Question about HD - Page 6

Myself i believe hd is caused primarily by genetics.  one other factor is the size of the dogs. the bigger you bred in any breed of dog you start seeing more hd.

Like it or not basically Jantie is the most correct in her statements. Her view may seem an over-reaction, but it is actually based on sound genetics and fits with what I havve learned in over 40 years.  However to be completely accurate, HD heritability can vary from near 100% to near 40-50%.  Here's how. It is my belief that the GSD has approximately the five gene pairs (one from each parent) that determines hip confirmation. Superb hip confirmation occurs when the offspring gets one of each of the five in healthy form from each parent, thus the five pairs occur in doubled or homozygous form. When this occurs the hips are deep, round, and have a Norberg angle of approximately 115 degrees, and they will stay that that way throughout the  lifespan, even if the GSD is underfed, overfed, under exercised or overexercised.  This is near 100% heritability.  On the otherhand if the dog has only some of the desired homozygosity of the desired 5 pairs of genes, then the GSD will develop bad hips (shallow with degernerative changes and laxity and flatness no matter what, even if the diet is restricted and exercise is limited (also near 100% heritable).  On the otherhand if the GSD has heterozygosity of only 2-3 of the five pairs then the hip confirmation is shallow but okay and stays that way if the GSD is carefully handled (kept thin during development and only mildly exercised (this is the result of approximately 40-50% heritability.  At this point what one doesn't easily find out is which GSDs carry good genes for each of the five pairs.  The more the better for any GSD and this GSD should then also be bred to a mate with as many as  possible of the same healthy genes in the five pairs.  VA Esko Danischen Hof has probably carried the highest proportion of these five genes in healthy form of any stud dog alive (the source is his dam's lines). He has been very prepotent as a source of genetic material for good, healthy hip confirmation.  The smart thing is to breed a bitch who has proven to be a great hip producer (and comes from lines known for such) with a stud dog which provides a high proportion of healthy hip producing genes such as Esko and then keep doing this in each future generation.  The only other factor here is the strange occurrence of the Xing or crossing over of genes which tends to occur in unpredicatble fashion.  This doesn't matter if all five pairs are homozygous but can matter if some of the gene pairs are heterozygous.

Here's what we know regarding hips...

The results are tainted as not all offspring are x rayed and submitted. (This along throws statistics off.)

 The experts will never agree.

Some dogs with good hips produce bad, and some with bad produce good.

Genetics may be an answer if technology ever reaches that level. It's not there now and even if it was, would the popular males ever announce their genetic results? Those few that had the desired genes would. What happens then? Breeders flock to the 3 or 4 dogs that fortunately have the desired genes. Talk about narrowing the gene pool.

So what's a breeder to do???

Here's my simple approach that lets me sleep at night. Based on the information compiled by the SV on the VA and high V males used over the past few years; (tainted as they may be) it appears there's credibility to breeding the best possible hips but it's still a crapshoot and sometimes you just have to accept you may improve and strive to improve realizing the factors involved are not under your control or anyone elses.

Breeders then need to decide where hip production falls in their breeding goals. There are those that breed strictly for hip production and those that breed without regard for hip production. I doubt breeding to either extreme will ever produce the balanced dog sought by most breeders. Just accept there is a degree of uncertainty, do the best you can, and look at where you value hips on your priority list and go from there.

I tried to post the SV Results. I'm not able to do so. I'll be happy to send them to someone that will.

As far as the cause of hip displaysia  look at these pictures . It's a proper or improper forming of the hip which sure seems genetic.        

http://www.offa.org/hipgrade.html

one big problem which has been mentioned in part is that some breeders 'hide'unfavorable hd results so that good breeders have trouble knowing for sure the overall hd picture of the gsd's they are breeding.

you breed two good hips together and really don't know the full history of the siblings and yes it turns into a crap shoot.

Breeding for clean hips is not a crapshoot if one knows how to do it.  The SV "a stamp" system is much better than none, but deficient in that the one year rule is insufficient for adequate screening for hip producing ability.  Much better would be the use of a two year requirement like the OFA.  If one breeds only using OFA good or excellent, within 5 years one can arrive with 4-5 pairs of double recessives in each of the five pairs that deterimine hip health.  Selecting hips that look the same at one year only will not give you this.  And one can use only GSDs with good structure and normal, correct temperament.  To do this it takes a big commitment to quality but it can be done.  It was rumored that a technique similar to this was done on the motherline of Esko.  That would explain his superb hip producing ability.  It may be true that he produced more "soft" progeny than desireable, be he also produced some GSDs with correct temperament.  With elbows it is even more critiocal to establish cleaness.  Some veterinary radiologists say that a one year xray fior elbows is sufficient if one only will use those that are completely clean (no evidencve of DJD or patchiness of any kind, including un-united anconeal oprocess.   I have never seen any advantage to anesthesize the GSD to relax the hip muscles for x-raying GSDs for hips.  This can create laxity in the hip that is not otherwise there.  Also, it is unwise to xray a bitch before, during or just after her heat, since laxity can result from the increase in female hormones and make a good hip look bad.  Hips can be easily and reliably screened in puppuies at 12-16 weeks (6 months even better) but this will only predict lack of disabling HD during the normal lifespan and not producing ability.  Good hip producing ability is best predicted at 2 years or older with a very clean hip xray and Norberg angle of 105 degrees or better(very deep sockets, smooth tight fitting ball and socket fit, ball nicely rounded).

About 40% is genetic when it comes to HD I heard from a genetecist. Actually, the governmental breeding programm with GSDs for military and other servicework in Sweden, reduced HD from about 40-50% in their population to under 10 % in a period of just 10 years in the late 70s. So selection against it could certainly be effective. The breedinganimal you use should come from HD-free parents and of course be free themeleves, also check that not more than one of their littermates has HD, and if it do, not worser than HD-C. I think this simple strategy was the one used by this breedingprogramm.

Many of the problem with HD/ED and other diseases in the GSD is also an effect of that people tend to breed in ways that wouldn´t occur in nature, one stud can produce several hundreds of puppies without anyone cheking the incident of HD in the offspring, before the damage is alreday done.  In nature such massbreeding  doesn´t exist.

jennie, you state that the swedish govt breeding program reduced HD to under 10%.  This means in practical terms that they created hip confirmation to be approx. 90% hereditary and approx. 10% developmental changes due to environment (or environmental or chemical/biological stress not related to genetics).  I stated that it can vary from near 100% to near 40-50% heritability.  No controls used usually quickly creates over 90% heritability with the result shifted to HD.  Well instituted controls like the Swedish Govt program you cite can give 90% or higher heritability, in this case shifted to producting health hips.  Your reference to this study fully supports my assertions. 

High rates of controlling HD through dietary restriction (can approach 40-50%) merely supports my contention that such animals in general have fair hip confirmation with a shallow but sound fit and a low norberg angle, typically less than 105 degrees.

Again I state that like it or not the best scientific genetic evidence supports Jantie's conclusions. It is obvious to me that Jantie had spent many hours studying this problem of HD and understands the scientific research supporting those conclusions. 

We can all assume that HD is polygentically recessive and that homozygosity of most or all of the associated pairs in one mate can produce the effect of "faux dominance" in breeding if the other mate gives at least half the progeny a blend wherein the majority of the genes for those parings are of healthy form.  Each mate has a double pair for each of these gene sets (probably five sets or pairs), and these are halved when the sex cells develop.  Thus each parent will provide one gene for each of the sets (pairs). 

The more resulting homozygosity of healthy genes in the pairs of the offs[pring, the more healthy the hips (less HD), the more homozygosity of unhealthy genes in the pairs of the offspring, the more HD; and  the more total number of unhealthy genes in the pairs of the offspring, the more HD, while the more total number of healthy genes in the pairs of the offspring, the less HD.  But overall, any homozygosity (doubling up of the genes, healthy or unhealthy is the mosdt potent determiner of good hip confirmation.

My best guess at this time is that the five genes are related to:  1)rear thigh muscle mass (ability to keep the joint stable and strong),  2)ball socket skeletal blueprint (joint confirmation), 3)ability to resist COX based inflamation metabolically (resistance to chemical stress from exercise), 4) bone plate growth rate with start and stop instructions (quality/robustness of bone laid on), 5)agility of ligamentation (resistance to shock). 

I have just stumbled upon this data base and here is where I landed. There are so many opinions on this subject that my head is reeling. First of all, the numbers are still out there, and may never be completely worked out. IMHO, heritability is about 60-70% of HD. Then comes diet.....most people tend to feed a diet far too high in energy and, especially in America, a fat puppy is perceived to be healthier. That is probably 25-30%. The rest is excessive stress on joints (diet plays a huge roll in this factor, making it less in overall importance over diet). I have a SAR GSD with bilateral TPO from parents with good hips.

I am speculating that there are six genes (simplified term) that act in HD. Factors include hip bone formation (there are three that form the acetabulum or socket), angle of attack of the femoral head, musculature, tendon strength and overall conformation. The jury is still out.

Somewhere I read that one breeder was pooh-poohing the use of glucosamine/chondroitin in puppies. This mystifies me. Why wait until it is broke to throw a little lubricant on a gear? Glucosamine/chondroitin are the building blocks of cartilage. With adequate blood levels to aid in quick healing, and sufficient joint fluid viscosity we may be able to ward off some of the degradation and breakdown of articular cartilage before pain and loss of function become apparent. This combination will not reverse or prevent HD, but it will ward off the crippling effects of the disease, and may award affected dogs a longer "normal life".