what is  corn
The major feed grains are corn, sorghum, barley, and oats. Corn is the primary U.S. feed grain, accounting for more than 95 percent of total feed grain production and use. 1  More than 90 million acres of land are planted to corn, with the majority of the crop grown in the Heartland region. 2  Most of the crop is used as the main energy ingredient in livestock feed.