WASHINGTON — Ethanol producers will use about a quarter of the U.S. corn crop this year, an amount that alarms ranchers and poultry producers who depend on corn to feed their animals. As the demand for corn and energy costs climb, so do prices at the grocery store.

But the ethanol industry's impact on the nation's supply of corn for feed isn't as dramatic as it may seem.

One-third of all the corn used to make ethanol ends up as an ingredient in feed that farmers in the upper Midwest — where most of the ethanol plants are located — give their cattle, poultry and pigs.