Improving the quality of cellulosic ethanol feedstocks through breeding and genetic manipulation could significantly impact the economics of this industry. Attaining this will require comprehensive and rapid characterization of large numbers of samples. There are many similarities between improving corn silage quality for dairy production and improving feedstock quality for cellulosic ethanol. It was our objective to provide insight into what is needed for genetic improvement of cellulosic feedstocks by reviewing the development and operation of a corn silage breeding program. We discuss the evolving definition of silage quality and relate what we have learned about silage quality to what is needed for measuring and improving feedstock quality. In addition, repeatability estimates of corn stover traits are reported for a set of hybrids. Repeatability of theoretical ethanol potential measured by near-infrared spectroscopy is high, suggesting that this trait may be easily improved through breeding. Just as cell wall digestibility has been factored into the latest measurements of silage quality, conversion efficiency should be standardized and included in indices of feedstock quality to maximize overall, economical energy availability.