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Fikse W.F.,Swedish University of Agricultural Sciences | Malm S.,Swedish Kennel Club | Lewis T.W.,Kennel Club Genetics Center at the Animal Health Trust
Veterinary Journal | Year: 2013

Pooling of pedigree and phenotype data from different countries may improve the accuracy of derived indicators of both genetic diversity and genetic merit of traits of interest. This study demonstrates significant migration of individuals of four pedigree dog breeds between Sweden and the United Kingdom. Correlations of estimates of genetic merit (estimated breeding values, EBVs) for the Fédération Cynologique Internationale and the British Veterinary Association and Kennel Club evaluations of hip dysplasia (HD) were strong and favourable, indicating that both scoring schemes capture substantially the same genetic trait. Therefore pooled use of phenotypic data on hip dysplasia would be expected to improve the accuracy of EBV for HD in both countries due to increased sample data. © 2013. Source

Lewis T.W.,Kennel Club Genetics Center at the Animal Health Trust | Blott S.C.,Kennel Club Genetics Center at the Animal Health Trust | Woolliams J.A.,Roslin Institute
PLoS ONE | Year: 2010

Hip dysplasia is an important and complex genetic disease in dogs with both genetic and environmental influences. Since the osteoarthritis that develops is irreversible the only way to improve welfare, through reducing the prevalence, is through genetic selection. This study aimed to evaluate the progress of selection against hip dysplasia, to quantify potential improvements in the response to selection via use of genetic information and increases in selection intensity, and to prepare for public provision of estimated breeding values (EBV) for hip dysplasia in the UK. Data consisted of 25,243 single records of hip scores of Labrador Retrievers between one and four years old, from radiographs evaluated between 2000 and 2007 as part of the British Veterinary Association (BVA) hip score scheme. A natural logarithm transformation was applied to improve normality and linear mixed models were evaluated using ASREML. Genetic correlations between left and right scores, and total hip scores at one, two and three years of age were found to be close to one, endorsing analysis of total hip score in dogs aged one to three as an appropriate approach. A heritability of 0.3560±016 and small but significant litter effect (0.0760±009) were estimated. The observed trends in both mean hip score and mean EBV over year of birth indicate that a small genetic improvement has been taking place, approximately equivalent to avoiding those dogs with the worst 15% of scores. Deterministic analysis supported by simulations showed that a 19% greater response could be achieved using EBV compared to phenotype through increases in accuracy alone. This study establishes that consistent but slow genetic improvement in the hip score of UK Labrador Retrievers has been achieved over the previous decade, and demonstrates that progress may be easily enhanced through the use of EBVs and more intense selection. ©2010 Lewis et al. Source

Woolliams J.A.,Roslin Institute | Lewis T.W.,Kennel Club Genetics Center at the Animal Health Trust | Blott S.C.,Kennel Club Genetics Center at the Animal Health Trust
Veterinary Journal | Year: 2011

This paper examines the outcomes from recent genetic analyses of hip and elbow scores from British Veterinary Association (BVA)/UK Kennel Club (KC) screening programmes targeted at reducing the prevalence of hip dysplasia (HD) and elbow dysplasia in UK Labrador retrievers. The analyses made use of 25,243 hip scores and 3613 elbow scores. Heritabilities (± standard error) for hip score, analysed on a log scale, and for elbow score were 0.35 ± 0.02 and 0.19 ± 0.04, respectively, with a genetic correlation of 0.41 ± 0.09.For both hip and elbow scores, there was a near perfect genetic correlation between the left and right joint; analysis of hip score showed a predictive benefit of using the total of left and right scores rather than worst score and the benefit of using all component scores rather than their aggregate score. 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. There are major opportunities for improving selection against elbow dysplasia through the use of bivariate evaluations, although progress against dysplasia would be improved by more widespread elbow scoring. The studies highlighted a number of ways in which data recording for addressing complex traits may be improved in the future. Ongoing advances in genomic technology may be utilised for increasing the rate of genetic progress in selection against HD and for complex diseases in general, through the use of genomic evaluations. © 2011. Source

Lewis T.W.,Kennel Club Genetics Center at the Animal Health Trust | Blott S.C.,Kennel Club Genetics Center at the Animal Health Trust | Woolliams J.A.,Roslin Institute
BMC Genetics | Year: 2013

Background: Hip dysplasia remains one of the most serious hereditary diseases occurring in dogs despite long-standing evaluation schemes designed to aid selection for healthy joints. Many researchers have recommended the use of estimated breeding values (EBV) to improve the rate of genetic progress from selection against hip and elbow dysplasia (another common developmental orthopaedic disorder), but few have empirically quantified the benefits of their use. 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.Results: The genetic trend with respect to hip and elbow condition due to phenotypic selection had improved in all breeds, except the Siberian Husky. However, derived selection intensities are extremely weak, equivalent to excluding less than a maximum of 18% of the highest risk animals from breeding. EBV for hip and elbow score were predicted to be on average between 1.16 and 1.34 times more accurate than selection on individual or both parental phenotypes. Additionally, compared to the proportion of juvenile animals with both parental phenotypes, the proportion with EBV of a greater accuracy than selection on such phenotypes increased by up to 3-fold for hip score and up to 13-fold for elbow score.Conclusions: 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 of selection 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 in this 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. © 2013 Lewis et al; licensee BioMed Central Ltd. Source

Lewis T.W.,Kennel Club Genetics Center at the Animal Health Trust | Woolliams J.A.,Roslin Institute | Blott S.C.,Kennel Club Genetics Center at the Animal Health Trust
Animal Welfare | Year: 2010

One option for improving the welfare of purebred dog breeds is to implement health breeding programmes, which allow selection to be directed against known diseases while controlling the rate of inbreeding to a minimal level in order to maintain the long-term health of the breed. The aim of this study is to evaluate the predicted impact of selection against disease in two breeds: the Cavalier King Charles spaniel (CKCS) and the Labrador Retriever. Heritabilities for mitral valve disease, syringomyelia in the CKCS and hip dysplasia in the Labrador were estimated to be 0.64 (± 0.07), 0.32 (± 0.125) and 0.35 (± 0.016), respectively, which suggest encouraging selection responses are feasible based upon the estimation of breeding values (EBVs) if monitoring schemes are maintained for these breeds. Although using data from disease databases can introduce problems due to bias, as a result of individuals and families with disease usually being over-represented, the data presented is a step forward in providing information on risk. EBVs will allow breeders to distinguish between potential parents of high and low risk, after removing the influence of life history events. Analysis of current population structure, including numbers of dogs used for breeding, average kinship and average inbreeding provides a basis from which to compare breeding strategies. Predictions can then be made about the number of generations it will take to eradicate disease, the number of affected individuals that will be born during the course of selective breeding and the benefits that can be obtained by using optimisation to constrain inbreeding to a pre-defined sustainable rate. © 2010 Universities Federation for Animal Welfare The Old School. Source

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