Our inbreeding calculators give you a percentage score. The lower the percentage, the lower the degree of inbreeding.
To put your result into perspective:
- 0% = a dog with two apparently unrelated parents (based on all available pedigree information)
- 12.5% = the genetic equivalent of a dog produced from a grandfather to granddaughter mating, or the mating of a half-brother/sister
- 25% = the genetic equivalent of a dog produced from a father to daughter mating, or the mating of full-brother/sister
- More than 25% = inbreeding is accumulative, so if it has occurred to a significant degree over several generations, the inbreeding coefficient may be greater than 25%
Results for individual dogs
In general the lower the result, the lower the risk of this dog having health issues. It's important to remember that these results are a measure of risk, rather than a direct measure of health. An individual's result should not be taken into consideration when selecting a dog for mating, instead it's the mating inbreeding coefficient that should be used, as this examines and compares both dogs' pedigrees.
- When choosing a mate for your dog, remember that it's the result for the two dogs that matters, not their individual results
- Where possible you should produce puppies with an inbreeding coefficient which is at, or lower than, the annual breed average for the breed, and ideally as low as possible. This average is shown to you each time you use our calculators
- In general the lower the result, the lower the risk of the puppies having health issues
- It's important to remember that these results are a measure of risk, rather than a direct measure of health. It is possible that two closely related dogs do not have the same disease-causing gene mutations, while two seemingly unrelated dogs do - it's all down to chance
Always check the number of generations
Always check to see how many generations have been used for the calculation. If only three generations are fully complete, you may wish to use these results with care. If additional pedigree information or inbreeding resources are available to you, you may wish to consult these.
For dogs that have been imported, we may only have a three-generation pedigree, so it may be difficult for us to calculate an informative COI.
The consequence of high levels of inbreeding
High levels of inbreeding can affect the health of the puppies you produce, but it is difficult to predict what this impact may be. In general, we do know that the higher the degree of inbreeding, the higher the risk is of puppies developing both known and unknown inherited disorders. Inbreeding can also have an impact on the breed as a whole, e.g. reducing litter sizes and fertility. Find out more about the impact inbreeding can have on individual dogs or a breed as a whole.
Making balanced breeding decisions
As well as considering the implications of a dog’s inbreeding coefficient, there are other equally important factors to consider when deciding whether two dogs should be mated together, such as temperament, genetic diversity, conformation, other available health test results, the general health of the dogs etc. Your breeding decisions should always be well balanced and take into consideration the qualities and compatibility of both the sire and dam that you are considering.
How is the breed average calculated?
Each CoI calculation is accompanied by a breed average. This number helps you compare any potential matings to the average of the breed’s current population and puts that CoI into perspective.
This breed average is calculated each June. First, we calculate the CoI of all dogs in the breed using all available electronically held pedigree information. We then calculate the average of those CoIs for the dogs that were registered with The Kennel Club born in the UK during the previous year. Comparing the CoIs of a litter you may be planning to the current breeding population is a more effective way of reducing inbreeding than by comparing it to an average of both living and historic dogs.
The CoIs of historic dogs born many years ago may be generally higher than the current breed average. This suggests that inbreeding levels in the breed as a whole are decreasing. It is possible that the CoIs for some of those historic dogs, although higher than the current breed average, may have fallen below the average of dogs living at the time and could have met with breeding guidance given.
In smaller breeds, if no dogs have been born in that year, the breed average will default to the last year in which a calculation could be performed. In breeds where there is no available breed average data for the past five years, the annual breed average will display as N/A. This may include breeds where no dogs have been born in the UK for five years or more, or some newly recognised breeds.
Where can I find out more about inbreeding?
Read more about inbreeding.