Anyone who believes that having a hip x-ray done tells you anything more than whether or not a dog has HD should read the following dissertation

http://ethesis.helsinki.fi/julkaisut/maa/kotie/vk/maki/breeding.pdf

It is a big pdf file and a slow down load.

But I will give you the scoop. In Europe, despite 40 years of strident requirements for hip gradings to be able to breed dogs, there has been little to no improvement in HD.

The truth of the matter is that your dog's hip grade is a very poor indicator of whether or not any of its offspring will develop HD. Because it is such a poor indicator, using it as a major component in a breeding decision may actually do more harm than good, you might as well be breeding via the horoscope.

The only way hip gradings begin to have any real value as a breeding tool is if you know the hip grades of pretty much every animal in the breed and accurately know how they are all inter-related. At a minimum, for hip gradings to have breeder value, you have to know the grades of all the siblings of your dog, the hip grades of your dog's parents and ALL the parent's siblings. Having the gradings of all the grandparent's and all their siblings may be useful too. Short of that, if you are using Hip Xrays as a major tool to help you decided whether or not to breed a dog, you are wasting your money and putting your dog through and unnecessary medical prodding. Furthermore, you may also be culling your breed’s gene pools to the point that you may actually be increasing the risk of genetic diseases. The less prevalent Hip dysplasia is in a breed, the more dangerous it is to that breed to use Hip Xrays as a way to cull the population.

Thomas,
I've read this study, and my conclusion of what it says is not matching yours, it seems.
Unfortunately I can't cut & paste out of a PDF document, but there are a lot of caveats in that study.
On page 25 - 2/3's of the way down the page, closely read the part about inbreeding populations and the increase in HD. This is more of a discussion about the lack of good data then a discussion about whether the screening is useful.

The most valid part of this study is the discussion of better screening methods being needed. It does state that genetic inheritence for HD was "positive" ( page 19 ) for all breeds except for Golden's.
If it's a tool that can be used to improve the breed, I'll use it. If a better tool comes along, I'll change to the better tool.
The screening x-rays aren't perfect ( far from it ) but they're better than nothing.

Wasn't it Guide Dogs for the Blind that practically eliminated HD from their breeding stock by checking back 5 generations? I remember reading that somewhere...

Anyone with conformation on this? It would be an interesting read, esp. if they presented in a phenotype vs. genotype study.

Will,

I believe that her conclusions were that having even a higher selection standard, ie only breeding dogs with near perfect hips might help.
I don't agree with her "solution", but her analysis of the failure of doing what is currently being done, is correct. So I think you read it correctly.

The important thing I take away from it is that in registries where having a passing hip xray has been a STRIDENT requirement to breed it has not done much. The European registiries are aware of that and that is why some have gone to the point of having every dog graded and calculating a breeding coefficient based on it. That method SHOULD work.

But an X-ray, byitself, has been proven not to tell much of anything in terms of breeding value.
In GSD's I think it becomes and issue in cases where an Excellent protection dog is not bred soley because of a poor/fair hip grading, and a poor protection dog is bred because of an excellent hip rating.

Does the document go into the fact that selecting dogs based upon phenotype *can* have no alteration in genotype? A dog with good hips can still throw bad ones, particularly if it is a breeding in which the ancestors have not been selected rigoriously. You just diminish the odds, and increase heritability by selecting phenotypically sound dogs, for many generations.


Sorry I am at a computer that can't download adobe.


Here is a link that talks a bit more about the complex interplay between genes, fixation, and geno/phenotype:

Heritability

At work right now and couldn’t read the article in full, but I believe the genetic marker for HD has been found. I recall reading it in an article and recently on another board someone has posted that.It joged my memory.
Now that being true it would be possible to genetically test dogs for the gene. I have been researching this and will have to do some digging through some paperwork, but I will post the article once found.

Here is the Abstract

"The objective of this study was to develop breeding strategies to reduce the incidence of canine
hip and elbow dysplasia. For this purpose, investigations were conducted on the mode of
inheritance as well as genetic parameters, genetic trends and selection differentials for the traits.
Population structure and inbreeding were also examined, and finally, various selection schemes
were compared by a simulation study to find out potential genetic responses and possibilities for
a comprehensive breeding program.
Screening information for hip and elbow dysplasia, collected within the health program of
the Finnish Kennel Club, was used. A total of 42 421 records on hip dysplasia and 13 543 on
elbow dysplasia were available on seven breeds, the German Shepherd, the Golden Retriever, the
Labrador Retriever, the Rottweiler, the Bernese Mountain Dog, the Finnish Hound and the
Rough Collie.
Based on the results of this thesis, both hip and elbow dysplasia seemed to be quantitative
traits. Neither of the traits fitted to a mitochondrial or sex-linked inheritance. According to
segregation analysis, a major gene could be segregating in hip dysplasia in four studied breeds.
Estimates of heritabilities in the studied breeds indicated that there is sufficient genetic
variation for successful selection of breeding dogs according to their dysplasia status. The
positive, although mainly low, estimates of genetic correlations between hip and elbow dysplasia
allow for simultaneous selection for both traits. In spite of this, the genetic level of hip dysplasia
had improved over the study period only in the Rottweiler, while the genetic levels were getting
worse in the other three studied breeds. For elbow dysplasia, a slight improvement was noticed in
all studied breeds. However, the phenotypic selection differentials for both hip and elbow
dysplasia were quite small in all studied breeds.
Despite of the weak selection practised against hip and elbow dysplasia, the populations
studied in this thesis were observed to be otherwise under stringent selection, since only a small
proportion of annually born animals were used later for breeding. In addition to the small
proportion of breeding animals, a few sires had been excessively favoured in breeding. Besides
passive inbreeding due to the resulting small effective population sizes, inbreeding had also been
used actively in the studied breeds. The inbreeding coefficient of a dog had a significant
detrimental effect for hip dysplasia in the German Shepherd and the Labrador Retriever. No
inbreeding depression for elbow dysplasia was observed. However, the amount of pedigree
information used in this thesis was not necessarily sufficient to properly study inbreeding
depression.
Potential genetic responses for hip and elbow dysplasia were studied by simulation. When
simultaneously selecting for hip and elbow dysplasia, as well as behaviour and appearance, a
very small relative index weight for appearance was enough to maintain the trait without negative
genetic gain. The only way to reach the breeding goal set for hip and elbow dysplasia was to
clearly favour the traits in the selection. Behaviour traits should receive also much more
emphasis than has been given to them so far.
The most effective selection against hip and elbow dysplasia would be based on BLUP
breeding values. However, the accuracy of the breeding values could be improved if a larger
proportion of the dogs were screened for hip and elbow dysplasia. Further, if major genes
affecting hip and elbow dysplasia exist, considerable genetic progress could be achieved by
selection for them, since the possibly existing unfavourable alleles were found to have relatively
high frequencies.
Systematic breeding programs, including preservation of genetic variation, should be
developed and followed to maintain or improve the desired behaviour and working traits, as well
as the health of the dogs in the current populations."