We bought our daughter a horse just a few days before Thanksgiving. He was doing great. But I have been trying to find a go feed for him. About a week ago I started him on a new feed. It is 14% protein and 7% fat. He ate one bag of the food and everything was going great, but about 4 days ago he started to have very loose stools. I took him off the food and started feeding him just hay and water. The stools got a little firmer, but not much. I am hoping that someone can tell me what is wrong with him, a what I can do to get him well. Thanks for any help that you may be able to give.

Had he been eating some other kind of grain up until you changed to the 14%? Even if he hadn't been eating grain at all, a rich grain like that is going to cause a little stomach upset in the beginning. How long has it been since you stopped giving him the grain? If his feces firm up, I would consider re introducing it in small amounts first. Don't give him a whole scoop, maybe about 1/4th scoop for a day or 3, then slowly increase. It's the same w/dogs, if you switch the brand of dog food you should mix it in w/the old brand at first so it doesn't upset their system.

Where I keep Jackson, there is alfalfa hay that is so rich it gives them all runny poo. Give them grass hay or a blend and they're back to normal. The foals are the only ones that get it and in small doses.

Congrats- A new horse is very exciting.

The first thing you need to do is locate a Vet in your area. You can simply use the phone book or word-of-mouth of other horse owners. You should contact one before your first call is for an emergency @ 2am. They will appreciate it.

Any type of change is high stress to horses, ideally you should have gotten a feed schedule and purchased some of the same feed as what he was on. But you can work without that.
If you don't feel the need to call the Vet out, take him back to hay/pasture and water just as you have. Then go to your feed store, tell them what your horse is-age/breed/sex/size and work load, also your grazing acreage and amount of time he is on it. They will give you a recommended diet, do remember they are feed reps so they will recommend something from their company. The name of the feed is not as important as its make-up. Then with a little computer time you can find comparable feeds.
Don't completely rule out a disease/parasite infestion, a Vets exam would be best.

Howdy and congrats on the new horse! Sounds like he had a bit too much of your new grain. 14% is a bit high, is he accustomed to this level of protein? I feed grain depending upon breed, age, amount of work per day, and type of forage. If he is not used to the type and amount you are feeding, give it to him increasing in small amounts. It is easier to drop a horse off of supplementation than it is to add. Hope you are able to figure out the problem soon. I know, not fun! Good luck!