Corn usually provides the most energy for horses. also Rolled oats.
corn corn
howse answer riding level 3 - corn
Corn.
Corn is a grain that provides horses with a high amount of energy due to its high starch content. However, it should be fed in moderation as excessive amounts of starch can lead to digestive issues in horses. High-quality hay should still be the main component of a horse's diet.
oats that's my guess
On talking about a horses diet he needs everything in a fair amount.
the type of grain that has the best energy source for your horse is wheat.
Corn
energy food barley or oats
Alfalfa hay gives the most energy and so does alfalfa based grains. Alfalfa is much like eating sugar, in how it can makes you hyper. Racehorses are fed this to have a better performance in races.
Watch the horse closely, provide plenty of water and call your veterinarian. Too much grain or concentrated feed (pellets etc) at one time can cause a horse to founder or colic. Call the veterinarian with the amount eaten and when and they will either give you instructions or come out to treat the horse.
You could, but only a small amount per day. Usually 1 or 2 lbs of grain per day (no more than 2), depending on the size the horse, is sufficient. Any more and they could get colic or founder.