Estimated Breeding Values
Pedigree information and population-wide data on disease, such as that collected for the British Veterinary Association/Kennel Club (BVA/KC) health screening schemes, are analysed using advanced statistical techniques to calculate the extent to which a disease is genetic (its heritability) and this information is used to determine the Estimated Breeding Values (EBV) of individual dogs. Complex diseases, such as hip dysplasia, are caused by a combination of genetic and environmental effects. EBVs are an objective numerical assessment of the genetic status of an individual dog, with environmental effects removed. Using EBVs will allow breeders to distinguish between dogs of high and low genetic risk when selecting parents.
EBVs can be obtained for all dogs in a breed, in the first instance this will be all KC registered dogs of that breed. They can be calculated for most dogs even if they have not been health screened themselves, as long as they are related to enough dogs that have been screened. The EBV of the puppies at birth will be half the EBV of their sire plus half the EBV of their dam. A puppy’s EBV may be modified in the light of its own subsequent clinical record or screening results, by information coming from other relatives and eventually by information from its progeny.
EBVs for hip score are available for the following 15 breeds through the Kennel Club’s Mate Select. EBVs for elbow score are also available in the breeds marked with a *.
|Bearded Collie||Labrador Retriever*|
|Bernese Mountain Dog*||Newfoundland|
|Border Collie||Rhodesian Ridgeback|
|Flat Coat Retriever||Siberian Husky|
|German Shepherd Dog*||Tibetan Terrier|
EBVs could be produced for many different conditions and breeds. However, it is important to consider the type of data that is required. There must be minimal bias in the data: affected and unaffected diagnoses must be equally likely to be submitted to the database. Mechanisms must be in place to allow routine and regular updating of the database.
The disease diagnosis or phenotypic evaluation must be consistent and provided by a person trained in the diagnosis or evaluation of the condition. Quantitative measurement is preferred, if appropriate, rather than a simple affected/unaffected status.
Finally, a reasonable proportion of the population must be measured to ensure that the resulting EBVs have a sufficient level of accuracy to be useful to breeders.