Energy and carbon inventory of Iowa swine production facilities

Abstract

This study evaluates energy and carbon use by two types of facilities—conventional confinement and hoop barn-based—within farrow-to-finish pig production systems scaled to produce 5200 and 15,600 market pigs annually in Iowa. The United States is the world’s second largest producer of pork with pig production centered in the state of Iowa. Conventional confinement facilities are typical of pork industry practice in the United States and are characterized by individual gestation stalls and 1200 head grow-finish buildings with slatted concrete floors and liquid manure systems. The hoop barn-based alternative uses group pens in bedded hoop barns for gestation and finishing. Both systems use climate controlled farrowing facilities with individual farrowing crates as well as climate controlled nursery facilities. Feed is the single largest operating resource in pig production systems and feed fed to grow-finish pigs accounts for 63–65% of total energy use in raising pigs. The other stages of production are more reliant on non-renewable fuels and ignoring these stages of production misses 54–80% of the non-renewable fuel use associated with pig production. Taking into account demonstrated performance differences, hoop barn-based pig production requires 2.4% more feed and similar total energy as conventional pig production. Hoop barn-based pig production requires 63–64% less non-renewable fuel and results in 35% less emissions. There is little (<0.3%) energetic advantage to increase the scale of pig production from 5200 to 15,600 market pigs annually. Excluding the gross energy of feedstuffs fed to pigs, producing pigs in Iowa requires 7.2–8.2 MJ/kg live weight and results in emission of 1.0–1.6 kg CO 2 equivalents/kg live weight. This compares favorably with published energy assessments of pig production for European systems. Using hoop barns for grow-finish pigs and gestating sows is an effective strategy to reduce direct use of fossil fuels for pig production and may minimize global climate altering emissions.