The elbow dysplasia scores were determined by two genetically different traits. The possibilities for selecting German shepherd dogs with respect to elbow dysplasia might be improved by taking into account these two traits in the prediction of breeding values.

Complex segregation analyses were carried out to clarify the mode of inheritance of canine hip dysplasia (CHD) in German shepherd dogs. Data were used from 8,567 animals examined for CHD from 20 families with three to four generations. The existence of a major gene in addition to polygenic gene effects was detected. In the present study, a mixed model with a dominant major gene effect seemed to be most probable for dichotomous encoding (0: dogs without signs of CHD; 1: dogs with borderline/slight to severe CHD). In addition, mixed major gene inheritance was shown for a binary trait where borderline was assigned to dogs scored free from CHD and for a trichotomously encoded trait (0: dogs without signs of CHD; 1: borderline CHD; 2: mild to severe CHD). Although only small frequencies were found for the unfavorable homozygotic genotype AA, the probability of the AB genotype was high in affected animals. Selection schemes to reduce the frequency of the allele A should therefore efficiently improve existing breeding programmes in German shepherd dogs.

Elbow angles were measured in X-rays of both elbows to elucidate the usefulness of such data for selecting against elbow dysplasia (ED) in German shepherd dogs. These measurements record the size, proportions and alignments of the anconeal process (PA), the radius (RA), the olecranon (OL), and the ulnar trochlear notch (UL). The reference system for evaluating the information content of the measurements was the score for ED (ED-SV) as recommended by the International Elbow Working Group. Data from 2645 X-rayed dogs born from 1998 to 2001 in 1331 kennels were analysed by using residual maximum likelihood procedures to estimate heritabilities, additive genetic correlations and residual correlations. The pedigree file included 11,426 dogs and contained ancestors for up to six generations. ED-SV was significantly influenced by sex, by age within sex and by month of birth. The elbow angles were significantly influenced by the month and year of birth, X-ray positioning of the dog's forelimbs, angle of elbow flection, litter size and number of dogs X-rayed by the veterinary practitioners. The following heritability estimates were found: h2=0.18+/-0.04 for ED; h2=0.76+/-0.04 for OL; h2=0.52+/-0.05 for PA; h2=0.50+/-0.04 for UL; and h2=0.39+/-0.04 for RA. The additive genetic correlations of ED-SV with three elbow angles (OL, UL and RA) were close to zero. A higher additive genetic correlation to ED-SV was found only for PA, for which r(g)=0.31. The distributions of predicted breeding values for susceptibility to ED were not affected by regarding the elbow angles as additional traits in the multivariate prediction procedure. Measurements of elbow angles were thus shown to be unsuitable for use in selection programmes against ED in German shepherd dogs.