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 on account of a shared ancestor further back in the pedigree. A higher figure indicates greater shared ancestry between the sire and dam, and generally more risk, but it remains just one factor among several and not a simple pass or fail test.
The figure means little without context
A COI figure that would be alarming in one breed may be quite unremarkable in another breed that descends from a naturally smaller founding population. Comparing a pairing's COI against that breed's typical range is far more useful than looking at the raw percentage in isolation.
What COI percentage is considered safe?
There is no universal cut off. Most breeders aim to remain below their breed's average, which varies quite considerably from one breed to another.
How is COI calculated?
COI is calculated from a pedigree, by tracing shared ancestors across multiple generations. Most breed registries, as well as several online tools, can calculate it once a pedigree is submitted.