HIP & ELBOW DYSPLASIA
by Carol Beuchat PhD
Trends in EBVs (estimated breeding values) for Hip Dysplasia by breed
Data from -
Data from -
- Hou Y, Y Wang, X Lu, X Zhang, Q Zhao, RJ Todhunter, and Z Zhang 2013 Monitoring hip and elbow dysplasia achieved modest genetic improvement of 74 dog breeds over 40 years in USA. PLoS One 8(10): e76390. doi:10.1371/journal.pone.0076390 (pdf)
The investigators obtained from OFA (Orthopedic Foundation for Animals) the publically-available records for hip and elbow evaluations of dogs born after 1970 and through 2009. After editing for errors, multiple entries, mis-recorded sex, etc., the database contained 760,455 hip scores and 135,409 elbow scores. The pedigree records of these dogs and their ancestors without phenotypic records were used to compute an "estimated breeding value" (EBV) for each dog.
Every dog has a "breeding value" or breeding potential for every trait a breeder might be interested in. This value is based not only on the evaluation of the trait in the particular dog, but also on the evaluations of its relatives - parents, siblings, offspring, etc. Using data for relatives provides a better statistical prediction of the value of a particular dog by estimating its genetic potential to produce a certain trait. The trait can be anything the breeder might care about - temperament, structure, color, or even health problems. The animals are evaluated for each trait, and that information is used in a computation that produces an EBV value for each dog for every trait of interest.
For hip and elbow dysplasia in this study, the data for hip evaluations were used as scored by OFA. For example, the categories used by OFA for hips are excellent, good, fair, borderline, mild, moderate, and severe, and these were given a numerical value from 1 (excellent) to 7 (severe), so animals with better hips have lower numbers. These scores for individual dogs, together with the data for relatives, are used to compute the EBV for hips and elbows for the animals born each year.
By plotting the average EBV per year over the 4 decades of this study's data, improvement in the hip or elbow joints will be apparent in scores that decrease over time. EBV scores for hips are provided for 74 breeds and scores for elbows for 20. The graphs below were included in the Supplemental data for the study that is available for downloading on the PLoS One website.
Every dog has a "breeding value" or breeding potential for every trait a breeder might be interested in. This value is based not only on the evaluation of the trait in the particular dog, but also on the evaluations of its relatives - parents, siblings, offspring, etc. Using data for relatives provides a better statistical prediction of the value of a particular dog by estimating its genetic potential to produce a certain trait. The trait can be anything the breeder might care about - temperament, structure, color, or even health problems. The animals are evaluated for each trait, and that information is used in a computation that produces an EBV value for each dog for every trait of interest.
For hip and elbow dysplasia in this study, the data for hip evaluations were used as scored by OFA. For example, the categories used by OFA for hips are excellent, good, fair, borderline, mild, moderate, and severe, and these were given a numerical value from 1 (excellent) to 7 (severe), so animals with better hips have lower numbers. These scores for individual dogs, together with the data for relatives, are used to compute the EBV for hips and elbows for the animals born each year.
By plotting the average EBV per year over the 4 decades of this study's data, improvement in the hip or elbow joints will be apparent in scores that decrease over time. EBV scores for hips are provided for 74 breeds and scores for elbows for 20. The graphs below were included in the Supplemental data for the study that is available for downloading on the PLoS One website.
EBV for Hip Dysplasia |
EBV for Elbow Dysplasia
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