Body weights and carcass measurements from Holstein and crossbred organic dairy steers were compared for growth while grazing 2 different cover cropping systems. Bull calves were born at the University of Minnesota West Central Research and Outreach Center organic dairy from March to May 2015 and assigned to 1 of 3 replicated breed groups at birth. Breed groups were: crossbreds comprised of Montbéliarde, Holstein, and Viking Red (MVH; n = 10), crossbreds comprised of Jersey, Normande, and Viking Red (NJV; n = 9), and purebred Holstein (HOL; n = 10). Steers grazed either winter wheat (WW) or winter rye (WR) cover crops planted the previous fall. The WW and WR cover crops were planted in September 2015 on 2 adjacent 10 acre plots. In April 2016, each breed group was randomly assigned to either cover crop and grazed rotationally until June 2016 for a total of 7 weeks. Steers were weighed individually on the first and last day of grazing and twice during the grazing season for a total of 4 weights. Steers were harvested in 2 groups at an average age of 16 mo. Statistical analysis was with PROC MIXED of SAS with forage, breed, and the interaction of forage and breed as fixed effects and the individual steer within the forage and breed interaction as a random effect. For body weights, the HOL and MVH steers were heavier (P < 0.02) than the NJV steers throughout the grazing season. For cover crops, HOL and MVH steers did not differ (P > 0.30) in weight between cover crops throughout the grazing season. However, NJV steers grazing WW tended to be heavier (P < 0.09) than NJV steers grazing WR throughout the grazing season. For average daily gain (ADG), breed groups did not differ (P > 0.12) throughout the grazing season. At harvest, MVH and HOL steers weighed more (P < 0.05) than NJV steers, and steers grazed on WW (483 kg) weighed more (P < 0.05) than steers grazed on WR (458 kg). Dressing percent, marbling score, back fat, ribeye area, and yield grade were not different (P > 0.10) between breeds or cover crops. In summary, steer breeds gained weight comparably to each other on cover crops and had similar carcass characteristics.