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. 2019 Feb 22;14(2):e0212544.
doi: 10.1371/journal.pone.0212544. eCollection 2019.

Genetic improvement of hip-extended scores in 3 breeds of guide dogs using estimated breeding values: Notable progress but more improvement is needed

Eldin A Leighton  1 , Dolores Holle  1 , Darryl N Biery  2 , Thomas P Gregor  2 , Mischa B McDonald-Lynch  2 , Mandy L Wallace  2 , Jennifer K Reagan  2 , Gail K Smith  2
Affiliations

Genetic improvement of hip-extended scores in 3 breeds of guide dogs using estimated breeding values: Notable progress but more improvement is needed

Eldin A Leighton et al. PLoS One. .

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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Conflict of interest statement

Most of the data collection for this publication occurred while PennHIP was a not-for-profit service wholly owned and operated by the University of Pennsylvania. In December, 2013 PennHIP was acquired by Antech Imaging Services of Fountain Valley, CA, United States of America. Antech Imaging Services is a segment of VCAAntech, which was purchased in 2018 by Mars, Inc. Since 2013 PennHIP has been a for-profit diagnostic service available world-wide. Dr. Gail K. Smith is currently an employee of Antech Imaging Services, where he is the Director of AIS PennHIP. The Seeing Eye, Inc. is a not-for-profit charity with a focused mission to provide healthy, well-trained dogs to serve as guides for blind people. In pursuit of this mission, The Seeing Eye has, occasionally, funded targeted research in areas of canine health. One such project was to develop an improved, alternative method for assessing hip quality in young dogs. Funding for much of this targeted research support was channeled through Morris Animal Foundation, who provides oversight and an established peer-review process for awarding research grants. Some of the funds dispensed by Morris Animal Foundation for developing the distraction index method originated with The Seeing Eye, Inc. During some of the years when this funding support was provided by The Seeing Eye, Drs. Eldin A. Leighton and Dolores Holle were employed by The Seeing Eye and participated in the decision-making process that led to this funding support. After the PennHIP program was established as a service provided by the University of Pennsylvania and later by AIS, The Seeing Eye was a consumer of the service, obtaining PennHIP scores on thousands of dogs under contract with the University of Pennsylvania and later with AIS. The Seeing Eye holds no patents or income producing interest in PennHIP. Our disclosure of these relationships is intended to provide transparency to our readers. Furthermore, these relationships do not alter our adherence to PLOS ONE policies on sharing data and materials.

Figures

Fig 1
Fig 1. Genetic change in hip extended score across 11 generations of selection in German Shepherd Dogs.
Fig 2
Fig 2. Genetic change in hip extended score across 10 generations of selection in Labrador Retrievers.
Fig 3
Fig 3. Genetic change in hip extended score across 8 generations of selection in Golden Retrievers.
Fig 4
Fig 4. PennHIP distraction index values summarized by generation class for German Shepherd Dogs.
Fig 5
Fig 5. PennHIP distraction index values summarized by sex within generation class for German Shepherd Dogs.
Fig 6
Fig 6. PennHIP distraction index values summarized across 11 generation classes for Labrador Retrievers.
Fig 7
Fig 7. PennHIP distraction index values summarized by sex within generation class for Labrador Retrievers.
Fig 8
Fig 8. PennHIP distraction index values summarized across 9 generation classes for Golden Retrievers.
Fig 9
Fig 9. PennHIP distraction index values summarized by sex within generation class for Golden Retrievers.
Fig 10
Fig 10. Distribution of DI values observed among dogs given each HESC.
All dogs are shown in panel A, GSD are in panel B, LR are in panel C, and GR are in panel D.
Fig 11
Fig 11. Distributions of DI values as a function of HESC class among dogs born into the latter generation classes.
GSD’s born into generation 9 and later are in Panel B; LR’s born into generation 8 and later are in Panel C; and Golden Retrievers born into generation 7 and later are in Panel D.
Fig 12
Fig 12. Scatterplot of estimated breeding values for PennHIP DI versus each dog’s own observed PennHIP DI value.
All dogs in the study are shown in Panel A. Within breeds are shown in Panel B for GSD, C for LR, and D for GR.
See this image and copyright information in PMC

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References

    1. Johnson JA, Austin C, Breur GJ. Incidence of canine appendicular musculoskeletal disorders in 16 veterinary teaching hospitals from 1980 through 1989. Veterinary and Comparative Orthopaedics and Traumatology. 1994; 7: p. 56–69.
    1. Mateescu RG, Burton-Wurster NI, Tsai K, Phavaphutanon J, Zhang Z, Murphy KG, et al. Identification of quantitative trait loci for osteoarthritis of hip joints in dogs. American Journal of Veterinary Research. 2008; 69(10): p. 1294–1300. 10.2460/ajvr.69.10.1294 - DOI - PubMed
    1. Zhou Z, Sheng X, Zhang Z, Zhao K, Zhu L, Guo G, et al. Differential Genetic Regulation of Canine Hip Dysplasia and Osteoorthritis. PLoS One. 2010. October 11; 5(10): p. e13219 - PMC - PubMed
    1. Soo M, Worth AJ. Canine hip dysplasia: phenotypic scoring and the role of estimated breeding value analysis. New Zealand Veterinary Journal. 2015. March 1; 63(2): p. 69–78. 10.1080/00480169.2014.949893 - DOI - PubMed
    1. Breur GJ, Lust G, Todhunter RJ. Genetics of Canine Hip Dysplasia and Other Orthopaedic Traits In Ruvinsky A, Sampson J. The Genetics of the Dog. New York: CABI Publishing; 2001.

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