EPSM in simple laymans terms

[Alexie]

Can someone put into simple terms exactly what EPSM is?
And exactly how it causes the symptoms that it does?

I have read that it is related to (or the same thing as) tying up or azorturia, but i've also read that this is not the case :confused:

Do they know for sure how it works, or is it still on-going research?

My knowledge of EPSM comes from a lot of reading material about it from the internet and also from horse forums, and wikipedia.

Has anyone got access to academic papers about EPSM or even better can anyone provide links to these resources?

Thanks in advance :)

[JB]

SIMPLE terms = the horse cannot use simple sugars to convert to energy. That means those have to be reduced (similar to an IR horse's diet), and *sometimes* that's enough. In many cases though that energy has to be replaced by something else. Since protein is a very poor source of energy, that leaves fat.

Go to www.ruralheritage.com and look around the Vet Clinic - that's where you need to start in your EPSM research :)

There is also a new-ish biopsy to determine EPSM in some breeds, so if you search along those lines you may find some of the papers you're looking for.l

[Tackpud]

Can't direct you to any research on it, but have dealt with it in real life. It is a glycogen storage disease. It results in the accumulation of high muscle glycogen and abnormal polysaccharide in the skeletal muscles. Basically the horse doesn't process carbohydrates properly and ends up with storage of unmetabolized carbs in the muscles.

This creates an imbalance in the muscles being unable to work properly, leading to the cramping that you see in the hind end. The horse may pick up the hind legs extremely high, or refuse to pick them up at all to be cleaned. When turning they may hold the leg up an extra few moments, or seem to be unable to put it down where they want to.

I think there is research going on in many different places.

[BornToRide]

SIMPLE terms = the horse cannot use simple sugars to convert to energy. That means those have to be reduced (similar to an IR horse's diet), and *sometimes* that's enough. In many cases though that energy has to be replaced by something else. Since protein is a very poor source of energy, that leaves fat.

Go to www.ruralheritage.com (http://www.ruralheritage.com) and look around the Vet Clinic - that's where you need to start in your EPSM research :)

There is also a new-ish biopsy to determine EPSM in some breeds, so if you search along those lines you may find some of the papers you're looking for.lI do not believe that is quite correct. The horse can still use glycogen as fuel.

EPSM horses are simply far more effective in storing extra dietary sugars in their muscle tissue which leads to an overload that eventually damages the muscle tissue. That's why feeding grain to draft horses on Sundays without work would lead to tying up on Monday mornings.

If they could not have used glycogen for energy production, they would have all died. Glycogen is still the preferred fuel over fat. Fat can be utilized, but for the body is a poor choice to produce energy.

Dr. Valberg's research on the subject makes more sense to me....

http://www.re-leve.com/documents/Feedingfattomanagemuscledisorders.pdf
http://www.re-leve.com/documents/Muscledisorders-untyingtheknots.pdf

[Alexie]

JB thanks for the link, I've already had a nosey at the material on there but will read it in more detail :)
There seems to be the draft horse EPSM research and the QH EPSM (or is it PPSM?) research, the two lines of reseaarch not yet brought together?

Tackpud thanks for your explanation :)
so it's the overburden of carbs in the muscle that causes the damage? I've read in the QH research that there is a muscle sensitivity to insulin but I wasn't clear if they meant that it was this that caused the damage - confusing. I know it's not really important as long as you stop the damage, I'm just keen to find out what's happening :o

BTR thanks for the links, have saved them to read later :)

[Tackpud]

Check on what you have read in the QH research - it may be about HYPP, not EPSM. HYPP is the muscular disorder restricted to QH's that comes from sodium ions leaking into cells and forcing the potassium ions out. That leads to a drop in insulin.

[JB]

Anything you read about sensitivity to insulin is about Insulin Resistance.

HYPP is about a sensitivity to potassium.

[Cielo Azure]

I much prefer the Univ of MN site to the rural heritage site for information on PSSM.

[Tackpud]

JB - agreed HYPP is a sensitivity to Potassium, but it is treated with Insulin - that's why I mentioned the drop in insulin. Didn't mean to sound like it was an insulin created issue. Sorry if I confused anyone.

[Alexie]

just to clarify the insulin comment :)

3. What causes PSSM in horses?

Polysaccharide storage myopathy (PSSM) is characterized by the abnormal accumulation of the normal form of sugar stored in muscle (glycogen) as well as an abnormal form of sugar (polysaccharide) in muscle tissue. About 200 horses of Quarter Horse and warmblood/draft horse breeding have been identified with tying-up associated with polysaccharide accumulation in muscles. This disorder is inherited in Quarter Horses and breeding individuals with PSSM has produced affected offspring.

Horses with PSSM accumulate muscle glycogen due to an unregulated uptake of sugar (glucose) into their muscles and the synthesis of its storage from in the muscle called glycogen.One aspect of the defect involves enhanced sensitivity of the muscles to insulin, resulting in more transport of sugar from the bloodstream to skeletal muscle. The diet can be adjusted to decrease the amount of insulin and sugar in the bloodstream. Carbohydrates that are high in starch, such as sweet feed, corn, wheat, oats, barley, and molasses, should be avoided and extra calories can be provided in the form of fat. An important part of the management of PSSM horses is daily exercise. This suppresses glucose uptake, enhances glucose utilization, and improves energy metabolism in skeletal muscle. If only the diet is changed, we found that approximately 50% of horses improve. If both diet and exercise are altered, then 90% of horses have had no or few episodes of tying-up.

I got this quote from here:
http://www.cvm.umn.edu/umec/lab/PSSM/home.html

which is on this site:
http://www.cvm.umn.edu/umec/lab/home.html

[JB]

You're right, my bad, sorry! I blame it on being up too early to do something I wasn't planning on doing and making the mistake of passing a little (foggy-brained) time here :D

[Androcles]

Can't direct you to any research on it, but have dealt with it in real life. It is a glycogen storage disease. It results in the accumulation of high muscle glycogen and abnormal polysaccharide in the skeletal muscles. Basically the horse doesn't process carbohydrates properly and ends up with storage of unmetabolized carbs in the muscles.



Do we know why the carbohydrates are not able to be metabolized properly?

[Tackpud]

Do we know why the carbohydrates are not able to be metabolized properly?

I think research is being done on this now, but I don't have an answer to what is being done or how far along the research is. What I've outlined above is what I teach in Vet Science - a little more depth, but no definitive answer that I've been able to find yet.

[ivy62]

I have a horse that we thought might have had EPSM. We did not do the biopsy but changed the diet anyway. We modified it so he was not getting the oil but the basis of his diet is rice bran with a nice Ration Balancer and forage..The difference in him is HUGE. He looks like a million bucks...He is moving nicely, he was lame before, and his weight and coat are awesome!
If a horse does not have this condition is it hazardous to have them eat like this anyway?

[Alexie]

JB don't be sorry, this is why forums are good. If I couldn't kick around what I read with others I wouldn't digest it half so well, so thanks :)

ivy, i think the epsm based diet is closer to what horses were intended to eat (apart from the high oil obviously), and I put all my horses on it, even the ones with no EPSM symptoms.

I've read somewhere (forgotten where as I've been reading lots) that rice bran is a good way to get fat into the EPSM horse.

I personally think it's a good way to feed any horse and not hazardous at all.

it's all very interesting and confusing too!

[BornToRide]

Be aware though that rice bran tends to be high in NSCs!

[RiverBendPol]

If you spend the 20 bucks to join Rural Heritage, you can talk directly with Dr. Valentine. She quite literally saved my Mikey's life 8 years ago. I had turned him out. I told him if I couldn't figure him out I would have to put him down but in the mean time, he was to stand out in his field and stop breaking my bones and tearing down my barn! My vet's tool box was empty, we had spent 2 years and thousands of dollars trying to get to the bottom of his issues and I was given permission to access the internet with hopes of finding help. Right here on the COTH, Roundbale (:winkgrin:) directed me to Dr. Valentine who educated me and helped me find the diet that turned my raging bucking crashing maniac into a lovely, successful, Preliminary event horse. Dr. V. is the champion of EPSM.

[Alexie]

RiverBendPol
My horses get lethergic and lacking in any sparkle or energy when fed grain.

I'm really interested that your horse was a bucking maniac until you put him on the EPSM diet because mine started bucking when he was ON the diet (increased feel good factor kicked in and he got opinionated).

Can you tell me why you think it stopped your horses bad habits?

[monstrpony]

RiverBendPol

Can you tell me why you think it stopped your horses bad habits?

Because muscle cramping (from inadequate energy in the muscles) is uncomfortable. Horse misbehaves because he is in discomfort/pain. Remove the cause of discomfort/pain and "bad" behavior goes away.

Horses who start on the diet often go thru a brief period of being a bit of a handful--that's becuse they've forgotten what it feels like to feel good and feel the need to express the joy of it. They actually have adequate energy for the first time. The yahoos pass after a while and you just have a happy, cooperative horse.

The polysaccharides are stored in the muscle, but the muscle cells don't know how to use them as an energy source and the muscle cells actually starve; large muscled horses (draft crosses) who have inadequate muscle development are lethargic and even clumsy--as was mine; he looked like a large-framed TB, but never developed adequate muscle to move that large frame, so he was impossible to condition and downright clutzy. His muscles were supposed to be much larger, and became so after diet change. If you see slides of EPSM muscle tissue, there are some healthy muscle cells, some completely atrophied cells, and pockets of the stored polysaccharides.

While it is true that pure fat is not a normal feedstuff for horses, remember that forage is not digested, but rather fermented in the hindgut. And the products of that fermentation are fatty acids that are then used for an energy source. Seen that way, it is not unreasonable for the horse to be able to adapt to fat as an energy source, even though it does not seem like a natural food for an herbivore.

[RiverBendPol]

Good, Monstr. Thanks!
Mikey was an interesting case in that when I bought him, he had 'become too much' for his person. No details were offered. Got him into the trailer to drive him home on purchase day and he began to rock and ROLL, which he always did in the trailer (till after the diet). Previous owner had also told me he loved to take naps. Well, those turned out to be lying FLAT, dead-horse-style, for 20 minutes of every hour while turned out. The rest of the time he spent bucking. When he was in the stall, he shot his feet through the walls and bashed his head on the ceiling. Eventually, I got smart and let him live out 24/7, with a shed. Under saddle, he was a leaper. Less bucking, more launching. Canter transitions were horrific, coming down worse than going up. He could not physically jump 2 jumps in a row, even with 5 or 6 strides between them. He was mouthy and constantly tried to grab everything within reach. His eye was hard. His back muscles were tight tight tight, they felt like piano wire running from wither to croup, his whole rump was hard as concrete. He had a palm sized dent of muscle waste on his right rump. He had stabbing painful cramps. He would trot around, trying to be good and would suddenly say "OOOOOOOOPH" like he'd been kicked in the stomach. He was a most miserable thing. Once the diet started (alfalfa pellets, soaked in hot water and a cup of canola oil 3xday), everything changed. His eye softened in the first week. His mouthiness went away during the 2nd week. He was far less frantic and he generally improved so much that he went from not being able to walk up hills with his head down nor being able to jump 2 cross rails 60 feet apart to running a CCI* (full format) and being written up in the Chronicle magazine. He was a 17.1hh TB and was one of the very early TBs to be known to have the illness. My own vet even said, when I told her I'd diagnosed the horse on the internet, that only draft horses get EPSM. Mikey continues to be the poster child for her veterinary practice.

The "bad behavior" Mikey showed us was nothing but downright misery. He told us that early on in our relationship. Mikey was a good horse in a bad body. I knew that and am so grateful that in the 8 years I had him, I NEVER was rough or hard on him. He was a great educator. I wish he hadn't broken my bones and given me 2 concussions but hey, I sure learned alot from him and Dr. Valentine!

[monstrpony]

RBP--yeah, I have trashed SI joints from trying to ride that trot that felt like an unbalanced washing machine! Monstr threw the occasional buck, but mostly it was the heartache of having a *brilliant* canter one day and not being able to stay out of his own way the next five. He had the draft horse work ethic and kindness that kept me from getting seriously hurt. Monstr's symptoms were subtle (inasmuch as a 17.3 draft cross can have anything subtle about him), no one could ever put their finger on it, and it wasn't always reproducible. Horribly frustrating for us both, and as much as it tore me up, I'm sure it was even more painful for him. But I will *never* forget the moment when I read Dr. Beth's email that told me, yes, there is a reason, and, no, it wasn't my bad riding. When I told one of Monstr's vets of the diagnosis, her reply was that it couldn't be, because he'd never tied up (tho, in retrospect, I think he had, but even that was confused with another issue--he was kind of a medical marvel horse, I think largely due to the underlying and undiagnosed EPSM).

It is quite the experience. As much as we get accused of "disease of the week" for mentioning EPSM, I envy the heck out of people for whom it is now more main-stream to consider it, rather than having to stumble across it as an incidental during a web search on, oh, say, equine arthritis, as was the case for me.

[RiverBendPol]

.....It is quite the experience. As much as we get accused of "disease of the week" for mentioning EPSM, I envy the heck out of people for whom it is now more main-stream to consider it, rather than having to stumble across it as an incidental during a web search on, oh, say, equine arthritis, as was the case for me.

MP-
I remember your hell-it was right after mine. I think we owe our education in part to my pal ROUNDBALE who read my list of symptoms right here on COTH and sent me directly to Rural Heritage. You're right, there was a time when EPSM was all I could talk about but when you're in the thick of it, you want everyone who's having any trouble to at least THINK about it!

My vet worked so hard to try to figure Mikey out-we did Lyme titres, treated for ulcers, food allergy testing (positive to wheat, corn, beet pulp, cotton seed), hock injections, magnets...I can't remember what else but I do know I spent THOUSANDS of dollars on his medical bills and mine!:eek: Who knew it could be as simple as taking away the sugar and adding fat!

Is The Monster still with you? Mikey went to heaven on July 3, 2007 after a year of trying to rehab a torn SI ligament....

[Alexie]

thank you both for sharing your experiences.

yet more alarm bells are going off now after reading your posts :o :o

EPSM is not at all straight forward, it seems the more I read the more I need to find out.

[BornToRide]

I disagree with the EPSM diet on one thing - although fat can be used as fuel, it is NOT the preferred energy source for muscles. Horses are also not designed to eat large amounts of fat in their diet! Fat in the gut will however slow doen/reduce the NSC uptake.

I have heard many stories from people who found that the high fat diet did not work well and they had to change their approach. Remember that draft horses would do fine on their diet all week, except Mondays when they would tie up, because they had no chance working the excess off on Sunday when no work was done.

The main issue is to bring the NSC intake down to a tolerable level depending on work load. Therefore Dr.Valberg's research and approach makes a lot more sense to me :)

[ivy62]

When we switched to an EPSM style diet, I was not convinced that the horses liver would handle that much oil for a long period of time so I use a diet that is made up of the rice bran as a base and then an organic feed that has no sugar in it almost....and very low in NSCs..It has taken months but he is doing well on it....At least with the rice bran it has not only fat but protein also..
JMHO