[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.