LIFE–CYCLE GREENHOUSE–GAS EMISSIONS OF FIVE BEEF PRODUCTION SYSTEMS TYPICAL OF THE SOUTHERN HIGH PLAINS

A life cycle assessment (LCA) of the beef cattle feeding systems in the Southern High Plains is needed to acknowledge climate change legislation concerns and the sustainability of the industry as it currently operates. The goal of this research was to develop a systems-based model capable of generating carbon-footprint estimates for five typical Southern High Plains beef-production systems. The systems included a native grass pasture (System One); a native grass pasture with feedlot finishing (System Two); a modified pasture (wheat) with feedlot finishing (System Three); a feedlot-only system (System Four); and a native grass pasture, modified pasture (wheat), and feedlot (System Five). The spreadsheet-based model estimates net emissions of greenhouse gases (CO2, N2O and CH4), expressed as CO2e, from the individual processes within each system. The net emissions from production System One (NGP) totaled 6,632 kg CO2e, resulting in 26.49 kg CO2e/kg gain. System Two (NGP-FY) net emissions totaled 2,918 kg CO2e, resulting in 7.61 kg CO2e/kg gain. The net emissions from production System Three (MP-FY) totaled 3,255 kg CO2e, resulting in 7.64 kg CO2e/kg gain. Production System Four (FY) net emissions totaled 1,799 kg CO2e, resulting in 4.84 kg CO2e/kg gain. System Five (NGP-MP-FY) net emissions totaled 3,737 kg CO2e resulting in 8.15 kg CO2e/kg gain. Greenhouse gas emissions were lower in System Four (feedlot only) than in all other systems.