Life cycle assessment of alternative swine management practices.

Life cycle assessment of various alternative management strategies in the swine industry was performed to evaluate their impact on greenhouse gas (GHG) emissions, cumulative energy use, and cumulative water use. The management strategies included the use of immunocastration (IC), production without ractopamine (NoRAC), production without antimicrobials used for either growth promotion (NoAGP) or disease prevention (NoPREV), production of entire males (boars) (EM), and use of gestation pens (PENS). A common baseline scenario representing standard management practices in the swine industry was created against which all alternative management practices were compared pairwise. The study scope was from cradle-to-farm gate with a functional unit of 1 kg live weight at the farm gate. The baseline and each alternative management scenario was simulated in Pig Production Environmental Footprint Calculator (PPEC) model by varying key variables to populate life cycle inventory inputs for SimaPro V7.3 (Pre' Consultant, the Netherlands), a life cycle assessment modeling program. Increase in GHG emissions, energy use, and water use were observed for NoAGP (1.56, 1.75, and 1.03%, respectively), NoPREV (17.32, 18.40, and 15.58%, respectively), and NoRAC (6.52, 4.87, and 7.52%, respectively) scenarios. For EM scenario, GHG emissions and energy use increased by 2.09 and 3.75%, respectively but water use decreased by 2.29%. Lower GHG emissions, energy use, and water use were observed for PENS (0.97, 1.50, and 0.97%, respectively) and IC (2.39, 2.57, and 2.96%, respectively) scenarios. These changes in the impact categories were statistically significant (P < 0.05) for all scenarios except for changes to GHG emissions for EM and changes to water consumption for PENS and NoAGP. However, the uncertainty analysis showed that the tails of distribution for baseline and alternative management scenario pair overlapped. The impact of management practices on sustainability metrics resulted from differences in pig performance parameters, manure production, feed consumption, etc. between various management practices and the baseline scenario. Due to uncertainties in input parameters, the results should be interpreted as general trends which specifically highlight trade-offs that may result from shifts in production practices. The study identified some of the hot spots in pig production and can be useful in determining best management practices to make swine production more environmentally sustainable.