Horses primarily eat hay and grass, with grains like corn or oats added for extra calories. Horses are also provided with salt, either added into a concentrate mix of grains, flax seed, beet pulp, bran and molasses or separately as a salt block in the pasture. Horses also receive treats in the form of apples, carrots and sugar. Some horses occasionally enjoy a bite of meat.
The bulk of horses' calories come from hay and grass. Too many grains leads to ulcers, dental problems and colic. Not all grains are healthy for horses; for example, wheat is not recommended except in small doses as a treat, since it leads to mineral imbalances. Horses are designed to eat small, frequent meals throughout the day, allowing for better and more efficient digestion.
During the summer, horses typically seek out salt sources more than they do in the winter. Their diets can change based on individual needs. Pregnant or nursing mares and working horses are often fed concentrate mixes to supplement their typical diets, since the mixes provide extra nutrition and energy.
Although horses are herbivores, some acquire a taste for meat. They can safely eat a bite of a hot dog or piece of hamburger every once in a while, but they should be monitored for signs of discomfort after.