A review of the progress in canine hip dysplasia control in Britain.

Results of the British Veterinary Association/Kennel Club program for controlling canine hip dysplasia (CHD) were reviewed for 6 breeds to determine whether there had been any progress in reducing the prevalence of CHD. Although there was a decrease in mean hip dysplasia score for some of the 6 breeds when results for the 1991 to 1995 period were compared with those for 1987 to 1990, there were not any consistent trends in 5 of the breeds, and there was a clear worsening of the mean hip score in Siberian Huskies. In general terms, not only has there been a steady increase in the percentage of parents that were scored or, more accurately, an increase in the use of scored parents when breeding, but in broad terms the weighted mean score for the parents was lower (ie, better) than the mean score for all dogs in the breed during each period. In all breeds, there appeared to have been some selection to reduce total hip score, but in all but 1 instance, the expected result was not achieved, with actual values being higher (ie, worse) than those expected from theory. If the incidence of CHD is to diminish in Britain, then, as a first step, the Kennel Club must insist that, in affected breeds, only progeny of scored parents may be registered. Thereafter, a gradual tightening of the parental scores that will be accepted in each breed should be attempted, and best linear unbiased predictor-type indices should be established and applied to sires and dams to ensure wider usage of the better parents.