associated with, other health conditions.

Using carriers and affected dogs for breeding

Automatically removing every carrier from breeding can reduce genetic diversity, particularly in a numerically small breed. This can increase inbreeding and allow other inherited problems to become more common.

For a straightforward autosomal-recessive condition, a carrier can be mated to a DNA-tested clear dog without producing genetically affected puppies. The expected puppies will be either clear or carriers.

An affected dog may sometimes be considered for breeding to a DNA-tested clear dog. For a straightforward autosomal-recessive condition, this mating should produce carrier puppies rather than affected puppies.

However, this advice does not apply automatically to every disease or DNA test. Some conditions have dominant, X-linked, complex or incompletely understood inheritance. Risk-based tests may also require different interpretation.

The health and welfare of the individual dog must always be considered. A dog should not be bred from if mating, pregnancy or whelping would compromise its welfare.

Always check the breeding advice for the specific DNA test. If there is any uncertainty, seek advice from the testing laboratory, your veterinary surgeon, a canine geneticist or the relevant breed health coordinator.

What is a veterinary health check?

The term “vet health check” usually refers to a general examination carried out by a veterinary surgeon.

When a breeder takes a litter for a veterinary health check, the vet may:

A veterinary health check provides an overall assessment of the puppy on that particular day and may identify matters requiring further investigation.

It is not the same as breed-specific health screening or DNA testing, and it cannot guarantee that a puppy is free from every inherited or developmental condition.

Which health tests should be carried out?

The appropriate tests depend on the breed and the conditions known to affect it. Recommendations may also change as new research and DNA tests become available.

Breeders should check:

Health testing should be completed well before a mating takes place so that the results can be considered when choosing a suitable mate.

Why health testing matters

Some inherited conditions do not become apparent until later in life, after a dog may already have been bred from. DNA testing can identify certain genetic risks before symptoms develop.

Clinical screening can identify physical changes that may not be obvious during an ordinary examination. Results from individual dogs and their relatives can help breeders make decisions intended to reduce the frequency and severity of inherited disease.

Health testing is one part of responsible breeding. Breeders should also consider:

For information about health conditions and testing relevant to Rough and Smooth Collies, please visit the Collie Health Main Page.

Please note: This information is provided as a general guide and is not a substitute for veterinary or specialist genetic advice. Breeding recommendations depend on the particular condition and its mode of inheritance.

Further information: