Review of Life Cycle Assessment in Environmental Performances of the House- Feed Sheep

Life cycle assessment is widely used to assess the environmental impact of the sheep industry. This paper sorts out some common methods of LCA application in the sheep industry and summarizes the environmental performance and hot spots of house-feed sheep. Literature review shows that most scholars use the systematic boundary of “from cradle to farm gate”, and the selection of functional units and distribution methods is similar. Most studies focus on carbon footprint, and its sources are mainly enteric fermentation, manure management and feed production. The GHG emissions range from 10.0 to 20.0kg CO2- eq per kg live weight for meat sheep, and 2.0 to 3.0kg CO2-eq per kg FPCM for dairy sheep. Other environmental categories have also been evaluated such as acidification, eutrophication and terrestrial ecotoxicity. The release of ammonia from fertilizer and manure and the loss of nitrate and phosphorus caused by fertilization are the main sources of acidification and eutrophication, respectively. Compared with grazing, the carbon footprint of the house-feed sheep system is lower, but it has a great impact on acidification and eutrophication. More research needs to be conducted to put forward potential mitigation schemes, such as the benefits of carbon sequestration and improvement of production efficiency