EPSM?

I've been doing a lot of research on tying-up recently, and in the process have also come across a lot of references to Equine Polysaccharide Storage Myopathy (abbr. PSSM, EPSSM, or, most commonly, EPSM).

According to wikipedia: "EPSM is a genetic predisposition to fail to digest grains properly in the horse. The result leads to damage to muscle tissue during exertion. It is estimated by DNA testing that approximately 2/3 of all draft horses have the predisposition for EPSM."

EPSM is now thought to be one of the most common causes of tying-up in situations without extreme over-exertion - such as was the case with Barokko. Starch:work ratio is still the trigger factor, but EPSM horses will tie up with less provocation than other horses, and these are typically also the horses with chronic tying-up problems, and slow recoveries.

EPSM is primarily controlled through diet: low starch, high fiber, high fat (usually via vegetable oil).

Looking into EPSM, I realized Barokko fits really well into the EPSM profile. EPSM can only be diagnosed through a muscle biopsy, but alternatively it's worth a try to just put the horse on an EPSM diet, and see if it improves. If it does, keep it on the diet, if not, it's probably not EPSM, so off to find another diagnosis. Non-EPSM horses will often also benefit from an EPSM diet, and under any circumstances it won't harm them.

So I'm going to try adding oil to Barokko's diet and treating him as recommended for EPSM horses (re exercise etc). If it works and prevents future problems, great. If it doesn't have any effect then there's no harm done.