A carbon footprint analysis of egg production and processing supply chains in the Midwestern United States

摘要

We conducted a carbon footprint analysis to quantify the scale and distribution of life cycle greenhouse gas (GHG) emissions in contemporary intensive egg production and processing supply chains (up to the breaker facility gate) in the Midwestern United States. Feed production and use in pullet and layer fa-cilities was found to contribute the largest share of supply chain emissions. Further optimization of feed use efficiencies and sourcing least-environmental cost feed inputs are therefore key leverage points for reducing the GHG intensity of regional egg products. Of particular efficacy will be reducing the fraction of animal-derived materials used as inputs to poultry feeds and/or sourcing least-GHG intensive (i.e. poultry rather than ruminant) animal-derived feed inputs. Managing supply chains for nitrogen (N) use efficiency is also a key consideration - both in terms of sourcing N-efficient crop inputs, and selection of manure management strategies to minimize N losses. Breeding for N use efficiency may also be effica-cious in this respect. In contrast, contributions from egg processing and breaking stages to overall emissions were small (1% and 2% of supply chain emissions, respectively). Although making relatively minor contributions to supply chain emissions, the high degree of variability in reported energy and other (non-feed) resources used between facilities for pullet and layer production along with egg pro-cessing and breaking stages also indicates opportunities for streamlining towards more efficient industry norms.