Mark Billadeau Posted October 22, 2014 Report Share Posted October 22, 2014 Additional NEWER articles indicating radiographic selection of breeding stock has not been as effective as touted in the earlier studies. ************************************************************************************************************************ Selection against canine hip dysplasia: Success or failure? Bethany Wilson, Frank W. Nicholas, Peter C. Thomson The Veterinary Journal Volume 189, Issue 2, August 2011, Pages 160–168 Canine hip dysplasia (CHD) is a multifactorial skeletal disorder which is very common in pedigree dogs and represents a huge concern for canine welfare. Control schemes based on selective breeding have been in operation for decades. The aim of these schemes is to reduce the impact of CHD on canine welfare by selecting for reduced radiographic evidence of CHD pathology as assessed by a variety of phenotypes. There is less information regarding the genotypic correlation between these phenotypes and the impact of CHD on canine welfare. Although the phenotypes chosen as the basis for these control schemes have displayed heritable phenotypic variation in many studies, success in achieving improvement in the phenotypes has been mixed. ******************************************************************************************************************* Assessing the impact of genomic selection against hip dysplasia in the Labrador Retriever dog E. Sánchez-Molano1, J.A. Woolliams1, S.C. Blott2 and P. Wiener1, Journal of Animal Breeding and Genetics Volume 131, Issue 2, pages 134–145, April 2014 In general, reports on the response to current phenotypic selection schemes in several breeds showed mixed results, with a small improvement against the disease in some cases (Malm et al. 2008; Lewis et al. 2010) or no discernible improvement in others (Willis 1997; Leppanen & Saloniemi 1999). These results may be due to various factors, for example, no attempt is made to remove systematic environmental influences (e.g. age) from the raw phenotypes or to reduce random environmental variation by including information from relatives. ********************************************************************************************************************* Estimated Breeding Values for Canine Hip Dysplasia Radiographic Traits in a Cohort of Australian German Shepherd Dogs Bethany J. Wilson, Frank W. Nicholas, John W. James, Claire M. Wade, Peter C. Thomson PLOS October 29, 2013 Canine hip dysplasia (CHD) is a serious and common musculoskeletal disease of pedigree dogs and therefore represents both an important welfare concern and an imperative breeding priority. The typical heritability estimates for radiographic CHD traits suggest that the accuracy of breeding dog selection could be substantially improved by the use of estimated breeding values (EBVs) in place of selection based on phenotypes of individuals. ********************************************************************************************************************** Canine hip and elbow dysplasia in UK Labrador retrievers J.A. Woolliamsa, T.W. Lewisb, S.C. Blottb The Veterinary Journal Volume 189, Issue 2, August 2011, Pages 169–176 Downward genetic trends were observed in both hip and elbow scores, although the latter was consistent with it being correlated to response to genetic change in hip score. Estimated breeding values (EBVs) offered substantial benefits in accuracy and hence genetic progress when compared to the use of phenotypes for both hip and elbow scores. ************************************************************************************************************************* Diagnosis, genetic control and preventive management of canine hip dysplasia: A review M.M.D. Ginjaa, A.M. Silvestreb, J.M. Gonzalo-Ordenc, A.J.A. Ferreirad The Veterinary Journal Volume 184, Issue 3, June 2010, Pages 269–276 The diagnosis of HD may be used for the purpose of selecting breeding stock or to decide on the best treatment approach. Breeding programmes based on individual dog phenotypes have been ineffective and a selection procedure based on breeding value (BV) estimation is recommended. Quote Link to comment Share on other sites More sharing options...
Mark Billadeau Posted October 22, 2014 Report Share Posted October 22, 2014 Liz, What do you think is the rate of HD in working bred Border Collies? For the entire breed the OFA reports 7.9% for dogs born between 2006 and 2010. For reference the rate of congenital deafness in Border Collies (UK) is 2.4%. Mark Quote Link to comment Share on other sites More sharing options...
Eileen Stein Posted October 22, 2014 Report Share Posted October 22, 2014 The ABCA had a long running hip study (ca. 8 years) of working bred Border Collies with Cornell to compare a new (at the time) radiographic hip evaluation method called DLS to OFA and the Norberg angle. We ended with 60 dogs in the study where the hips were evaluated around 8-12 months and then just after 24 months. The problem with the data set is we had only 60 dogs AND that none of the dogs volunteered for the study by owners or breeders had abnormal hips. Hip studies take a long time (waiting for puppies to mature) and require a statistically large enough sampling of dogs (100s) with a wide range in hip quality (HD to perfect) in order to evaluate the predictive information of the method being evaluated. Mark, I may be remembering wrong, but late in that study didn't the PI request that we (ABCA) allow non-working dogs to be added, in an effort to get some affected dogs included in the study, but we felt that would defeat our purpose? Quote Link to comment Share on other sites More sharing options...
Mark Billadeau Posted October 22, 2014 Report Share Posted October 22, 2014 Eileen, you are correct about the request (which we did not allow). We also discussed including goose dogs, which we did not do. Quote Link to comment Share on other sites More sharing options...
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