6 ms·

You can screen out hip dysplasia genetically, but the fundamental breed standards for bracycephalic dogs mean they always have compromised respiration. There is

You can screen out hip dysplasia genetically, but the fundamental breed standards for bracycephalic dogs mean they always have compromised respiration. There is no way to breed them that avoids it.

mgarfias 4y ago
No, you can’t screen it out. Genetics only account for about 30% of the causes of hip dysplasia
- bayesian_horse 4y ago
  I generally agree. With the breeding standards of German Shepherds for example there will always be a tendency. But also in general, I'd like to caution about overinterpreting the "x percent genetic" figures. They are computed for a particular population of individuals at a particular time. If a breeder's association then changes their guidelines to screen, for example, for HD, and they actually do a good job at it, that figure will go down, because the following generations will have fewer variation in the genes responsible for it.
  - mgarfias 4y ago
    Yet, diet and environment have a huge impact on hips. Also, OFA’s ratings are crap
    - m-ee 4y ago
      What are the issues with OFA ratings? They’re treated as sacrosanct on the dog reddits but I’ve never really investigated further
      - mgarfias 4y ago
        Completely subjective. The final rating is the average of what three radiologists think about the joint conformation. And, it gets worse, some breeds are rated more harshly that others. For instance, a GSD with an ok looking hip joint will get a “good” rating, but a white Swiss shepherd with the same hip would get a “fair” as OFA wants the WSS to have better hips, so they judge it differently. Also, they take age into consideration, so a 2yro dog will be judged more harshly than a 4yro. We use PennHip, which measures the distraction in the joint, and uses it as a predictor of future health. GSDs on average have a median rating (working from memory, numbers will be handwavy) of something like .5. Thd WSS is more like .4. I’ve seen our kids come back with a pennhip rating of .28/.29, and a fair OFA rating. We’ve stopped sending X-rays for Ofa hips as it doesn’t give us any actual information.

You can screen out hip dysplasia genetically, but the fundamental breed standards for bracycephalic dogs mean they always have compromised respiration. There is no way to breed them that avoids it.

mgarfias 4y ago

No, you can’t screen it out. Genetics only account for about 30% of the causes of hip dysplasia

bayesian_horse 4y ago
I generally agree. With the breeding standards of German Shepherds for example there will always be a tendency. But also in general, I'd like to caution about overinterpreting the "x percent genetic" figures. They are computed for a particular population of individuals at a particular time. If a breeder's association then changes their guidelines to screen, for example, for HD, and they actually do a good job at it, that figure will go down, because the following generations will have fewer variation in the genes responsible for it.
- mgarfias 4y ago
  Yet, diet and environment have a huge impact on hips. Also, OFA’s ratings are crap
  - m-ee 4y ago
    What are the issues with OFA ratings? They’re treated as sacrosanct on the dog reddits but I’ve never really investigated further
    - mgarfias 4y ago
      Completely subjective. The final rating is the average of what three radiologists think about the joint conformation. And, it gets worse, some breeds are rated more harshly that others. For instance, a GSD with an ok looking hip joint will get a “good” rating, but a white Swiss shepherd with the same hip would get a “fair” as OFA wants the WSS to have better hips, so they judge it differently. Also, they take age into consideration, so a 2yro dog will be judged more harshly than a 4yro. We use PennHip, which measures the distraction in the joint, and uses it as a predictor of future health. GSDs on average have a median rating (working from memory, numbers will be handwavy) of something like .5. Thd WSS is more like .4. I’ve seen our kids come back with a pennhip rating of .28/.29, and a fair OFA rating. We’ve stopped sending X-rays for Ofa hips as it doesn’t give us any actual information.