Co-efficient Of Inbreeding
Every dog has a COI.
It stands for Coefficient Of Inbreeding. Your dog’s COI tells you how inbred your dog is. It is expressed as a percentage (%). The lower the COI, the less inbred your dog is.
Why does COI matter?
Choosing a puppy from a litter with a low COI will give your pup the best chance of developing into a healthy and long-lived dog.
When COIs get too high, fertility drops lower, offspring are smaller, more dogs die earlier than they should, and their lifespan is shorter.
For more information about COIs, see this excellent article from the Institute of Canine Biology.
7.3% = the breed average COI for Weimaraners
What COI should I look for, in a litter?
Definitely a COI which is below the breed average. This is 7.3%, for Weimaraners.
The lower, the better.
A COI less than 5% is ideal, as explained in this article.
It’s important to point out that the Royal Kennel Club’s online COI calculator is not a great source for calculating COIs.
This is because any dog imported which is new blood for the UK, will have 0.0% COI. Even if they are inbred. As long as the dogs were outside the UK, they don’t exist to the UK KC. This greatly distorts many COIs and makes them appear much lower than they really are.
We need to use the international Weimaraner Pedigrees database to get a true COI. For Roche, this is just 0.08%. This COI is reflective of all the dogs behind her, no matter which countries they are from.
(Make a free account with Weimaraner Pedigrees to access full information. Select 10 generations from the drop down list and then the COI tab.)