HD Zuchtwert - Breed Value Assessment Number
The best tool for breeders in the fight against canine hip dysplasia (CHD), to come along in years, is the SV's HD Zuchtwert, or Breed value assessment number (HD ZW). The HD ZW number is an estimation of the probability that a dog will produce progeny with CHD.
On 5 February 2000, representatives of the WUSV and the responsible HD evaluation officials met in Viernheim to consult over possibilities for a common Breed Value Assessment. Since various nations' issue official HD classes based (grounded) on differing claims, a standard needed to be devised to guarantee the comparison through controlled interpretation/evaluation/analysis and technical measurements of the x-ray film. For that purpose, the SV measured about 900 films. In conjunction with this international standardization, the SV found it necessary (they changed from using) to no longer set the the BREED Average (Cross-section of the Breed = starting figure of 100) as the reference basis, but instead to select a constant' figure (measure) as the reference point.
On 8 April 2000, the Breed Advisory expressed the recommendation to set the
The Breeding Plan of the SV is reworded in §2 accordingly.
The committees were of one opinion that, in setting restrictions on the permissible pairings, no adjustments are necessary at the present.....breeders
will be responsible for, and relied upon to, supply the appropriate information to other breeders.
The Breed Value Assessment itself has not changed. The HD (Breed) values are calculated as before, apart from the fact that new data will be updated quarterly. In a second step, the existing heritability numbers will be converted into a relative calculation whereby the BREED average (cross-section of the Breed = 1.70) will no longer be used, but rather the heritability factor of the fictional' GSD with fast normal' hips (2.0) will be set as the reference point (=100).
Online database for GSD HD values (schaferhund.de)