I want what is best for my horse?

I am feeding her two slivers of alfalfa hay in the morning and at night. Normally I would feed one leaf but the bales that I have now have very small (3 inches wide) slivers. She just started training about a week ago and want to make sure she is getting what she needs to grow and build good lean muscle. She is two now, 730 pounds. She is kind of a slow grower. She gets worked about an hour a day, mostly walking and trotting (little cantering). What do you feed your horses and what would you recommend for mine. Price isnt an issue, ill pay for whatever she might need.