I found this an interesting article:
http://www.thehorse.com/ViewArticle.aspx?ID=13273
Quote:
A prominent Arabian horse breeding operation based in the United Arab Emirates recently became the first to publicly announce one of its stallions is a carrier of cerebellar abiotrophy (CA). Albidayer Stud released the news that World Champion Arabian stallion Marajj is a carrier for the inherited neurologic disease, for which a DNA test recently became available.
End Quote.
I have to applaud the owners of this horse for acting proactively in regards to this disease. I only wish the stock horse industry had done the same with HYPP, HERDA, GBED and OLWS.
http://www.marajj.com/news.htm
Does anyone have any more information on this disease and how it may effect the Arabian show industry?
24 comments:
Thanks for posting.
Here's a quote from the article I find disturbing:
"Mare owners who plan to breed to a known carrier are encouraged to test their mares to discern each animal's genetic status. Carriers bred to other carriers have the potential to produce an affected foal 25% of the time."
I don't care if your horse is super awesome, worth millions of dollars, etc. I don't see why people continue to breed horses that have the potential to pass on bad genetic defects.
Yes I know breeds want to make money off their stallions. However, if they were truly thinking about what's best for the breed, then maybe they wouldn't breed horses that were carriers for bad genetic problems.
For instance--HYPP. If people would just stop breeding horses that carried this gene, it wouldn't be too hard to eliminate it from the population.
I agree Mary H. He's a gorgeous horse and some of his get are stunning, but he is a *carrier*.
I don't think he needs to be bred more. I think he should be gelded, retired and enjoyed for the horse his is. All of his get should be tested, and those that are also carriers should be neutered.
What I find most alarming is looking at his bloodlines and seeing what he comes from. Fame VF is in there, as is Bey Shah. So which two recessive lines are the ones carrying the gene?
Jean
He should be gelded. Even if he does not pass on the disease, he could create a foal who is a carrier and who could then be bred unknowingly to another carrier.
If he is not gelded, they should at least be refusing to breed him to carriers after demanding all prospective mares be tested.
I agree with Mary, except for the comment about HYPP being easy to breed out of the QH's.
This Nov I went to the AQHA world show and watched the auction. Do you know how many of those horses were HYPP N/H? Probably 3/4 of them. It was crazy. There are just so many affected (effected?) QH's at this time, and so many people unwilling to test/uneducated about testing.
It could happen, but it would not be at all easy to breed the gene out.
Yes Rachel, I agree that HYPP would be hard to breed out at this point.
However, I think this is because AQHA has failed to properly educate people and has failed to hold people responsible for breeding horses that carry the HYPP gene.
If AQHA would stop registering N/H horses and launch a massive education campaign, I think the number of N/H horses could be greatly reduced.
Part of the problem is that people don't still understand HYPP. As well, the general consensus I get from a lot of horse people is that there's nothing wrong with breeding N/H horses (which is the reason they keep breeding them).
I even had someone telling me the other day about how sad it would be if N/H horses couldn't be registered. She thinks if AQHA stops registering N/H that it would be nice to have a separate breeding registry for all those poor horses AQHA is discriminating against. (This is a person who is well educated and who I usually consider to have fairly sound judgement.)
Getting rid of registered horses that carry the gene would be fairly easy if AQHA would take some initiative. The real problem is backyard breeders and irresponsible breeders who are happy to sell unregistered N/H horses to unsuspecting buyers.
Definately agree, Mary.
I do feel bad for AQHA, though, because there are people who simply do not want to be educated. This year AQHA produced a booklet explaining HYPP, and had it everywhere, but they can't force anyone to read it.
But totally agree with no registry for N/H horses. Breeders should be punished for producing any horse with any degree of genetic defect.
"If your mare tests positive you can then decide if you wish to take the risk in breeding, or else would like to choose a different mare to breed."
So it's OK to breed a mare that tests positive to a stallion that tests positive, just as long as they know what they're getting into.
Money-grubbing much?
I agree with all of you. Marajj should definitely be gelded. And if the Arab association was smart, they would require it of them, or at least refuse to register his offspring.
Rachel said: "I do feel bad for AQHA, though, because there are people who simply do not want to be educated. This year AQHA produced a booklet explaining HYPP, and had it everywhere, but they can't force anyone to read it."
I don't really feel bad for AQHA, actually. I think it's right for them to provide information about it, but because it's such a serious disease and is so widespread, they should be doing more than just trying to educate people. Not registering N/H horses would be a definite start. I think we'd see a lot of the big barns stop breeding N/H horses at least, even if the BYBs wouldn't stop.
Overall, I know we can all agree that it's all about the money. The same problem is with the RMHs and KMSHs with that eye defect that is linked to the silver gene. People still breed for the color even if the horse is only a carrier of the defect. UGH.
MaryH. I must respectifully disagree with your accessment of the C.A. problem with Marajj or any other horse that has "bad genetic defects" that can be passed on.
Think about your own horse(s) Mary. Do they have some conformation fault that you do not like? Do you realize that it is more than likely this defect was gentically passed on from their parents. Should any horse that has some sort of genetic problem not be bred on? If this is the case then many horse breeds will soon parish. Breeding any horse is a matter of responsibility of the person doing the breeding. Throwing the baby out with the genetic bathwater is clearly not the answer to Marajj's carrier status. Knowing what the problem is, like with C.A. and how to deal with it in a rational way is much better than the ignornace suggested when one says such things as you suggest. Know the facts Mary, study up on genetic diseases and how they are transmitted and know what it would really mean if everyone followed your advise of "maybe they wouldnt breed horses that were carriers for bad genetic problems.
Troy,
>Think about your own horse(s) Mary. Do they have some conformation fault that you do not like? Do you realize that it is more than likely this defect was gentically passed on from their parents. Should any horse that has some sort of genetic problem not be bred on? If this is the case then many horse breeds will soon parish.
Troy, with all due respect: Cowhocks never killed anybody. There is a huge difference between a flaw like a set of long cannons, or a common head, and a neurological disorder that either kills the horse outright, like OLWS or, CA or just causes a life of misery with a shorter lifespan like HYPP, HERDA, GBED, and the eye defect mentioned in RMHs.
Disorders that can result in prenatal or neonatal death need to be avoided at all costs. Knowing passing them on, even at such a small ratio is irrsponsible.
The difference between a mild conformational flaw and these types of diseases is exetreme.
Now if you're talking about a major conformational flaw, such as lordosis, ewe neck, undershot jaw then those should be avoided too and the horse removed from the breeding pool. The weird thing is that these flaws won't kill a horse either, but because they are so visible people will be proactive and not breed the animal.
The fact that genetic flaws are usually hidden from the eye is what leads to their propogation. There is no doubt Marajj is beautiful. But he needs to be a beautiful gelding, because the contribution of even one more wasted foal is not acceptable to any real horseman.
Jean
"Mare owners who plan to breed to a known carrier are encouraged to test their mares to discern each animal's genetic status. Carriers bred to other carriers have the potential to produce an affected foal 25% of the time."
Gee, I may be going out on a limb here, but why not geld him? That would put an abrupt halt to him passing on the problem to any of his get...
Well then, there wouldn't be any so end of story.
Maybe if this had been the case with a few others who propagated genetic issues within their breeds- there wouldn't be any issues?
I know, I know. That would be the responsible thing to do. What a concept!
Troy, you are seriously deluded in your thinking. A genetic disease and a genetic defect are vastly different.
One can kill you while the other may make your life difficult.
Crooked legs or a long back in a horse, may be unpleasant for someone to look at or make the horse a little less of a candidate for one discipline over another, but it doesn't kill them, make their skin fall off or endanger their rider or handler when they have an attack, fall over and panic because they cannot breathe.
I'm thinking you are the one who should, as you stated- "Know the facts, study up on genetic diseases and how they are transmitted and know what it would really mean if everyone followed your advise"
Hypp would be difficult to breed out? How? Mandate testing with registration and don't register any that are positive. Yes, there will still be unscrupulous dicks that breed unregistered horses, but the numbers would certainly be lower. It's not as if the AQHA or APHA can whine about losing too much genetic diversity from weeding out the positives. Well, I guess they can whine, but in the end I'm 100% certain that there would still be enough Quarter horses and spotted Quarter horses to keep breeding.
CA doesn't affect carriers with one copy. HYPP does affect carriers with a N/H status, it is far worse than CA because of this.
CA would be more accurately compared to LWOS
Jessica,
>CA doesn't affect carriers with one copy. HYPP does affect carriers with a N/H status, it is far worse than CA because of this.
>CA would be more accurately compared to LWOS
CA effects every horse that descends from a carrier, because it limits their breeding, therefore their marketing, potential. Any suspected carrier becomes one more disposable horse to be tossed out because it costs just as much to feed a bad speciman as it does a good speciman.
" "If your mare tests positive you can then decide if you wish to take the risk in breeding, or else would like to choose a different mare to breed."
So it's OK to breed a mare that tests positive to a stallion that tests positive, just as long as they know what they're getting into."
That sounds EXACTLY like the HYPP situation. I do applaude the stallion owners for making a public statement, but in the same sentence, I can not critise AQHA for doing exactly the same thing.
I'm against breeding carriers. No carriers, eventually no disease.
CNJ, yet again here, here! I have all the respect in the world for you!
I am not against registering positive horses. However, I would like to see it happen this way:
All potential carriers MUST be tested before full registration granted. Registration will remain pending and no number/papers will be granted until testing provided.
All male carriers MUST be gelded before showing allowed, and registration complete. All Female carriers will be granted limited registration (breeding not allowed, clearly marked across papers). In get from carriers born after the rule change goes into effect will be unable to be shown. Give breeders a full year of warning and there should be no issue with breeding's already taken place.
No futurities will accept carriers.
Horses still can be registered keeping some value for the affected foals. However, you take away the monetary gain for breeding these horses. Pretty quickly most of the main players get rid of their stock and start over with new horses. Yes there will be screaming but they WILL get over it.
Ztig wrote:
>All male carriers MUST be gelded before showing allowed, and registration complete. All Female carriers will be granted limited registration (breeding not allowed, clearly marked across papers). In get from carriers born after the rule change goes into effect will be unable to be shown. Give breeders a full year of
warning and there should be no issue with breeding's already taken place.
No futurities will accept carriers.
I think what you outlined is exactly what needs to happen in every breed with known genetic defects.
What is truly bizarre about these "hidden" genetic defects is that they are always worse than visible genetic defects, yet they are ignored because they don't look ugly to the casual observer*
If any of these defects caused roman noses, or mule ears or inverted necks you can bet they'd be bred out so fast it wouldn't survive a second generation. But because CA doesn't cause roman noses in Arabs, the breeders will ignore or condone the breeding of carriers because those horses are "pretty". It's the same with HYPP. If it cause ewe necks or mule ears it'd be gone already.
Tracy M
*the exception being HERDA which looks really fricking bad, but usually not until the horse is well past the fuzzy cute foal stage.
Ok, let's start with defining cerebellar abiotrophy. It is a neurological disease characterized by the die off cells in the brain which control balance and coordination. It isn't limited to Arabian horses, it also exists in other horse breeds, cattle breeds, sheep breeds pig breeds and cat breeds.
The cell die-off begins early and by six months of age is generally noticeable. It will affect the adult horse although in horses it tends to stabilize and the horse can live a "normal" life if euthanisia isn't recommended. Some are rideable but ideally of course the animal would be a pasture pet.
Not a nice disease but also a disease that only expresses itself when a foal gets the recessive gene from both parents. By knowing the status of the stallion and mare it can easily be avoided. A horse with one recessive gene is completely fine as a riding horse although its use as a breeding horse would depend on market tolerance for avoiding the gene.
I am not in favor of a complete ban on carriers. I wouldn't object to noting carrier status of SCID on every breeding animal in the registry and a notation of CA test markers although since there is no established test it would be difficult to require it just yet.
By refusing to register a breeding between two carriers the organization would ensure the disease is not expressed in the individuals, the general incidence of the gene would continue to decline and all the positive characteristics of the animals in question could still be maintained in the gene pool.
If it were a case like HYPP which resulted in harm in the foal even as a carrier, eliminating the gene is the proper course of action. HERDA is different in that by knowing status and selecting against it, no affected horses need to be born. And that can be accomplished with no carrier to carrier registration restrictions.
HERDA entered the gene pool through one particular stallion line. He was a carrier. If, as you all say, any carriers should be gelded and not used for breeding, this stallion would have been gelded. There would have been no HERDA horses. Of course there would also have not been any champion cow horses descended from him either. All the wonderful attributes he added to his breed would have been lost. Where would the breed be without his positive contributions?
It is important not to limit the gene pool to such an extent that only one or two popular lines are perpetuated and inbred constantly to throw up whatever hidden genetic problems exist. If more people had focused on adding other good cow horse lines instead of inbreeding constantly to the HERDA source HERDA wouldn't have taken root so forceablly. That being said, removing any carriers from the pool would also limit what you have left in the breed- you might wind up discovering something else that is currently hidden.
Drastic reaction to something that can be resolved gradually isn't useful. A reasonable course of action would work in the case of recessive non-expressed diseases.
huh, I would agree with you except we are talking about Arab's and QH's two breeds that have a huge gene pool. Having removed the one horse and his get, responsible from the word go we would not even be discussing this, spending money on research, vet care, meds and what ever else comes with it. IF the owners would have been immediately responsible many horses would not have suffered.
Yes, something else may pop up, or it may not. It still is no excuse for irresponsible breeding. And a breeders responsibility is to improve the breed NOT pass on genetic defects. Once the breeders prove they are unable to control themselves, then the breed association should step in and set up regulations.
Now a rare breed I would be in agreement with you. But a breed which is overproduced to begin with...take the carriers out of the gene pool no need to pass it on.
I find some of these comments ridiculous.
If we removed every horse that was a carrier, the gene pool would be severely reduced. The witchhunt that occurred with SCIDS rendered many stallions dumped in backyards, vanished off the face of the earth, etc even if they weren't actually carrying SCIDS (since it took years before the genetic test was available).
HYPP and SCID shouldn't even be compared IMO. HYPP in heterozygous form causes pain and agony in the form of attacks. Been there, done that having taken care of stallions that were HYPP +/- (not my own..I do not support the use of HYPP horses).
SCID, CA, LFS, etc can be carried by spectacular individuals. I give immense credit to a stallion's owner for revealing and requiring mares to be tested. That takes serious cajones I think. Even more credit is the dam of the stallion is being tested for CA. CA is not a widespread Arabian disease. It has nowhere near the influence of Lethal White or HYPP.
There is not a ton of research being done on CA. Some, yes, but no major research has been published in the databases or magazines in the past few years.
Instead of saying a stallion should be gelded, I feel that they should be given credit for stepping forward.
I would be more inclined to agree with you except for two things:
A) There is no shortage of Arab lines. There may be less then there were 20 years ago, but no shortage none the less.
B) The mare owners are only being encouraged to test NOT required. They will still breed to a carrier.
It is responsible to announce it, but it IS irresponsible to still breed a carrier.
I agree that the responsible position of the owner should be to require each mare be tested to ensure she is not a carrier and refuse breedings to those who are.
Eventually when there is a definite test I support the registry refusing to allow breedings between two affected carriers of the disease. I support status being listed on registration certificates.
I don't condone throwing all carriers of recessive genetic diseases being thrown out of the gene pool. As long as you can test for the gene, you can ensure you never produce an affected foal. These diseases spread in the gene pool because the possessors of the genes have sought after qualities. It is possible to eliminate the problem while still retaining those good qualities.
I'm trying to imagine what the Quarter Horse would look like if you had eliminated King from the gene pool. HERDA has its origins with that line but look at all the positive sought after qualities Poco Bueno passed on. By testing and avoiding breeding carriers together you can still use all those positive qualities.
My position isn't based on any one particular individual. If there is a test to determine a carrier of a recessive non-affective in the heterozygous state disease, it is more logical to use that knowledge and avoid the homozygous affected rather than shift to a different population simply because it is that particular disease free. Whatever genetic defects that lurk in the new population are not likely to be known or testable and you may wind up in a similar situation but without testing to ensure there are no affected foals.
This happened in Basenji dogs. They developed a test for one disease, eliminated all carriers from the breeding population and promptly found that all they had left to breed were dogs who carried another recessive disease which increased but they could not test for. Using testing to their advantage in the first genetic disease would have eliminated the original disease eventually and still not increased the presence of the other.
I belong to a group which suffers from recessive genetic diseases. Thankfully current technology allows couples to be tested and avoid producing affected children. Some of these people belong to families that have made commendable contributions to the world-not people I think should be eliminated from the gene pool simply because they are carriers of recessive genetic diseases.
And for what it is worth there are shortages of varied bloodlines even in breeds with large numbers. I am not saying this particular individual is one of them, but another individual may be.
There is very little variance in Thoroughbred tail male lines, for example, and getting to be very little variation in general which isn't a good thing for diversity or improvement or change should it become necessary.
I simply do not support eliminating quality individuals from breeding when by management no affected individuals will be produced.
huh, Ok I see your point and am in agreement with you. Amendment to the original post non-carrier to carrier recessive breeding ok. :)
Wish I could comment.
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