[Estimation of population genetic parameters for radiographical findings of elbow dsyplasia in the Labrador Retriever].
The aim of this study was the analysis of non-genetic and genetic factors influencing elbow dysplasia (ED) in a Labrador retriever population. We analysed scores of elbow dysplasia from the official screening programme of the Labrador Club Deutschland (LCD) following the protocol of the International Elbow Working Group. The data set included X-rays from 2931 Labrador retrievers. These dogs were born between 2000 and 2004 and originated from 834 litters and 315 kennels. The pedigree file contained 27 305 dogs pertaining to 20 generations. We analysed four different traits including ED-Mit as the averaged result of ED scores from both elbow joints, ED-Max as the higher score of both elbow joints and ED-links and ED-rechts as the ED score of left or right elbow joint. Animal models were employed to estimate heritabilities, additive genetic correlation and residual correlation using residual maximum likelihood (REML). Significant effects for all four ED-traits were gender, month of birth and inbreeding coefficient. The fixed effect of birth year showed only significant effects for ED-Mit and ED-rechts. Age at examination was not significant. Heritability estimates for ED-Mit were 0.12 +/- 0.03, for ED-Max 0.11 +/- 0.03 and 0.13 +/- 0.03 for ED-links as well as 0.07 +/- 0.02 for ED-rechts. Heritability for female dogs was 0.12 +/- 0.03 and 0.10 +/- 0.03 for male dogs. The additive genetic correlation between ED-links and ED-rechts was 1 and the residual correlation 0.64. The heritabilities for ED were low to moderate based on models employed here and taking this into consideration, selection response will be small when employing phenotypic ED scores from breeding animals as the sole selection criterion. Therefore, breeding programmes should be supported by breeding values as tools for selection of breeding dogs. There was no difference in heritabilities between the mean ED score of the joints or the ED score of the joint with the higher ED grade. Furthermore, either specific genetic effects from a body side or sex-specific genetic effects could be observed for the expression of ED. Dogs showing radiographic signs of ED or dogs having been submitted for a surgery due to clinical signs of ED have to be precluded from breeding. The veterinary practitioner can help to reduce the frequency of dogs exhibiting a genetic disposition to ED when the radiographs of the elbow joints of many as possible purebred dogs are submitted to the respective dog breeding associations.
Engler
Jennifer
J
Institut für Tierzucht und Vererbungsforschung, Stiftung Tierärztliche Hochschule Hannover.
Hamann
Henning
H
Distl
Ottmar
O
D000818:Animals; D001848:Bone Diseases, Developmental / Q000235:genetics / Q000662:veterinary*; D004283:Dog Diseases / Q000235:genetics*; D004285:Dogs / Q000235:genetics*; D004551:Elbow Joint / Q000000981:diagnostic imaging*; D005260:Female; D005552:Forelimb / Q000000981:diagnostic imaging; D005828:Genetics, Population; D008297:Male; D011859:Radiography