Health & Screening Explanations
What Is Coefficient of Inbreeding (CoI)?
The degree of inbreeding can be measured using a calculation called the coefficient of inbreeding (CoI), or inbreeding coefficient. The lower the degree of inbreeding, the lower the inbreeding coefficient.
The Kennel Club's inbreeding calculators give you a percentage score. The lower the percentage, the lower the degree of inbreeding. To put the 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%
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. Copyright The Kennel Club
What Are Estimated Breeding Values (EBVS)?
Estimated breeding values (EBVs) predict whether a dog is more or less likely to have, and pass on, genes related to a particular health problem. EBVs link information about a dog's family with data on whether they or their relatives have this health issue and to what degree. EBVs can then be used to tell us how an individual dog compares to the rest of the breed.
EBVs are a more effective way of reducing the risk of producing puppies with hip and elbow dysplasia than by only using the sire and dam's individual scores. These conditions are partly influenced by environmental factors and by better understanding a dog's risk it can lead to faster progress in reducing the prevalence of disease in the breed. Source: The Kennel Club
- Your dog's EBV score will always be calculated in relation to the breed average (which is always set at zero)
- Dogs with a higher than average risk of passing on genes for hip/elbow dysplasia will have an EBV higher than zero (i.e. a positive number, e.g 10). The higher the number the greater the risk
- Dogs with a lower than average genetic risk of hip/elbow dysplasia will have an EBV lower than zero (i.e. a negative number, e.g. -10). The lower the number, the less the risk
- A dog's EBV can change during its lifetime, either upward or downward, as more information becomes available, either about the dog itself or its relatives
- At birth a puppy’s EBV will be the average of its parents’ EBVs, e.g. a sire with an EBV of -5 and a dam with an EBV of +5 will produce a litter of puppies with an EBV of 0
- The confidence indicates how much scoring information has been used to calculate the EBV
- The more scoring information available, from the dog itself and/or its relatives, the more confident we are that the EBV is close to the actual genetic risk
- The confidence of the EBV can increase if more relatives are, or the dog itself is scored
- A dog with just its own hip score and no relatives scored, will have a confidence of about 60%
- A dog without its own hip score, but with the score of both parents, will have a confidence of around 40%
- A dog without its own hip score, but with only one parent scored, will have a confidence of around 30%