Steer growth performance and enteric gas flux across backgrounding phases in the western Great Plains

Authors: MESA GANDOLFO, INES - Colorado State University; Derner, Justin; ENNS, R. MARK - Colorado State University; Kuehn, Larry; Johnston, Melissa; KEARNEY, SEAN - Thunder Basin Grasslands Prairie Ecological Association; PLACE, SARA - Colorado State University; RAYNOR, EDWARD - Colorado State University; RITTEN, JOHN - Colorado State University; SHADBOLT, ANNA - Colorado State University; STACKHOUSE-LAWSON, KIMBERLY - Colorado State University; VARGAS, JUAN - Colorado State University; CARVALHO, PEDRO - Colorado State University

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/18/2025
Publication Date: 9/24/2025
Citation: Mesa Gandolfo, I., Derner, J.D., Enns, R., Kuehn, L.A., Johnston, M.K., Kearney, S.P., Place, S.E., Raynor, E.J., Ritten, J.P., Shadbolt, A.M., Stackhouse-Lawson, K.R., Vargas, J., Carvalho, P.H. 2025. Steer growth performance and enteric gas flux across backgrounding phases in the western Great Plains. Rangeland Ecology and Management. 103:247-257. https://doi.org/10.1016/j.rama.2025.08.010.
DOI: https://doi.org/10.1016/j.rama.2025.08.010

Interpretive Summary: This study aimed to assess the impact of the production environment on the growth performance and gas flux of growing yearling steers. In the initial postweaning phase, one group of steers grazed rangeland, and two groups were managed in confinement before all three groups grazed rangeland during the stocker phase. In the initial postweaning phase, steers managed in a winter extensive grazing system had the lowest average daily gain (ADG) and emitted the least amount of enteric methane (CH4) when compared to steers that were managed in a confined system and fed a forage-based total mixed ration (TMR) before the stocker phase. In the stocker phase, all steers grazed in the same summer extensive grazing system in the Colorado shortgrass steppe. Steers that grazed rangeland before the summer stocker phase had the greatest ADG and CH4 production (MP), but the least methane intensity (MI) compared to steers managed in confinement before the stocker phase. In conclusion, results highlight the importance of the production environment (i.e., diet and environment) in understanding the variation of growth performance and gas flux emissions along the backgrounding portion of the beef production sector.

Technical Abstract: The objective of the current study was to evaluate the impact of the production environment (e.g., local climate, management system, and diet) of yearling steers on growth performance and gas flux in two phases (initial postweaning and stocker) of the backgrounding stage prior to the finishing stage in confinement. In the postweaning phase, one group of steers grazed rangeland, and two groups were managed in confinement before the three groups grazed semiarid shortgrass rangeland during the stocker phase. One hundred and twenty steers were evaluated for growth performance and gas flux in the postweaning phase (40 Colorado-grazing steers with average ± SD initial body weight (IBW) = 305 ± 22 kg; 40 Nebraska-confined steers with IBW = 292 kg ± 23 fed a forage-based diet, and 40 Colorado-confined steers with IBW = 191 ± 17 kg fed a 45:55 forage: concentrate-based diet). For the subsequent stocker phase before finishing, the 20 steers from each initial production environment that met the automated head chamber system (AHCS) visitation requirement in the postweaning phase were then evaluated for gas flux and growth performance in a summer rangeland grazing system. Data was analyzed as a completely randomized design and planned contrasts were conducted to compare specific group postweaning pairs (Colorado-confined vs. Nebraska-confined, Colorado-confined vs. Colorado-grazing) using R. In the postweaning phase, Colorado-grazing steers rangeland had the lowest (P < 0.01) average daily gain (ADG) and least (P < 0.01) CH4 production (MP) compared to Nebraska or Colorado steers in confinement. Colorado-grazing steers had the greatest (P = 0.05) methane intensity (MI) in comparison to steers managed in confinement for the postweaning phase. In the stocker phase on rangeland, where all steers collectively grazed Colorado shortgrass steppe, Colorado-grazing steers had the greatest (P < 0.01) ADG, produced the greatest (P < 0.01) MP, but the least (P < 0.01) MI when compared to Nebraska or Colorado steers that were confined in the postweaning phase. Although steers that maintained the same extensive grazing production environment across backgrounding phases exhibited greater MP in the stocker phase compared to postweaning confined steers, their greater growth performance on rangeland pasture resulted in less CH4 emissions per kg gained. Further, efforts should be context-specific for comparative efforts across animal production environments in the backgrounding phases to inform more accurate assessments of the sustainability of beef cattle related to greenhouse gas mitigation strategies.