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.

Genetic aspects of lens luxation in the Tibetan terrier.

Analyses were undertaken of 20 cases of lens luxation in British-bred Tibetan terriers, together with a further seven from Sweden. General proband segregation tests showed that the data were consistent with a simple autosomal recessive hypothesis (P = 0.152 +/- 0.0563). This was supported by high levels of inbreeding ranging from 0 to 24.3 per cent, with a mean of 14.3 per cent (SD 5.32 per cent). All affected cases traced back to one or more of three animals (born mid 1950s) on both sides of their pedigrees, all three being breed champions. Inclusion of data from repeat litters between presumed heterozygous animals gave a ratio of 25 lens luxation cases in 121 progeny, which again supported the same genetic theory. The age at onset (three to five years) mitigates against test mating of animals within the breed.