Supplementation of yearling steers grazing Northern Great Plains rangelands

Abstract

Growing yearling steers on summer rangelands as part of a cow-calf-yearling operation would allow producers to maximize forage utilization, and selling yearling steers when forage was in short supply would minimize potential genetic losses in the cow herd. A series of summer supplementation and intake studies were conducted from 1988-1992 to determine if weight gains of grazing yearling steers could be increased by supplemental energy (ground barley), phosphorus (P), or crude protein. Studies were conducted at 2 locations on pastures of approximately 51 ha each, which contained quite different mixtures of forage species. Forage P, crude protein and IVDOM levels were monitored throughout the grazing season. Supplementation results varied among years and between locations. There were significant (P < 0.14) location by treatment interactions in 1989 and 1990 because steers at the WEST location tended to respond more to supplementation than steers at the EAST location, but EAST location steers had the highest rates of gain. Providing supplements at gradually increasing rates produced results comparable to supplementing at a constant rate all summer. Supplemental crude protein showed no significant benefit, but crude protein levels in pasture forage were generally above steer requirements. Weight gains averaged over all 5 years were greater (P < 0.05) for steers supplemented with barley or barley and P, compared to unsupplemented control steers. The response to supplementation should be beneficial most years, but results may vary with the quantity and quality of available forage.