Individual precision feeding reduces the environmental impact of pig production in Québec, while timothy hay inclusion lowers performance and limits its environmental benefits

Abstract Nutrient excretions are among the main potential sources of environmental contamination in growing-finishing pig operations, while feed ingredients are major contributors to global warming-related emissions. Nutrient excretion can be reduced by feeding pigs with diets tailored daily to their estimated nutrient requirements using individual precision feeding (IPF) techniques. To explore additional mitigation strategies timothy hay, a perennial forage, was included in growing-finishing pig diets formulated for both a conventional 3-phase feeding system (CON) and IPF. A cradle-to-farm gate life cycle assessment (LCA) was conducted using SimaPro software (v.8.0.3.14; PRé Consultants, Amersfoort, The Netherlands). The model included all stages of feed and animal production, including feedstuff cultivation, feed mill processing, transport, animal rearing, and manure spreading. All feed ingredients were assumed to originate from the Montérégie region of Quebec, and agricultural practices were modeled using real management data from an average farm in the province. Based on observed pig growth data, the CON and IPF systems, with and without timothy inclusion, were compared for the growing-finishing phase. All diets were formulated by blending three experimental feeds: Feed A (nutrient-rich), Feed B1 (nutrient-poor, conventional ingredients), and Feed B2 (nutrient-poor, with 40% timothy inclusion). Evaluated impact categories included global warming potential (GW), eutrophication (EU), and acidification (AC). The functional units were 1 ton of feed ingredient or feed at the feed mill gate and 1 ton of live pig weight at the farm gate. A Monte Carlo analysis assessed uncertainty in growth performance results, and feeding treatments were compared using analysis of variance. Cereal grains produced in Quebec were identified as the dominant contributors to GW and AC impacts. In contrast, GW and AC impacts related to timothy meal production were 50% and 97% lower, respectively, than those of corn. Incorporating timothy meal into Feed B, thereby reducing cereal inclusion, decreased GW and AC emissions from feed production by 19% and 35%, respectively, but increased EU by 17%. Timothy inclusion (TI) reduced average daily gain and final body weight, while IPF did not affect animal performance. Compared to non-timothy diets, TI increased GW by 6%, and EU by 8%, without affecting AC. In contrast, IPF significantly reduced environmental impacts across all categories due to improved nutrient use efficiency, with reductions of 8% in GW, 11% in AC, and 9% in EU. In conclusion, IPF reduces the environmental footprint of pork production systems. Although timothy hay inclusion decreased the environmental burden of feed production, it did not reduce overall impacts at the farm level because of its negative effect on animal performance. Further work is needed to mitigate these performance drawbacks to enhance the sustainability benefits of timothy inclusion in Québec pig production and in other regions that rely on corn- and soybean-based diets.