EPSM - Equine Polysaccharide Storage Myopathy (also known as PSSM) is a problem affecting horses of many breeds, in any discipline. It was recently discovered by Dr. Beth Valentine, and is just beginning to make it into the conciousness of veterinarians and horse owners. It is often not considered until it is fairly advanced, and the symptoms are quite dramatic - early symptoms can be subtle. Catching it early is important, and treating it is simple and generally has good results. The key is a better understanding in the equestrian community, so that it can be one of the first things to come to mind, not the last.
Note - Many of the links on this site go to the Rural Heritage site, where there is a wealth of excellent information about EPSM, and a message board where Dr. Beth Valentine answers questions from horse owners. Apart from these links, my site is not associated with Rural Heritage, and they do not endorse or review any of the information presented here.
Horse Owners Tell Their EPSM Stories
If you have a horse who has EPSM, and would like to share your story with other horsepeople and veterinarians, please contact me about posting it here.
Sabrina's EPSM Story...
As of June 2001 we think we have the mystery solved. Sabrina has been diagnosed with EPSM - Equine Polysaccharide Storage Myopathy, which answers a whole collection of questions, and offers hope for a better future for her. As I was writing out the whole saga I realized it's a bit long, so here's the short version of her story...
Note - if you are dealing with any draft horse, or any EPSM horse, I strongly recommend you buy the book Draft Horses - An Owner's Manual. I ordered it because I thought after all the advice I'd gotten from Dr. Valentine the least I could do was buy her book. Well it turns out to be indispensable. I ordered two more copies the day I received mine - one for my vet, and one for a friend who just bought a Belgian.
Sabrina's Early History
I bought Sabrina in November 1997, as a trail horse and backyard pet - my first horse. She's a 15 hand Friesian/Morgan mare, about 1200 pounds, and was 7 years old at that time. She had some good basic training, but aside from puttering on trails and ponying youngster she was pretty green.
Things to know from our test ride and the pre-purchase exam:
Otherwise, the perfect horse. Sweet, quiet, sound, and perfect for riding bareback. So I bought her.
In general, Sabrina is a friendly, outgoing, inquisitive, enthusiastic horse. Likes to trot, likes to get out and go - "whoa" was kinda an iffy thing at first - very "forward", but not silly. If anything, she's "anti-barn-sour". Never pins her ears, never swishes her tail. Gentle with everyone. No attitude problems. If you ask her quietly to "step over", she does. Impeccable ground manners. Loves to go to the mountains, and play in water. A fun, nice horse. Mean to most other horses, but great with people.
Problems Developed...
I am not a highly disciplined horseperson, so I get to see lots of behaviors that might be easy to suppress if I didn't let Sabrina do as she pleased most of the time. They include:
I figured these were just behavioral things - her little quirks - and being out of shape, and I tried to accommodate her as best I could.
Udder Swelling
At some point in dealing with Sabrina I had noticed that her udder was sometimes more swollen than other times. Sometimes there was even a little clear-white fluid there (one small squirt, max). I eventually learned that isn't a normal thing, and called the vet. To complicate things, once I got to poking around, I noticed a knot of hard tissue just forward of the right side of her udder. My initial concern was that the knot was something nasty. The first vet to look at it poked around a bit. He said it was too far forward to be mammary tissue, and not to worry, "your horse doesn't have cancer". At first I was relieved, and really didn't worry about it. But the swelling continued. It didn't seem to be a big deal, but I kept an eye on it.
Starting to Notice Patterns
I started to see that the colicky symptoms, and requests for belly rubbing, preceded the swelling. She'd act weird during or after a ride or lesson, then swell up after about 2-4 hours. The swelling would go down mostly by the next morning.
In an effort to figure out what was up with this udder swelling problem, I started keeping track of when it happened. I had already figured out that it happened after work, especially if there was stress involved, but sometimes we wouldn't do anything, and she'd swell up anyway, and other times I'd work her a bit (like, trying to get her to swell up so the vet could see), and she wouldn't swell at all.
So I started keeping track. It happened with a saddle, and bareback (no pad), so it wasn't a girth thing. It happened with trailer rides, and when I rode her around the neighborhood. It happened with riding, and with hand walking, and with just turnout. Sometimes it didn't happen, which made things hard to figure out. Sometimes she'd just swell up (maybe running around the pen when I wasn't looking?). I took her off each kind of feed, supplement, and treat one at a time - no change. Stopped using fly spray. Tried exercising, and not exercising. Tried cold hosing, warm towels, various ointments, massage... No definite pattern. It seemed worse with exercise or excitement (a big spook, or snorty trail ride), maybe worse when she's in heat, and worse in hot weather - but not every time.
Swelling Something Awful
We tried a ride only at a walk, on flat ground, to see if that was OK. About 2 hours, on a hot day. She was balky and uncomfortable. I walked her in-hand part of the way. Cold hosed her udder several times afterward. Even with that, in a few hours her udder was swollen hard to the size of about half a football, and the swelling continued all down the insides of her legs - bumpy-looking, like the surface of a brain, not smooth. Very strange. She was uncomfortable and swollen for several days - decreasing with time. This was clearly a big problem for her. After this ride I did not do any further lessons or rides longer than about 30 minutes of just slow puttering.
Things We Though It Might Be
Allergy or other reaction to something she was eating. One thing I particularly looked into were avocado leaves. Several trees are near her pen, and eating avocado leaves can cause mastitis in some goats.
Stones - Enteroliths bouncing around in there, causing generalized edema, which settles to the udder after a few hours. Would have explained the apparent belly pain and swelling. Took her to the local equine hospital for x-rays - clean, no stones.
Something out of whack internally. The hospital vet did a rectal on her at the time of the x-rays, and found nothing unusual.
Lymphangitis/lymphedema - Whatever that lump was, it could have been blocking lymphatic drainage, and causing swelling. We needle-biopsied the lump and found fibrous, non-cancerous tissue - very dense. Things we considered were scar tissue from a kick, bug bite, or other injury, an old, possibly walled-off pigeon fever abcess, or scarring from possibly mastitis, which we figured could have happened after she lost her foal. I didn't see much point in doing surgery to remove it, since that can cause more scarring and worse problems (in humans, at least), but we did try cold laser therapy, ultrasound, and NitrOxide - all to no avail.
Chronic, sub-clinical mastitis, or a still-active pigeon fever abcess.
Adhesions, torn muscles, or other internal injury from her hard labor and "foal-ectomy". We were considering doing laparoscopic surgery to see if anything odd was going on in there. I've had laparoscopic surgery recently, and didn't like it one bit (even less than abdominal surgery, which I've also had recently), so this wasn't something I was going to do lightly.
Something hormonal. We didn't get far in investigating this one, but if it were hormonal, it would still be wierd that it happened with exercise - maybe an ovarian cyst getting bounced around? Still, would that cause swelling down the insides of her legs, too?
Cancer, tumors, organ malfunctions... Except for blood tests, below, (neg. for cancer, etc.), we also didn't get into investigating these.
Congested Liver Qi - Hey, you gotta consider everything after 3 years of being a mystery. Tried a course of 2 months on PuripHy, from Hilton Herbs. A fine product, the vets OK'd it, and Sabrina enjoyed it, but it didn't fix the problem.
A blood clot (thrombus) partially occluding the arteries to her hind legs.
Chiropractic problems - The chiropractor saw a little off-ness in her right hip, and did a few adjustments. I let that go while Sabrina was away for udder therapy, figuring it was probably unrelated, and we could work on it later. She also suggested MSM and Glucosamine, which I bought, but didn't start because I only wanted to be doing one new thing at a time.
Behavioral issues - Maybe the "rub my belly" thing was just learned, or maybe she was treating me like a foal (she'd chase the donkeys away if they approached - protecting me?), but then why did it only happen after exercise, especially when she was going to swell up.
Things Get Consistently Worse
Between some layoff time with no work (due to my surgeries mentioned above), and the time she was away for udder therapy (staying in a 24 x 24 corral), she got worse. Now she was swelling up every time she did anything. She had injured a tendon while she was away (kicked a corral), and I couldn't even hand walk her for 10 minutes without her getting ouchy and swelling (her udder, that is, not the leg) afterward. So I couldn't rehab the injury. Very frustrating. I had to do *something* . Now she wasn't even happy just hanging around and going for walks. She seemed cranky and listless - walking off to a far corner and turning her back instead of wanting to be scratched. Remember, this is *not* a horse with a "attitude". Very grumpy with the donkeys (we have two, as her buddies). Still happy to see her food, but generally feeling sorrier for herself than I'd seen up to that point.
Having a Surgeon Take a Look
Finally enough people told me to have a surgeon take a look (all recommending the same guy), and see if the lump might be operable. I didn't think the lump was the problem (why would she seem so uncomfortable hours before any apparent swelling?), or if it was the lump, I thought operating couldn't help. But it couldn't hurt for him to take a look.
We went back to the hospital (now about a year later). He looked her over very, very carefully, including an abdominal ultrasound and thorough rectal exam. The ultrasound showed one "hmmm" thing, that didn't seem to be reason for concern, just odd. The rectal revealed ouchy abdominal muscles - I could tell by the look on her face (she wasn't sedated, at my request) - it looked like he'd goosed an ovary (ladies, you know what I mean), but be hadn't - it was the intestinal wall. He said that wasn't normal, but wasn't particularly alarming, either.
After the exam, I rode her for about 10 minutes at a walk/jog (her option) in their arena (the most we'd done in 6 months). She started looking around at her left side. I got off to let her run around or roll, but she stuck right next to me, demanding that I rub her belly - even when I ran some distance away - she was right there again. This was the first time a vet had seen this happen with Sabrina. He'd never seen anything quite like it.
They parked us in a pen, where we waited for Sabrina to swell up. Conditions were perfect - she'd done a little work, gotten a little snorty over all the new sights, shown her usuall pre-swelling behaviors... Sure enough, about 3 hours later she was good and swollen. First time a vet has seen this happen, too - before this, everyone was just having to go by my descriptions, so I was glad to have a vet get an actual look at her "in action."
I asked him to take whatever blood tests he thought might show anything - since she was in the midst of whatever causes the swelling. If anything was off, I thought the timing might be important. The vet drew 5 or 6 samples of blood. We headed home, still a mystery.
One Enzyme High After Exercise
I was relieved to hear that nothing was drastically wierd about her blood work. The only thing that was a little strange was "one blood enzyme was a little high". I forgot to ask which one, at first, so set off on the Internet searching for "elevated enzyme equine", and stumbled upon EPSM - Equine Polysaccharide Storage Myopathy. This could cause AST and CK to be elevated 4 hours post-exercise - about when Sabrina's udder swells up. Hmmmm.
That got me reading more about EPSM - exercise intolerance in draft crosses, colicky behavior, worse with stress... too close to be a coincidence. It turns out her elevated enzyme was LDH, not a classic EPSM indicator, but still shows muscle damage. After reading through a bunch of posts on the Rural Heritage message board, where Dr. Beth Valentine, leader of the inquiry into EPSM, very generously answers questions from anxious horse owners, I found references to horses kicking at their bellies, and wanting to roll. Nothing about swelling udders - yet... I posted Sabrina's story, and someone responded that their gelding's sheath swells up in the same pattern, complete with the horse demanding to have his butt rubbed before "an episode". (Sheath swelling and udder swelling can have similar sources, since they are in similar locations.) Later, another owner posted about her mare, whose udder swells like Sabrina's. I was convinced. We set up an appointment for a muscle biopsy, which came back positive for EPSM.
Hindsight being 20/20, I'm thinking her foaling problem (before I owned her) was not a bad presentation, but she just didn't have the strength to deliver the foal. We're lucky she survived. I had been thinking of it from the perspective of how losing the foal might have caused the other problems, but not that whatever was causing everything else might have caused her to lose her foal. From what I've learned so far, EPSM would account for her colicky behaviors during/after exercise, being balky during lessons and on rides, wanting to roll, wanting her belly rubbed, the udder swelling, grumpy, anti-social attitude... everything.
Having a Muscle Biopsy Done
Several people have written to me in the past couple of weeks asking about having a muscle biopsy done - what's involved, how much does it cost, how much does it hurt, etc. So here's what I can tell you.
First, have your vet contact Dr. Valentine for a copy of the instructions. It's different from a needle biopsy, and needs to be taken from one of two particular places, and needs to be prepared and handled in a specific way, to be most useful.
I didn't have to do anything special to get Sabrina ready (no fasting or other prep work) - just showed up at the hospital. I was allowed to go in and watch - I don't know if all vet hospitals work that way, but it couldn't hurt to ask. Of course she was sedated (standing in stocks), and a local anesthetic was used around the incision. The vet bandaged her tail and secured it out of the way, then started by clipping, then shaving, a patch of hair next to her tail. He cleaned that patch, and stuck basically a big sheet of tape over the whole patch (to keep things clean, I'm guessing). He made a vertical incision, about 3" long, cut through her thick layer of fat, and into the muscle, then cut out a little sliver of muscle. He stitched up the muscle with stitches that will dissolve later, then stitched her skin back in place.
It sounds awful, but Sabrina didn't seem to mind - she snoozed right through the whole thing - only looked around when someone made a noise with a plastic bag (treats!?). It can also be done further down on their butt, where the tail might cover it better. Sabrina has such a fuzzy, stiff tail that it's covered pretty well even up higher. The higher incision might heal more easily, but if you have a show horse you might prefer the lower one.
The incision was roughly 3" long. Sabrina is a bit fat, so it might even be shorter on a less "padded" horse. I was surprised by the way the incision looked after it was done - kinda "gathered" and bumpy, like it was held together with a drawstring, but it healed together perfectly flat - I doubt if it will be visible after the hair grows back.
I expected it would need cleaning and dressing, and maybe some ice or hot packs, and I thought it might get a little swollen. But aside from putting sunscreen on her bare patch the first couple of days, and wiping it with a damp towel it didn't seem to need any attention. It didn't seem to bother her at all. I was expecting her to rub the stitches on the gate (I'd think they'd get itchy as she healed), but she never paid the slightest attention to it. She never took an off step on that leg, or stretched it funny, or did anything to make me think it was bugging her. For the first few days she did prefer I not mess with it though, so I'd just take a quick look and leave it alone. At about 12 days I took the stitches out (I think the vet said to wait 10 days), and aside from being bored with the whole process (it took me a while to figure out how they worked) that didn't seem to bother her either. I took them out the same day I received my first honest kick (from another horse), so I was being really careful about it! Just snipped one part near the knot, and pulled the un-knotted end through.
Between the vet, the hospital fees, the lab work, shipping (sample to Dr. Valentine), and drugs I think it came to around $300-400.
The Diet
The good news about EPSM is that it can frequently be controlled quite well by a simple change of diet. See the Rural Heritage site for details on The Diet. I started Sabrina on Dr. Valentine's special diet for EPSM horses on Friday, June 8th, 2001.
The First Few Days
I started Sabrina (and the donkeys) on the above diet on June 7th, 2001. (Amounts given below apply to Sabrina. The donks each get half of that.)
Sabrina is not a picky eater, and ground up alfalfa pellets with oil in it, and carrots on top, is just fine with her - in addition to her usual bermuda hay, of course. I cut all the alfa-mo and apple wafers out right away, and cut way back on the Senior feed (to just a sprinkle on top of her other food. I'm only using 1/4 C of corn oil per feeding to start (working up to 1-1/4 to 1-1/2 C per feeding). She snarfs it down just like everything else. It's hard to believe I could be seeing results so soon, but here are my observations so far:
At the end of day two, Sabrina seemed happier, and more social. Instead of going to her corner and sulking when I came out to say good night, she jostled for attention along with the donkeys. She even noticed dust in the beam of the flashlight, and kept trying to touch it with her nose.
Day 3 - More active than I've seen her in weeks. It was a hot day, so cool weather can't explain it. Several times she trotted around the big pen. I gave her a bath (just rinsing, for the heat), and afterward she *ran* and bucked (OK, so she was feeling refreshed). After a roll, she came back for more hosing-off, twice! She met me at the gate several times today wanting scritchies. I don't know if it's accurate to attribute it to just the change in diet - maybe she can sense a change in my attitude, for all I know - but she was definitely acting more like her old self than I've seen in months. Less cranky, more interested in life.
Day 13 - I still am feeding the bermuda hay, and now have her on alfalfa cubes soaked in water, with the oil mixed into that, and cut-up carrots tossed on top. She loves it. I'm seeing even more improvement. I've increased the oil by 1/4 cup per feeding every 4-5 days, so we're up to 3/4 now, and working up to 1-1/2, I think.
At one week, on a hot day, I went out with the hose, and offered to spray her. She came right over and wanted me to spray her all over. When I offed to quit, she came closer asking for more. She especially wanted her left side sprayed (where she usually likes to be rubbed), and her left hip, which she usually does *not* like me to spray - she usually likes me to stick to her shoulders and neck. When I tried to quit and go inside she kept insisting I continue. She was also pretty enthusiastic about splashing in the plastic kiddie pool I got her. She doesn't go to it on her own, but when I asked her to step into it she seemed happy to play in the water.
A few days ago (around day 9-10) I thought I noticed that the right side of her udder was a bit more swollen than the left. This was disappointing because that's the side the lump is on, and I'm hoping that lump hasn't actuallly been causing any trouble, and that the swelling has been the EPSM all this time. But after feeling around some more later I figured out that what was really happening was that the chronic low-level swelling I'd been seeing for the past year or so was actually going down. I'd had kinda forgotten what she used to feel like. I had a vague sense that "she didn't used to be this swollen all the time", but now I'm sure of it - she's "un-swelling" back to where she was when I first got her. As of now (day 13) both sides have un-swollen to a more normal size.
Here's a wierd one - I think Eeyore is feeling better - maybe more relaxed, or more comfortable. Eeyore is our 10 hand, sweet-but-nervous donkey. He likes having his face and shoulders petted, but not his back, sides, or butt (except for butt scritchies, of course). He's always run from grooming implements. Brushes! Horrors! In 3 years I've never given him a good brushing, because he hates it - soft brushes, stiff brushes, it doesn't matter. Well a few days ago I had the dog slicker (you know, the ones with a zillion little bent wire bristles) out there for Clementine, and snuck up on him with it. In the past, as soon as he figures out I've got a brush, he's outta there, but this time he stayed put. I brushed him all over, on his back, sides, flanks, belly, hips, shoulders, neck, tail, legs... He never objected a bit. I work with everyone at liberty, so if he doesn't like something, he can just leave. The only times he moved were to "repositiion" me, to get me to work more on his shoulders, for instance. Otherwise he just stood there, nose 2" from the ground, lips and ears flopping. This is unheard of behavior for Eeyore. I'm thinking either the oil is mellowing him out, or it's making his skin more healthy, and less irritated. Or maybe his muscles have been hurting too?
Sabrina had not been her usual attention-hog self recently, but she's coming around. She's walking over to the gate to visit with people. Over the past months she's come to the gate, then left when no treats were to be found. But now (as in the more distant past) she'll stay around to have her shoulders scratched, and even chase the donkeys out of the way - something I haven't seen her do in months.
Aside from a few hand-walks around the pen I haven't started her on regular exercise yet - I'm working up to that slowly and will start early next week.
August 11 - 2 months: Last month we experienced the infamous "EPSM setback" for a few weeks, with Sabrina seeming grumpy, swelling a little... but have pulled out of that OK. It's been really hot, and hard to get up much enthusiasm for working, but we've been diligently hand-walking and trotting in the pen, at least, with a few short "rides" just to get her muscles thinking about carrying a rider. There's definitely some improvement going on - I see Sabrina trot from place to place in the pen, where she only ever used to walk. She even runs and bucks, whooping it up, now and then. She's enjoying her baths on hot days - turning this way and that - even asking me to spray her butt, which she used to avoid. Even though she is getting more food, and 3 cups of oil per day, she is looking more fit. The other day I felt some hard bumps behind her elbow - at first I thought Clementine (the bolder donkey) might have kicked her - then I realized they were ribs! She seems more comfortable in the sun, too. I don't know how much of that is due to weight loss, and how much is due to the improvement in her muscle functioning, but where she used to hide out in the shade all day I now see her standing out in the sun sometimes.
My Thoughts on Diagnosing EPSM
If there is something wrong with your horse, and you look in most horse health books, you'll find problems categorized by systems of the body - digestive, circulatory, neurological, skeletal/joints, respiratory, etc. But you'll rarely see "muscular". Myopathies (muscle problems) just aren't considered very often - but they really need to be.
Everything I read on the Internet - written by vets (some of the best in the country) - describes horses with fairly advanced EPSM. Lists of symptoms include dramatic situations like down horses unable to rise, lack of strength and coordination in the hind end, listlessness and weakness, shivers, stringhalt, inability to canter, trembling, etc. I never saw anything like this in Sabrina. Nobody thought of EPSM in Sabrina's case because she didn't show any of those symptoms. It's not that the lists out there are inaccurate, and I'm not disagreeing with anything in them, but I believe they are compiled by people who only see EPSM at its worst, possibly after years of mislabeled or misdiagnosed minor problems, mild colic, stubborness, attitude problems, laziness, off-ness, strange little lamenesses, things most horse owners might not even ask the vet about. I'll bet there are a lot of horses out there with vague, mysterious problems that are being missed because they don't fit the profile of *advanced* EPSM. Signs that I now recognize as evidence of a problem were things most people would never mention to a vet - stopping during lessons, wanting her belly rubbed, being grumpy...
I think it's possible to catch EPSM a lot earlier, if we can just get the word out to vets and horse owners that this isn't "rare", it isn't "new", it's just that we've only recently begun to recognize it and look for it. It doesn't even need to be a big problem. Horses diagnosed early have a very good chance of living happy, healthy lives, with just a simple change in diet. The diet is fine for normal horses, and is worth trying, even without the muscle biopsy. This should be among the first things considered, not a last resort.
Checklist for EPSM Patterns of Behavior and Conditions
Keep in mind, I am not a vet, I am a horse owner (with just one horse, at that). I am not constrained by having to produce statistically significant samples or control groups. I can say whatever I want, without having to prove things. I understand the scientific method, but am not bound to use it here. I try to be very observant, and listen to my horse, who is very expressive. I don't have an agenda here, except to get the word out. There are no drugs, supplements, or vaccines to sell, so you won't be hearing about this in full-page ads from pharmaceutical companies. While my observations may not be acceptable for publication in scientific journals, they may offer a view of EPSM that is unavailable to veterinarians otherwise.
This list is based on my experience with Sabrina, and on discussions with a few (5-6) other confirmed-by-biopsy horse owners. I hope vets will keep this checklist of behaviors and conditions in mind, and quiz horse owners about them, as many are things an owner might not think to bring up, or might not think are related. I hope horse owners who see these patterns in their horses will look into EPSM, and suggest the possibility to their vets. The things listed below aren't necessarily problems, and they individually certainly aren't necessarily signs of EPSM - but if enough of them happen together, it should be considered, along with the more widely known symptoms, of course.
The horse itself
_____ Is the horse a draft, draft cross, heavy pony, heavy QH, or other heavily muscled breed? (Note, EPSM can happen in Arabians and TBs, too, so don't rule out any breed.)
_____ Is the horse on grain? Does it get alfa-mo, oat-mo, or other sweet feed? (Again, if not, don't rule it out. Grain/sweet feed are not necessary to have EPSM.)
_____ Is the horse quiet, friendly, gentle, stoic, kind, uncomplaining, etc.?
_____ Is the horse perpetually "out of shape"? Has poor muscle development/definition?
_____ Has the horse been losing weight or condition?
"Behavioral problems" while riding:
_____ Does the horse "poop out" easily on rides or during lessons, and repeatedly ask to stop?
_____ Does the horse get balky, stubborn, or doggy 10-20 minutes into rides or lessons?
_____ Does the owner report instructors regularly shouting "Don't let her get away with that! Horses shouldn't just stop when they want to"?
_____ Has the owner needed to wear spurs recently? Carry a crop? (Especially with a horse who otherwise seems to like to go, or used to like to go.)
_____ Does the horse look around at its flanks, touch its nose to the rider's boot, kick at its belly, and/or paw like it wants to roll?
_____ Does the horse swish its tail at its flanks, like swatting flies, but there are no flies?
_____ Does the horse want to scratch its belly on brush along trails?
_____ Is the horse often described as disobedient, resistent, lazy, or stubborn?
_____ Does the horse complain about going down hills? Up hills? (Does it get balky, swish its tail, refuse?)
_____ Is the horse described as cold-backed, sore, or having trouble with its saddle?
After work, and while being handled generally:
_____ Does the horse whoop it up during turnout initially, then suddenly seem uncomfortable and just stand or follow the owner?
_____ Does the horse sometimes "just stand there" when turned out - with no interest in running around?
_____ Does the horse seem mildly colicky at times (either during/after work, or when confined - stalled/penned/trailered)?
_____ Is the horse passionate about rolling after work?
_____ Does the horse seem "itchier" than most horses?
_____ Does the horse demand to be rubbed or scratched, especially after work? Does it follow the owner around, presenting some part for attention (belly, butt)? Is this more emphatic at times?
_____ Or alternatively, does the horse seem unusually annoyed with anyone touching its belly, or hindquarters? Does it turn away from bushing on the rear parts?
_____ Do any odd behaviors get worse during/after exercise? During/after having their feet cleaned, or when the farrier visits?
_____ Does the horse have trouble standing for the farrier? Especially if it used to be OK?
_____ Does the horse prefer that you not brush or wash its back, butt, and hips?
When on its own, where it lives:
_____ Does the horse resent being penned up (bucks, kicks at panels or walls, runs around the pen), but stands around quietly when "turned out"?
_____ Does the horse mostly stand around by itself, not running and playing with the others?
_____ Is the horse really mean to other horses (kicks to injure them, can't be turned out with others)?
_____ Does the horse lie down more than most horses? Or have its habits regarding lying down changed recently?
_____ Has there been any change in personality, from sociable and sweet, to grumpy or cranky? (If the horse is always cranky, consider that the horse may have been feeling bad the whole time this owner has known it.)
Movement:
_____ Is there anything off about movement in the hind end (a hip "out", stumbling)?
_____ Do the horse's hind legs ever tremble - when standing funny, or when a foot is picked up?
Other Issues:
_____ Has the horse had several "mild colics", which the owner may attribute to changes in food, water, weather, etc.?
_____ Does the horse's udder or sheath ever swell up? Is there any pattern to it? Exercise, in heat, stress, weather?
_____ Has the horse ever tied up?
_____ Has the horse ever had a difficult delivery, or lost a full-term foal?
Keep in mind that "changes" may not be obvious, especially if the horse is new to this owner - so be on the look out for things that have "always been this way" as well.
I am lucky to have Sabrina at home, where I can visit with her several times a day, and at night. In a boarding kind of arrangement, or where a person has several horses (and doesn't go out to say good night to them with a good all-over scratching), an owner might put the horse away and go home, and never notice swelling that begins hours later, then is gone the next morning. I suspect the udder/sheath swelling is more common than we think.
I'm also lucky to recognize that when my horse says something is bothering her, she isn't just "being difficult" - something is actually bothering her. Owners/riders who follow the more classic "the horse should do what you tell it, without question" way of thinking might not see many of these behaviors until they are more advanced.
EPSM owners and vets: If you have seen things in your EPSM horses or patients that should be included in this list, please send me a note at lseskin@home.com, and I'll add it. Again, these aren't definitive signs of EPSM. But if you know 2 EPSM horses who both do the same strange thing, maybe it should be on this list. Please contact Dr. Valentine with such information as well.
For more information on EPSM and other myopathies in equids, visit the Rural Heritage site, or contact Dr. Beth Valentine, the veterinary pathologist leading the charge for horses with EPSM.
Contents of this page are copyrighted. © 2001, Linda Eskin. Permission to copy, store, forward, and reprint in not-for-profit publications (such as newsletters) is granted, provided this notice is included.
Other publications request permission from Linda Eskin - lseskin@home.com. I will be happy to provide a more concise "article" for magazines.
Do not copy this page to your web site - link to it, as it will be updated in the future.
Nothing here should be construed as veterinary advice. If something is wrong with your horse, talk to your vet. This page only reflects my experiences and opinions.
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EPSM, Equine Polysaccharide Storage Myopathy, PSSM, Polysaccharide Storage Myopathy, myopathy, glycogen, tying up, shivers, tied up, Monday morning disease, stringhalt, locking stifle, rhabdomylosis, wasting, muscle mass, enzymes, elevated enzymes, blood enzymes, LDH, AST, DK, lameness, high fat diet, udder, swelling, colicky, colic, foaling complications, exercise intolerance, Horse, Donkey, Mule, Equid, Equestrian, Trails, San Diego, Beth Valentine, Linda Eskin, Linda Myers, Eskin, Sabrina