Nutrient use efficiency: a valuable approach to benchmark the sustainability of nutrient use in global livestock production?

Livestock have a large impact on nutrient cycles, with repercussions on environmental and public health issues. Designing interventions for better environmental sustainability will require indicators adapted to the increasingly long and complex supply chains. Nutrient use efficiency is a well know approach to benchmark nutrient management at the animal level, and to some extent at the farm level. Integrating the life cycle approach into NUE allows for the computation of supply chain level NUE, which is proposed as a valuable indicator of nutrient management sustainability. It characterizes the use of finite nutrient and energy resources and the losses of nutrients per unit of product, likely to have impacts on the environment and public health. Further research is required to harmonize life-cycle-NUE and test its validity as an indicator of nutrient management sustainability.