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 probability that two copies of a gene in an animal are identical because both descend from a shared ancestor. A higher figure means the sire and dam share more ancestry between them, and generally carries more risk, but it remains one consideration among several rather than a simple pass or fail test.
The figure only tells a story alongside context
A COI that would be a cause for concern in one breed could be entirely unremarkable in another that came from a smaller founding population. Setting a mating's COI against that breed's typical range matters a great deal more than looking at the raw percentage in isolation.
What COI percentage is thought of as safe?
There's no single cut off that applies everywhere. Many breeders aim to stay under their breed's average, and that average differs quite a bit from breed to breed.
How is COI calculated?
It's calculated from a pedigree, tracing shared ancestors back across the generations. Most breed registries, and several online tools besides, can calculate it once a pedigree has been submitted.