Lifecycle assessment of US egg production

Few research studies have applied the approach known as lifecycle assessment (LCA) to food production but one of the more interesting and readable studies of this type was published last Fall by researchers at the Egg Industry Center of Iowa State University. The report demonstrates. within certain limitations, that the egg production sector achieved significant environmental performance gains over the 50 years between 1960 and 2010.

The report shows that the biggest environmental impact associated with egg production stems from feed production. Reported environmental improvements in the egg industry over the 50 year period include:

  • 30% lighter body weight at onset of lay (1.2 vs. 1.7 kg)
  • 48% less feed use over pullet-rearing period (5.3 vs. 10.2 kg)
  • 70% lower mortality over pullet-rearing period (3.5% vs. 11.7%)
  • 26% less daily feed use (9.03 vs. 12.23 kg/100 hens)
  • 42% better feed conversion (1.98 vs. 3.44 kg per kg of egg)
  • 32% less direct water use per dozen eggs produced (4.5 vs. 3.1 L)
  • 65% lower acidifying emissions (70 vs. 200 g SO2-e) per kg egg
  • 71% lower eutrophying emissions (20 vs. 70 g PO4-e) per kg egg
  • 71% lower GHG emissions (2.1 vs. 7.2 kg CO2-e) per kg egg
  • 31% lower Cumulative Energy Demand (12.3 vs. 17.7 MJ).

Some of the limitations of the research include:

  • LCA did not exist in 1960 so the data used have had to be derived from sources that may not be as reliable as today’s data sources
  • LCA does not provide robust tools for measuring animal welfare and, in GallonDaily’s opinion, may not, in this regard, differentiate sufficiently between the inputs and outputs of machines and those of living organisms
  • the research does not include the environmental impacts of egg distribution systems.

The report has been published in a slightly revised form in a peer-reviewed journal and there is no reason to think that the limitations will have a major impact on the overall conclusions. To GallonDaily’s knowledge there is no similar study relevant to egg production in Canada.

The full 25 page report and a summary in the form of a press release are available at The methodology and overall findings are likely to be relevant to GallonDaily readers interested in the environmental impact of food production systems.

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