COI & AVK explanation


An animal’s Inbreeding Coefficient (Wright’s Coefficient, or, COI or F) is a numerical value that responds to the presence of common ancestors on both the dam’s and the sire’s side of the animal’s pedigree.

The Inbreeding Coefficient is expressed as a percentage. The Inbreeding Coefficient is expressed as a percentage.
The more common ancestors there are in a pedigree, and the closer they are in terms of generations to their descendant, the higher the Inbreeding Coefficient of that descendant.

The coefficient of inbreeding statistic ranges along a continuum from 0% to 100%.
Any given individual is on this spectrum.
So what’s it all mean? Let’s explore some typical values and how they are used and interpreted.

Zero percent means that there is no evidence of shared ancestors in the dog’s genomic sequence data and thus no inbreeding.
If you took two unrelated dogs and bred them, and then bred a brother-sister pair from the resulting litter, the coefficient of inbreeding would be 25%.
You’d end up with an even higher number if the sire and dam were themselves related farther back.

Mixed breed dogs, on average, tend to have a coefficient of inbreeding around 5% (see references below for more details).
This is not always the case; breeding related mixed breed dogs together can result in high COI puppies, just as in purebreds.

The average COI for purebred dogs is ~20%.
Specific breeds can be higher or lower than this value.
For some breeds, the average coefficient of inbreeding can approach or even pass 40%.
Because these are average numbers, individual COI can vary.
For example, some breeding lines may have more genetic diversity than others.

It’s worth noting that zoo-based, species conservation programs have set a target COI at 10%. This means that they want to design breeding programs that will keep the level of inbreeding at or below this level.
While this metric is a bit arbitrary, it can be useful when comparing the inbreeding consequences of various pairings.

Source: Dog Aging Project
ODIS - pedigree database - COI & AVK explanation
ODIS - pedigree database - COI & AVK explanation


AVK is the German acronym for AhnenVerlust-Koeffizient, which means “ancestor loss coefficient”.

The purpose is to measure how many ancestors occur multiple times in a family tree of five generations.
If every ancestor is unique, the AVK is 100%.
But if there has been line breeding in the past, then the value is lower.
When all five generations are complete, there are 62 animals in the pedigree.

Suppose that two animals occur twice in the pedigree, then 62 – 2 = 60 unique animals remain.
The calculation is 60 divided by 62, multiplied by 100.
So, in this case the AVK is 96.77%.

An AVK of less than 100% is always an indication that there has been inbreeding in the pedigree of an animal, but you cannot tell if it is this animal or one or more of its ancestors that has been inbred.
The AVK of an animal is therefore not necessarily related to the inbreeding coefficient of the animal, but could relate to its ancestors.

What does inbred mean?
0 = no inbreeding.
0.25 = for example, a full-brother and sister have been bred.
1 = complete inbreed: each pair of genes is equal.

Source: ZooEasy