Estimation Of Population Genetic Parameters And Breeding Values For Elbow Dysplasia In Rottweilers

We analysed scores of elbow dysplasia following the IEWG protocol from the official screening programme of the Allgemeiner Deutscher Rottweiler Club (ADRK). The data set included X-rays from 5100 Rottweiler dogs born between 1995 and 2004. Out of these 5,100 dogs, 46.9% were free from ED, 9.8% showed borderline signs (ED-UG), 31.8% ED-grade 1 (mild ED), 10% ED-grade 2 (moderate ED) und 1.6% ED-grade 3 (severe ED). Male dogs were more often affected by ED-grade 2 and 3 than female dogs. Traits analysed were ED-grade (dogs free from ED and dogs with ED-grades 1 to 3) and borderline ED (ED-UG). Birth year, birth season and inbreeding coefficient were significant for ED-grade. Higher inbreeding coefficients were associated with higher ED scores. ED-UG was significantly influenced by birth year and the interaction of birth year and birth season. A bivariate linear animal model was employed to estimate heritabilities using Residual Maximum Likelihood (REML) for ED-grade and ED-UG. Heritability estimates and their standard errors were 0.387 +/- 0.028 for ED-grade and 0.017 +/- 0.009 for ED-UG. The additive genetic correlation between ED-grade and ED-UG was -0.5. Heritabilities for ED-grade in female and male dogs were 0.350 +/- 0.033 and 0.497 +/- 0.047. We do not recommend use of ED-UG in breeding work because of the low heritability estimate and the negative additive genetic correlation with ED-grade.