Why Breeding Value is Preferred Over the Raw OFA Score
Experienced dog breeders or buyers choose their dogs not only based on the qualities of the dog they are interested in but they also consider the qualities of their relatives.
In this case, we are specifically estimating the genetic quality of a dog for hip and elbow conformation and its genetic potential to transfer its genes for good hips and elbows to its offspring.
How We Develop the Breeding Value
• This process was optimized into a single criteria called the BLUP (best linear unbiased prediction) using data simultaneously for both hip and elbow conformation.
- 'Best' means the mathematical result we provide you has a minimum prediction error. The quality of the data available in the OFA database determines the accuracy of the breeding values.
- 'Linear' means a linear relationship between the OFA hip and elbow score and the genetic makeup in the dog’s pedigree as far back, and as widely, as data is available in the OFA database.
- 'Unbiased' means the prediction equals the expectation of the true breeding value.
- 'Prediction' is the actual prediction of the genetic makeup underlying the OFA hip and elbow score. This genetic basis is called “breeding value”.
• Calculation of BLUP is a process of integration of available phenotypes and pedigree information. The calculation also removed the influence of the related factors such as sex, age and time of year when the scores were measured. The details of the calculation can be found in the statistical model section of the paper here. A new paper about the current results is in progress.
- AS THE BREEDING VALUE HAS THE SAME DIRECTION AS THE OFA SCORE, A SMALLER BREEDING VALUE BASED ON THE OFA SCORE MEANS A BETTER HIP AND/OR ELBOW GENETIC QUALITY, OR VALUE.
- Dogs with excellent hip and normal elbow scores were categorized as a "1", while the worst hips were categorized as "7" and worst elbows a "4".