One of the guide dog organizations breeds their own dogs (others get
dogs from select breeders). The one with their own closed selection
has virtually eliminated CHD from their dogs by properly applying OFA
- which basically means xraying all dogs and applying the results
forward. With OFA the parents and grand parents xrays are important
but so are uncles, aunts, cousins, siblings, and the whole broad
family so results from OFA are slow because you so seldom have enough
datapoints. Still, over time, even poorly applied OFA will bring
results.

I can offer my own experience. My Cally came from un-xrayed parents.
At the time her father's line hadn't been bred on, the dogs and their
owner were quite old and I was afraid this 50 year family line would
disappear (much like farm collie folks worry about the Dunrovin
dogs...). Ultimately Cally's father OFA'd good at 9 or 11 years of age
- so he certainly had some good hips (good hips at 2 years of age is
much easier to get than at 10 once you've put some wear and tear on
them...).

Anyway, Cally had one hip that wasn't great. I decided to breed her
anyway, to a stud with good hips. Of the 8 pups only 1 didn't pass
OFA (he prelim'd fair but by the time he was old enough to be
certified he did not pass.). Like his dam it was his left hip that
wasn't good. One of the OFA good pups was bred and all her pups were
OFA good. The dog with the one bad hip also fathered two litters and i
have a grand pup of his - like her grandfather and great grandmother
her left hip is not as good as her right.

I personally believe in Cally's line (and I've seen this with some
other ES where there's one pup with good hips from a litter with
mostly bad) that her bad hip came from her mother and its
inheritability is pretty predictable - either a dog gets that bad hip
gene or it doesn't and if it doesn't then it's gone from the next
generation. Not all hip problems are so easy to explain or breed away
from. Sometimes it seems to come out of the blue.

The good news about the Jarratt line of dogs is that Russ fathered a
couple more litters as did Cally's brother (OFA Fair, again the left
hip the less good one, but better than Cally's) and there are still
Jarratt dogs out there carrying on a really great line ES.



On Jan 23, 2011, at 11:12 PM, Merry C. wrote:
>
> My main question on writing that last novella was whether the odds
> really do improve. Overall, rates of hip dysplasia have not decreased
> very much since OFA screening started, but this can also be due to
> the aforementioned
> inconsistent testing. I did find an article giving odds on
> labradornet (2 in 10 pups will have dysplasia with unaffected
> parents, 5 in 10 if one parent has dysplasia, 8 in 10 if both
> parents are affected), but these numbers are not cited properly. Do
> you have any idea where they got this information from? I would
> like to have an article on file supporting these numbers, preferably
> from a scientific journal. I'm also seeing a lot of breeders
> adopting the notion that the development of debilitating joint
> degeneration due to CHD is only 25% influenced by genetics, but
> again - no proper citations to studies that support this notion and
> the searches I've done haven't turned anything available online up.