For the past decade, the amount of ethanol fuel produced from corn each year has increased dramatically. This increase in ethanol production increases the demand for corn to be used as fuel and decreases its supply for livestock feed. The increasing ethanol production also increases the supply of corn co-products, feeds produced in the conversion of corn to ethanol. Traditionally co-products have been included in beef feedlot rations to decrease costs. The increasing supply of co-products and decreasing supply of corn due to ethanol production have made co-products an economically attractive energy source for cattle producers leading to their higher inclusion in diets.