Here's my 2 cents on some things she might like if you and your vet ok them:
Some grass pellets or grass hay in addition to her alfalfa - if she's corraled and only out to exercise when she's worked, it would give her some extra "something to do" as well as round out her diet without her getting a hay belly on you. It wouldn't necessarily have to be high quality hay, just a low protein grass for munching.
You may only need to supplement her with a 9-12% protein balanced pelleted feed which can be easily soaked, and she likely wouldn't need more than 2-3 pounds 2x a day if that's how often you feed, well before or after she's been worked. If you decide to try beet pulp, she probably wouldn't need more than 1 pound (dry) 2x a day, as after it soaks it expands 3 to 4 times, so you could soak half a pound of beet pulp pellets for one feeding, and another half pound at night, if you feed 2x a day. These are pretty affordable and safe alternatives for a mash. Some thoughts or ideas for you. Oh, something else you and she might like are some microbials to add to mash.
Last edited by DRichmond; 05-10-2012 at 12:05 AM.