QUESTION (b) Does PennHIP recommend that a longitudinal study be done in the English Shepherd breed to establish the age at which the English Shepherd’s DI score will not change?
Thus far, we only have a longitudinal study addressing correlations of DI over the 16 week to 2 year time period in German Shepherd dogs and Borzois. Ideally, it would be nice to have similar studies in each breed, but time and resources make this extremely difficult, if not impossible. More recent research from PennHIP and other laboratories have confirmed the data and conclusions from these early studies, making extrapolation from the German Shepherd breed to other breeds appear reasonable. Additionally, we know that hip dysplasia is a developmental disease, and thus it is expected that the best correlation of degree of hip laxity (DI) with later scores will occur after skeletal maturity (1 year of age in large breeds). As mentioned above, longitudinal studies are recommended, to establish the relationship of DI with the long-term outcome and development of DJD in each breed. This information is most important and useful in determination of true disease susceptibility rates and will allow us to evaluate improvement in hip status with the implementation of selective breeding.