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United States Department of Agriculture

Agricultural Research Service

2010 Annual Report

1a.Objectives (from AD-416)
Objective 1 - Determine the influences of diet composition on odor compound, nitrogen, and greenhouse gas emission from manure in beef cattle and swine confinement facilities. Objective 2 - Define the beef cattle feedlot surface conditions affecting microbial activities that minimize the environmental impact of animal manure. Objective 3 - Develop strategies and technologies to reduce ammonia and odor emissions from beef cattle and swine confinement facilities

1b.Approach (from AD-416)
Objective 1 - The hypothesis to be tested is starch, nonstarch carbohydrate, and protein excretion in manure differ by diet, and these compounds are differentially utilized by microorganisms to produce malodorous compounds, ammonia, and greenhouse gases. Multiple experiments will evaluate swine and cattle manure from diets differing in starch, fiber, and crude protein contents from diverse feed sources in order to determine the effects that diet has on.
1)odor compound production and emission,.
2)nitrogen transformation and loss, and.
3)greenhouse gas emission. Manure slurries and soil/manure mixtures mimicking feedlot surfaces will be incubated over time at ambient temperature and analyzed for microbial fermentation products including straight and branched chain volatile fatty acids, aromatic, sulfur-containing, and nitrogenous compounds, alcohols, and the greenhouse gases-methane, carbon dioxide, and nitrous oxide. Follow-up field studies will seek to validate results from the laboratory by monitoring the production and emission of compounds of concern from the production environment. Objective 2 - The hypothesis to be tested is moisture content, the ratio of manure to soil, and the temperature of the feedlot surface are the dominant factors that contribute to an anaerobic microbial environment on the feedlot surface, which produces more offensive odor compounds, enhances detrimental nitrogen transformations, and contributes to greater greenhouse gas production than an inactive or aerobic microbial state. The approach will be to evaluate a range of environmental conditions affecting dominant microbial physiologies (inactive, aerobic, and anaerobic) in multiple manure and soil incubations which vary the manure moisture content, manure to soil content, and temperature. Conditions favoring beneficial microbial activities (N immobilization, odor compound consumption, and nitrification/denitrification) relative to unfavorable activities (ammonia production and emission, odor compound production and accumulation, and greenhouse gas emission) will be targeted for further characterization and ultimately evaluated in field experiments. Objective 3 - The hypothesis to be tested is a combination of plant essential oils and urease inhibitors will limit microbial activities in stored cattle and swine manure that lead to odor compound production, ammonia formation, and greenhouse gas emissions. Once an effective compound, both in least cost and inhibiting properties is selected, it will be evaluated in the laboratory with a urease inhibitor for control of ammonia and odor emissions. This combination of the urease inhibitor and plant oil will also be incorporated into a granule material. The granule will be evaluated in the laboratory for effectiveness in releasing the chemicals from the granule by quantifying volatile fatty acids, urea, and ammonia in cattle manure slurries. Field studies in a cattle feedlot will be conducted with the granule containing the two chemicals. Field studies in an anaerobic deep pit swine production facility without the granule will also be conducted.

3.Progress Report
This is the final report for the project 5438-31000-080-00D terminated in May 2010. Significant results were realized over the duration of the project. After this project expired a bridging project (5438-31000-087-00D) continues the work until the new 5-year project can be implemented in FY 2011 (5438-41630-001-00D).

Laboratory and field studies in beef feedlots demonstrated that odor formation, pathogen prevalence, and nitrogen losses can be controlled using antimicrobial plant oils and urease inhibitors topically applied to the waste. As a result of this work, patent # 6,902,726 was issued for use of plant oils to control odor emissions from livestock manure and a company is currently submitting an application to license the patent. Another company is marketing a urease inhibitor (Conserve-N/Agrotain) for reducing nitrogen emissions from manure. Application of plant oils to swine manure in deep pits indicated odor production can be reduced > 90%; methane production - 93%, and coliform bacteria - 99%.

Volatile emissions from finishing cattle manure were assessed using a volatile emission chamber. In addition to analysis of emissions by gas chromatography/mass spectroscopy (GC/MS), the gaseous emissions collected from the chamber were also analyzed by a trained olfactory panel. It was determined that there was a positive correlation between the two methods and the volatile emission chamber can be used as a quick and inexpensive method to assess the odor of cattle manure.

Studies with various levels of wet distillers grains with solubles (WDGS) in cattle diets indicated that as the level of WDGS increased in the diet, odorants increased in manure slurries, as did ammonia, phosphorus, and hydrogen sulfide. These studies also indicated that feeding WDGS can extend the persistence of E. coli O157:H7 in manure slurries. Diets including 40 and 60% WDGS had decreased efficiency of energy utilization, indicating that cattle can have decreased performance in the feedlot.

Studies were initiated to characterize the environmental parameters in and surrounding beef deep-bedded mono-slope facilities (BDMF). Initial results indicate ammonia concentrations are greatest during the summer and lower in the winter. High ammonia emissions were found throughout the barns, however, four hours after cattle were removed, peak ammonia emissions began to decline. Concentration of odorous compounds was lower on the bedded pack compared to the concrete area surrounding the bedded pack. The manure from BDMF has 80% volatile solids, which may provide additional value beyond use as a fertilizer. E. coli O157:H7 and generic E. coli concentrations were higher during the summer compared to winter. Future planned research on further emission monitoring, pathogen survival in the manure, and best management protocols for bedding these facilities has resulted in a $600,000 AFRI Grant in collaboration with Iowa State and South Dakota State University.

The overall impact of these accomplishments is that producers have information to make decisions concerning production systems for sustainable agriculture and being a good neighbor to the surrounding community.

1. Antibiotics in Swine Diets and Resulting Odorants in Waste and Antibiotic Fate after Anaerobic Digestion. It is unclear what effect dietary antibiotics have on odor production from manure and their fate once excreted. ARS scientists at U.S. Meat Animal Research Center in Clay Center, NE, conducted a study with 160 animals, with one group of 80 pigs as control; the second group of 80 pigs was fed a diet with chlortetracycline for two months, and then switched to a diet with bacitracin for the last month before slaughter. This research concludes that there was no significant change on odorant production with the two growth promoting antibiotics, even though some bacterial populations were modified. Similarly, anaerobic digestion of the waste at room temperature did not degrade chlortetracycline over a 25-day period. It suggests that a temperature for anaerobic digestion be evaluated which is greater than what might be common in deep-pits where swine manure slurries are stored and anaerobic digestion occurs.

2. Concentration of Ammonia in Cattle Deep-Bedded Monoslope Facilities. ARS scientists from the U.S. Meat Animal Research Center in Clay Center, NE, collected air samples from two pens in two commercial deep-bedded monoslope barns in NW Iowa (n =.
4)from March 2008 until October 2009. Environmental (temperature, moisture content, pH, and electrical conductivity of bedded pack) and management factors (frequency of bedding and animal density) were recorded and correlated to gas measurements. Concentration of ammonia in air samples collected from the deep-bedded barns is greatest during summer months and lower during winter months. Concentration of ammonia increased with increasing temperature of the bedded pack but was poorly correlated to other environmental factors. Locations with high ammonia emissions were found throughout the entire pen and were not consistently concentrated in any particular area of the pen. Samples collected at 0, 4, and 10 hours after animals were removed from the pen demonstrated the peak ammonia concentration occurred immediately after the animals left the pen and that ammonia concentration stabilized to a “baseline” 4 hours after animals were removed from the pen. The data collected from this project was the first of its kind to quantify the spatial distribution of ammonia emissions in deep-bedded cattle confinement facilities. Research in this area resulted in the award of a $600,000 AFRI Grant in collaboration with South Dakota State University and Iowa State University to determine emission factors for ammonia, hydrogen sulfide, carbon dioxide, methane, and nitrous oxide in deep-bedded monoslope facilities.

Review Publications
Parker, D.B., Caraway, E.A., Rhoades, M.B., Cole, N.A., Todd, R.W., Casey, K.D. 2010. Effect of Wind Tunnel Air Velocity on VOC Flux from Standard Solutions and CAFO Manure/Wastewater. Transactions of the ASABE. 53(3):831-845.

Varel, V.H., Wells, J., Berry, E.D., Miller, D.N. 2010. Manure odor potential and Escherichia coli concentrations in manure slurries of feedlot steers fed 40% corn wet distillers grains. Journal of Environmental Quality. 39(4):1498-1506.

Last Modified: 4/23/2014
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