Great post!! So now we can stop talking about potential issues in carriers and also we can stop about talking that carriers need to be removed from breeding just because QH breeders missed to stop breeding horses with a dominant genetic problem!!
Well, no, we actually can’t, because there isn’t any reasonable proof there isn’t an issue, just like there isn’t enough reasonable proof there is.
and also we can stop about talking that carriers need to be removed from breeding just because QH breeders missed to stop breeding horses with a dominant genetic problem!!
Maybe you can, but I’m not, and neither are any number of other interested parties who choose to adopt a wait and see stance.
If you truly understood the actual issue that relates the HYPP debacle to WFFS, you might have a different view on having no problem continuing to breed WFFS carriers to produce more carriers. The qualifier on all this “remove from breeding” (at least for the majority on this thread) that you continue to miss or ignore is “for now”. That is all Hilltop has ever said so far, and that is all most of us have said.
8 Likes
Wow… again… You say there is no proof for it and no proof against it… BTW I agree with that…
And still you insist on arguing there might be an issue… And thats exactly whats spreading rumors… The next person takes it for granted that there might be problems with carriers and then all the persons that next person is talking to will know for sure that there are problems with carriers… Thats the way the cookie crumbles… 
And Hilltop did exactly the right thing. They got everybodys attention and wait until everybody is developing breeding strategies…
Fair enough. I’m still not sure how the numbers work as in “50% of the foals are clear.” That doesn’t work for either phenotype or genotype.
3 Likes
That’s sort of how this kind of thing works. Until we know more, with enough horses over a long enough period of time with the right study criteria in place, we don’t know either way
And thats exactly whats spreading rumors…
Did you not see the definition of “rumor”? Theories are not rumors. Unknowns are not rumors.
The next person takes it for granted that there might be problems with carriers and then all the persons that next person is talking to will know for sure that there are problems with carriers… Thats the way the cookie crumbles…
That is their problem. If nobody EVER made any comments, published any theories or hypotheses about what might be, what could be, then nothing would ever get discovered and researched and proven or disproven.
The “Telephone Game” is a terrible thing in real life. Don’t play it.
12 Likes
But that is how the recessive gene stays and the spread in the population. And if no one minds owning heterozygous horses, sooner or later, you will find fewer homozygous dominant animals out there… which all breeders with your strategy need.
7 Likes
Do you really believe you can eliminate the gene?? It has been in the population for quite a while and if it can be controlled there will be no dead foals. The world is not perfect and horses are not perfect. Nobody is. But its nice to have a little more control about something…
Look, this is literally a mathematical problem. It does get considered in the field of theoretical population genetics. It probably is not possible to eliminate the recessive allele for various reasons:
-
We don’t know it’s prevalence in the existing interbreeding population… That’s because it “hides” (phenotypically in heterozygous individuals… or so we think so far since we don’t know what, if any, physical trait the heterozyous state produces).
-
We don’t know the boundaries of the closed, interbreeding population. Not only is that large (and that slows down the elimination of an allele), but we can’t even quite establish its boundaries.
-
We haven’t tested all individuals, nor is it likely that we ever will. And so now, as well as in the future, there are those heterozygous individuals in which the recessive allele can “hide out” and survive to the next generation.
-
There is not the political will nor the mechanism required to really control breeding patterns.
But none of that means we can’t limit it… or that we should wish to.
Again, as I see it, the facts of population genetics means that folks like you who care only for the phenotypic health of your horses… and who will require the availability of homozygous dominant individuals to pair with your heterozygous ones mean that you have to be on board with this policy too. I think I explained why in the post you quoted.
Again, if you look into the technical details of how Mendelian inheritance works for really simple cases like this and think about how alleles spread or do not in a population, I think that might make this all more clear. I know it’s a tad technical, but it’s not impossible to understand, at least in this case.
14 Likes
Now you really confused me.
You agree that it will probably be impossible to eliminate the gene from the population and you listed some reasons for it (I agree with you on that)
But you still want to reduce the gene by eliminating horses whose owners are honest about it (BTW I think honesty is one of the highest qualities a breeder can have and I chose all my studdogs also because of their owners…) and their horses might be outstanding samples of the the breed. But because you can’t control everything you wil punish those owners but leave horses with dishonest owners which also might not have the same quality in the breeding process.
For me that is a negative selection of the population…
Sorry I think we have different opinions about this.
But you can’t both limit the frequency of the allele in the population and allow owners of the animals holding it to continue to breed them.
I think the conflict is between scientific reality and politics, nothing more and nothing less. So there is not point of “disagreement” about the scientific consequences of allowing breeders who own carrier horses to continue on as they are. Though it’s true, as Hilltop Farm pointed out intially, that the effects (in terms of the allele’s rising frequency in the breeding population is unknown at present.) It is a disagreement about the politics of it all. I think it’s inaccurate to call culling a “punishment” for a breeder. It’s bad luck that they own a horse whose genetics are deemed less valuable, not an earned consequence. Rather, lowering the frequency of the allele in the population necessarily means culling some individuals.
You can blame me for “punishing” the people who discover that their horses have this allele, but the science stands. Shooting the messenger won’t help, nor will it help to pretend that the scientific facts are a matter of disagreement, in the sense of arguing whether vanilla or chocolate is better; there are some technical points on which experts in quantitative population genetics can and will argue. I think I was pretty candid about those in earlier posts.
6 Likes
I think you did not understand me. For now you will punish the honest ones. And did you ever campaign a stallion?? Do you have any idea how much. Money and engagement goes into that??? You want to punish honesty and leave carriers whose owners are not honest about it in the population… that’s for sure not a scientific strategy. Because that way you do make a negative selection about honesty. If everybody would be simply required to publish their results there would’be a positive selection because breeders could make decisions about the quality of a stallion and if it’s worth breeding him even if he is a carrier.
sorry we have very different opinions. For me honesty and transparency is one of the highest values a breeder can have.
rules which are just produced by personal assumptions of some are pretty contraproductive.
when I started to breed my dogs I found out that the requirements for them to breed in Germany were the highest in the world and much higher then other retriever breeds… I guess now you would think that the quality of that breed in Germany would be the highest in the world… no you are wrong, There were no litters in Germany for 10 years because of that. There was one stud dog with borderline health results (the requirements for them were not extremely high) and that was it… and guess who made those rules?? Not breeders of that breed but of other breeds because that breed was not represented… when Istarted they told me I should be happy about the requirements :(. Well I bred my 3 litters each fullfilling the requirement. and I also learned everything about cheating around them. It was pretty ridiculous and I produced some extremely successful dogs but I also learned that these requirements were just a hurdle for breeders they had nothing to do with improving quality… because that depends on breeding decisions made by the breeder.
In my opinion, which may not count for anything, I would not breed any carriers for this specific disease, because by doing so you essentially say that a horse’s possible death is an acceptable risk for you. There is going to be someone down the line that will not genetically test a horse, breed two carriers, and have a dead foal as a result. We see this with backyard breeders and frame overo. They don’t know, they don’t have the education, they haven’t done the test, they just see two blingy horses and breed them, and have a nightmare as a result. As others have said, there’s really no reason to breed to a horse that is a carrier when there are horses with similar genetics at play that are not carriers at all.
It’s not like these are horses running around in the wild who are breeding without control. The people making the decisions on the breedings are completely in control in the matter of if they want to propagate the disease or not.
8 Likes
Well, I’d test all stallions for scientific reasons, not moral, political or economic ones.
I’d do that because there are fewer breeding stallions out there than mare owners and, so testing is easier to demand from that smaller group.
I’d also test stallions as opposed to mares because each stallion can produce many, many more offspring in his life than can a mare… so whatever alleles he has on board will have a larger effect on allele frequency in future generations than will a single mare.
I would not test “all carriers.” In fact, those can be either stallions or mares!
Last, I don’t think anyone be discriminating against “honest” stallion owners if all of them had to be tested. That’s equal treatment of all.
Again, it’s just shitty luck for the owner of a stallion who holds the recessive allele just now. But doing nothing only insures that more and more breeding stock (mare and stallions) will also carry it.
9 Likes
In this scenario involving a backyard breeder who chooses from breeding stock that hasn’t been well-regulated, I guess I’d test my own mare and learn which stallions/alleles would not be compatible with her genotype… as best I could. It would be hard and imperfect.
And the irony of your last statement about wild horses breeding willy-nilly. If natural selection were in play rather than artificial selection, this allele would stay around at low frequencies in a large or diverse enough population. In a very small or inbred one? It could be the cause of extinction.
3 Likes
See I think different. I think at this moment it makes much more sense if mare owners test, and hopefully they will publish their results.
If a mare owner knows his mare is a carrier he has more power to ask a stallion owner for a result… So there will be some pressure on stallion owner.
Also by testing a lot of mares there will be information which lines might carry the gene.
The other way is not going to work IMO. The stallion owners will never test without pressure. They have not published any results so far maybe they tested, but nobody knows
I don’t know that much about WB registries… is there some reason they couldn’t just require the test as part of the inspection process and then put a * next to the names of horses that are carriers? Is there some reason they couldn’t just require that anything having registered foals be tested? I sort of thought the point of having them was quality control, rather than just pedigree tracking.
7 Likes
Not sure about the * as a marker but otherwise basically a good idea. In dogs it is common that there are health databases where data like this is collected.
And I am pretty sure that there will be more tests available in the future so a * would be not be sufficient then.
It would make more sense to just collect the health data for each horse and make it accessible for breeders.
But somehow so far registries do not seem to be crazy about anything like this (at least not in Germany) And thats exactly why I try to be encouraging for testing and try not to make assumptions without any scientific proof. Because in order to get something started you have to be encouraging…
Otherwise read what I cited before. Omertà the breeders code of silence… You can google it. This is what will happen if you talk about marking horses as carriers… IMO it has to be a neutral collection of data…
But what do I know…
Yes, the registries could. The question is, will they? As a group, they have been very, very slow to jump on issues like this. Registry politics are often very much dominated by stallion owners, and it is a very fine line to walk to initiate an additional licensing requirement that could very possibly affect a fair number of stallions. It would cause quite an uproar in the breeding community if popular stallions are identified as carriers. Look at Sternlicht’s pedigree - Sandro Hit, Donnerhall, Rotspon/Rubinstein I, Weltmeyer, all show up within the first four generations. Those lines have been hugely popular in dressage breeding, and identifying one or more of those stallion lines as “carriers” could have a devastating effect on breeding programs.
Compounding the problem is the fact that most breeders in NA are hobby/backyard breeders, and they will probably remain blissfully unaware this genetic condition even exists, unless the registries get involved in identifying and “disallowing” carriers. But again - a mandate that both parents certify as “non-carriers” in order for a foal to receive full registration papers, would create a huge backlash from mare owners who are going to resent like heck an additional requirement such as blood testing for WFFS.
My personal opinion is that given the tragic outcome for the poor foals born with this condition - not to mention the toll on the mares that lose their babies, and the breeders that lose money and a year of production from their mare - the registries need to get in front of this issue - and ASAP. Several top registries such as KWPN and AHS have issued statements that they are “studying” the situation, and it will be interesting to see what additional steps they take. And also interesting to see if other registries follow suit.
This is a terrible situation for the owner and breeder of Sternlicht - not to mention the mare owners who have used him - and my hat is off BIG TIME to Hilltop for coming forward with this news. As painful as it has been for them, they have done the responsible thing by bringing this condition to light, and by pulling the stallion from breeding until more is known.
12 Likes
A good article that starts putting context to the inherently vague nature of the propagation that mvp has spent several threads trying to explain about what happens when you continue to breed carriers of any disease/condition
5 Likes
I’ve been watching this thread since the start, and feel the need to address some of the population genetics being mentioned here. The math in this link is not correct. You’re not going to eventually end up with a higher and higher and higher % of carriers, unless there is selection or the population is very small. The allele frequency will remain constant. The math behind this has been studied for many, many years.
As someone who took several population genetics, my concern would be selection. As several folks have pointed out, we cannot rule out that there is a heterozygous phenotype. Considering the movement we’re breeding for in dressage these days, I’d be very wary of breeding heterozygous animals until more research is done. If there is selection for these animals, that is when you start to see an increase in allelic frequency. HERDA and HYPP are great examples.
We have a great opportunity here to stop this with the warmblood breeding structure. Require the test before breeding approvals, and don’t approve mares or stallions for breeding if they are carriers.
I see two major issues here. First, right now we’re faced with owners who have already put considerable investment into their current breeding animals. I can understand how reluctant an owner would be to simply shelve an animal because of their carrier status. Especially considering how many mares enter broodmare-dom after a career ending injury (which I think is another issue with the animals we are breeding, but that’s a while 'nother can of worms).
The second issue are folks who don’t care enough to test/don’t have a vested interest in the future health of the breed. They could simply go to another studbook that does not require genetic testing. That has certainly happened in the past.
So almost certainly there would have to be a future date set when carriers would not be approved, years down the line. You’d still have mare owners gambling and trying to produce non-carriers in that time. It’s easy enough to remove males from the breeding population; it would be a heck of a lot easier if spaying was that straight forward. This is another reason why a dog analogy is non-viable.
Folks like Hilltop are a perfect example of what should be done. Test your own stock and make the results available. People need to be aware that this is an issue and news/results/advertising gets the word out.
6 Likes
