If two litter sisters were hip scored and one scored 0 and the other, say, 40 (just making this up) and had HD, then both bitches were mated to the same male who had, say a score of 10 - what would be the chances of the pups being the same scores from each bitch? Is it much more likely that the high scoring bitch will produce high scoring puppies? Is there evidence to support either way? If it was the case that statistically both bitches, having the same pedigree, are just as likely to produce dogs with poor hips if bred to the same dog, then surely if ANY pup in a litter had really bad hips, then NONE of the pups from that litter should be bred from?

Think you have explained why improvement in hips is such a slow business - to do the job properly you need to now the score of the progeny not just those who are going to be used for breeding. At one time this was done more often than now but with the hike in price it is hard to get people to check their pups if they are not breeding lets face it there are those who will not check even if they are breeding.

The answer to your question is the two litter sisters may have an equal chance of producing pups with the same average score. The propensity to produce hips that will be effected with HD is so difficult to define because the method of hereditary is so complicated and the best way at the moment is to test all breeding stock and as may of the others as possible. Look at not just the parents but the ancestry and hope.

the best thing of course is not to breed from the one with HD, the other one was lucky in her gene make up so I would be careful to try and avoid line breeding in case of coming up with the genes she missed first time ....

It would also depend on whether the 40 was made up of 20/20 (most likely genetic) or was e.g. 5/35 which would point more towards trauma.

I think you'd need to look at the bigger picture and factor in grandparents, great grandparents and other relatives scores.

I have a bitch with a score of 11, and from her first litter to a dog of 10 the two scored offspring have lower scores than either parent.  Her sire is an A score in Finland.

her sister scored out at 20, but she lived and played hard with a up to size puppy dog a few months older than her in her new home and may have had rather more wear and tear than ideal.  Her offspring so far scored are better than the parents and in lien with my bitches offspring.

The sire you mated her to has consistently sired low hip scores, though, and his low scoring mother came from a litter which contained a 0 score. Good genes on either side. :-)

That is exactly why I think you have more success with generations of scores and the pattern through the lines than relying on parental scores alone.

I had a male that I imported.  Country of origin excellent score, over here 41 although people abroad and even my vet were shocked by the score.  He was 6 when done but they really didn't look bad on the x-ray.  Three generations and scores are still really low, a couple have been slightly high, but not near his, but the majority have been around half of the breeds average. 

That is exactly why I think you have more success with generations of scores and the pattern through the lines than relying on parental scores alone. But what if you can't get the scores of the ancestors?

I had a male that I imported.  Country of origin excellent score, over here 41 although people abroad and even my vet were shocked by the score.  He was 6 when done but they really didn't look bad on the x-ray.  Three generations and scores are still really low, a couple have been slightly high, but not near his, but the majority have been around half of the breeds average. Did you breed from him?

> But what if you can't get the scores of the ancestors?
>
>

Then your taking a much bigger chance, and when I say scores I don't mean just UK scheme

But what if you can't get the scores of the ancestors?

sometimes you have to start from somewhere, some lines/breeds haven't a history of hip scoring, in shelties it is fairly recent, so making a start is important, in other breeds there's more history and you can build on this....