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 they came from a shared ancestor. A higher number means more shared ancestry between the sire and dam, and usually more risk, but it is just one factor to consider, not a pass or fail test by itself.
The number only matters in context
A COI that would be alarming in one breed might be perfectly normal in another with a naturally smaller founding population. Comparing a pairing's COI with that breed's typical range is more useful than looking at the raw percentage alone.
What COI percentage is considered safe?
There is no universal cutoff. Many breeders try to stay below their breed's average, which can vary a lot from breed to breed.
How is COI computed?
COI is computed from a pedigree by tracing shared ancestors across generations. Most breed registries and several online tools can compute it once a pedigree is submitted.