Eliminating conventional cages from EU egg production in favour of more welfare-friendly methods will increase the sector's carbon footprint.
Addressing the recent International Egg Commission conference in Paris,
Dutch researcher Impke de Boer explained how the role of livestock production in global warming had only become an issue since the FAO had published its report Livestock's Long Shadow in 2006.
This had revealed that global livestock production generated an equivalent of 40bn tonnes of carbon dioxide equivalent (CO2-e) a year, or about 18% of all greenhouse gasses.
"But the report did not look at the relative contribution of different types of livestock or different production systems," said Prof de Boer.
Subsequent research had shown that chicken and egg production generated significantly less CO2e than either pork or beef, both against the amount of edible product and the amount of edible protein produced.
Wageningen University had then investigated the so-called carbon footprint of each of the main egg production systems in Holland.
This revealed that the main gasses produced by cage, barn, free range and organic systems were carbon dioxide and nitrous oxide, arising from fuel and feed used respectively. Methane output was very low.
And between the four systems, caged eggs had the smallest carbon footprint, producing 2.2kg of carbnon equivalent per kilo of eggs, compared with 2.75kgCO2e per kilo of eggs for free range systems.
"Most of this difference relates to the cultivation of feed and the fact that caged birds are far more efficient at converting the feed into eggs," explained Prof de Boer.
For example, in the Dutch flock, caged birds used 2kg of feed for 1kg of eggs, whereas organic birds used 2.6kg of feed for 1kg of eggs. Organic flocks also produced more manure than caged birds, contributing to the greater emission of greenhouse gases.
Prof de Beer said that the impending ban on conventional cages would have a negative effect on the impact of egg production on the sector's carbon footprint. But it would still be low compared with other livestock categories and this presented the sector with a "catchy" marketing opportunity.
• As for the economics cost of banning conventional cages, Barbara Grabkowsky from the University of Vechta in Germany estimated that the total capital cost came to about €6bn for the EU, and €612m in Germany alone.
The impact on running costs was an 11% increase to produce eggs from enriched cages and 21% more to produce eggs from a barn system.
• For a comment on the conference see Phil Clarke's Business Blog