Date of Graduation

7-2015

Document Type

Thesis

Degree Name

Master of Science in Biological Engineering (MS)

Degree Level

Graduate

Department

Biological and Agricultural Engineering

Advisor

Marty D. Matlock

Committee Member

Greg Thoma

Second Committee Member

Rick Ulrich

Keywords

Social sciences; Biological sciences; Applied sciences; Carbon footprint; Life cycle assessment; Management practices; Pork; Sustainability; Swine

Abstract

Life Cycle Assessments (LCAs) are quantitative analyses of complex systems for evaluation of impacts and risk associated with management decisions. LCAs can be effective tools for determining comparative advantages of management strategies across specific impact concern. In this study, life cycle assessments of pork production management alternatives was performed. The alternative management practices included in this study were production of entire males (boars), use of pens for gestation housing, immunocastration, production without growth promoting antimicrobials, production without growth promoting and preventive antimicrobials, and production without ractopamine. These LCAs evaluated the impact of each management strategy on greenhouse gas emission (GHG), cumulative energy use, and cumulative water use compared to the common baseline. Each alternative management strategy was simulated in Pig Production Environmental Footprint (PPEF) model by varying key variables. Life cycle inventory inputs for unit process created using PPEF model were used for SimaPro V7.3 (Pre’ Consultants, The Netherlands), an LCA modeling program. The functional unit for the analysis was one kilogram live weight at the farm gate. Influence of temperature on impact categories was evaluated by testing all alternate management practices at five temperature regimes. While, temperature influenced the changes to the impact categories, hypothesis testing was performed for alternative management practices for scenario at Wright County, Iowa that used typical meteorological year to control temperature inside the barn. LCAs of alternative management practices yielded a range of results. Increase in GHG emissions, cumulative energy use, and cumulative water use were observed for no growth promoting antimicrobials (1.559, 1.746, and 1.038% respectively), no growth promoting or preventive antimicrobials (17.321, 18.399, and 15.577% respectively), and removal of ractopamine (6.515, 4.867, and 7.518% respectively) scenarios. For entire males scenarios GHG emission and cumulative energy use increased by 2.092 and 3.748% but cumulative water use decreased by 2.294%. Lower GHG emissions, cumulative energy use, and cumulative water use were observed for gestation pens (0.973, 1.499, and 0.972% respectively) and immunocastration (2.385, 2.567, and 2.963% respectively) scenarios. These changes could be concluded with at least 75% confidence only for lower water consumption for entire males, decreased GHG emissions and water consumption for immunocastration, increased cumulative energy consumption for no growth promoting antimicrobials, increase in all three impact categories for no growth promoting or preventive antimicrobials, and increased GHG emissions, cumulative energy and cumulative water consumption for removal of ractopamine scenarios. A null hypothesis that changing management practices in the pork production in the US does not affect impact category metrics used for sustainability assessment was rejected using one tailed paired t-test at P < 0.001. However, it is important to understand that these results are the product of simulation of pork production strategies combined with the unit process LCAs and considering possibilities of uncertainties in the model and life cycle inventory, these results should be interpreted with caution. Results of this study should be interpreted as general trend, rather than absolute numbers observed in this study.

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