1a.Objectives (from AD-416):
Determine the effect diet formulation has on the potential for swine manure to foam.
1b.Approach (from AD-416):
The proposed project will characterize the effect swine diet formulation has on the potential for swine manure to foam. The goal of the project is determine the cause of swine deep pit foaming and enhance the scientific understanding of pit foaming. Areas of interest include diet formulation contribution and development of pit foaming potential indexes for both chemical and biological properties.
The animal feeding trial will be carried out at the ISU swine farm with multiple diet formulations. Diet formulation will be dependent on the initial survey of producers feed inputs and analysis of manure collected from both foaming and non-foaming deep pits. Survey information is being developed by researchers from University of Minnesota, University of Illinois, and Iowa State University.
Animal feeding trial manures will be tested for potential to foam from both a physical/chemically characterization and biological methane forming potential. The physical/chemical potential will include bubbling of nitrogen gas into manure to measure foaming potential, measuring the surface tension of the manure, quantifying a number of chemical components from fatty acid concentrations to protein levels in the manure. Biological properties of the manure will include methane forming potential and community analysis.
In 2013, analytical methods for determining both short chain fatty acids (SCFA) and long chain fatty acids (LCFA) in swine manure were developed. The methods were used to process over 800 samples for determining levels of SCFA and LCFA in both foaming and non-foaming barns. Foaming barns had lower SCFA levels and there were higher levels of LCFA in the foaming pits. Gas emissions from two animal feeding trials explored the role diets had in foaming pits. Methods are being developed for characterizing foaming material.