Hi Dawn,
Years ago, we had an older horse. Been my daughter's fav. ride for years. After getting her teeth floated, we started feeding her a senior feed. I am searching my brain and my computer but cannot find or remember the name of it. Anyway, it sure helped Molly. Put on some much needed weight and gave her a lot of energy without the hot side effects of straight grain. Check with your vet to see what he thinks of senior feeds, and what brand is best for your horse. (boy, that sounded like a commercial, sry)
hugs, Jupiter