French Bulldog health tests: what every parent should have

Why test before breeding

Many inherited conditions in dogs are recessive. A dog can carry a variant without ever being ill, and only when two carriers are paired can a puppy inherit two copies and be affected. DNA tests make these hidden variants visible, so pairings can be planned to avoid them.

Other problems, such as breathing difficulties or loose kneecaps, cannot be read from DNA. They need a veterinary examination. A good testing programme combines both.

The DNA panel

These are the core markers for French Bulldogs:

• CMR1 (canine multifocal retinopathy): small blister-like lesions on the retina. Often mild, but it can affect vision.
• DM (degenerative myelopathy): a slowly progressing disease of the spinal cord in older dogs. The test shows risk, not certainty.
• HUU (hyperuricosuria): high uric acid in the urine, which can form bladder and kidney stones.
• JHC (juvenile hereditary cataract): cataract that can develop in young dogs.
• CDDY (chondrodystrophy, linked to IVDD risk): a variant associated with early disc degeneration and a higher risk of intervertebral disc disease.

Colour loci are tested as well, so the colour genetics of every litter are known in advance. This matters most for merle, where two copies must be avoided. Our colour guide explains why.

CDDY is very common in the breed, so it is usually managed by careful selection over generations rather than excluded outright. Ask the breeder how they handle it.

Breathing assessment

Breathing is the most important health topic in the breed. In respiratory function grading, a trained veterinarian listens to the dog's breathing before and after a short exercise test and grades it from 0 (no signs) to 3 (severe). Parents graded 0 or 1 are preferred. Our BOAS guide explains the test in detail.

Veterinary examinations

Alongside DNA and breathing, a veterinarian can check things that genes alone cannot show. Which checks are done varies between breeders and countries, so ask what each parent has had:

• Patella: whether the kneecaps stay in place or slip (luxation).
• Spine: X-rays can show malformed vertebrae such as hemivertebrae, which are common in screw-tailed breeds.
• Eyes: an eye examination by a veterinary ophthalmologist can find problems not covered by DNA.
• Heart: auscultation, and further examination if a murmur is heard.
• General health: weight, skin, ears and overall condition.

Reading a result: clear, carrier, affected

• Clear (N/N): the dog carries no copies of the variant and cannot pass it on.
• Carrier (N/m): one copy. The dog is usually healthy but passes the variant to about half of its puppies.
• Affected (m/m): two copies. The dog can develop the condition and passes the variant to all of its puppies.

A carrier is not a bad dog. Excluding every carrier would shrink the gene pool and create new problems. What matters is how carriers are paired. Our policy is simple: We never pair two carriers of the same condition; a carrier may be paired with a clear dog, so no puppy can be affected.

How to check that a report is genuine

1. The report comes from a recognised laboratory and has the laboratory's name and a reference number.
2. The microchip number on the report matches the dog's chip.
3. The dog's name and registration details match the pedigree.
4. The report is dated, and the test was done before the pairing.
5. If in doubt, contact the laboratory and ask them to confirm the reference number.

You can see how we present results for each parent on our breeding dogs page, and our full testing standard on the Health page.

Questions to ask a breeder

Use these questions on any breeder, including us. Clear, documented answers are a good sign; vague answers are not.

1. Which laboratory ran the DNA panel, and can I see the full reports for both parents?
2. What is each parent's breathing grade, and when was it assessed?
3. Which veterinary examinations have the parents had, and can I see the certificates?
4. Are either of the parents carriers of anything, and how was the pairing planned around it?
5. What does the puppy receive before it leaves: veterinary check, vaccinations, microchip?

What tests cannot tell you

DNA tests only cover the variants science has identified. Many common problems in French Bulldogs, such as skin allergies, ear infections and some spinal issues, are influenced by several genes and the environment, and have no single test.

That is why testing is a floor, not a ceiling. Structure, moderate features, a healthy weight, good food and early veterinary care all matter just as much. Book a check-up with your own veterinarian within the first week after homecoming, and keep the parents' reports with your puppy's papers so any future vet can see them.