This report combines existing research and further economic analysis to suggest that, with one notable exception, animal feed customer are unlikely to be willing to pay a premium for many of the genetic modifications that are under development in seed corn. This conclusion is based on an assessment of apparent economic barriers to adoption of new genetic modifications; barriers that are unique to the animal feed industry. The conclusion contradicts previous work by the co-author of this paper, Dermot Hayes, and others at Iowa State University.* First, and most important, the widespread use of least-cost rations in the animal feed industry ensures that any genetic modification will be valued at the commodity cost of the modification. This makes the interests of the animal feed customer different from those of other consumers who typically demand, and are prepared to pay a premium for, a customized bundle of attributes. Second, animal feeding is an old- and well-researched industry. As nutritional deficiencies have been discovered in traditional grain rations, industries have arisen to produce the missing attributes. These industries have very inelastic supply curves, and any attempt to supplant the synthetic additive will result in a price drop for that additive. Third, U.S. grain processing and transportation systems have achieved large economies of scale in the handling and processing of undifferentiated crops. Therefore, initial attempts to market differentiated products will incur significant additional costs. This report suggests that the most economically profitable scientific research in the seed corn business is that which increases yields (or reduces production costs) for bulk commodity corn. A second profitable avenue is one that would double the protein content of corn while maintaining yields at 80 percent or more of current levels. A third advance is one that would anticipate a federal or state mandate to reduce the phosphorus and nitrogen content of animal waste. And, a fourth possible avenue of research is to monitor developments in new additives (flavor enhanced milk substitutes, enzymes), and to modify the corn plant to produce these additives before capital-intensive production facilities are built.