The amount of food a horse needs depends on its age, health and the physical activity it requires.
The character of the horse is also important in determining its food, and the other way around. An overweight horse can be unhappier than a well-fed one. As with people, the climate or environment is another factor that determines their diet. In the winter, they have need for more food than in the summer, mainly to maintain their body temperature.
A domestic horse is not the same as a wild horse that lives free. In the wild, the horse eats almost constantly. The horse's stomach is relatively small, so they recommend keeping it moving frequently. To feed a horse, three times a day is recommended, and if their activity is not very intense, you can reduce it to twice a day. If the activity of your horse is intense during the day, it is better to feed it in the afternoon.
It is important to follow a routine for equine meals, so that it doesn't get nervous waiting and suffer indigestion. Furthermore, before riding it, you should wait at least an hour after the last meal.
As it is with people, water is the most important food that you should never miss. It should be clean and fresh and about 10 degrees Centigrade, and also not have a different flavor, or the horse will not drink it.
If you give the horse water that is too cold, it could cause colic. You should also allow the horse to drink as much water as it wants, but at the same time seeing that it doesn't drink too much at the same time, in one drink.