Has anyone bred a mare who has shivers? I’ve talked to various vets with multiple opinions, but curious if anyone has any experience, or known complications, with breeding a mare with Shivers. I’m looking to use her as a recipient mare – not to genetically pass on her shivers. Her shivers have not advanced since she was young, and when in full work shows little signs. Certainly not an advanced case of shivers. Curious as to people real-life experiences. Thanks!
I would absolutely NOT do it. Talk to Dr Stephanie Valberg at MSU. Until it’s proven that there is no genetic component to this, there’s a very real risk you’re perpetuating a horrible disease that can shorten the life of a horse significantly and cause all sorts of problems for the owner till then.
Got to run - I’m off to pay an exorbitant amount to the only farrier who will attempt to put 2 shoes on my 5 yr old shivers gelding, heavily sedated, and it’ll take several hours to manage it…
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ETA: OP has since clarified that she did not intend to breed as originally stated, just to use as recipient. I’ll withdraw the below…
Gee, post #1 made on the day the member joins COTH, and it’s an inflammatory topic. This oughta go well.
One known complication with breeding a mare with shivers is that you are perpetuating a painful genetic disorder that is progressive and incurable.
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I should be clear. I was thinking of using the mare as a recipient mare for another horse.
Using a mare as a recipient is not breeding her. That’s where you’re confusing people.
Changing the title of your thread would help a lot 
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And editing your post after the fact makes the thread hard to follow unless you state the reason for editing…
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Clearly trying to clarify the post. Changed the title. Still looking for feedback on whether anyone has EXPERIENCE with a shivers mare carrying a baby.
I managed and foaled out a mare with shivers, she was in my care for roughly a year and a half (from breeding to weaning). She was a bit tricky to work on her hind feet, and she struggled to back up or turn in tight circles but it otherwise didn’t really affect her much. She had no trouble foaling or anything. I know it’s a couple years later now and the mare is in foal again.
N=1. but a friend of mine owns a Trakehner mare with mild shivers. She’s bred her three times. Gorgeous mare, wonderful foals… 2/3 of them have shivers as well. The mare is in her late teens now and she did not know the mare had shivers until after the 2nd foal.
I’m pretty convinced there’s a hereditary component.
The thing is even recipient mares pass on genetic traits to the foal. I would be very wary.
Personally I would not do it. Shivers is a heartbreaking disease. I’ve seen it up close, cared for horses with shivers, and it is just such a sad and drawn out affair. It’s very hard to find farriers that are sympathetic to horses that seemingly “wont” cooperate and it’s also very hard financially to care for them, as they tend to need a lot of maintenance most boarding barns won’t require (24/7 turnout, for instance).
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Shivers definitely has a genetic component, and I’d never breed anything with it, unless it can be more or less proven it’s the result of some type of injury.
Recipient mares only contribute mitochondrial DNA, which, to my knowledge, doesn’t contribute to this sort of thing, but I guess I don’t know that for sure. We know it contributes something, which is why the ideal recipient mare is from the same mare line as the egg producer, but in general, there isn’t a lot of genetics to include there.
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NO and NO!!! I cannot say NO enough times!! :no::no::no::no::no::no:
A recipient mare is just that…a recipient of another mare’s embryo. An incubator. The DNA has already been established from the stallion and the donor mare. A recipient mare contributes absolutely ZERO DNA to an embryo transfer foal.
JB, what you are talking about relates to cloning only. A donor egg must be used when cloning and it does involve mitochondrial DNA…but this is TOTALLY UNRELATED to embryo transfers and donor/recipient mares.
While I cannot offer advice on using a mare with shivers as an embryo transfer mare, there is no way for the foal to genetically inherit anything from the recipient mare. Zip! Zero! Nada! NO!
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Sorry, that’s not what I have been told or read. We know so little about ET/AI that I don’t know how you could possibly say “no DNA is inherited period”, as far as I have seen and read, that simply has not been proven true - it used to be people said that recipient mares had no effect on offspring size, and we know that is not true either. As JB says, the the recipient mare can contribute mitochondrial DNA.
So just because JB spews out that information, that makes it correct? JB is misinformed and is quoting literature in regards to cloning, NOT embryo transfers.
How on earth you can think an “incubator” can contribute DNA to an embryo that is already formed is beyond me. (banging head on desk) Please provide the links to the literature that you’ve read that states otherwise.
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Sheesh, a simple “I think you have that confused with cloning” would have sufficed.
I’m still not convinced it can’t happen. I don’t think we remotely know enough to say for certain that it can’t. I mean, if the uterine environment can affect the amount and shape of white markings from clone to clone, who’s to say the MtDNA can’t affect an ET?
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Let me know when you get tired of banging your head…
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The reference to cloning here simply sets up the conditions for the experiment; they used clones with identical nuclear DNA as the subjects so that they can isolate the existence and cause of mitochondrial DNA transfer from recipient to fetus. Use of cloned subjects is absolutely common in animal research-- eliminates an enormous variable so you can study what you want to study.
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Agreed! 
But when people venture on to a forum and read what is written as gospel, it’s important to make sure people understand what is accurate information and what is not so they don’t pass it on to others as being accurate.
A foal’s white markings are an “environmentally” influenced response. The white markings are already there. It is hypothesized that the size and shape is influenced by the uterine environment…but it doesn’t MAKE white markings where none are genetically not.
The study you posted involves cows. The problem is, you cannot compare one species with another. Obviously, horses are a very different species than cattle. For example, cows are able to have identical twins. They may not be common, but do happen in approximately 1 out of every 4,000 births. One of the reasons you almost NEVER see identical twins in horses is because a hard shell develops around the embryo, so the chance of it “splitting” are remote.
There is a lot that is not understood, I will acknowledge that…and the recipient mare obviously offers a lot of potentially influencing “environmental” issues, i.e., nurture vs. nature, BUT…and this is a big but, the DNA in foals produced via embryo transfers are their parents. Otherwise, there would be some issues when the foal was DNA typed. Lots of hypothesis out there, but so far, the research shows that embryo transfer foals are a result, genetically, of their parents. Finding circulating levels of mitochondrial DNA in a fetus’ blood is not the same as having the fetus DNA typed as from the recipient mare.
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Considering my original post was before JB’s, not sure what you’re going for there.
As of now, what you have said (foal gets nothing from recipient) is unprecedented and unproven.
I respect your opinion and generally enjoy your posts, but find the manner you’re engaging in this discussion unpleasant. There is no need to be rude to JB, or me. It’s easier to have a polite discussion than one that is condescending. I guarantee you, people are much more receptive to contrary information when it is presented politely.
You have no sources that prove your statement is correct. You know, fifty years ago, people also said that cats can’t have a litter with several (more than one) sire. We know that is not true now.
There are several sources that suggest the opposite.
I have tried combing the internet for any research articles or peer reviewed papers that supports your opinion, but so far, I have come up empty. I am interested in reading anything that suggests an alternative finding in regards to equine embryo transfers. You keep saying that there are several sources that suggest the opposite of what is currently know about equine embryo transfers…and I have already asked if you could provide the links to those resources. If you can post them here that would be great.
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You can google pretty easily:
https://www.google.com/search?client…0.m9YIsJDefoQ
Or Yahoo:
https://search.yahoo.com/yhs/search;…&hsimp=yhs-002
Since it is documented in clones, I am not convinced it is impossible in ET or other oocyte transfers. I don’t profess to be a scientist or an expert on the subject, but ET and cloning fascinate me. Partially because there is still so much we don’t know about it.
Example - 20 years ago, we as humans believed the DNA you were born with is the DNA you got. Period. No changes. Now we know that’s not true - environmental factors, senescence, life events all play a hand in how your DNA changes over time, and how that DNA is passed onto your offspring.
Re: “not being able to compare species to species” - on the contrary, it is usually the discovery of something in another species that often prompts an unrelated industry to look into how it affects the species of their choice. Mice are a fantastic example. So much of what we know scientifically comes from mice & rat studies first. Of course, they share 92% of our genes - which is why they are so useful in lab settings. Look at the supplement industry - half of the horse supplements marketed are based off of scientific findings in other species first. It has only been in the last decade that studies proving their efficacy (or in some unfortunate cases, disproving) has substantiated the bold claims many supplement companies make about their product. The cattle cloning industry is larger than the horse cloning industry – and also much more illustriously funded. Studies are incredibly expensive to produce. Once there is a big enough interest in learning more about the absolute limits of oocyte transfer, you’ll see an equine funded one.
Heteroplasmy is a pretty well studied thing in other species, not so much in horses.
The thing is, if we know that the recipient mare in ET does affect the foal: growth rate, foal height, bone length… This is proven. We also know that environmental stimuli during pregnancy can cause epigenetic changes. Part of being a scientist is looking at the abstract and combining/collecting data to make an educated guess. This guess is a theory - and then you perform studies to collect data to prove or disprove this theory.
With both of those proven concepts in mind, I would not risk putting a valuable ET foal into a Shivers recipient mare. I think it’d be cruel to the mare to have that additional weight and body-work load - I don’t know many Shivers horses who aren’t perpetually uncomfortable – all I’ve known have had overall body malaise – a foal could only compound that discomfort. And for two, we don’t know what supplements can be detrimental to the development of the foal, and most Shivers horses need an excessive amount of Vit E and sometimes Selenium, as well as other supplements, to keep them minimally comfortable.
Now I would request that you do the same: provide a source that says ET recipient mares do NOT pass on any mtDNA to their foals.
Actually, I did.
The “changes” in the DNA are environmentally influenced…but the DNA does not actually change. DNA characteristics can be influenced by environment. Horses with OCD is a good example of that. If you feed the horse properly, while they may be genetically predisoposed to the problem, the switch isn’t flipped. You’re not comparing apples to apples.
There’s no doubt that environment influences the final outcome of what the foal is and will be. I’m genetically predisposed to Type II diabetes. However, I watch what I eat and while my brother is now diabetic, I have, so far, managed to dodge that bullet. But, even if I am diagnosed with diabetes at some point, my DNA will NOT change.
The links you posted are referring to cloning, not embryo transfers. Again, cloning is a completely different process than a simple embryo transfer. Cloning involves the use of a donor egg and it does involve mitochondrial DNA…but this is different than an already formed egg being put into a recipient mare for an embryo transfer.
My suggestion is that you go to the EquineRepro group on Facebook and post your findings on there. There are lots of top theriogenologists and cutting edge researchers that can discuss this issue with you…as it is above my pay grade. www.facebook.com/groups/EquineRepro
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