Can the environmental impact of pig systems be reduced by utilising co-products as feed?

The implications of using co-products from the supply chains of human food and biofuels in pig diets for the environmental impacts of Canadian pig systems were examined using Life Cycle Assessment. The functional unit was 1 kg expected carcass weight (ECW) and environmental impacts were calculated as: Acidification Potential (AP), Eutrophication Potential (EP), Global Warming Potential (GWP), Nonrenewable Energy Use (NRE) and Nonrenewable Resource Use (NRRU). Maximum inclusion limits which would not negatively affect animal performance were defined for: meat meal (55), bakery meal (87), corn DDGS (261) and wheat shorts (291) (numbers in brackets represent average across all feeding phases in g/kg as fed). Nutritionally equivalent grower/finisher (G/F) diets containing maximum inclusions of these co-products were formulated individually. These diets were compared to a simple control diet based on corn and soya meal using 1000 parallel Monte-Carlo simulations. The maximum inclusion of meat meal reduced NRRU and NRE per kg ECW by 9% and 8% compared to the control (P