hips and OFA

[Valhalla]

I was wondering what the opinion is on breeding to dogs with questionable hips? I am not convinced enough to rely solely on the findings from OFA because I feel that there is too much variation in how the radiographs are read.

 

I have a dog that is OFA Fair. His sire and dam were both Good. A litter sister was Good and a litter brother was Excellent. I called OFA and found that 2 vets read him as Fair and one read him as Good. I was told breeding him to a Good or Excellent would be acceptable.

 

It is obvious that the genetic history goes further back than just the parents, but there have been breedings between dogs with good hips that passed down pups with very bad hips. This, to me, demonstrates that it can be a crap shoot even if you try hard to eliminate it.

 

In addition, I know of a few dogs that were OFA Excellent and at 5-6 years of age, began having lameness issues that have been diagnosed in the hip area. On the other hand, some other dogs that would most likely not pass OFA are completely sound and are still actively trialing (in Open no less) at 8 years and older. One person even had their dog x-rayed again and there were no arthritic changes at all compared to previous radiographs.

 

I would think that a dog that has more laxity in the joints is going to stay sound longer than a dog with tighter joints, due to the way the Border Collie works and moves.

 

I understand the importance of breeding in soundness and am all for improving the breed, but how accurate is OFA and should we rely on that so much? Can anyone's experience with Cornell provide a better answer?

[Shoofly]

Hey Christine - there are lots of folks more qualified to answer this than me, but the way i understand it is that the qualitative part of the rating (exc, good, fair) is a whole lot less meaningful than we try to make it. Either a dog has HD or he/she doesn't and that's what's really the important thing. Human nature makes us want the "better" rating but i wonder if we don't attach way too much importance to it.

 

Gael's a product of a Fair to Fair breeding and it's never bothered me, and her hips are fine. I've not had them OFA'd but they have been checked by my orthopedist.

[Valhalla]

Robin, you hit the nail on the head. If so many continue to adhere to the OFA "standards", there might not be more dogs like Gael out there, shining with superb athleticism.

[Shoofly]

I don't think OFA is a bad thing but i don't think we need to get caught up in "only breed from Good or Excellents". A Fair is a dog without HD after all.

 

I don't see anything wrong with breeding a really good working "Fair". I'd sure rather see that than breeding a lousy working "Excellent".

[Pipedream Farm]

I'll have to find the article, but we looked at stats that showed little or no statistical difference (when you factor in the population sample sizes) in producing HD pups from Excellent x Fair, Good X Fair, Excellent x Good, and Good x Good; there was a statistically significant increase in the Fair x Fair in producing HD pups.

 

Denise should know where this article was published; I think it was 3-4 years ago in either Working BC or American BC.

 

As far as the Cornell service, we have submitted x-rays to Cornell for evaluation but have not used either the new evaluation service for getting an "@" on ABCA papers or the new study. I do like getting a written description of the hips that I can read while looking at the x-ray; however in the end it still comes down to "within normal limits" or HD positive.

 

Mark

[Denise Wall]

From the FAQ thread on HD and OFA:

 

Confinment for hip dysplasia

 

I wrote:

 

The reference for that study is as follows:

 

Reed AL, Keller GG, Vogt DW, Ellersieck MR, Corley EA. Effect of dam and sire qualitative hip conformation scores on progeny hip conformation. J Am Vet Med Assoc. 2000 Sep 1;217(5):675-80.

 

My summary of their study is:

 

1. When dogs with Good or Excellent ratings are mated, there is a 12.5% incidence of puppies developing CHD, 87.5% will have normal hips.

 

2. When a dog with hips rated Good or Excellent is mated to a dog with hips rated Fair, the incidence of CHD puppies rises to 15%, with 85% normal.

 

3. When a dog which is dysplastic is mated to a dog rated Good or Excellent, the incidence of normal-hipped puppies drops to 75%, and the incidence of CHD jumps to 25%.

 

For those who want to read other details on statistical significance -

 

The abstract

 

Effect of dam and sire qualitative hip conformation scores on progeny hip conformation.

 

Reed AL, Keller GG, Vogt DW, Ellersieck MR, Corley EA.

 

Orthopedic Foundation for Animals, Columbia, MO 65201, USA.

 

OBJECTIVE: To determine in dogs what effect using hip conformation scores assigned by the Orthopedic Foundation for Animals (OFA) as a criterion for breeding selections would have on hip conformation scores of the progeny. DESIGN: Longitudinal study. ANIMALS: English Setters, Portuguese Water Dogs, Chinese Shar-peis, and Bernese Mountain Dogs for which OFA hip conformation scores were known. PROCEDURE: Pedigree data were obtained from the national breed clubs and the American Kennel Club and merged with data from the OFA hip conformation score database. An ANOVA was used to evaluate the effects of sex, age at the time of radiographic evaluation, and year of birth on the variation in hip conformation scores among the progeny. Heritability was estimated by use of within-year midparent offspring regression analyses. RESULTS: Significant differences in progeny hip conformation scores between sexes were not detected, but age at the time of radiographic evaluation and year of birth had a significant effect on hip joint conformation of the progeny. Estimated heritability (mean +/- SE) was 0.26 +/- 0.03, and dam and sire hip conformation scores had a significant effect on progeny hip conformation scores. Annual decreases in percentage of dysplastic progeny and increases in percentages of progeny and breeding dogs with phenotypically normal hip joint conformation were detected. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that hip conformation scores have moderate heritability in dogs and selection of breeding stock with better hip conformation scores will increase the percentage of progeny with phenotypically normal hip joint conformation.

[Pipedream Farm]

Thanks Denise. What were the results for fair x fair?

 

Mark

 

P.S. Never mind I found this via a google search using the article title:

 

The Use of Genetic Databases to Reduce Disease Prevalence

[Denise Wall]

Excellent reference, Mark.

 

In another excerpt from the thread I linked above, I wrote:

 

Here are the final compiled figures from these five studies of various crosses resulting in data from 1,712 total progeny. It looks like most, if not all, of these dogs were German Shepherds, a breed with a high incidence of HD. A high carrier rate would be likely, hence the high incidence of HD even in the Normal times Normal crosses.

 

Normal X Normal = 74.6% Normal progeny (25.4% Dysplastic)

 

Normal X Dysplastic = 51.6% Normal progeny (48.4% Dysplastic)

 

Dysplastic X Dysplastic = 13.2% Normal (86.8% Dysplastic)

 

 

References:

 

Snaveley, J. G. 1959. Genetic Aspects of hip dysplasia in dogs. J. Am. Vet. Med. Ass. 135:201-7.

 

Bornfors, S., Palsson, K. and Skude, G. 1964. Hereditary aspects of hip dysplasia in German Shepherd Dogs. J. Am. Vet. Med. Ass. 145:15-20.

 

Riser, W.H., Cohen, D., Linguist, S., Mansson, J. and Cheb, S. 1964. Influence of early rapid growth and weight gain on hip dysplasia on the German Shepherd Dog. J. Am. Vet. Med. Ass. 145:661-8.

 

Kaman, C. H. and Gossling, H. R. 1967. A breeding program to reduce hip dysplasia in German Shepherd Dogs. J. Am. Vet. Med. Ass. 151:562-71.

 

Henricson, B., Norberg, I. and Olsson, S. E. 1966. On the aetiology and pathogenesis of hip dysplasia. J. small Anim. Pract. 7:673-88.

[Shoofly]

Thanks guys! Mark, i was trying to find that too.

 

Ok, off to the trial. See ya!

[Pipedream Farm]

Based upon my gut feeling (I haven't decided upon the appropriate values to calculate the confidence intervals such as the appropriate population size) the sample sizes listed in the table in the reference I posted are large enough to assume no larger than +/- 1% in the probability of HD offspring from the various matings (i.e. fair x fair will yield 16.3% +/-1% HD offspring). However, Denise brings up a good point about some breeds carrying the gene more than others and how this may influence the probability of HD progeny from "normal" parents. All in all, the table should be a good guide for choosing crosses.

 

Mark

[Valhalla]

Thanks so much you guys! I'll have lots of reading to do during the eves in the hotel this weekend at Parker's!

[Denise Wall]

However, Denise brings up a good point about some breeds carrying the gene more than others and how this may influence the probability of HD progeny from "normal" parents. All in all, the table should be a good guide for choosing crosses.

 

I should also point out that these studies are very old. The overall incidence of HD in these study breeds and other breeds has decreased over the years.

 

One point to take away from the link Mark provided is that in polygenic diseases such as HD with strong environmental influences, initial progress can be made fairly quickly, like in three to four generations. However this progress may level off despite continued selection. This maybe be where we are now in the our breed.

 

In trends stats for border collies at the OFA site:

 

http://www.offa.org/hipstatbreed.html?view=2

 

Tested dogs born up 1980 HD was 21%

Born from 1990-1992 HD 9.9%

Born 1998-2001 HD 7.2%

 

The overall from all years is 11.3% HD from 5726 tested border collies.

 

The percent of excellents have gone up as the HD percent has decreased.

[mayflower]

The only problem I have with the stats on the OFA site is that those are only the dogs that are reported, what about the dog whose hip x-rays are too bad to even bother sending into OFA?

 

It might not be enough to change the numbers, but.....

 

I think that if you take your dog in to have the hips x-rayed, those results should automatically be sent to OFA, no choice, mandatory. Unless this is done, I think the results are only reflecting part of the population. Granted, it might not change the overall stats but I do think all the x-ray results need to be part of the stats that are being recorded by OFA.

 

Just my two cents.

 

Donna

[Pipedream Farm]

I think that if you take your dog in to have the hips x-rayed, those results should automatically be sent to OFA, no choice, mandatory.

 

I disagree. I have a problem with OFA on two aspects. The first has to do with those OFA evaluations made before OFA required the owner to agree to having the results posted in the public domain when submitting to the evaluation. The OFA went back without owners? consent and posted the results in the public domain. This goes against the principle of disclosing private information without the owner?s consent. We called the OFA on this and would pull our ratings if we so requested; in other words they were counting on owners not knowing or complaining and therefore did not seek consent prior to disclosure. The second has to do with the OFA failure to properly educate the public on their rating system. There is a widely held belief that OFA fair hipped dogs should never be bred. This may be related to the OFA's choice of words (fair, good, excellent) and/or not properly educating the public on what these ratings really mean. By requiring all passing ratings to be posted in the public domain the OFA is impacting the breeding value of the fair hipped dogs; in other words the OFA had devalued an owner's property. Fair hipped dogs DO NOT have HD; but that is how these dogs are viewed by many.

 

Having the data base is a good thing; making it available for studying how inheritable diseases are passed on is a great thing; making it available to the public so that anyone can look up an individual dog's rating is not necessary and is intrusive. I don't need the OFA to find out the hip quality on a dog I may wish to breed to; I just ask the owner. If I want to know the hip ratings on the parents of a litter; I ask the breeder. If they won't answer my questions; I move onto another breeder.

 

Here ends my rant on OFA practices.

 

Mark