Multi-objective formulation is an efficient methodology to reduce environmental impacts of pig feeds

The production of pig feeds has a major contribution to climate change, energy use and land occupation impacts of the animal product. Nonetheless, the traditional least-cost (LC) feed formulation methods minimize the cost of the feed mix, without consideration of its environmental impacts. The objective of this study was to estimate the potential mitigation of environmental impacts calculated by Life Cycle Assessment through a multi-objective formulation of pig feeds, in the French context. The linear programming problem built searches the best feed formula under nutritional constraints with a multi-objective function including an economic price index (price of the feed mix relative to LC formulation) and an environmental impacts index (environmental impacts relative to LC formulation). A weighting coefficient between price and environment (α) ranging from 0 to 1 was included. Growing and finishing feeds were formulated with two scenarios of feed ingredients availability (current limited LIM, increased NLIM) and 4 scenarios of feed ingredient prices. When increasing α from 0 to 0.5, the environmental indexes of the growing and finishing feeds dropped down to -10% in LIM and down to -17 to -20% in NLIM scenario, respectively. Concomitantly, the average feed price increased by 1.5% in LIM and 1.7% in NLIM. For α higher than 0.5, the environmental index was almost no further reduced. At α=0.5, all the impacts considered were reduced relatively to LIM-LC, excepted for land occupation in NLIM. The low-impact feeds incorporated higher proportions of pea and wheat middlings and lower proportions of meals (rapeseed and sunflower) than LC formulated feeds. The multi-objective formulation of pig feeds is an efficient methodology to find low-impact feeds according to a given economic scenario. Improving the availability of some feed ingredients (pea, co-products of wheat…) at the territory level would allow (at same feed’s nutritional composition) further reduction of pig feeds impacts relatively to the current French context. Multi-objective formulation can provide a decision support tool to the feed industry to produce low-impact feeds for the pig production chain