CANINE hip dysplasia (CHD) arises from incorrect coxofemoral joint development in dogs. CHD has been described in many dog breeds, but is generally considered a problem associated with larger breeds, suggesting CHD may have a genetic basis. This has resulted in several investigations into breed-specific studies (Wood and others, 2000, Lewis and others 2010) which have supported the hypothesis that CHD arises due to a combination of polygenic interactions (Wilson and others 2011). These have resulted in a variety of conclusions: differences in heritability scores between breeds, for example, labrador retrievers (Wood and others 2002) and Gordon setters (Wood and others 2000); reports of differences between left and right hips (Tsai and others 2007) with others reporting symmetry of hip scores (Wilson and others 2011) and differences in maternal versus paternal effects (Wood and others 2000). These differences between breeds suggest that there may be minor differences in the major causal genes/alleles in different breeds, meaning …