Coffey, K.P.Brazle, F.K.2010-09-092010-09-092010-09-09http://hdl.handle.net/2097/4864Forty-eight mixed-breed steers from two sources were used in a 141-day feedlot study to compare a control ration (C) with a ration containing magnesium-mica (MM; 9 lb/ton). No diet cattle source interactions were detected. Steer gain, efficiency, and cost of gain did not differ (P>.10) between diets. Marbling score tended (P<.10) to be greater and the percentage of cattle grading USDA Choice and net carcass value were greater (P<.05) for steers fed MM. Feeding MM in a feedlot ration may have a substantial economic impact on feedlot cattle.BeefMagnesium-MicaFeedlot cattleMarbling scoreConference paper