Tieing up in Thoroughbreds

Hi, I am looking at TB mare that retired from the track and apparently had an episode of tying up. After 2 years pasture rest and now being brought back to work,4 months there have been no recurring episodes.
I would use her primarily for dressage, with a healthy dose of trail, working equitation and low jumping.

Of course I am preparing to have a PPE done, so my question is if it was indeed tieing up isn’t it genetic, meaning it doesn’t go away?
What should I be thinking about? Other than a different horse, lol

You could have her tested for PSSM.


Sometimes tying up is as simple as a major enough electrolyte imbalance, which could pretty easily happen if the weather is hot enough while working.

But I agree with Scribbler, test for PSSM. RER isn’t uncommon in TBs, and is one form of PSSM2

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Rule of thumb when buying a horse, don’t buy trouble.

We had a very few TB’s that tended to tie-up and they were hard to manage.
You had to watch them very carefully and if they were sore, assume it was a possibly mild case.
We didn’t have any medications, other than E-Sel and vets didn’t always prescribed it for every horse.

Horses that tie-up, for whatever reason, have good and bad days, not sure they are the right horse for some that want to do much with their horse.
On the other hand, they need regular exercise, so don’t make good pasture ornaments or when relegated to light riding.

I would see what your vet finds and recommends at PPE.
I doubt that they would pass a horse known to tie-up without a warning that may be a problem.

Our riding center had a smallish school and endurance horse that started tying up at about ten years old. We managed him because we could keep him in lessons, just enough so he was exercising every day, easing up if he seemed stiff and sore at times and he did fine.

Let us know what your vet tells you, would be interesting to hear what he thinks.

It’s not uncommon, especially in fillies.
A lot of it has to do with management. Turnout, regumate for fillies, etc. if she tied up once and then trained without another incident, I wouldn’t worry about it at all.


Feeding and Managing to Reduce Recurrent Exertional Rhabdomyolysis in Horses - Kentucky Equine Research (ker.com)

Recurrent Exertional Rhabdomyolysis | College of Veterinary Medicine at MSU
In that last one, they reference the Px genetic marker. That’s done through EquiSeq, as are all PSSM2 tests with hair. They are questionable since their research is still not published. BUT, so many people are finding dietary and management changes that improve their horses after getting results, that I’m not nearly as against their testing as I was. There is some ongoing research at U of Minnesota (I think that’s who’s doing it) that will hopefully start validating hair/genetic testing

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I was getting deja-vu, thinking we’d had this thread before – OP, you started one like this a few months back right?

Tying up is a catch-all phrase. It could be from anything to extreme exercise induced muscle tremors, to RER, to PSSM2…

TBs don’t have PSSM1 - which is the disease most people think of (besides HYPP) when someone mentions tying up. They can have PSSM2, which runs the gamut for clinical symptoms.

In all of my years managing TBs, I’ve never had a TB tie up after the track, and never dealt with PSSM2 in a TB. That’s not to say it doesn’t exist, but it’s not common in my experience. I think there are a lot of external factors that contribute to tying up in racing horses and not all of it is genetic.

So to answer your question specifically – if it is genetic,no it won’t go away and anything you breed might have it too. But if it was environmental, it was likely a one time thing.

If you are concerned, you can manage her like she is clinically PSSM. High fat, low starch grain, vit E and selenium, and lots and lots of turnout.

I would take it as a good sign she has been in work for several months now with no issue. In no way does any sport home come close to reproducing the environmental and physical stressors of the track.

There are PSSM groups on FB that are worth joining, but take their input with a grain of salt. As with all things FB, there’s a lot of misinformation circling these groups and a lot of conspiracy theories (like Northern Dancer being the cause of PSSM in TBs… lol)


Yes, I did start this thread a short while back. I was trying to use my ipad which seemed to be gliching that day, to start a new thread and somehow reposted this thread! There has been some great information posted so have still learned. I apologize to everyone for the repost.
Thank you to all who posted again on this thread!!

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Bah. I had a QH who tied up ONCE. added some Red Cell to his feed and it never happened again. We had been at a show and he didn’t want to pee or drink. From that point on I made sure he had access to either a stall or a trailer with shavings so he would pee. No biggie at all.

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I am in a barn full of OTTBs and my OTSTB that have some form of muscle issue that leads to tying up. We have had them all tested through Equiseq for PSSM Type 2 and they do have type 2 genes present but I don’t fully trust their methods for ‘diagnosis’. None of them have tested positive for type 1.

What I do know is putting our horses on a higher protein and vitamin e/selenium diet with good exercise and ample turnout has turned most of them around. A few of them have also done really well on a low sugar diet with soaked hay and a grazing muzzle when outside. I know PSSM Type 2 isn’t usually associated with sugar issues like type 1 is but I do think too much sugar can lead to inflammation. When we first started to ‘treat’ our horses we did put them on higher levels of magnesium as a muscle relaxer. It did help to loosen muscles and get them more comfortable but can make horses loopy or spooky. We are now weaning them off of it after about a year of being supplemented with it. It is also important to balance their Calcium/Phosphorus ratio and salt levels. I recommend joining a few of the FB groups for PSSM as the community as a whole has a lot of good information.

Good luck! It’s been a real journey the past year or so with our horses to get them into shape without causing tie ups and crashing but they are all doing well now.


It’s these correlations, more and more, which give me more belief in their testing. I’m still not 100% on it, but more and more I run into horses who are tested, with diet changes, not necessarily in that order, with more often than not showing a relationship between 1 or more Type 2 variants, and improvements in the typical Type 2 dietary changes. Not all, I think it’s more complicated than that, we may find that some of these are markers to the actual gene, not the gene itself, so not 100% reliable. Maybe. I don’t know LOL

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I agree! My horse has always been hard to get muscle on and has had off and on hind end lameness that could never be pinpointed to one area. It wasn’t until 2020 (2.5 years into owning him) when I thought I should do bloodwork to have a normal baseline of his levels. Through the routine bloodwork we did find out his ACT and CK levels were elevated. That is when I did the type 1 test and then used my insurance to pay for the type 2 test. He is n/P2 and from the diet changes, increased blanketing in the winter (and honestly any temp below 60), and increased/regular exercise, he is thriving. A few of the horses in our barn who have more than 2 variants struggle with management but they are still good riding horses. I just wouldn’t count on them being comfortable for as long as a normal/healthy horse.

I wish Equiseq would actually get peer reviewed and publish but as long as they have paying/satisfied customers, what really is the incentive for them?

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Their incentive will come if/when U of MN or U of MI are able to publish results of the research they’re doing now.

U of MN is actually working WITH EquiSeq .
MSU is where Dr Valberg has been doing her research

I’m still a skeptic on the worth of paying $300 for EquiSeq for now. I think a lot of the management & diet changes with PSSM are beneficial for almost all horses, regardless of disease status. Kind of a well duh moment that a horse does better with more turnout and better quality forage/grain.

It honestly reads like a cult following on a lot of the PSSM pages.


I think the burden should be on the company, not public universities to fund the peer review.

But regardless, Valberg has published two studies that concluded the equiseq variants weren’t predictive of MFM of PSSM2.


I’m also not totally sold on the “working together” claim regarding U of M. They are studying the variants but specifically state the harm in the commercialization of unvalidated genetic tests…

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It wasn’t just the more turnout and better forage/feed that changed our horses but it did help. My horse was out 24/7 on a lovely 32 acre grass pasture when he was diagnosed and was not doing great. He had access to great forage and 24/7 turnout. What really made the difference for us was pinpointing particular supplements that aid in muscle repair and building. We also started doing research on diseases similar in humans and trying to understand the physiology of it in horses.

I agree, the pssm fb groups are pretty cult like. They helped a ton when I first got started but after initial research and questions asked, I started to find I did better on my own.

I wanted to put my guy in that study but was unlucky in finding a horse in our barn I didn’t suspect of some type of myopathy. I can’t wait to see the outcome of their research though

Also the amount of posts I have read where people argue over which magnesium is better for horses or which vitamin e is the most worthwhile and how much they should dose makes my head spin.

A lot of these horses need a change in diet and exercise management, not just one supplement and they are better. I swear that’s what a lot of people think in these groups think, though.

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Those shouldn’t be that complicated LOL

Magnesium oxide is the most bioavailable, and with the highest elemental Mg, and the cheapest, so is a great place to start. If it doesn’t do the job, then you either move on to another form, or you recognize the issue isn’t about Mg in the first place.

All d-alpha tocopherol the same (yes, there are a few that contain ALL the natural forms, it’s debatable whether they’re better enough to warrant the cost.

All water-soluble forms are the same.

There are very cheap ways to do regular natural E, and there is a cheapest way to do w-s (Emcelle).

We know how much horses generally need. 1-2IU/lb. Some need more, which is where you just try things with some blood work to see what works.

Vit E is pretty black and white.


Seriously. I have never understood this argument over Mag Citrate, Mag Malate, Mag Oxide, etc. Some swear that each has a beneficial property. I went with MVP Magnesium and its been just fine for what we need it to do. As for the vitamin e, I dont think most people (or maybe enough people) know to look for the bio-available version.

I think sometimes people make these things way more complicated than they need to be and are unwilling to just try something and see if it works.