Nitrogen and phosphorus excretion are among the primary potential sources of environmental contamination in growing-finishing pig operations. Nutrient excretion can be reduced by feeding pigs with daily tailored diets to their estimated nutrient requirements using individual precision feeding (IPF) techniques. The environmental impact of moving from conventional group 3-phase-feeding (CON) to IPF systems in Québec, Canada, was evaluated in this study using life-cycle analysis. A cradle-to-farm gate life-cycle analysis was conducted using Simapro software (v. 22.214.171.124; PRE Consultants, Amersfoort, The Netherlands). The model included inputs and outputs of each sub-phase: raw materials/feedstuffs production, feed mill processing transport, animal rearing (maternity, weaning, and fattening units), and manure spreading in all livestock productions. All feed ingredients originated from Quebec (Montérégie region) and agricultural practices were simulated using real management data from an average farm in Quebec. Based on observed pig growth data, the CON and IPF systems were compared in the growing-finishing phase (Andretta et al., 2016). IPF diets were obtained by blending two feeds (i.e., A and B), while CON diets were formulated according to the ones used by the industry. The evaluated impact categories were global warming (GW), eutrophication (EU), and acidification (AC). The functional unit was 1 ton of feed at the feed mill gate, and 1 ton of pig live weight at the farm gate for finished pigs. A Monte Carlo analysis was performed to determine the uncertainty of the growth performance results. Feeding programs were compared with an analysis of variance. Corn was the ingredient with higher GW and AC impacts, therefore, diets with higher corn content were those with higher impacts in these categories. Feed B, which contained 83.2% of corn, resulted in impacts of 570 kg of CO2 eq., 8.21 kg SO2 eq. and 6,27 kg PO4 eq. Diets with higher EU impact were those with a higher percentage of soybean meal. Feed A contained 25.4% of this ingredient and impacted 554 kg of CO2 eq., 6,84 kg SO2 eq. and 7.05 kg PO4 eq. CON diets had environmental impacts between those of feeds A and B. Compared to CON, IPF decreased GW by 5.1%, AC by 14.2% and EU by 12.2%.
IPF significantly reduced the environmental impact in all categories due to the more efficient use of nutritional resources. IPF is an effective alternative to improve the sustainability of growing-finishing pig operations in Québec and likely other regions using corn and soybean-based diets.