Foam accumulation in deep-pit manure storage facilities is of concern for swine producers because of the logistical and safety-related problems it creates. A feeding trial was performed to evaluate the impact of feed grind size, fiber source, and manure inoculation on foaming characteristics. Animals were fed: (1) C-SBM (corn-soybean meal): (2) C-DDGS (corn-dried distiller grains with solubles); and (3) C-Soybean Hull (corn-soybean meal with soybean hulls) with each diet ground to either fine (374 μm) or coarse (631 μm) particle size. Two sets of 24 pigs were fed and their manure collected. Factors that decreased feed digestibility (larger grind size and increased fiber content) resulted in increased solids loading to the manure, greater foaming characteristics, more particles in the critical particle size range (2-25 μm), and a greater biological activity/potential. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. Foam accumulation in deep-pit manure storage facilities is of concern for swine producers because of the logistical and safety-related problems it creates. A feeding trial was performed to evaluate the impact of feed grind size, fiber source, and manure inoculation on foaming characteristics. Animals were fed: (1) C-SBM (corn-soybean meal): (2) C-DDGS (corn-dried distiller grains with solubles); and (3) C-Soybean Hull (corn-soybean meal with soybean hulls) with each diet ground to either fine (374 lm) or coarse (631 lm) particle size. Two sets of 24 pigs were fed and their manure collected. Factors that decreased feed digestibility (larger grind size and increased fiber content) resulted in increased solids loading to the manure, greater foaming characteristics, more particles in the critical particle size range (2-25 lm), and a greater biological activity/potential.

An experiment was conducted to determine the effect of feeding finishing pigs a corn-soybean (CSBM) diet or a CSBM diet supplemented with 30% dried distillers grains with solubles (DDGS), in combination with or without a growth-promoting ionophore (0 or 30 mg narasin/kg of diet), has on manure composition, microbial ecology, and gas emissions. Two separate groups of 24 gilts (initial BW = 145.1 kg, SD = 7.8 kg) were allotted to individual metabolism crates that allowed for total but separate collection of feces and urine during the 48-d collection period. After each of the twice-daily feedings, feces and urine from each crate was collected and added to its assigned enclosed manure storage tank. Each tank contained an individual fan system that pulled a constant stream of air over the manure surface for 2 wk prior to air (day 52) and manure sampling (day 53). After manure sampling, the manure in the tanks was dumped and the tanks cleaned for the second group of pigs. Except for total manure Ca and P output as a percent of intake and for manure methane product rate and biochemical methane potential (P ≤ 0.08), there were no interactions between diet composition and narasin supplementation. Narasin supplementation resulted in increased manure C (P = 0.05), increased manure DM, C, S, Ca, and phosphorus as a percent of animal intake (P ≤ 0.07), and increased manure volatile solids and foaming capacity (P ≤ 0.09). No effect of narasin supplementation was noted on manure VFA concentrations or any of the gas emission parameters measured (P ≥ 0.29). In contrast, feeding finishing pigs a diet containing DDGS dramatically affected manure composition as indicated by increased concentration of DM, C, ammonia, N, and total and volatile solids (P = 0.01), increased manure DM, N, and C as a percent of animal intake (P = 0.01), increased manure total VFA and phenols (P ≤ 0.05), decreased gas emissions of ammonia and volatile sulfur compounds (VSC; P = 0.01), increased emissions of phenols and indoles (P ≤ 0.06), decreased methane production rate (P = 0.01), and slight differences in microbial ecology (R ≤ 0.47). In conclusion, feeding a diet which contains an elevated level of indigestible fiber (i.e., DDGS) resulted in more fiber in the manure which therefore dramatically affected manure composition, gas emissions, and microbial ecology, while narasin supplementation to the diet did not exhibit a significant effect on any of these parameters in the resultant swine manure.

Methane emission is an important tool in the evaluation of manure management systems due to the potential impact it has on global climate change. Field procedures used for estimating methane emission rates require expensive equipment, are time consuming, and highly variable between farms. The purpose of this paper is to report a simple laboratory procedure for estimating methane emission from stored manure. The test developed was termed a methane production rate (MPR) assay as it provides a short-term biogas production measurement. The MPR assay incubation time is short (3d), requires no sample preparation in terms of inoculation or dilution of manure, is incubated at room temperature, and the manure is kept stationary. These conditions allow for high throughput of samples and were chosen to replicate the conditions within deep-pit manure storages. In brief, an unaltered aliquot of manure was incubated at room temperature for a three-days to assay the current rate of methane being generated by the manure. The results from this assay predict an average methane emission factor of 12. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. b s t r a c tMethane emission is an important tool in the evaluation of manure management systems due to the potential impact it has on global climate change. Field procedures used for estimating methane emission rates require expensive equipment, are time consuming, and highly variable between farms. The purpose of this paper is to report a simple laboratory procedure for estimating methane emission from stored manure. The test developed was termed a methane production rate (MPR) assay as it provides a shortterm biogas production measurement. The MPR assay incubation time is short (3d), requires no sample preparation in terms of inoculation or dilution of manure, is incubated at room temperature, and the manure is kept stationary. These conditions allow for high throughput of samples and were chosen to replicate the conditions within deep-pit manure storages. In brief, an unaltered aliquot of manure was incubated at room temperature for a three-days to assay the current rate of methane being generated by the manure. The results from this assay predict an average methane emission factor of 12.

This study explored the impact of swine diet on the composition, methane production potential, and foaming properties of manure. Samples of swine manure were collected from controlled feeding trials with diets varying in protein and carbohydrate levels and sources. Protein sources consisted of corn with amino acids, corn-soybean meal with amino acids, corn-soybean meal, corn-canola meal, corn-corn gluten meal, and cornpoultry meal. Carbohydrate sources consisted of corn-soybean meal, barley, beet pulp, distillers dried grains with solubles (DDGS), soy hulls, and wheat bran. Manure samples were tested for a number of physical and biochemical parameters, including total solids, volatile solids, viscosity, density, methane production rate, biochemical methane potential, foaming capacity, and foam stability. Statistical analyses were performed to evaluate whether different carbohydrate and/or protein ingredients affected these physico-chemical properties or the samples’ ability to produce methane gas. After conducting these trials, another feeding trial was performed to evaluate if the addition of Narasin into rations (corn-soybean and DDGS) could reduce the methane production rate or potential of the manure. These samples were also tested for the physical and biochemical parameters mentioned previously. Finally, an additional manure foaming study was conducted involving the addition of specific carbohydrates ground to different particle sizes and corn oil to observe the effects that the additives had on foaming capacity and stability.

Diet ingredients are thought to contribute to foaming problems associated with swine manure stored in deeppit systems. Two experiments explored the impact of protein and carbohydrate sources and levels in swine diets on the physicochemical properties, methane production potential, and foaming potential of swine manure. The first experiment was specific to protein and evaluated the impact of dietary protein level and source on manure properties, while the second experiment focused on evaluating the impact of different dietary carbohydrate sources on manure foaming properties. Manure from the animals was tested for total and volatile solids, methane production rate and biochemical methane potential, surface tension, foaming capacity and stability, and microbial community structure. No single diet yielded manure with all of the anticipated qualities associated with foaming manure. However, manure collected from pigs fed diets containing soy hulls and distillers dried grains with solubles (DDGS) exhibited higher methane production rates (0.95 ±0.20 and 0.96 ±0.20 L CH 4 kg -1 VS, respectively) and biochemical methane potential (322 ±25 and 269 ±22 mL CH 4 g -1 VS, respectively) when compared to manure obtained from pigs fed the other diets. Additionally, the results showed that both protein level and source exhibited greater influence over the microbial community than carbohydrate source, with manipulations in the protein diet leading to positive correlations with specific microbial community and higher methane production rates, foaming capacity, and foam stability. In this study, these parameters appeared to be tied to higher levels of corn, or corn protein, in the diet. Although some of the microbial community was explained by diet, this study also demonstrated that factors other than diet have significant influence on microbial community. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. Authors