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The brown midrib-3 ([bm.sub.3]) gene mutation has been incorporated into corn plants to potentially improve fiber digestibility. The objectives of this study were to determine the effect of [bm.sub.3] corn silage on digestion and performance of growing beef steers and to determine whether limiting intake would further enhance fiber digestibility of [bm.sub.3] corn silage. A [bm.sub.3] hybrid and its isogeneic normal counterpart were harvested at three-quarters kernel milk line. Neutral detergent fiber, ADF, and ADL were 4.5, 6.9, and 1.9 units lower, respectively, and DM was 5.4 units higher for [bm.sub.3] than for normal silage. In Trial 1, eight ruminally fistulated Angus crossbred steers (224 [+ or -] 24 kg) were randomly assigned to a 2 x 2 factorial arrangement of treatments in a replicated 4 x 4 Latin square design. Steers had ad libitum feed access or were restricted to 80% of ad libitum intake of diets containing 86% normal corn silage (Control) or [bm.sub.3] corn silage (BMCS). The remainder of the diets consisted of soybean meal, urea, monensin, vitamins, and minerals. Dry matter intake was greater (P [is less than] 0.01) for steers offered ad libitum access to BMCS than for those with ad libitum access to the Control diet. The BMCS treatment resulted in improved (P [is less than] 0.05) apparent total-tract digestibility of DM, OM, NDF, and ADF. Mean concentration of total VFA and molar proportions of acetate were increased (P [is less than] 0.05) by feeding BMCS. There tended to be a DMI x hybrid interaction (P = 0.16) for apparent total-tract digestibility of NDF. When diets were offered ad libitum, BMCS increased NDF digestibility by 10.5 percentage units compared with Control, but, when DMI was limited, BMCS increased NDF digestibility by 15.8 percentage units. In Trial 2, 128 steer contemporaries of those used in Trial 1 (245 [+ or -] 13 kg) were offered ad libitum access to BMCS or Control diets as used in Trial 1. After a 112-d treatment period, concentrate in the diet was increased, and all steers were fed a common finishing diet. During the 112-d treatment period, steers receiving BMCS consumed 0.45 kg more DM/d (P [is less than] 0.05) and had similar ADG (P [is greater than] 0.10), compared with those steers receiving the Control silage. This resulted in poorer (P [is less than] 0.01) feed efficiency for steers receiving BMCS. Finishing phase and overall performance of the steers was not different (P [is greater than] 0.10) due to treatment. Although feeding BMCS in growth-phase diets resulted in increased daily DMI and improved digestibility of DM and fiber, it did not result in improved steer feedlot ADG compared with Control silage. Key Words: Beef Cattle, Digestibility, Fiber, Food Restriction, Lignin, Maize Silage