A Cradle to Farm Gate Life Cycle Analysis of Water Use in U.S. Pork Production

The intent of this study was to analyze water use across a range of regions, scales and practices of the U.S. pork industry. A Life Cycle Assessment of water use within the pork supply chain was performed. Cumulative water use was the environmental impact category used in the LCA to evaluate the impacts of pork production processes throughout the pork supply chain. The functional unit for the analysis was the volume of water required to produce one kilogram of swine (live weight) at the farm gate. A comprehensive literature review was used to design and propagate algorithms for the National Pork Board Pig Production Environmental Footprint Calculator (version 2.0). The outputs from the calculator were used to generate lifecycle inventory inputs for unit processes in SimaPro (Pre’ Consultants, The Netherlands), an LCA modeling program. The LCA method was then used to assess the water footprint for swine production from cradle to farm gate production scenarios. There were 240 different scenarios analyzed that were a combination of ten regions, three production strategies and three scales. The grow/finish barn phase of the on farm water footprint requires approximately five times as much water as the sow and nursery barns irrespective of the barn infrastructure. Water used to irrigate swine feed crops contributed 89% of the total cradle to farm gate footprint. Since all 240 scenarios were analyzed with the same ration inputs, the final footprints did not vary drastically between scenarios. There were small deviations such as tunnel ventilated production systems consistently required more water than hoop barns due to cooling systems in warmer regions. Smaller scale operations consistently had higher water footprints due to economy of scale, although the footprint differences between scales were marginal. Regarding the water use that occurred on the swine farm, drinking water was by far the most significant contributor to the footprint (81%). Production strategies, production scale and region of production were all statistically significant (p < 0.0001) and affected the blue water footprint. This may seem self-evident, but these processes have not been quantified at this scale prior to this analysis. ACKNOWLEDGEMENTS I would first and foremost like to thank my family, especially my mother Lowell Collins and father Daryl Boles for their guidance, inspiration, and mentoring throughout my life. I am the person they shaped me to be. Immense gratitude is due to Drs. Marty Matlock and Greg Thoma for their guidance throughout this project. This project would not have been possible without their support. I would like to acknowledge the generous support of the National Pork Board, whose generous support made this work possible. TABLE OF CONTENTS 1. DEFINING THE PROBLEM . 3 Sustainability . 3 Water . 3 Animal Production . 3 Life Cycle Analysis . 4 Introduction . 4 Life Cycle Analysis as a Tool . 4 Objectives of this Project . 6 Hypothesis Statements . 6 2. LITERATURE REVIEW . 7 Overview of Water Use in Swine Production . 7 Blue vs. Green Water Definition . 7 Water Use from Field to Farm Gate . 10 Water Use in Crop Production . 10 Water Use at the Swine Production Facility . 13 Drinking Water Consumption in Swine Production Facilities . 14 Pig Drinker Systems . 14 Effects of Temperature on Drinking Water Consumption . 18 Sow Drinking Water for Gestation and Lactation . 20 Nursery Drinking Water Consumption . 20 Grow-Finish Water Consumption . 21 Cooling Water Consumption in Swine Production Facilities . 21 Cooling Technologies . 21 Effects of Regional Climate on Cooling Requirements . 22 Effects of Barn Infrastructure on Cooling Requirements . 22 Effects of Stocking Density on Water Consumption . 23 Cooling Requirements by Life Phase . 24 Manure Management Systems and Washing Water . 26 Types of Manure Management Systems . 26 Dry Cleanup Techniques. 27 Factors Affecting Washing Water Use Requirements . 28 Wash Water Requirements by Life Phase . 29 Water Used to Wash Pig Transportation Vehicles . 29 Wasted Water . 30 Current Gaps in Knowledge . 31 3. METHODS OF PORK WATER LCA . 32 Goal . 32 Functional Unit . 32 System Boundaries and Scope . 32 Scenario Development . 33 Production Strategies . 35 Regional Analysis . 37 Production Scales . 38 SimaPro LCA Model . 40 Life Cycle Inventory . 44 Allocation of Co-Products . 47 Water Use for Crop Production . 47 4. RESULTS AND DISCUSSION . 50 Sensitivity and Uncertainty Analysis . 56 Sensitivity Analysis . 56 Sensitivity Analysis Results . 57 Uncertainty Analysis . 58 Uncertainty Analysis Results . 61 Statistical Analysis of Hypothesis Statements . 65 5. CONCLUSIONS AND RECOMMENDATIONS . 68 6. WORKS CITED . 71 Appendix A: ANOVA Test for All Treatments . 75 Appendix B: Least Square Means Plot and T-tests Between Production Strategies . 77 Appendix C: Least Square Means Plot and T-tests Between Production Scales . 79 Appendix D: Least Square Means Plot and T-tests Between Regions of Production . 80