The performance of bison finished on grain and forage was evaluated in summer and winter. In the first experiment, 58 bison bulls were finished for slaughter (90 day period beginning in late October 1993 and 1994). Half of the bulls fed with a feed-weigh station were compared to bulls fed with industry standard self-feeders. No significant differences (P>0.05) were found in average daily gain between the two feed delivery methods. The feed-weigh station then was used to assess seasonal effects on average daily gain of 156 bison bulls. After correcting for initial body weight, average daily gain was higher in summer (1.1 kg d^-1±0.004) than in winter (0.7 kg d^-1±0.005). This was associated with higher average daily feed consumption in summer (14.3 kg d^-1±1.15) than in winter (10.6 kg d^-1±1.15). Although not as striking as in northern cervids, seasonal energetic cycles of bison are a significant consideration in commercial management.