My mare has confirmed EPSM. She has the high oil diet, 24/7 turnout, careful riding, soaked hay, restricted grazing in summer etc., yet continues to tie up annually; 3 Maytimes running and then 2 Marches. This year the attack was mild and blood enzymes were only slightly raised.

I feel there is something I am missing here! Does anyone have any idea why her episodes seem to be annual? Could it be a hormone surge making her more susceptible.

Dianna, please remind me - is your mare a Paint, Quarter horse, or Appaloosa related horse? And has she been genetically tested at Minnesota for the genes that we can relate to some (not all, but some) EPSM horses (Minnesota calls this PSSM)? Horses that are double positive (homozygous) for the GYS1 gene are more difficult to control. Minnesota has also recognized an MH gene in Quarter horse related breeds that may make an EPSM horse more difficult to control. It is not difficult to test using pulled mane or tail hairs so if she has not been tested yet this may be valuable. The Quarter horse related breeds and many drafts are the most likely to test positively for the GYS1 gene. Other breeds with EPSM are often negative, so a negative test does not rule it out.

Also, make sure that she is getting at least 1 pound fat per 1000 pounds of horse per day. It is hard to say why spring has been an issue for her, but hormones, day length, and spring grass could be factors. I'm glad to hear this year was so mild. My best advice for control would be to try to increase fat intake during spring to see if this helps to protect her.

Good luck with her!

Beth V

Thank you for your response.

I am in the UK and my mare is a Connemara cross; not sure what the cross is but she has a slightly dished profile so there could be Arab or Welsh in there too.

She weighs 1025 lbs and has 11/4 pounds fat daily.

Her condition was identified 4 years ago following a muscle biopsy done here. I think the genetic test is not readily available in the UK yet.

Can I send tail hairs to you?

She is a delightful little pony and as I am an older rider, she will probably be my last. It's so frustrating to see her in distress and not be able to identify the cause very readily.

Thanks for the additional information. That certainly sounds like enough fat although if she is not overweight slightly more fat during spring might be worth trying. I don't do the genetic testing - this is done at the University of Minnesota. Dr. Richard Piercy at the Royal College may also be able to help you here http://www.rvc.ac.uk/Staff/rpiercy.cfm

With her breeding you'd really only want the EPSM?PSSM test for the GYS1 mutation, not the MH as this has not been identified as a problem in her breed that I know of.

Meanwhile, hopefully she will recover from her mild episode quickly and keep going strong during the year.

Thank you very much; I will follow up the link to Richard Piercy.
My vet suggested I try scaling down Rhiona's exercise when the Spring comes and just walk with a little trotting when schooling and hacking. Although I can see what she is thinking, I'm not sure because I read elsewhere that lots of fast exercise helps to process abnormal polysaccarides.

Have you any view or advice here.

I am trying to be prepared well in advance!

I think being cautious with exercise and trying to "read" when she might be headed towards a problem so you can stop is definitely in order during spring. But you are right that the exercise conditioning is the other important part of therapy, so I wouldn't want to cut down too much.

You have given me good support over Rhiona and I'm hoping it'll work again! After 2 weeks of rest on restricted grazing, her follow-up blood results came back worse than the original ones taken when she had her recent episode.

The vet is talking about long term; only light hacking or even retiring. I am feeling rather glum and so is Rhiona.

Do you have any thoughts?

Without knowing exactly what blood results you have I can't say for sure, but muscle enzymes in EPSM horses can go up and down quite a bit and so they don't always mean something is worse. Can you please give me exact details of her diet so I can double check on things, especially fat intake?

Thanks for your help; I got back onto the vet for the bloods. The first AST was 469 and the CK was 1816. 2 weeks later, after rest on restricted grazing, they were 1084 and 4523 respectively and I went into a terminal decline!!!

Rhiona's dialy feed amounts, split over two feeds, are;

2 large scoops Hi-fi lite ( a British short chop alfalfa forage low in everything )
2 scoops Bailey's lo-cal balancer ( again a British non heating addition to give vits and mins )
vit E and selenium supplement
electrolyte supplement containing calcium and magnesium obtained from the vet
1 British pint of vegetable oil ( I think a British pint is a little more than an American one )

In addition, all winter she has been having 10mls of l-carnityne three times per week.

The oil is ordinary vegetable oil from a supermarket ( it's the sort people here fry their food in ) and I started to worry if it was the right sort. Then I read about large doses of oil causing insulin resistance. I guess I'm in a bit of a mess at present!!

I soak Rhiona's hay for at least 12 hours to get rid of sugars and get her on restricted grazing ready for spring. She's also in regular work and is ridden western rather than english because she's much more relaxed that way.

Thanks you again.

If that British pint is about 480 ml then this is a good pound = 0.45 kg of fat. As long as the oil is one you could use in salad dressing as well as fry in (that is, not one with added chemicals to prevent foaming at high temperature, often called frying oil rather than salid or cooking oil) this is pretty good. Try increasing this oil just slightly. Insulin resistance is not as big an issue here as her muscles, which clearly did not benefit from rest. I'm not sure you need the balancer, and if those are anything more than the smallest of scoops you might want to reduce or eliminate there to try to tip the balance towards more fat calories and less starch and sugar calories. That alfalfa chop will be low in starch and sugar but should provide quite a bit of other good things, including natural vitamins and minerals. Everything else looks very good. Try this along with careful exercise and repeat the bloodwork in a month or two. As always, good luck!

Thanks again for your input. I checked the oil I use and discovered to my horror it contains a foaming agent. I have been feeding it for 9 months. I have been bulk buying it from a supermarket. What have I been doing to her in my ignorance of this fact?

I honestly don't know for sure, other than I prefer feeding something I'd be happy to put on my salad. It may even be that this type of oil is not as digestable as other oils - I don't think anyone has tested this. Definitely change to a different, more natural, oil and then lets see what happens.

I have been struggling to source an affordable oil without the foaming agent and then my vet mentioned Equijewel. Of course any feed change is a big decision for me!! However, the advice is to feed 1lb per day, which provides the equivalent of 1 pint of oil. I could then drop the oil ( perhaps topping up a little at the crucial time of the year ) and the vit E supplement. It all sound OK but I wondered if you had a view.

Promise this will be the last query for ages and thank you so much for your support.

If this is the Equijewel that is rice bran based and 20% fat, then someone is quite misinformed about the fat content. Every pound of this feed has 1 x 0.20 = 0.20 pound of fat. Every pint of oil has 1.0 pound of fat. So, you would need to feed 5 pounds of Equijewel to equal the fat in 1 pint of oil. That would also have some starch and sugar calories so it really wouldn't be the same as oil. Look for a vegetable oil that is designed as a salad type oil and try to buy in bulk. Soya oil and rapeseed = canola oil should not be terrible expensive, but I realize that prices vary in different parts of the world.

I am so glad I asked your advice about Equijewel!!

I have found some rapeseed oil selling in 3 litre quantities at a local supermarket and it does not appear to contain an anti foaming agent. I'll just use that.

Rhiona is still out of work but improving. Many thanks for your invaluable advice.

Glad you found the rapeseed oil. In North America it is called canola oil becuase they were afraid people wouldn't buy it if the real name of the plant source was used! Some people prefer this oil as it is higher in omega 3 fatty acids than some other oils. I haven't seen convincing evidence that this is useful in horses, other than helping some horses with allergies to gnat bite (culicoides hypersensitivity = "sweet itch") but it certainly has been shown to help EPSM muscle. As always, good luck, and keep us updated!

Dear Dr Beth,

Here I am again with Rhiona, although earlier in the year than normal.. She suffered slight muscle stiffness after being ridden today.

We have had unusual weather; snow, hard frost and sunny days so perhaps the grass contained too high a sugar spike for her to tolerate. The stiffness was no longer apparent after about an hour.

I am considering not following the British vets' recovery advice on this occasion. Usually she rests and is not worked till blood enzymes return to normal. Instead I thought I might walk her in hand while she is walking freely and be guided by her well being before riding. I know an episode can be happening without any clinical signs but I though movement helped in recovery.

Does this sound a reasonable plan?

Thank you.

Dear Dr Beth,

Here I go again with Rhiona; she seems to have had a slight episode with some stiffness of gait following riding today. This had gone after about an hour.

This year the weather has been extreme; snow, hard frost and sunny days which may have caused the sugar to spike in her grazing.

British vets usually take blood tests and then advise complete rest till muscle enzymes return to normal, as determined by further bloods. This can take some time and can mean her programme of work is very stop/start. I wondered whether to begin walking her in hand immediately and to be guided by her well being before riding again.

Thank you.

Does this sound a sensible plan?

Yes, your weather has been quite unusual and so I am not entirely surprised here. I would not wait for muscle enzymes to return to normal. That is what I was taught, too, but in fact it is better to let the horse move around as soon as they are comfortable doing so, which it sounds like she is. Resting until muscle enzymes are normal is a bit like keeping children with mononucleosis home until their blood was normal. Now they know to let them back to school as they feel up to it. Good luck here!

Thank you for this support yet again.

I have some anti-inflammatories from the vet and she has started on a course.
I thought I would walk her in hand for a week and if there was no adverse reaction, commence riding, but only at a walk, extending the time each day and monitoring her condition.

She is due annual jabs and a health check at the beginning of February when bloods are routinely taken. I would have a check on enzyme levels then; I find it hard to change the habits of years and not be dependent on blood results when sorting her remedial programme!

This sounds like a good plan. Try to let her physical condition and activity guide you more than her bloodwork. If there is muscle breakdown the enzyme CK will rise rapidly and can get very high, sometimes over 100,000 units. It then drops by 50% every 12-24 hours, but you can see it will take awhile to get back to normal (under 350). The other common muscle enzyme AST doesn't get as high but takes 2 days or so to peak and then drops very slowly, by 50% every few days, so it will stay up for a long time. Of course, if the horse continues to have muscle injury these enzymes will also stay high. So it is worth checking them periodically, just not worth keeping a horse in the stall (which is bad for their muscles) waiting for them to be back to normal. I hope this makes sense and that she is fully recovered and stays that way for you!

Thank you; I will follow your advice and hope for a good outcome.

I am now thinking about the future and considering moving her to a yard with an indoor school. Her exercise programme at least could then be consistent whatever the weather, even though I can't control the weather effect on her grazing.

I wondered whether this would be more beneficial than her winter stop/start, weather dominated routine, and would perhaps help prevent her annual episodes.

I can't think of anything else I havn't covered!!!

I think anytime an EPSM horse can have more exercise that is a good thing. So if this type of move is feasible I am all for it!

Thank you yet again for all your support. I will work towards a move during the year. My vet is also in favour of lots of exercise with a consistent programme.

After a month of walking and being guided by Rhiona, I have just had good blood results. Jubilation!
For the past 3 years, her annual episodes have followed on from a period of severe winter weather; frost, low temperatures and snow. I have read recently that, while the additional sugars stored in frosted grass can affect laminitics, that is not the case in PSSM.
Do you have any comment? I had speculated that frosted grass could precipitate an episode, although my vet says not.
Thank you and best wishes.

Frosted or otherwise stressed grass does produce more sugar. Most EPSSM horses are not as sensitive to sugars as a laminitic horse is, but some do have issues with higher sugar grass. So, I would not rule that out here. If you can use a grazing muzzle during such times that might help.

Hello yet again,
The supermarket vegetable oil I usually buy has rocketed in price in the UK ( many people are using it as a bio-fuel in their cars ).

Linseed in seed form is available but I wasn't sure how much is equivalent to 1 pint of vegetable oil, or whether it's a good idea to change.

Best wishes

Seeds will have starch and sugar as well as fat so I don't think this is a good alternative to oil. Are all oils being used for biofuel? Soya oil and rapeseed = canola oil are just as good as other oils and are usually somewhat less expensive than corn oil. Also, can you buy in bulk somewhere?

Hello,

I'm really glad I asked that question!

Our cheapest oils are vegetable or corn; soya and rapeseed are prohibitive. I can buy in bulk but the ones I have sourced to date have an anti foaming agent.

I will continue with the status quo; better not to change what seems to work.

Hello again,

My mare Rhiona has tied up again, 11 months following the previous time. This has been a consistent pattern for the last 4 years, although last time and this the symptoms were mild. I have been walking her out and generally following the US management advice because it was successful last year.

The weather this year has been different so I can't blame sugar spikes in the grass caused by frost or snow.

Is it possible she experiences a gradual build up of sugars in her muscles during the year? Does an episode then cause the build up to reduce? I really would like to understand why the occurrences should be episodic in this way.

Thank you for all your past help.

How curious. I wish I had a good answer but I'm sorry to say that I don't. I do believe weather can affect EPSM horses, perhaps by altering their exercise patterns. I don't think that there is a sugar build up issue. Given the pattern you might want to think about trying to increase fat intake slightly this time of year. Glad to hear this was mild, and hopefully she'll get back on track quickly. Happy holidays!

Dear Dr Beth,

Today Rhiona's physio casually remarked that the supermarket vegetable oil I feed her is full of Omega 6 and contains virtually no Omega 3!! She suggested cold, pressed flax oil or flax in seed form, which, given her EPSM, would act as an anti-inflamatory.

I hope you can advise me; naturally I will change nothing without consulting you.

Thank you.

If your vegetable oil is soy oil, which most are, it is actually a reasonable blend of omega fatty acids, including omega 3's. It is definitely not particularly high in omega 6's - corn oil has the omega 6's. That said, I have yet to see any evidence that omega 6 fatty acids promote inflammation in horses or that omega 3 fatty acids are anti-inflammatory. These are theories not proven to be fact even in people much less in horses! I feed soy oil because it costs less :)

So, don't worry about what you are doing.

Thank you so much! I was anxious when she made the comments but I feel reassured now.