Table 1.
Percent of dogs within breed and generation class classified by degree of hip dysplasia, as reflected by the hip-extended score.
Fig 1.
Genetic change in hip extended score across 11 generations of selection in German Shepherd Dogs.
Fig 2.
Genetic change in hip extended score across 10 generations of selection in Labrador Retrievers.
Fig 3.
Genetic change in hip extended score across 8 generations of selection in Golden Retrievers.
Table 2.
Summary statistics describing distraction index values observed among three dog breeds, stratified by generation class.
Fig 4.
PennHIP distraction index values summarized by generation class for German Shepherd Dogs.
Fig 5.
PennHIP distraction index values summarized by sex within generation class for German Shepherd Dogs.
Fig 6.
PennHIP distraction index values summarized across 11 generation classes for Labrador Retrievers.
Fig 7.
PennHIP distraction index values summarized by sex within generation class for Labrador Retrievers.
Fig 8.
PennHIP distraction index values summarized across 9 generation classes for Golden Retrievers.
Fig 9.
PennHIP distraction index values summarized by sex within generation class for Golden Retrievers.
Table 3.
Estimates of genetic and residual variances and heritability of both the hip extended score and PennHIP distraction index observed in 3 breeds of guide dogs.
Also shown are estimates of genetic correlation between these two phenotypes.
Fig 10.
Distribution of DI values observed among dogs given each HESC.
All dogs are shown in panel A, GSD are in panel B, LR are in panel C, and GR are in panel D.
Table 4.
Expected correlated response in DI based upon direct selection on HES.
Table 5.
Selection differentials by generation class for PennHIP DI measured in 3 breeds of guide dogs.
In early generation classes, the selection criterion for hip quality was based on HES. Both HES and DI were considered in the mid-range of generation classes, while only DI was considered in the latter generations.
Fig 11.
Distributions of DI values as a function of HESC class among dogs born into the latter generation classes.
GSD’s born into generation 9 and later are in Panel B; LR’s born into generation 8 and later are in Panel C; and Golden Retrievers born into generation 7 and later are in Panel D.
Fig 12.
Scatterplot of estimated breeding values for PennHIP DI versus each dog’s own observed PennHIP DI value.
All dogs in the study are shown in Panel A. Within breeds are shown in Panel B for GSD, C for LR, and D for GR.