What Every Dog Owner and Breeder Should Know

Whether you’re buying a puppy, planning a litter, or just want to understand your dog’s background, it’s important to know how to read a pedigree, what inbreeding really means, and how genetic health testing plays a crucial role in long-term canine wellbeing.

Let’s break it down clearly and simply.

What Is a Pedigree?

A pedigree is your dog’s family tree, usually showing 3 to 5 generations. If your dog is registered with a national Kennel Club—such as The Irish Kennel Club here in Ireland—you’ll receive an official certificate that includes:

  • Dog’s registered name, breed, microchip
  • Dam (mother) and sire (father)
  • Grandparents, great-grandparents, and their registered names
  • Any official titles (e.g., CH for Champion, FTCh for Field Trial Champion)

But a pedigree alone won’t tell you everything. You need to know how to read between the lines. (Beuchat, 2020; Hekman, 2023)

How Related Are the Parents?

One of the first things to check in a pedigree is: Are the dam and sire closely related?

Look for:

  • Repeated names in both maternal and paternal lines
  • Shared ancestors within 3–4 generations

This is a sign of linebreeding or inbreeding, which increases the risk of inherited diseases and weakens genetic diversity. (Calboli et al., 2008; Beuchat, 2020; Canine Genetics UK, n.d.)

Using Breed Registries to Check Pedigree Lines

Many national and breed-specific registries provide online tools to trace pedigree lines and health history. These can be incredibly helpful not only for breeders planning litters but also for potential puppy buyers researching a breeder’s claims.

Examples include:

  • The Kennel Club (UK) database
  • Vizsla Database
  • Golden Retrievers K9Data
  • Labrador Net Database UK
  • Irish Setter Database
  • Spaniel Working Test & Pedigree Resources (varies by country and breed club)
  • OFA (Orthopedic Foundation for Animals – includes genetic test records for US dogs)

These databases often allow you to:

  • View lineage going back multiple generations
  • Identify repeated names or high-risk combinations
  • Check if dogs have been health tested and their results
  • Monitor longevity, causes of death, and health status of siblings and extended relatives

These tools support transparency and informed decision-making by offering publicly available lineage and health details that can help verify genetic compatibility and diversity in pairings.

What Is COI (Coefficient of Inbreeding)

Important: This section talks about genetic COI — which comes from DNA testing, not just what’s written in a pedigree. Genetic COI gives a clearer picture of how closely related two dogs really are.

COI is shown as a percentage:

  • 0% = completely unrelated
  • 6.25% = first cousins
  • 12.5% = half-siblings or uncle/niece
  • 25% = full siblings or parent-offspring

Ideally, we want a genetic COI to be under 5%, under 10% at most. The lower the number, the more genetically diverse the puppies are likely to be.

Higher COI numbers (over 10%) raise the risk of inherited health problems, smaller litters, and shorter lifespans. Experts recommend keeping genetic COI ideally under 5%, and definitely below 10%, to preserve breed health (Beuchat, 2020; Wijnrocx et al., 2021).

Pedigree COI vs. Genetic COI

Not all COIs are created equal. Most breeders calculate COI using pedigrees — but this is only an estimate.

  • Pedigree COI is based on registered names and ancestry. Assumes every ancestor contributes equally. Fails to detect hidden inbreeding or gene loss. May underestimate true inbreeding by 25% or more.
  • Genetic COI is based on real DNA — not paperwork. Identifies actual shared segments (runs of homozygosity). More accurate, especially in closed or popular breeds.

Takeaway: Use genetic COI when possible — especially for breeding decisions.

How to Measure Genetic COI

To get an accurate COI, use tools that test your dog’s DNA:

  • Embark for Breeders: Offers COI calculations, trait testing, and disease screening. Free
    predicted COI calculator for planned litters through embarkvet.com
  • UC Davis VGL: Offers diversity testing for many breeds. Useful for rare or less commonly studied breeds via vgl.ucdavis.edu

These services help confirm whether a pairing is likely to produce genetically healthy, diverse puppies.

Why Grandparents Matter (Even More Than Parents)

Testing the parents is essential — but looking at the grandparents gives a fuller picture.

Here’s why:

  • Genetic conditions may skip generations
  • Some diseases, like epilepsy, only appear between ages 2–5
  • Grandparents offer insights into long-term health and stability of the line

Ask about test results, health history, and longevity in older generations. Good breeders will know this information.

Health Testing: It’s About the Breed — Not Just the Basics

Health testing targets the most prevalent inherited conditions in each specific breed.

The Standard Minimum (for most breeds):

  • Hip scoring
  • Elbow scoring
  • Certified eye exam

These are required by many clubs, but they’re just the starting point.

Additional Testing Examples:

  • Cavaliers → Heart scans (MVD)
  • Labradors → PRA, EIC, CNM
  • Border Collies → CEA, TNS, CL
  • Boxers → Aortic stenosis, ARVC
  • Poodles → Addison’s, thyroid disease, PRA
  • Spaniels → PRA, AMS, hip and eye issues
  • Dachshunds → IVDD, PRA

Use Laboklin’s breed-specific disease search: laboklin.com

Age Matters: Why 18 Months+

All health testing should be done when a dog is fully developed — usually at 18 months or older.

  • Early hip/elbow scores may be unreliable
  • Eye diseases can emerge later
  • Epilepsy and neurological issues often appear at age 2–5

If a breeder claims their dogs were tested under 12–18 months, ask for proof of retesting.

A Word on Idiopathic Epilepsy

Idiopathic epilepsy is a polygenic, environmentally mediated disorder. That means:

  • No single gene test (yet)
  • Runs in families
  • Behaves like a threshold trait: symptoms appear when risk factors accumulate

“A trigger is not a cause. Just because we haven’t found all the genes doesn’t mean it’s not
genetic.” — Carol Beuchat, PhD

Although no single genetic marker has yet been identified, the condition is widely believed to be polygenic and influenced by environmental triggers—similar to complex hereditary conditions in humans. The lack of a definitive test underscores the importance of careful breeding choices and keeping detailed family health records.

This is why multi-generational awareness is crucial.

Final Checklist for Buyers & Breeders

  • Before committing to a puppy — or planning a litter — ask:
  • Have both parents been tested at 18+ months?
  • Are tests relevant to the specific breed?
  • Has genetic COI been calculated via Embark or UC Davis?
  • Are there repeated names in the pedigree?
  • Are grandparent test results and health history available?
  • What is the health history of the parents, their siblings, their offspring, and any other close relatives?

Healthy Puppies Start with Informed People

Pedigree papers and cute photos aren’t enough. If you care about your dog’s future — or the future of your breed — take the time to:

  • Learn the line
  • Ask tough questions
  • Understand COI
  • Look at generations, not just the parents
  • Use modern tools like Embark, UC Davis, and Laboklin

Because a dog’s best start in life begins before it’s even born.

References

Beuchat, C. (2020). Institute of Canine Biology. Retrieved from https://www.instituteofcaninebiology.org/

Calboli, F. C. F., Sampson, J., Fretwell, N., & Balding, D. J. (2008). Population structure and inbreeding from pedigree analysis of purebred dogs. Genetics, 179(1), 593–601. https://doi.org/10.1534/genetics.107.084954

Canine Genetics UK. (n.d.). Resources on genetic diversity and COI tools. Retrieved from https://www.canine-genetics.org.uk

Giger, U., Sargan, D. R., & McNiel, E. A. (2007). Breed-specific hereditary diseases and genetic screening. In E. A. Ostrander, U. Giger, & K. Lindblad-Toh (Eds.), Inherited metabolic disease in companion animals (pp.252–259). The Veterinary Journal, 174(2). https://doi.org/10.1016/j.tvjl.2006.08.017

Hediger, K., Borer, A., Giger, U., & Müller, E. (2019). Breed-specific genetic risk factors in dogs: A review. Veterinary Medicine and Science, 5(4), 367–376.

Hekman, J. (2023). IAABC Behavioral Genetics Lecture Notes. International Association of Animal Behavior Consultants.

Lewis, T. W., Blott, S. C., & Woolliams, J. A. (2015). Genetic evaluation of hip score in UK Labrador Retrievers. PLOS ONE, 10(10), e0140704. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0012797

Ostrander, E. A., Dreger, D. L., Evans, J. M., & Hayward, J. J. (2020). The canine genome and its role in understanding human disease. Genome Research, 30(4), 559–572.

The Kennel Club. (n.d.). Inbreeding calculators and health testing information. Retrieved from https://www.thekennelclub.org.uk

Wijnrocx, K., François, L., Goosens, E., Janssens, S., & Buys, N. (2021). Estimating genomic inbreeding and genetic relationships in dog breeds using genomic SNP data. Journal of Animal Breeding and Genetics, 138(3), 244–255.