Avoiding feed-food competition in practice; Environmental impact assessment of a novel egg production system

Feed cultivation on arable land (40% globally) results in less efficient food production than food crop cultivation. This inefficiency can be avoided using livestock feeds that do not compete with food production, so called “low-opportunity-cost feedstuffs” (e.g. food by-products & waste and grazing resources). livestock, then, converts nutrients otherwise lost to the food system into valuable food. While this new role of livestock is theoretically well supported, its practical feasibility remains unstudied. We, therefore, assessed the environmental benefits of feeding only “low-opportunity-cost feed-stuffs” to industrially-housed laying hens on the commercial Kipster farm. Simultaneously we underline the shortcomings of conventional methods to account for such benefits. We quantified global warming potential, energy use and land use per kg egg, using life cycle assessment (LCA), Kipster eggs have a lower environmental impact (1.3 kg CO2-eq; 10 MJ; 2.9 m2), than free range and organic eggs (2.5-3.5 kg CO2-eq; 19-27 MJ; 4.1-6.8 m2), mainly due to the use of “low-opportunity-cost feedstuffs”. Additionally, we illustrate that economic allocation used in LCA does not fully account for the environmental benefits of feeding “low-opportunity-cost feedstuffs”, as it ignores interlinkages in the food system between, for example, sugar and beet pulp. Alternative circular allocation – allocating the full impact to the main product – reduces Kipsters environmental impact with 44% for GWP, 37% for EU and 90% for LU. Adequately capturing such complexities of the food system in LCA is of major importance to avoid promotion of mitigation measures that counteract resource use efficiency of the entire food system.