Peer-reviewed veterinary case report
Genetic progress in hip scores of German Shepherds Labradors
By Leighton, Eldin A et al.·Published in PloS one·2019·The Seeing Eye, United States·View original on PubMed →
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Original publication title: Genetic improvement of hip-extended scores in 3 breeds of guide dogs using estimated breeding values: Notable progress but more improvement is needed.
- Species:
- dog
Plain-English summary
A study looked at hip quality in guide dogs, specifically German Shepherds, Labrador Retrievers, and Golden Retrievers, to see how breeding could improve their hip scores. The researchers found that while many dogs received excellent scores after several generations of selective breeding, a significant number still showed signs of hip joint looseness, which can lead to arthritis as they age. This means that even dogs with good hip scores might still be at risk for hip dysplasia. To truly improve hip health, breeders may need to focus more on reducing joint laxity in addition to just the hip scores.
People also search for: guide dog hip dysplasia · Labrador Retriever hip problems · Golden Retriever joint health · German Shepherd breeding hip scores
Abstract
Two hip quality phenotypes-a hip-extended score assigned by a board certified radiologist and the PennHIP distraction index-were analyzed to estimate genetic parameters and to calculate estimated breeding values used for selecting replacement breeders. Radiographs obtained at 12-18 months of age were available on 5,201 German Shepherd Dogs, 4,987 Labrador Retrievers and 2,308 Golden Retrievers. Obtained by fitting a two-trait model using Bayesian techniques, estimates of heritability for the hip-extended score were 0.76, 0.72, and 0.41 in German Shepherd Dogs, Labrador Retrievers, and Golden Retrievers, respectively, while estimated heritabilities for distraction index were 0.60, 0.66 and 0.59, respectively. Genetic correlations between the two hip quality measures were -0.28 in German Shepherd Dogs, -0.21 in Labrador Retrievers, and -0.29 in Golden Retrievers. Genetic selection for improved hip quality based upon the hip extended score phenotype began in 1980. Among first generation puppies, 34% of 273 German Shepherd Dogs, 55% of 323 Labrador Retrievers, and 43% of 51 Golden Retrievers had an Excellent hip extended score. After 8 generations of selection, mostly based on estimated breeding values derived from the hip extended score, over 93% of 695 German Shepherd Dogs, 94% of 528 Labrador Retrievers, and 87% of 116 Golden Retrievers received an Excellent hip extended score. With respect to PennHIP distraction index values among these same dogs, median values were at or above 0.30 for all 3 breeds meaning that half or more of dogs possessing the Excellent hip-extended-score phenotype remained susceptible to developing the osteoarthritis of canine hip dysplasia. Genetic improvement of the hip-extended-view phenotype to its desired biological endpoint left a surprising proportion of dogs expressing sufficient joint laxity to place them in an osteoarthritis at-risk state as they age. Only by directly applying selection pressure to reduce distraction index was marked reduction in joint laxity noted.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/30794614/