Life cycle assessment of seventeen environmental impacts in slaughter pig production farms using different management practices

Pork production systems exert considerable environmental pressure and thus, the need for the implementation of mitigation options. The present study aimed to assess seventeen environmental impacts (including soil quality, toxicity, biodiversity, and climate change) of slaughter pig production farms. A cradle-to-farm-gate approach was used to analyze the environmental profiles of five farms using different technologies and management practices (F 1: increased feed and animal productivity compared to the Danish average production (F 0 ); F 2 : chemical air purification (20%) during housing; F 3 : partial replacement of soybean meal with fava beans; slurry acidification and storage of slurry with tent and floating covers; F 4 : anaerobic digestion of manure; F 5 : increased share of by-products in feed rations compared to F 0 ; slurry acidification and storage of manure with tent covers). The best environmental profile was identified for farm F 5 . F 5 performed best for most impacts, including the pressure on land. However, the adverse effects on ecosystems and toxicity-related impacts of using sulfuric acid in slurry acidification could not be quantified because of methodological gaps. Focusing on increased productivity in F 1 was beneficial for many impact categories, but the use of soybean meal caused greater imacts for land use and land use change related indicators. When partially replacing soybean meal with Danish-produced fava beans in F 3 , direct land use change and toxicity-related impacts were lower compared to F 0 . Anaerobic digestion of manure in F 4 led to decreases in climate change, resource use, and ozone depletion potential compared to F 0 . The worst environmental profile was that of farm F 2 , where the reductions in NH 3 emissions during chemical air purification were offset by higher feed use per kg gain. The present study highlighted the need for using foreground region-specific characterization factors as opposed to background country-specific or global characterization factors in the soil quality model. Additionally, this study points out the risk of sub-optimizing when amending pork systems only according to one impact category.