Yeah, unfortunately, the discovery of EPSM is rather new in the grand scheme of things and that's the reason why so many plow horses got used up in a hurry in the old days. Farmer would feed them grain and cause an EPSM flare, the horse would lose tone and muscle and would be weak. Farmer would think "well, it's a hard keeper, just needs more feed" and up the grain ration....which would in turn make the horse lose muscle and strength faster. Vicious circle.
My draft gets a 20% fat top dressing, Omegatin, plus flax seed, oil, supplements and hay cubes to soak up the oil. He gets enough fat to make up about 20% of his diet (counting his hay).
Dietary Recommendations for a Horse with EPSM by Beth A. Valentine, DVM, PhD
"Overhauling your horse's diet is the first line of treatment against EPSM. The goal of the EPSM diet is to decrease soluble dietary carbohydrates (grain) and increase fat. You want to provide 20% to 25% of total daily calories from fat."
You'd think he would be fat from all the oils, but he isn't.
My girls shouldn't be getting ANY, but where I board she wants to give them "some" so they will associate her positively... So if they get loose, they'll come to her. Fair enough, but pretty sure Fi is a glaring example why these breeds don't need grain if they have pasture as an option!
When I originally brought Fi and Harley to the facility she wanted to charge us MORE because she was under the notion that they required MORE grain, when in turn required little to none... My intentions are to cease all grain, because... Well, they certainly don't need it.
Now, when Harley was on a dry-lot, she required grain to maintain her weight. The hay wasn't the best either (also a deciding factor on her weight loss/gain).