Canine hip dysplasia in Irish water spaniels: Two decades of gradual improvement

Canine hip dysplasia (CHD) results from incorrect coxofemoral joint development in dogs. Although CHD has been described in many breeds of dog, it is generally regarded as being associated with larger breeds. The breed-susceptibility of the condition prompted the suggestion that there may be genetic component associated with CHD, which has led to a number of investigations being undertaken to calculate heritability values for CHD in a range of breeds of dogs (eg, Wood and others 2000, Wood and others 2002, Lewis and others 2010). The values obtained reiterate the belief that CHD results from a combination of polygenic interactions, where each gene possibly makes variable contributions to the final phenotype (Wilson and others 2011). Various papers have resulted in different heritability scores for different breeds, for example, labrador retrievers (Wood and others 2002) and Gordon setters (Wood and others 2000); maternal versus paternal effects (Wood and others 2000); and some reporting symmetry of hip scores (Wilson and others 2011) and others a difference between left and right hips (eg, Tsai and others 2007). Hence, it is possible that there may be slight differences in the major causal genes/alleles in different breeds, and in order that a better understanding may be obtained for CHD generically, an argument could be made for individually studying as many breeds as possible. The current work makes a contribution to the understanding of this disorder by investigating hip dysplasia in the Irish water spaniel.