Preliminary research conducted by Iowa State University and funded by the Leopold Center for Sustainable Agriculture shows no difference in the performance of cattle that grazed Bt corn crop residues and those which grazed non-Bt corn crop residues. 'The bottom line is that in one year there was no effect of Bt corn on the quality of stalks for winter grazing,' said Jim Russell, forage grazing specialist at the Iowa Beef Center at ISU. Russell said there was little difference in the amount of hay required to maintain comparable body condition in cows grazing the crop residues from different hybrids.The research was conducted in direct response to cattle producers' questions about Bt corn stalks as a forage. Russell noted that the grazing research was conducted during the winter of 1998-99 and will continue for another year. The 1998 growing season was a light one for corn borers. The results could be different in a year of heavier corn borer infestation.  Previous research has shown that corn stalks are an under-utilized resource in Iowa, Russell added. 'The amount of corn stalks a producer uses in beef production is strongly related to his or her profitability,' he said. 'Grazing corn stalks costs 5 cents per day, while feeding hay costs 60 cents to $1.20 per day.' Russell's study comparing Bt corn crop residues to non-Bt corn crop residues as a forage was conducted at the Beef Nutrition Farm near Ames. Corn for the research was donated by Pioneer Hi-Bred International, Inc. and Novartis Seeds, Inc.  For more information, contact the Iowa Beef Center at http://www.ibc.iastate.edu/ or (515) 294-BEEF.