This statement is not completely true, but it is also not completely false. Corn is not the leading cause of laminitis and, when fed correctly, it serves a purpose in feeding horses. However, if not fed correctly, it could cause problems. Corn contains a lot of starch. Starch is rapidly broken down into glucose in the horse and used for energy. This type of energy is used up very rapidly and gives the impression to many people that their horse is acting "hot," which is why corn is called a "hot feed." Picture, for example, a child who has just eaten a lot of candy. What sometimes happens? The child may have a lot of energy, or is said to be on a "sugar high." What may happen next? The child may "crash," or get very tired very quickly. The same thing happens to horses that have consumed a lot of starch. They have a lot of energy all at once and then they crash. If a lot of starch is fed to a horse that is overweight or is at high risk for metabolic problems, it could cause colic or laminitis.
Many sweet feeds contain corn but only at about 20 to 30%. When fed to horses with a majority of their diet consisting of pasture or hay and only a few pounds of the sweet feed, it should not be enough to cause problems in most horses. Keep in mind, however, that overweight horses should not have any sweet feed in their diet, let alone much corn. But most horses on a good-quality hay or other forage diet and a sweet feed or other grain supplement should not have a problem.
