Life cycle impacts of sheep sector in Ontario, Canada

Purpose Sheep sector in Canada is growing, and producers have ranked their desire to estimate the environmental performance of sheep farming (for benchmarking and marketability) high. Life cycle assessment (LCA) studies on the Canadian sheep sector are underrepresented, however, and record on feeding options and pasture management on sheep farms is difficult to find. This study aims to address this knowledge gap by conducting a cradle-to-gate LCA on sheep production using Ontario-specific primary data. Methods Life cycle implications of Ontario's sheep meat production in the categories of global warming (GW), non-renewable energy demand (ED), and water depletion (WD) are estimated by considering the impacts of livestock emissions, feed production, manure management, and farming infrastructure/operations up to the point where the animal leaves the farm for slaughter (i.e., cradle-to-farmgate system boundary). Data on sheep farming practices from 23 farms in Ontario is gathered (primarily through surveys), parametrized, and inputted into the LCA model to estimate Ontario-specific impacts. Allocation of impacts to sheep meat is done through protein mass allocation (PMA), and impact scores are normalized using a functional unit of kilogram liveweight (kg LW). The LCA model code is made available under General Public License (GPL) for further application and improvement. Results and discussion Life cycle impacts per kg LW meat for over 90% of the sampled farms are in the range of 8.4-18.6 kg CO2 eq for GW, 18.6-92.4 MJ for ED, and 0.06-0.27 m(3) for WD. PMA factors for meat are in the range of 68-80%. On average, enteric emissions from livestock are responsible for 39% of greenhouse gas (GHG) emissions, followed by feed production (29%), farm operations (23%), and manure management (10%). ED and WD impacts are each roughly split evenly between feed production and farm operations. Regression analysis between farm practices and impacts shows that farming intensity does not have a significant effect on impact scores. Conclusions and recommendations Ontario sheep sector's impact scores, particularly for GW, are consistent with values observed in the literature. This study may represent an important first step in understanding the life cycle environmental implications of Canadian sheep farming, but room for improvement remains. It is recommended that a sensitivity analysis be carried to gauge the effect of farming practices on impact scores, and aquatic eutrophication impacts should be included in the model, considering the presence of algal growth in Ontario.

Automated summary

This study aims to fill the knowledge gap in Life Cycle Assessment (LCA) studies on sheep production in Canada by conducting a cradle-to-gate LCA using Ontario-specific data. The results show that sheep meat production has significant impacts on global warming, non-renewable energy demand, and water depletion. It is recommended to conduct a sensitivity analysis and consider the impact of aquatic eutrophication.