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By Ann MilliganKatariina Mäki
Academic dissertation -- 2004
By Ann MilliganARTICLE: Frequency of canine hip and elbow dysplasia decreasing in Finland
Original source: The Finnish Kennel Club
Excerpt: "Genetic trends for hip and elbow dysplasia were assessed for the dogs born during the years 1993-2012. In hip dysplasia, the largest improvement can be seen in the Saint Bernard, the Smooth Collie, the Newfoundlander, the Beauceron and the Bordercollie. In elbow dysplasia, the Rottweiler and the St.Bernard have improved the most.
Genetic trends for hip and elbow dysplasia were assessed from the mean EBVs of the dogs born during the years 1993-2012. EBVs are being estimated for about 55 breeds in the Finnish Kennel Club, and these breeds were included in the assessment. Improvement in the mean EBVs was proportioned to the phenotypic screening results (Tables 1 and 3). A change of one point means that the breed average has moved one letter (hip dysplasia) or number (elbow dysplasia) to either a better or a worse direction."
Comparative analyses of genetic trends and prospects for selection against hip and elbow dysplasia in 15 UK dog breeds
By Ann MilliganAuthors: Thomas W Lewis, Sarah C Blott and John A Woolliams
excerpts from the abstract...
"This study aimed to both determine recent genetic trends in hip and elbow dysplasia, and evaluate the potential improvements in response to selection that publication of EBV for such diseases would provide, across a wide range of pure-bred dog breeds."
"EBV are shown to be both more accurate and abundant than phenotype, providing more reliable information on the genetic risk of disease for a greater proportion of the population. Because the accuracy ofselection is directly related to genetic progress, use of EBV can be expected to benefit selection for the improvement of canine health and welfare. Public availability of EBV for hip score for the fifteen breeds included inthis study will provide information on the genetic risk of disease in nearly a third of all dogs annually registered by the UK Kennel Club, with in excess of a quarter having an EBV for elbow score as well."
Monitoring Hip and Elbow Dysplasia Achieved Modest Genetic Improvement of 74 Dog Breeds over 40 Years in USA
By Ann MilliganAuthors: Yali Hou1,2., Yachun Wang1., Xuemei Lu2., Xu Zhang1, Qian Zhao3, Rory J. Todhunter4*, Zhiwu Zhang3,5*
"Hip (HD) and Elbow Dysplasia (ED) are two common complex developmental disorders of dogs. In order to decrease their prevalence and severity, the Orthopedic Foundation for Animals (OFA) has a voluntary registry of canine hip and elbow conformation certified by boarded radiologists. However, the voluntarily reports have been severely biased against exposing dogs with problems, especially at beginning period. Fluctuated by additional influential factors such as age, the published raw scores barely showed trends of improvement. In this study, we used multiple-trait mixed model to simultaneously adjust these factors and incorporate pedigree to derive Estimated Breeding Values (EBV). A total of 1,264,422 dogs from 74 breeds were evaluated for EBVs from 760,455 hip scores and 135,409 elbow scores. These EBVs have substantially recovered the reporting bias and the other influences. Clear and steady trends of genetic improvement were observed over the 40 years since 1970. The total genetic improvements were 16.4% and 1.1% of the phenotypic standard deviation for HD and ED, respectively. The incidences of dysplasia were 0.83% and 2.08%, and the heritabilities were estimated as 0.22 and 0.17 for hip and elbow scores, respectively. The genetic correlation between them was 0.12. We conclude that EBV is more effective than reporting raw phenotype. The weak genetic correlation suggested that selection based on hip scores would also slightly improve elbow scores but it is necessary to allocate effort toward improvement of elbow scores alone."