Increasing energy costs and regulatory push for lower emissions of air pollutants is a fact facing swine producers throughout the upper Midwest. The primary objective of this project was to develop a new housing design for the pig finishing production phase in Minnesota and other surrounding Midwestern states. A secondary objective was to provide guidance for reducing energy and air emissions for a majority of the existing pig finishing barns currently being used in the upper Midwest. This new building design is referred to in this report as the “Greener Pig Barn” or GPB. In addition to an extensive literature review, project leaders from the University of Minnesota worked with an advisory team of researchers, extension educators from surrounding states, consultants, and swine industry leaders to develop this new building design and barn retrofit ideas for existing facilities.
Design concepts for the GPB focused on providing optimum environmental conditions for maximum pig production efficiency. It was anticipated that the additional investment in building a barn to provide these optimum conditions must be significantly offset with production efficiencies. Two other principles guided the team in the GPB design development. First, reductions in emission must be integrated into the housing design rather than by add-on emission control technologies. This integration rewards the appropriate management and operation of the housing system because it is tied to production economics. Secondly, the design must result in improvements to worker and pig safety/health by providing better indoor air quality and reducing hazardous gas emissions from the barn. In addition, trends in animal welfare were considered and addressed in the final GPB design.
A 2400-head double wide, tunnel-ventilated, fully slatted, deep pit finishing barn was used as the reference facility to compare energy use and air emissions with the new GPB housing design. The tunnel ventilated (TV) barn was used as a baseline in this study because it has been the most commonly built pig finishing facility in the upper Midwest for the past 5 to 10 years. It is estimated that over 80% of all pig marketed in the upper Midwest are either grown in a tunnel ventilated (TV) or the deep pit, fully slatted, curtain sided (CS) barn.
This report includes four GPB design variations. Version A features pens with partially slatted floors and in-floor heating and cooling in the solid floor section, shallow gutters under the slats with mechanical scrapers for manure removal to an outside covered manure storage tank, and an evaporative cooling system. Version B is similar to Version A but integrates a mechanical (geothermal) cooling system (rather than evaporation pads). Version C is similar to Version A, but has fully slatted floors and is cooled only with evaporative cooling pads. Version D is similar to Version B (mechanical cooling) but has fully slatted floors. All GPB design versions use shallow gutters with mechanical scrapers and an in-ground, covered, concrete manure storage tank located adjacent to the barn.
All versions of the Green Pig Barns are expected to save energy in the winter due to better insulation and environmental control. Reduced emissions are also expected due to the lack of long term manure storage inside/under the barn and to the incorporation of barn cooling. Building construction costs per pig space, which includes an outside, covered, in-ground concrete manure storage tank, are expected to be 1.3 to 2 times higher than typical construction of the baseline TV barn. These costs are offset by a 3-7% increase in average daily gain and 5-10% decrease in feed consumption per pound of pork produced. Other benefits include better pig health and worker environment. Using these assumptions in a standard economic projection, annualized net present value per pig space is between $2.43 and $9.03 with 6.0 to 12.8 years to payback over the baseline (TV) facility. These economic projections would improve significantly with additional gains in animal performance. It is generally thought that these performance gains are anticipated but there is currently no research data to confidently predict the magnitude of these performance improvements on an annual basis in commercial scale operations.
Barn retrofit concepts reported in this document focus on structural upgrades such as insulation and mechanical items like improved environmental control, fan and heater maintenance and management, along with manure pit management. Recommendations are outlined in a factsheet that can be found in the Appendix D of this document and on-line at www.bbe.umn.ed/Animal_Housing_and_Livestock_Systems.html .
Moving the swine industry forward to a more sustainable production facility was the focus of this project. Results from the project indicate that current facilities in the upper Midwest can be modified or managed to reduce energy inputs. Results also indicate that there are alternatives to the current finishing facilities in the Midwest that could result in reduced energy and emissions per pound of meat produced while still being economically viable. Construction and monitoring of the design housing concepts laid out in this report is a critical next step in moving the industry forward in sustainable pig finishing production.
Further information concerning the findings from this study can be obtained by contacting Larry D. Jacobson at the University of Minnesota, firstname.lastname@example.org or 612-625-8288.