OP, what part of the U.S. are you located? How/why did the vet call it for EPM? Specifically, not just a wonky horse because that could be EPM or a lot of other non-EPM things.
I ask because EPM can be a tricky diagnosis even for vets. I had a horse misdiagnosed with EPM by an experienced vet when the blood test drawn the same day later turned out to be negative. Re-diagnosis with a second opinion from a chiro-vet (DVM also a chiro) was a sacroiliac problem, which was cleared up with appropriate rehab done by self according to chiro-vet’s instructions. There are other physical and neuro issues with symptoms that can be misinterpreted as EPM.
If I were you I’d get the blood test done (about $100 in this area) just to have that positive/negative information. If it’s positive, it may not mean much, but if it is negative that is important to know right now. There is no second chance to get the blood for this moment in time.
I’d also get a second opinion from the most experienced, BTDT vet available, especially one who has handled a lot of EPM diagnosis explorations, and more especially if they have chiro experience as well. Just me, but after my own experience I would not go by one vet’s opinion with no testing.
Making it more complicated, in the southeastern U.S. many vets actually discourage the standard EPM blood test because so many horses in this area will have a “sort of” positive for a barely-there “sort of” EPM that never affects the horse. Vets don’t want clients galloping off down the EPM trail when that is not actually the problem. The positive test can be widespread because opossums are widespread, and the urine/feces of opossums will sooner or later find its way into hay and grain pastures, before harvesting, but not infect to a degree that many horses ever actually have active symptoms. (I had to insist on having the test run, promising that I wouldn’t over-react to a positive. And then it was negative, so back to the drawing board.)
https://equusmagazine.com/uncategorized/eqepmtest310
https://kppusa.com/2018/05/09/epm-sy…and-treatment/
On the other hand, crazily, under-testing for EPM also sometimes means that EPM is missed. And the owner is trying to correct for everything else, and none of it really works and the horse doesn’t significantly improve, because an active EPM is unidentified and unaddressed.
In my case, my horse blood tested negative. It wasn’t EPM. I won’t post the video of the vet exam where the initial diagnosis was made, because I am not looking to embarrass anyone who might be recognized. But the video looked a lot like your second video, although not as pronounced. My horse just couldn’t seem to get his hind legs sorted out and comfortable. Off balance on the tail pull. As explained in 1st para, it was sacroiliac.
As I understand it, there is a spinal-tap that is fairly horrifying in pain and expense, rarely done, but has a more definitive result for EPM. Rarely ever recommended due to the pain, but mentioning it just for the record.
There are a lot of things, and combinations of things, that can look a little or a lot like EPM. Physical and neuro. It’s possible that your journey to a diagnosis has just begun.
Here’s a video “what sacroiliac looks like” – I know nothing about the source, hope it is credible. But just an example to compare with your horse.
https://www.youtube.com/watch?v=gE0g…oHhtpFaod7JrCc
