Determination of environmental impacts of antimicrobial usage for US Northern Great Plains swine-production facilities: a life-cycle assessment approach

摘要

Purpose This study used life-cycle assessment (LCA) methodology to examine the environmental effects associated with sub-therapeutic tylosin and chlortetracycline (CTC) antimicrobial use within US Northern Great Plains (NGP) swine-production facilities. Antimicrobial feed-additive use is widespread within this industry and is expected to play an integral role within future carbon-management strategies due to its ability to increase feed efficiency and control disease. Materials and methods The LCA model system boundaries for this study were: (1) antimicrobial manufacturing; (2) feed manufacturing; (3) transport of antimicrobials to the feed-mill and completed feed to the swine-production facility; (4) electricity and propane use associated with swine-production operations; and (5) swine enteric and manure-storage and handling emissions. The functional unit is the growth life cycle of one head of swine from starter (7 kg) to finisher (111 kg market weight; "wean-to-finish") production stages. Environmental impacts considered include global warming, acidification and eutrophication, ecotoxicity, and fossil-fuel use following Ecolndicator 99 assessment methodology. Results and discussion High-estimated energy requirements associated with CTC and tylosin manufacturing, coupled with the large transportation distances to the feed manufacturing and swine-production facilities increased climate change and ecotoxicity impacts compared with a no antimicrobial-use scenario. However, feeding CTC resulted in several local positive changes including increased feed utilization, lower producer costs due to shortened production times, and reduced manure greenhouse gas emissions. These positive changes in the local environment however did not offset negative global impacts associated with material manufacturing and transport for the specific scenarios analyzed. Increased use of renewable-energy sources for both swine and antimicrobial production resulted in net environmental enhancement. Conclusions This study demonstrates both the beneficial and negative environmental aspects associated with sub-therapeutic antimicrobial within the swine-production industry, and provides swine producers and environmental practitioners with tangible alternatives for meeting both livestock-health management and future carbon-management constraints within a reduced-carbon-emission consumer and regulatory marketplace.