Technical Abstract: Pastures seeded to cool-season grasses may be used to reduce grazing pressure on native rangelands. They may also provide high quality forage for livestock during early spring and autumn. Many varieties have been seeded, evaluated for forage production and quality and persistence. As a result, some are recommended for use in the Northern Great Plains. Average gain/head/day (lbs) in 2000 was greatest on Hycrest and Luna (2.1), intermediate on Rosana (1.6), and least on native rangeland (0.6); and gains in 2001 averaged 2.0 on seeded pastures versus 0.02 on native rangeland. When gains were compared for the period from early spring through late summer, no significant differences were detected among the pastures, and gains averaged 1.2 lbs/head/day. The increased gains on seeded pastures compared to native rangeland in spring did not have an effect on heifer pregnancy rates. During autumn, gains were significantly greater on Prairieland and Bozoisky (average 1.1 lbs/head/day) than on Alkar (0.5) or native rangeland (0.11), and gains on Newhy (0.74) were intermediate. Increased gains can occur on seeded pastures compared to native rangeland during spring grazing, but these gains may not be maintained through summer in the Northern Great Plains.