SPONDYLOSIS DEFORMANS IN THE BOXER - ESTIMATES OF HERITABILITY

This study presents the estimates of heritability for spondylosis defo rmans in the boxer based on 353 offspring from 24 randomly selected si res, each with at least three radiographically investigated offspring. The: estimated heritability (h(2)) for maximum degree of osteophyte d evelopment was high, both when estimated by paternal half-sib correlat ion (0.42) and by the regression of offspring based on the parents (0. 62). The heritability for the number of affected discs estimated by pa ternal half-sib correlation was also high (0.47). The estimate of heri tability for the number of affected discs based on regression of offsp ring on the parents was lower at 0.13. All heritabilities had large st andard errors. A positive phenotypic correlation between spondylosis d eformans and hip dysplasia was observed. Assuming a significant portio n of the correlation is genetic, this fact may permit selection agains t spondylosis deformans without negatively influencing the incidence o f hip dysplasia. Since the incidence of spondylosis deformans is high even in young dogs,it should be possible to detect a large proportion of genetically predisposed animals by radiographic examination of the spine at one year of age; at the same time that dogs are presented for a routine test for hip dysplasia.