[Ambrey]

Okay, help me out here. If you breed a carrier to a non-carrier, does the recessive HERDA mutation just go away? Or does it stand a chance -- by my reckoning a 50 percent chance -- of being passed on to an offspring?

If the answer is no, there is no chance it will be passed on, then no problem.

But if the answer is yes, there is a chance it will be passed on, then why perpetuate the mutation?

Carrier is carrier, meaning they are not symptomatic but carry the gene. That gene can be passed on... it's not a 25% chance, it's a 50%.

The 25% chance would be having a symtomatic horse from two carriers.

[Ambrey]

I believe HERDA is recessive, unlike HYPP which is dominant.

No, hypp is incomplete dominant- an N/H horse has a chance of symtomatic HYPP. An H/H horse is almost assured symptomatic hypp.

[county]

I don't think dogs suffer like horses either. Each species suffers in its own way.

If mare owners don't test theres nothing I can do about that if they don't care theres really no reason the stallion owner should that I can see. Everyone has their own right even though someone else may think differantly.

[Ambrey]

If mare owners don't test theres nothing I can do about that if they don't care theres really no reason the stallion owner should that I can see. Everyone has their own right even though someone else may think differantly.

And I can disagree and think they shouldn't do it. That's what makes it a free country.

I can also think that AQHA should prohibit breeding of HERDA and HYPP carriers.

When you're breeding, you're creating life and have some responsibility not to purposefully create life that has a greater than "normal" chance of suffering. That means not propagating a genetic defect that is common enough to make it probable that somewhere down the line, horses will suffer if you let it continue.

It also means not breeding horses for which there is little market or use (that's where I am right there with FHOTD).

[county]

I don't see where I said you couldn't disagree. In the title of your post it says " WWYD " I took that as a question I had no idea there could be a right or wrong answer.

[Ambrey]

I don't see where I said you couldn't disagree. In the title of your post it says " WWYD " I took that as a question I had no idea there could be a right or wrong answer.

It's not my post. I'm just an interested observer

[county]

Ah my mistake I thought you were the one who started the thread.

[Plumcreek]

I can also think that AQHA should prohibit breeding of HERDA and HYPP carriers.

).

AQHA has been around and around the pond trying to disallow registration of horses with various genetic flaws. They cannot afford all the lawsuits that result, and now pick their battles very carefully.

[horsecrazykid]

Not so simple for people to test their mares because will they all know who they go back to if the horse is not on the papers? how many people know zippo pine bar was a herda carrier???

[Dazednconfused]

I am not up on all of the HERDA genetics, but I would think, given the nature of the problem, that it would be sensible to breed it OUT rather than keep the genetic mutation going by continuing to breed to known carriers. No?

I disagree. I researched HERDA a bit more after I posted - and like SCID it is an autosomal recessive. There is no reason whatsoever to reject carrier horses from the gene pool if they are otherwise excellent individuals. The Arabian breed would be missing some of its best, brightest, and most prominent individuals were carriers to be eliminated - The Real McCoy, Tornado, Versace, possibly Nariadni. I expect it's no different in the QH world. With a test, no HERDA affected horses ever need be born ever again. The gene pools in both breeds are huge - there is no reason to fear that this genetic problem would take over the breed.

Really, if you think about it - most conformational and temperamental faults are genetic - the only difference is, we don't have a test for those. Most sensible breeders would never eliminate a horse from breeding just because it had one fault, especially if it were outstanding in other respects.

In addition to those reasons - if you eliminate carriers, you may trade HERDA for something different and something worse. Not only that but you decrease the available gene pool.

In a perfect world, anyone breeding to this stallion would ask to see results of the test and then not breed to him. Unfortunately there's not much you can do other than to be a constant pest to AQHA, APHA and all the rest of the breed registries to ban registration of carriers.

Why would you ever ban registration of carriers? The disease is within the breed now - and the test was only recently developed. They are not affected by the disease, a test is now available, and no HERDA foal should ever be born again.

I believe HERDA is recessive, unlike HYPP which is dominant.

Appears so.

Exactly. It's NOT just like breeding an HYPP carrier; the offspring have NO chance of manifesting the disease if the mare isn't a carrier. Personally, I think that the stallion owner should be discussing HERDA status with people who choose to breed their mares to his stallion, but the stallion's carrier status alone should not determine whether or not he should ever breed.

Ditto.

Okay, help me out here. If you breed a carrier to a non-carrier, does the recessive HERDA mutation just go away? Or does it stand a chance -- by my reckoning a 50 percent chance -- of being passed on to an offspring?

If the answer is no, there is no chance it will be passed on, then no problem.

But if the answer is yes, there is a chance it will be passed on, then why perpetuate the mutation?

Again, if you eliminate carriers, you may trade HERDA for something different and something worse. Not only that but you decrease the available gene pool.

[Bluey]

More information here:

http://www.bringinglighttohypp.org/HERDA.html

[Ambrey]

But people aren't testing, HERDA status isn't on the papers, and as long as the QH breeders are being so lackadaisical about something that can be so awful for a horse, there's no way to justify continuing to breed carriers.


If a breeder had a carrier stallion and bred only to non-carrier mares, and had mare owners sign papers promising to test carrier status of offspring, etc. it would go a long way. But they don't.

If at least all QH had HERDA marked on registration, and breedings of carriers to carriers would be unregisterable, that would discourage them.

BTW

HERDA is characterized by abnormal skin along the back that tears easily and heals into disfiguring scars. The skin is loose, and hyper-elastic in affected horses. Symptoms typically don’t appear until the horse is subjected to pressure or injury on their back, neck or hips, usually around two yrs of age. However foals can show signs when injured, while other horses mature and only show signs in the joints.[3] The expression of HERDA is variable, and the phenotypic range of expression is still being determined.

[county]

People aren't testing? Maybe your not but that hardly means everyones not.

[Ambrey]

People aren't testing? Maybe your not but that hardly means everyones not.

Not everyone is. Until everyone is and there are no carriers being bred to carriers, the problem isn't solved.

[county]

I agree but thats in a perfect world and this isn't one. Unless a law gets passed to require it ( which I'd be shocked ) its never going to be 100%. I'm sure the AQHA would love to just make it a rule and like I said I'd love to see it but after the ET lawsuit they are very careful what they try to pass as far as limiting peoples right legally. Tx. has one of the strictest Right To Free trade laws on the books which the AQHA found out after spending a very large sum of money.

[ttldr1]

Haven't read all of the responses but the short answer is there is nothing you can do. AQHA has not taken a stand on breeding HERDA positive horses so contacting them about this breeder still breeding thier positive stallion wil do you no good.

http://www.bringinglighttohypp.org/HERDA.html

If the mare owners are breeding thier HERDA positive mares to stallions that they do not know the status of (or don't care) they are just as guilty as the stallion owner for propigating the disease.

Just like in the paint world when a OLWS carrier breeds to a carrier they will almost always get a lethal white foal but to some it is still worth the risk.

[county]

Almost always get a lethal white? 25% isn't what I'd call almost always.

[ThatIrishTemper]

Question time...

If a carrier is bred to a non-carrier, isn't there still a chance that the resulting foal would also be a carrier without showing symptoms? Then what happens when someone wants to breed THAT foal?

Honestly, I would never do any business PERIOD with someone knowingly breeding a HERDA carrier. That mutation is just horrible and to knowingly breed a stud (which SHOULD BE A GELDING) is just plain irresponsible IMO.

[Ambrey]

If a carrier is bred to a non-carrier, isn't there still a chance that the resulting foal would also be a carrier without showing symptoms? Then what happens when someone wants to breed THAT foal?

Yes, a 50% chance.

If a carrier is bred to a carrier, there is a 25% chance the horse will have HERDA, a 50% chance it will be a carrier, and a 25% chance it will be free of the gene.

eta:

http://www.thehorse.com/images/conte...hc_herda2.html

'nuff said.

[Ambrey]

Just like in the paint world when a OLWS carrier breeds to a carrier they will almost always get a lethal white foal but to some it is still worth the risk.

Breeding OLWS to OLWS makes NO sense. The chances of a healthy frame are the same 50% as if you bred to a solid, but you get the 25% chance of a dead baby. Maybe only having a 25% chance of a solid baby is why (they'd rather have a dead baby than a solid one?).