POPULATION GENETIC-ASPECTS OF HIP-DYSPLAS IA (HD)-DIAGNOSTICS IN DOGS- EVALUATION UNDER CONSIDERATION OF DIFFERING HD-FINDINGS

The present study investigates the repeatability of HD-findings based on the correspondence between three different examiners in 449 beagles . Two of the experts have long time experience in HD-findings, the thi rd was an inexperienced beginner. Further, the correlation between tho se criteria, the HD-finding is based on, was calculated. Based on the similarity of paternal half sibs the heritability of each of the singl e criteria and of the HD-finding was estimated. In single cases the HD -findings of the three examiners show great differences concerning the same dog, nevertheless concerning the whole population a significant repeatability of the HD-findings as well as of the single criteria cou ld be established. A significant correlation of the single criteria mu tually as well as with the HD-finding was found. Concerning the practi cal breeding work especially the correlation between the Norberg-Olsso n-angle and the other HD-criteria seems remarkable. Concerning the est imated heritability values a distinct difference between the unexperie nced and the experienced examiners was found. In the first case they a ltogether showed lower values. This points out that the unexperienced examiner has investigated a smaller part of the real genetic variance. Selection based on his HD-findings therefore would result in smaller breeding efficiency. This result points to the necessity of a central evaluation of X-ray pictures concerning HD-selection.