Inbreeding coefficient (COI)

What the number means and how to plan a mating with it.

The coefficient of inbreeding (COI) shows how closely related the parents are. The higher it is, the greater the risk of hereditary diseases and lower vitality in the litter.

Where to find it

On the page of every animal with a pedigree — that animal's COI.
In the COI calculator — choose the sire and dam of a planned mating and see the COI of the future litter.

How to read the result

For comparison: offspring of full siblings is 25%, half-siblings 12.5%, cousins 6.25%. Many breeding programmes recommend staying below 6.25%, but norms differ between breeds — check your breed club's recommendations.

We calculate COI from the pedigree entered in the app (up to 10 generations). The more complete the pedigree, the more accurate the result — missing ancestors lower the COI.

Next: Matings and litters →