We had a 34yr gelding that passed away a couple of years ago, but we fed him senior feed and beet pulp because his teeth were nearly nonexistent. However we also got a big thing of canola oil (I think, it was from costco) and added that to his grain. At first he would only eat a little but he got used to it and I would say that he got almost a cup a day. It really helped him gain weight and keep it.