Anecdotally we hear a lot about oats making horses “hot” in the sense of forward energy (not just acting out from ulcers). It’s a longstanding practice and belief, so there must be some truth to it. But has there been any research?
I have a big Paint mare of variable energy level. The things that affect her energy are weather, rest, novelty (new trails or venues), other horses, and her feet and saddle fit. Diet has never seemed to play a role. It’s fair to say she can be lazy until she wakes up, and then she can be hot and fast. Some days I can warm her up to be really forward, other days it just isn’t there. She does best on 4 days riding, one day off.
She gets good Timothy hay, and a mash of beet pulp and alfalfa cubes with salt and Omniety VMS.
Our main nutritional concern is not getting totally obese. She is otherwise very healthy shiny muscled. She is now 19 but has been like this since I started riding her at 6.
From time to time I’ve had her on up to two pounds of oats with absolutely no overall change in her energy levels. For a while I fed a big flake of alfalfa, but one winter stemmy alfalfa gave her repeated impaction colic so I stopped.
Anyhow, would more carbs actually give a horse like this more energy, or just make her fat or give her metabolic disorder (which is what l have always assumed)?
If so, would feeding oats at night work, or should they be fed in the morning before she is ridden?
I think the answer is: do not feed a fat lazy Paint 5 lbs of oats, because you’ll push her into pre-diabetes 
. But is there any research on diet and energy?
