Estimated breeding values

Estimated Breeding Values (EBVs) are a resource that has been commonly used in livestock breeding for many years. An EBV is a calculation (normally based on phenotypic or clinical data) that estimates the genetic risk of complex inherited diseases. Recently, EBVs have been developed for a number of conditions in the dog, particularly for hip and elbow dysplasia. Using EBVs to make mating decisions is more accurate than using the observed clinical data, or “score”, and will lead to faster progress in reducing the prevalence of disease.

Within the UK, The Kennel Club has developed Estimated Breeding Values (EBVs) for hip and elbow dysplasia across a number of breeds. These EBVs utilize the data generated from the BVA/KC hip and elbow scheme, and are freely available for Kennel Club registered dogs (where an EBV is in place). These EBVs indicate the genetic risk of hip/elbow dysplasia for individual dogs relative to the entire breed. Owners can use the EBVs to determine which breeding animals have a higher or lower genetic risk than breed average, and more accurately indicate any genetic risks to offspring/progeny. In the US, EBVs have been developed from Orthopedic Foundation for Animals (OFA) hip and elbow scores.

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Currently, there are EBVs freely available for Kennel Club registered dogs, for hip and elbow dysplasia across most medium/large breeds. The EBVs available in terms of diseases and breeds are expected to increase over time as more data becomes available. EBVs can, in theory, be developed for any complex inherited disease, where there is suitable clinical data and pedigree or lineage information. It would not be unreasonable to expect more EBVs for more conditions to be developed over the next few years.

Outside of the UK, there are a number of international Kennel Clubs that provide EBVs for some diseases, but access and types are variable.

Where a dog is not Kennel Club registered, or does not otherwise have access to EBVs, the calculations and clinical data required to generate EBVs normally requires the involvement of a quantitative geneticist and large pedigree datasets.

An EBV estimates the genetic risk of a complex inherited disease, allowing owners to select the lower/lowest risk dogs for breeding. As the EBVs are a more precise indication of the genetic risk than clinical data/”scores” alone, they allow greater flexibility in choosing suitable mates – making it easier to balance all of the qualities of a dog. The owner doesn’t necessarily have to seek out the very lowest EBVs to see improvement over their lines and/or the breed as a whole.

Without a consistent stream of clinical data from recognized schemes such as the BVA/KC hip and elbow scheme, it is not possible to maintain accuracy (confidence) in the EBV. In addition, the EBV cannot indicate precisely to what degree, if any, a dog will go on to develop a disease, as environmental effects impact severity and age of onset. Clinical data is vital to understanding the impact (or not) of a disease on an individual dog and to guide management. For example, even with a low risk EBV, a high hip score at a young age might allow more effective management of feeding/exercise, etc to mitigate the risks of developing osteoarthritis.

For those breeds without an EBV, it is especially important to continue to screen, as when sufficient data is available, new EBVs can be created. The volume of data needed to calculate an EBV varies depending on the breed and condition.

For Kennel Club (UK) registered dogs, and general information, go to: http://www.thekennelclub.org.uk/services/public/mateselect/ebv/Default.aspx

Detailed information for clients is available at: https://www.thekennelclub.org.uk/health-and-dog-care/health/getting-started-with-health-testing-and-screening/estimated-breeding-values/

USA: information can be found at: vet.cornell.edu/health-topics/estimated-breeding-values-ebvs