Environmental impacts of the Australian poultry industry. 2. Egg production

Abstract

Context Eggs, a dietary staple, are a low environmental-impact animal protein, although no quantified analysis has been published for the Australian egg industry. Aims This study determined baseline greenhouse-gas (GHG) emissions, fossil energy use, freshwater consumption, water stress, and land-occupation impacts for the Australian egg for 2020 and identified hotspots. Methods To understand the environmental credentials of the industry, an attributional life-cycle assessment was conducted using primary data collected from all major Australian production regions. Impacts were reported per kilogram of table eggs and per kilogram of shell- and protein-corrected eggs for cage (C), cage-free (CF) and free-range (FR) production. Monte Carlo analysis was used to assess uncertainty, and results are presented using the means and standard deviations. Key results Statistically significant (P < 0.05) differences among all systems were found for GHG and land occupation, and between cage and non-cage systems for fossil energy use. Impacts were 1.2 ± 0.04 kg carbon dioxide equivalent (CO2-e), 10.7 ± 0.2 MJ, 177.2 ± 19.0 L, 84.5 ± 9.6 L H2O-e and 16.0 ± 1.6 m3, and 7.6 ± 0.1 m2/kg C eggs, 1.4 ± 0.03 kg CO2-e, 12.0 ± 0.3 MJ, 190.6 ± 23.1 L, 88.9 ± 10.3 L H2O-e and 17.5 ± 1.9 m3, and 8.1 ± 0.1 m2/kg CF eggs and 1.5 ± 0.04 kg CO2-e, 12.2 ± 0.3 MJ, 204.6 ± 23.9 L, 100.8 ± 10.7 L H2O-e and 19.1 ± 1.8 m3 and 8.7 ± 0.1 m2/kg FR eggs. Land use and direct land use-change emissions associated with imported soymeal were significant, contributing a further 0.6 ± 0.1, 0.7 ± 0.1 and 0.7 ± 0.1 kg CO2-e/kg C, CF and FR eggs respectively. More efficient feed conversion ratios (FCRs) drove lower impacts in C production. Feed production was the major hotspot, followed by the layer farm and pullet rearing operations. Conclusions Reducing impacts will be most effective through changing diets to reduce reliance on high environmental-impact feed commodities, FCR improvements and energy efficiency measures to reduce housing energy demand. Improved land management is likely to have resulted in isolated small levels of carbon sequestration in Australian cropland over the analysis period, offsetting some GHG emissions. Further reduction in environmental impacts will rely on decarbonisation of feed supply chains and prioritisation of low environmental-impact feed commodities. Implications Being the first industry-wide environmental assessment of Australian egg production, this study has highlighted the need for ongoing assessment to isolate inter-annual variability, determine long-term trends, and investigate pathways to reduce impacts into the future.