Systems were designed, simulated and analyzed to assess the economic feasibility of producing ethanol from high-moisture grain, gradually separated from mature whole-plant maize silage. The residual stover fraction containing some grain fines was fed, along with ethanol production by-products (stillage or maize gluten feed), to growing steers. Three systems were compared. In the control, regular maize silage was fed to growing steers with extra maize harvested later and sold as grain for cash. In one alternative (system 2), the separated grain fraction was processed to ethanol and stillage at a local farmer-cooperative plant. In another alternative (system 3), the grain fraction was transferred to a regional industrial plant for wet milling to ethanol, corn gluten-feed and other products. System comparisons were based on estimating gross costs per farm during 1980 to 1982, minus credits for products such as grain maize (control) and ethanol (alternative systems). System 3 was the more attractive alternative. When ethanol was valued at wholesale prices for regular leaded gasoline, these costs were similar in 1981 and 1982 for System 3 and the control. Further refinements of a separation unit, and detailed assessment of the feeding value of the stover fraction plus stillage or corn gluten feed, are warranted.