interesting study

http://www.pennhip.org//09230v7.pdf

Key Points
"Keeping dogs lean did not change the genes of dogs predisposed to hip dysplasia. Rather, leanness was shown to delay or prevent the expression of radiographic signs of CHD and therefore confounded diagnosis using the OFA scoring method at 2 years of age."

"The normal OFA designation of hips at 2 years of age was conservatively wrong 46%
of the time when compared to end-of-life radiographic results. Even more telling, when 2 year OFA score was compared to histopathological findings in aged dogs, a 56% false-negative diagnosis rate was found."



"Recommendation: Dogs susceptible to CHD should be kept lean for life."

" The high false-negative rate of OFA type diagnoses at 2 years of age (46% end of life OFA type score) (56% histopath OA) warrants a more accurate test for selecting breeding stock."

"Recommendation: Hip films are warranted well beyond 2 years of age, and in the case of breeding dogs, hips should be evaluated at regular intervals for life."