A high fat feed is a good start. 14% protein is about as much as you want to feed, especially if you have good forage on top of that. I wouldn't feed her alfalfa though if you have 14% feed and good grass, you'll be overdoing the protein. On a horse I'm trying to get to gain weight, I will generally work up to feeding her a 4 qt. scoop twice a day, very rarely do I feed any more than that at one feeding.

Deworming regularly is also important, but the most important thing is to have a vet check her teeth. The number one cause of weight loss in horses is poor teeth. You can feed the best feed in the world, but if she can't chew it to break it down, it won't do her much good!

Good luck with her!
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PH Cody
HorseHobbyist Site Coordinator