A purebred dog is one whose parents are both registered in the same breed with a breed registry; in Canada that registry is usually the Canadian Kennel Club (CKC), which says it registers purebred dogs of the breeds it officially recognizes. Registration proves documented ancestry, not health, and a DNA test cannot create purebred status: the American Kennel Club states that breed heritage tests are not purity tests. On health, the research gives a mixed answer. In a University of California, Davis study, 13 of 24 inherited disorders were equally common in purebred and mixed-breed dogs, 10 were more common in purebreds and 1 was more common in mixed breeds. The Canadian Veterinary Medical Association (CVMA) applies the same standard to every dog: whether the progeny are purebred or crossbred, breeding animals should be health tested.
Below: a plain glossary, how Canadian and other registries count breeds, how to check a dog's status, the studies with their limits, and a checklist for buying a puppy.
What does "purebred" mean?
Purebred is a registration status. A dog that resembles a Golden Retriever is not a registered purebred unless the paperwork shows both parents registered as Golden Retrievers. The CKC describes itself as the country's main record-keeping body for purebred dogs, offering registry services for the breeds it recognizes.
A breed standard is the written description of how a breed should look and move. The FCI says the breed's "owner" country writes it. A studbook is the registry's record of which dogs belong to the breed, and most accept puppies only when both parents are already registered in that breed.
| Term | Usual meaning | What proves it |
|---|---|---|
| Purebred (registered) | Both parents registered in the same recognized breed | A registration certificate and pedigree |
| Purebred without papers | May descend from one breed, but is unregistered | Nothing official. A DNA test can suggest ancestry only |
| Mixed breed (mutt) | Ancestry from several breeds, often unknown | A DNA ancestry test gives an estimate |
| Crossbreed | Parents are two different recognized breeds | The parents' papers |
| "Designer" crossbreed | A deliberate, marketed cross of two purebreds, such as a Goldendoodle or Labradoodle | The parents' papers. Registries generally do not list these as breeds |
How many purebred breeds are there?
The CKC's About page says it "currently recognizes 193 breeds." Other registries publish different totals because each decides for itself what counts as a breed, and counts change as breeds are added. Treat every figure below as a dated snapshot from October 2026.
| Registry | What it published | Notes |
|---|---|---|
| Canadian Kennel Club | "Currently recognizes 193 breeds" | States that it registers purebred dogs it officially recognizes |
| American Kennel Club (US) | 205 recognized breeds from January 1, 2026 | Its breed index page still says 200 |
| Royal Kennel Club (UK) | "Showing 230 results" | Includes "(Imp)" entries not explained on the page |
| FCI (international) | Ten groups; 20 provisional breeds | 101 members and partners, each issuing its own pedigrees; the FCI ensures mutual recognition. No overall total on the pages read |
How can you tell if your dog is purebred?
- Do you have a registration certificate and pedigree from the CKC, or from another registry (for example one in an FCI member country, for an imported dog)? If it lists both parents in your dog's breed, your dog is purebred in the registry sense.
- Did the seller hand over only a vaccination record or a sales contract as "papers"? That is not registration. Ask for the registry name and your dog's registration number, then confirm them with the registry.
- No papers? A DNA breed test estimates ancestry but cannot make a dog registrable. The AKC says breed heritage tests "are not purity tests and do not determine whether a dog is purebred."
- How accurate is breed identification? In a 2025 Dog Aging Project analysis of 5,673 dogs, about 80% of owners' reported breeds matched the genetic report; most disagreements involved breeds missing from the reference panel.
Are purebred dogs less healthy than mixed-breed dogs?
It depends on the condition, the breed and how health is measured. No study cleanly separates "purebred" from body size, head shape and breeding practice. The large datasets below are American and British; none of the studies reviewed was drawn from the Canadian dog population.
| Study | What it found | Main limits |
|---|---|---|
| Bellumori et al., JAVMA 2013: 27,254 dogs with an inherited disorder, UC Davis teaching hospital (US), 1995 to 2010 | No difference for 13 of 24 disorders (including hip dysplasia, cancers, patellar luxation). Purebreds more likely to have 10 (including dilated cardiomyopathy, elbow dysplasia, cataracts, hypothyroidism). Mixed-breed dogs more likely to have ruptured cranial cruciate ligament | One referral hospital. Only 24 disorders, and only dogs brought for care |
| Donner et al., PLoS Genetics 2018: more than 83,000 mixed-breed and 18,000 purebred dogs, 330 breeds, 152 gene variants | About two in five dogs carried at least one copy of a tested disease variant. Most variants appeared in both groups. Mixed-breed dogs were more likely to carry a common recessive variant; purebreds were more likely to be genetically affected | Covers known variants only, in dogs whose owners bought a commercial test. A correction was published in 2019 (PMID 30657768); its content was not reviewed here |
| O'Neill et al., Vet J 2013: 102,609 dogs in English first-opinion practices (RVC VetCompass), 5,095 deaths | Median longevity 12.0 years. After adjustment, crossbred dogs lived 1.2 years longer than purebreds (95% CI 0.9 to 1.4). Heavier dogs lived shorter lives | England only; observational |
| Mata and Mata, PeerJ 2023: 30,563 dogs from VetCompass | Survival was highest in mongrels, then crossbreds with one purebred ancestor, then purebreds. Breed-level genetic-illness scores tracked mortality risk | Uses a breed-level index, not each dog's own inbreeding. Does not isolate size |
| Bannasch et al., Canine Med Genet 2021: 227 breeds | Average genotype-based inbreeding across breeds was 0.249. Body weight and inbreeding both predicted insurance-claim morbidity. Smaller, less inbred breeds were healthier than larger, more inbred ones | Breed-level analysis; insurance data reflect owners who insure |
| O'Neill et al., Sci Rep 2020: 22,333 UK dogs sampled from 955,554 (VetCompass) | Flat-faced (brachycephalic) dogs differed in 10 of 30 common disorders: predisposed to 8, protected from 2. The authors call it strong evidence that these breeds are generally less healthy | UK data, one year of records |
| Bryson et al., PLOS ONE 2024: 9,402 dogs; Cavapoo, Cockapoo and Labradoodle vs. their parent breeds (UK) | No statistically significant difference in 86.6% of 342 comparisons; crossbreeds higher in 7.0% and lower in 6.4%. No evidence of a strong hybrid-vigour effect, and no evidence of poorer health either | Owner-reported, UK only, three poodle-type crosses |
What this adds up to
- Strongest evidence: breeds with extreme conformation, such as flat faces, have more health problems (O'Neill 2020, Bannasch 2021). That describes particular breeds, not purebreds in general.
- Moderate evidence: mixed-breed dogs lived somewhat longer on average in two UK analyses (1.2 years in the larger, adjusted one), but both are observational.
- Mixed picture: some disorders are more common in purebreds, many are equal, and a few may be more common in mixed breeds.
- Size matters on its own: heavier dogs fared worse in two studies, and many large dogs are purebreds.
- Uncertain: whether the UK and US results apply to Canadian dogs, and how much would change with less inbreeding and more moderate body types.
The CVMA's statement on responsible breeding (February 1, 2024) applies to animals "whether the resulting progeny are considered purebred or crossbred." It says that all breeding animals should be genetically tested for the most common and most debilitating heritable diseases, that affected and carrier animals should not be selected for breeding, and that where no genetic test exists, other appropriate health testing should be done. It also says breeders advertising a "genetic tested" animal should disclose the specific tests and results, and that selective breeding for increasingly extreme conformation has led to severe health and welfare consequences.
Myths versus evidence
| Belief | What the evidence says |
|---|---|
| "Mutts are always healthier" | Not always. Mixed-breed dogs had more cruciate ligament rupture and share many disease variants, though they lived longer on average in UK data |
| "Papers mean a healthy puppy" | No. Papers record parentage. The CVMA asks for health testing and disclosure of the specific tests on top of registration |
| "A DNA test proves my dog is purebred" | No, according to the AKC |
| "Breed tells you the temperament" | Only weakly for an individual. A 2022 Science study of 18,385 dogs found breed explains about 9% of behavioural variation |
A checklist for buying a purebred puppy in Canada
- Ask for the registry and both parents' registration numbers, and verify them.
- Ask which genetic and health tests the parents had, and ask to see the actual results. A vague claim of "health tested" is not enough, as the CVMA statement makes clear. The Orthopedic Foundation for Animals (OFA), based in Missouri, keeps public databases for hips, elbows, eyes, heart and other conditions, which some breeders use.
- Research the breed's known problems first, especially for flat-faced or very large breeds, and ask your vet what to expect.
- Meet the mother, and the father if possible, and see where the puppies are raised.
- Treat papers as the start of your checks, not proof of health or temperament.
What we do not know
There is no clean comparison that holds size, head shape and breeding practice constant and changes only registration. The large health datasets here do not come from Canadian dogs. The designer-crossbreed study covers three poodle crosses with owner-reported health, so it says little about other crosses. Genetic testing covers only known variants. And breed totals change as registries add breeds.
Frequently asked questions
What is a purebred dog?
A purebred dog has two parents registered in the same breed with a registry, giving it a documented pedigree. The status comes from registration, not appearance.
Does the Canadian Kennel Club register only purebred dogs?
Its About page says the club registers purebred dogs and offers registry services for the breeds it officially recognizes, currently 193.
Can a dog be purebred without papers?
It may descend from one breed, but nothing official shows it. Without registration it is treated as unregistered, however closely it matches the breed standard.
Can a DNA test prove my dog is purebred?
No. The AKC says breed heritage tests are not purity tests. A test can estimate the breeds in a dog's ancestry. In a 2025 study, owners' stated breeds matched genetic reports for about 80% of 5,673 dogs.
Are purebred dogs less healthy than mixed-breed dogs?
Not uniformly. In a UC Davis study, 13 of 24 inherited disorders were equally common, 10 were more common in purebreds and 1 in mixed breeds. Flat-faced breeds have clearer problems, and mixed breeds lived longer on average in two UK analyses.
Is a Goldendoodle purebred?
No. A Goldendoodle is a deliberate cross, so it is a crossbreed. A 2024 UK study of three poodle crosses (not including the Goldendoodle) found no statistically significant health difference from their parent breeds in 86.6% of comparisons.
What health tests should a breeder show me?
The CVMA says breeding animals should be tested for the most common and most debilitating heritable diseases, and that a breeder advertising genetic testing should disclose the specific tests and results.
How many breeds does the CKC recognize?
Its About page says 193 as of our October 2026 reading. Figures differ between registries and over time.
Sources
- Bellumori TP, Famula TR, Bannasch DL, Belanger JM, Oberbauer AM. Prevalence of inherited disorders among mixed-breed and purebred dogs: 27,254 cases (1995-2010). J Am Vet Med Assoc 2013;242(11):1549-55. PMID 23683021, DOI 10.2460/javma.242.11.1549.
- Donner J, Anderson H, Davison S, et al. Frequency and distribution of 152 genetic disease variants in over 100,000 mixed breed and purebred dogs. PLoS Genet 2018;14(4):e1007361. PMID 29708978, DOI 10.1371/journal.pgen.1007361.
- O'Neill DG, Church DB, McGreevy PD, Thomson PC, Brodbelt DC. Longevity and mortality of owned dogs in England. Vet J 2013;198(3):638-43. PMID 24206631, DOI 10.1016/j.tvjl.2013.09.020.
- Mata F, Mata A. Investigating the relationship between inbreeding and life expectancy in dogs: mongrels live longer than pure breeds. PeerJ 2023;11:e15718. PMID 37483958, DOI 10.7717/peerj.15718.
- Bannasch D, Famula T, Donner J, et al. The effect of inbreeding, body size and morphology on health in dog breeds. Canine Med Genet 2021;8:12. PMID 34852838, DOI 10.1186/s40575-021-00111-4.
- O'Neill DG, Pegram C, Crocker P, Brodbelt DC, Church DB, Packer RMA. Unravelling the health status of brachycephalic dogs in the UK using multivariable analysis. Sci Rep 2020;10:17251. PMID 33057051, DOI 10.1038/s41598-020-73088-y.
- Bryson GT, O'Neill DG, Brand CL, Belshaw Z, Packer RMA. The doodle dilemma: how the physical health of 'Designer-crossbreed' Cockapoo, Labradoodle and Cavapoo dogs' compares to their purebred progenitor breeds. PLoS ONE 2024;19(8):e0306350. PMID 39196904, DOI 10.1371/journal.pone.0306350.
- Morrill K, Hekman J, Li X, et al. Ancestry-inclusive dog genomics challenges popular breed stereotypes. Science 2022;376(6592):eabk0639. PMID 35482869, DOI 10.1126/science.abk0639.
- Sexton CL, Reichel C, Keyser A, Dunbar MD, Ruple A. Comparing owner reported and genetic breed identification reveals high concordance in a large cohort from the Dog Aging Project. Sci Rep 2025;15:30493. PMID 40830175, DOI 10.1038/s41598-025-15095-5.
- Parker HG, Kim LV, Sutter NB, et al. Genetic structure of the purebred domestic dog. Science 2004;304(5674):1160-4. PMID 15155949, DOI 10.1126/science.1097406.
- Parker HG, Dreger DL, Rimbault M, et al. Genomic analyses reveal the influence of geographic origin, migration, and hybridization on modern dog breed development. Cell Rep 2017;19(4):697-708. PMID 28445722, DOI 10.1016/j.celrep.2017.03.079.
- American Kennel Club. Why breed heritage tests are not 'purity' tests. Updated 29 May 2025.
- FCI. Presentation of our organisation; Breeds nomenclature.
- Royal Kennel Club. Breeds A to Z; Health testing and screening.
- UC Davis. Purebred dogs not always at higher risk for genetic disorders, study finds. 28 May 2013.
- Canadian Kennel Club. About the Canadian Kennel Club.
- Canadian Veterinary Medical Association. Responsible breeding of companion animals. Position statement dated 1 February 2024.
- Orthopedic Foundation for Animals. OFA health databases.
- American Kennel Club. Newly recognized breeds 2026, December 30, 2025; AKC dog breeds index.
Veterinary disclaimer: This article is general information, not veterinary advice. Breed health risks vary by individual dog and by line. Talk to your veterinarian about screening and care for your own dog, and about any symptoms you notice.