Coefficient Of Inbreeding

Unlike the other menu items, COI is not a condition or disease!  

Every dog has a COI.

COI stands for Coefficient Of Inbreeding.  Your dog's COI tells you how inbred your dog is.  It is expressed as a percentage (%) and the lower the COI, the less inbreeding. 

You can find out the COI of any dog on Mate Select.  You just need to know the dog's KC name.

In addition, every breed has an average COI, for the breed.  

What is the average COI?

The average COI differs according to breed.  (This means that some breeds are more 'inbred' than others.) 

You can find out the average COI of any breed, using Mate Select.

The current COI:

• Labradors = 6.5%

Why the coi presents a tricky issue for breeders...  

Breeds of dog are defined by a collection of physical and behavioural traits.  

These breed traits are preserved through selectively breeding dogs together, in order to preserve the physical and behavioural characteristics of the breed.  

Without breeders deliberately breeding dogs together of the same breed, we would only have a mishmash of Heinz 57s.  All dogs would, within a few generations, look very alike.  The characters, personalities, appearance and working abilities of the various breeds would be diluted and lost.

In short, we would 'lose' different breeds of dogs.  If you love any breed of dog, you can imagine what a loss for the world, this would be.  (Sometimes there is a lot of anti-breeder sentiment around - but, without breeders, there would be no breeds.  Dogs would breed with their choice of partner.)

Breeders must 'fix' qualities by breeding back to the same genes - so that these qualities persist for future generations, resulting in the predictable and consistent traits and appearance which we all know and love.   

However, too much, or too close 'breeding back to the same genes' carries fallout, in terms of health.  Inbreeding causes shortened life-spans, increased mortality, smaller litters and poor fertility.  Genetic diversity can be lost within a breed, and once particular genes are gone - they are gone for good from a breed.  Eventually, this can lead to some breeds of dog dying out - as is happening today. 

To maintain health within a breed, the gene pool needs to stay as large as possible.  

So:  Breeders are caught between wanting to breed for specific physical and behavioural traits (which means breeding to genetically similar dogs) versus breeding for genetic diversity, vitality, longevity and all the health-related benefits of breeding to dogs which are genetically dissimilar.  

So what is a (reputable) breeder to do?

The 'tipping point', over which the health of the breed begins to be affected, is 10% - as explained in this useful article.  

Breeders should definitely not be breeding litters with COIs higher than 10%.

Below 5%, is ideal.

We try to breed litters that are below the breed average and ideally also below 5%.

In short, what COI do I look for?

Ideally, you're looking for a COI which is at or below average for the breed - which is 6.5% for Labradors.

And below 5% is ideal...