2008 Annual Report for GNC07-078
Energy use and nutrient cycling in pig production systems
Summary
This project examines resource use by different types and scales of pig production systems. Two types of facilities—conventional confinement and hoop barn-based—scaled to produce either 5,200 or 15,600 market pigs annually are compared. Conventional confinement facilities are typical of pork industry practice and are characterized by individual gestation stalls and 1,200 head grow-finish buildings with slatted concrete floors and liquid manure systems. The hoop barn-based alternative uses bedded group pens in hoop barns for gestation and finishing. Construction resources needed to build and energy required to operate different types and scales of swine production facilities have been quantified.
Objectives/Performance Targets
This project will quantify energy use by several pig production systems in Iowa using process analysis techniques. Energy embedded in the manufacture and construction of different types of pig facilities and equipment commonly used in Iowa will be determined. Energy use in operation and maintenance of different types of pig facilities for all phases of production will be compared. Energy embedded in the production of feed ingredients will be determined. Energy use, nutrient cycling, and ecological impact of different phases of pig production, under different facility and diet scenarios will be evaluated.
Once collected this information will be communicated to producers, agricultural consultants, policy makers, and the general public through publications in appropriate academic journals, popular press releases, ISU Extension bulletins, and oral presentations at field days and meetings. Knowledge of energy use and nutrient cycling in pig production systems will enable pragmatic allocation of those resources to systems resulting in preferred outcomes.
This project will contribute to individual producer's ability to better prepare for a world with limited energy resources and greater penalties for negative ecological impacts. This project may influence policy towards a greater sustainability for the North Central Region and the nation.
Accomplishments/Milestones
Accomplishments to date:
Two types of facilities—conventional confinement and hoop-barn based—for pigs have been detailed and examined. The conventional confinement system is typical of pork industry practice in the United States and is characterized by individual gestation stalls and 1,200 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 farrowing crates and climate controlled nursery facilities.
Hoop barn-based pig production requires less concrete, steel, lumber, and thermoplastics than identically scaled conventional facilities. The building site for hoop barn-based pig production requires 30–40% more land area than conventional facilities. Land costs for building sites is a relatively small factor in the total cost of constructing pig production facilities. Hoop barns for gestation and grow-finish pigs require dramatically less construction materials to build per pig space and cost less (50-300%) to build compared to conventional facilities. After taking into account additional storage area for bedding and similar farrowing and nursery facilities, building hoop barn-based pig production systems requires 70–80% of the capital investment per pig space required for identically scaled conventional systems. Increasing from 5,200 to 15,600 market pigs annually reduces building costs per pig space within a system. However the hoop barn-based system scaled to produce 5,200 market pigs annually costs slightly less per pig space than the conventional system scaled to produce 15,600 market pigs annually.
The embodied energy and carbon of materials used in construction of pig production systems were examined. The hoop barn-based production system requires 10–20% less embodied energy and carbon than identically scaled conventional facilities. The hoop barn-based system producing 5,2000 market pigs annually requires more embodied energy but less carbon per pig space than the conventional system producing 15,600 market pigs annually.
In all systems examined, feed energy accounts for 95% of energy required to operate pig production facilities. Feed is a renewable resource and no net greenhouse gas emissions are associated with its consumption in this part of our analysis. Nonrenewable energy use is dominated by liquefied petroleum gas used to heat barns and electricity used to run ventilation systems. If performance and feed conversion is identical for both systems hoop barn-based pig production requires 3% less total energy per pig sold but results in more than 50% less greenhouse gas emission per pig sold. Taking into account demonstrated performance differences (improved reproduction in hoop barns but increased feed consumption per market pig housed in hoop barns) results in similar energy use per pig sold by both production systems. Non-renewable energy use per pig sold in conventional pig production systems is 260% more than the non-renewable energy use by hoop barn-based systems.
Work remaining to be completed:
Examination of pig production systems should consider not only the facilities housing pigs but also the resource use associated with pig diet cultivation and manufacture. The next phase of this project will examine energy and nutrient cycling in cropping systems under the context of pig feed production. The energy required to process crops and other raw materials into pig diet ingredients and ultimately deliver pig feed to farms will be estimated. The implications of different cropping systems and diet formulation strategies on pig performance and systemic energy use, nutrient cycling, and ecological impact will be considered for the two types of pig facilities at different scales of production.