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Selection against HD - best practice


Maja
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I wanted to ask what is best practice in breeding against HD. I don't mean of course the simple "don't breed affected dogs" and "don't repeat a mating that gave lots of HD".

For example you have two dogs HD-A (lets call them Jack and Jill), they breed and get a lot of pups that have dysplasia.

A pup out of that dysplasia riddled litter (let's call it Kelly) has HD-A and is mated with a dog HD-A (let's call it Kaper) and gives a pup with HD-A , lets call it "Nell".

So questions: Should pup Kelly have been bred? If so what would have been the best strategy for it ?

What is best area in the pedigree to look at for pup Nell? Its parents' siblings? Its own siblings? Its parents' offspring?

Is there any research on the directions in which the search should go? Eg. looking at the parents that produced the dysplasia whether they produced them in other matings and which areas in the pedigree overlap, etc. Anything that indicated a strategy better than others?

I have some opinions on the topic but I would like to hear yours, and get some info on research if there has been any.

I enclose a pic of Darine, which I am sure you've all missed, for ornamental purposes only.

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  • 2 months later...

Long time ago I read an article, which I can't find now, trying to explain why in spite of years of border collie selection for work the breed has  less than stellar results in hip dysplasia. It is a bothersome problem for those who believe that selection for working ability should eliminate such things as HD.  I have now, in addition to having an almost blind dog and an almost deaf dog,   Darinka, who should be the lame dog, but  isn't. She has one sided dysplasia  and the bad  hip is  C/D or thereabouts.  She is now over 5 years old, and the reason why dysplasia has not been bred out of working  dog is obvious to me:  The dysplasia in no way impedes her working ability. If I had not done the X-ray, I would have bred her (as it was I had thought the X-ray to be a mere formality) absolutely certain of her excellent health.  She runs like the wind, jumps like a grass-hopper on RedBull, she works like a draft horse.  And if I bred her to a similar male, their off-spring would be likely a total disaster.  Darinka, I might add, is of excellent working background,

Clearly, the demands of stock work must be of the sort that allow the dog to maximize its abilities  without compromising the quality of work, even in the presence of dysplasia, which is not possible in other sports like dog racing.  So it is really no surprise at all that the HD in border collies did not get bred out, and it is really obvious that  tests and x-rays can greatly improve the quality of the working dog.  

I think this is an important piece of information, because I have come across somewhat flippant attitudes of working dog people who seem to think that the various tests are for the wimpy show dogs, and as long as the dog performs, we are all set.  I am not saying that working dog people neglect to test their breeding dogs, I am just noting how important the tests are for maintaining and improving the health of the working border collie.  Obviously in case of hip dysplasia there is no way we can rely on the dog's working ability to determine its  health status, and Darinka reminds me of it everyday  when I watch her beautiful work. 

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I really haven't kept up on the CHD issue in recent years but some of the reasons it's so difficult to breed out are that a) it's not a simple recessive, b) it's most likely polygenetic and the mode of inheritance isn't really understood and c) environmental factors that are also not clearly understood play a part. And, of course, as you mentioned, some "affected" dogs do not seem to be "affected" in terms of work performance and/or apparent signs of pain or limitation. I'm sure you know all this already (and I really hope someone will correct me if I got any of this wrong).

I can't really add much to this but wanted to mention an intriguing article I read a while back that suggested that the surface that pups are raised on can have a big influence on HD development. It said said that pups raised on flat and/or slippery surfaces tend to develop HD more than pups raised in a bowl-like depression that offers some traction for the pups. IOW, something more like a natural earthen den that prevents them from both wandering aimlessly and slipping while doing so appears to contribute to the formation of good hip joints. I don't recall if there was a specific "study" done or if it was observation over time and I seem not to have bookmarked the article.

A couple of these things (e.g. there being no simple genetic answer, critical period for development being up to 8 weeks of age, and pups on slippery surfaces) are mentioned in this article: http://www.instituteofcaninebiology.org/blog/the-10-most-important-things-to-know-about-canine-hip-dysplasia. Interestingly it mentions that pups born in summer with access to playing outside (i.e. traction on natural ground) have less incidence of HD, which also seems to align with the whelping surface hypothesis.

I know if I were breeding I'd be paying a lot of attention to the surface that the pups were whelped and raised on.

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Maja,

I think the reason the work didn't necessarily show the condition of the hips is because working dogs are generally fit and well-muscled, and that muscling provides support to bad hips so they may go unnoticed (without radiographs) when the dog is of breeding age. My Jill had terrible hips, discovered on radiographs when her original owner wanted to breed her. She never had any problems from her hips until she was quite aged, no longer working, and of course less muscled.

Now that it's possible to view a dog's hips, dogs  with bad hips shouldn't be inadvertently bred, but the nature of the beast is such that there can be no guarantees. I honestly think in the case of a dog with relatives with HD that the overall incidence in that family, how good a worker the dog is, and the overall hip "history" of the potential mate would all need to be taken into account.

J.

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4 hours ago, juliepoudrier said:

I think the reason the work didn't necessarily show the condition of the hips is because working dogs are generally fit and well-muscled, and that muscling provides support to bad hips so they may go unnoticed (without radiographs) when the dog is of breeding age. My Jill had terrible hips, discovered on radiographs when her original owner wanted to breed her.

This could also definitely be a factor.  Years ago I had a dog once who'd originally been rated OFA mildly dysplastic because of laxity rather than remodeling. When discussing it with another vet, she mentioned that prolonged periods of inactivity can cause this and then I remembered that he'd been sick and pretty much resting for a couple months just prior to the rads being taken. So I decided to do them again now that he'd been back to normal activity for some time. When they were resubmitted the score came back fair. Not great perhaps, but still better than being dysplastic.

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21 hours ago, GentleLake said:

Great pic.

I'm beginning to think you really just started this topic as an excuse to post some more pictures of Darinka. :lol:

Dang it! How did you know!  :lol:

17 hours ago, juliepoudrier said:

I think the reason the work didn't necessarily show the condition of the hips is because working dogs are generally fit and well-muscled, and that muscling provides support to bad hips so they may go unnoticed (without radiographs) when the dog is of breeding age. My Jill had terrible hips, discovered on radiographs when her original owner wanted to breed her. She never had any problems from her hips until she was quite aged, no longer working, and of course less muscled.

Now that it's possible to view a dog's hips, dogs  with bad hips shouldn't be inadvertently bred, but the nature of the beast is such that there can be no guarantees. I honestly think in the case of a dog with relatives with HD that the overall incidence in that family, how good a worker the dog is, and the overall hip "history" of the potential mate would all need to be taken into account.

I agree with you. I feel very strongly about taking the entire breeding picture of a dog into account, together with the entire breed picture, looking for a balance between selecting from the gene pool and depleting it (my, I got that one really convoluted didn't I ? :D

I have heard, and believed it too, that when the dog puts in a hard day's worth of work up on the brae, this is sufficient testimony of its  health in relation to muscle, skeleton, heart, lungs.  But there is a difference in how the dog works with livestock versus how racing dogs or sled dogs work because their muscle compensation, however fantastic, was not compensating enough and the dogs with CHD didn't cut the grade as racing dogs,  and this produced a low incidence of HD. Livestock work obviously does not have this effect. 

Darinka pic for those you saw through me :D 

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