Why low inbreeding isn't always the priority in purebred dog breeding
A look at why purebred dog breeding doesn't always prioritize low inbreeding coefficients, what pulls against it, and how pedigree data and genetic testing can shift that balance.
Inbreeding & COI
COI is a measurement, not a verdict
The coefficient of inbreeding estimates the likelihood that two copies of a gene in an animal are identical because both trace back to the same ancestor. A higher number points to more shared ancestry between the sire and dam, and typically more risk, but it's only one factor in the decision, not a pass or fail test on its own.
Context matters more than the raw number
A COI that looks alarming in one breed can be completely normal in another that started from a smaller founding population. Checking a pairing's COI against that breed's typical range tells you more than the percentage by itself ever will.
Is there a COI percentage that's considered safe?
No, there's no single number that applies across the board. Most breeders try to stay under their own breed's average, and that average can differ quite a bit from one breed to the next.
How do you calculate COI?
It's calculated from a pedigree by tracking shared ancestors across multiple generations. Breed registries and a handful of online calculators can generate it once a pedigree is entered.