Feed or feedstock? A case study evaluating the environmental and food supply consequences of utilizing food waste as cattle feed

Interest in local and regional meat production coupled with high population density provides a significant opportunity to repurpose food waste as livestock feed in the Northeastern U.S. However, food waste may also be used in... [ view full abstract ]

Interest in local and regional meat production coupled with high population density provides a significant opportunity to repurpose food waste as livestock feed in the Northeastern U.S. However, food waste may also be used in waste-to-energy programs, providing cleaner power than the status quo. We used consequential life cycle assessment (C-LCA) to assess the net environmental and food supply impacts of substituting food waste for corn in Northeast dairy beef cattle (DB) rations, instead of using it for a substrate in anaerobic digestion. The impact scope was global warming potential, acidification potential, and the land use ratio (LUR), which addresses feed-food competition. We accounted for the changes in processes and marginal products required as a result of the proposed shift. The functional unit was the amount of food waste that could reasonably replace corn in rations of a herd of growing and finishing DB cattle (71,492 kg dry matter), subject to several constraints. Converting this quantity of food waste to feed instead of using it as a substrate for anaerobic digestion reduced net global warming potential and acidification potential by 9,975 kg CO2-eq and 48,785 moles H+-eq, respectively. While sensitivity analyses demonstrate the reduction in GHGs is less certain, acidification reductions were robust. Feeding food waste to dairy beef cattle also keeps food in the food supply, reducing feed-food competition by 11% as measured by the LUR. Regional policies to divert food waste from landfills ought to prioritize transformation to livestock feed to reduce ecological burdens and improve regional self-reliance of food.