Location: Livestock Nutrient Management Research2014 Annual Report
1a. Objectives (from AD-416):
Long-term goals are to: 1) provide nutritional and management strategies for use by cattle producers to decrease potential adverse effects of feeding operations on the environment without adversely affecting animal performance, 2) quantify and minimize gaseous emissions from feedyards and dairies that may adversely affect the environment, and 3) produce on-farm energy that increases the value of manure and reduces dependence on fossil fuel. We seek to provide science-based information and technologies that can be used by livestock producers, extension specialists, and regulators to best manage feedyard and dairy manure to protect air quality, maintain or improve production efficiency, and improve sustainability of livestock production systems. Over the next 5 years we will focus on: Obj. 1. Develop feeding strategies that optimize utilization of energy, nitrogen, and phosphorus contained in beef cattle diets formulated with and without byproducts such as distiller's grain, in order to minimize excretion in manure. 1A. Measure effects of finishing diet composition on nitrogen and phosphorus excretion, nitrogen volatilization losses, and manure composition of finishing beef cattle in feeding trials. 1B. Measure effects of finishing diet composition on energy excretion, enteric methane losses, and energy metabolism of finishing beef cattle using respiration ca1orimetry. 1C. Determine relative degradable intake protein (DIP)/non-protein-nitrogen (NPN) value of distiller's solubles compared to urea. Obj. 2. Develop methods to quantify, and management strategies to minimize, the generation of greenhouse gases and other atmospheric emissions from feedyards and dairies. 2A. Monitor emissions of ammonia and greenhouse gases from beef cattle feedyards and dairies in the southern Great Plains. 2B. Quantify physical and chemical processes controlling and regulating ammonia and greenhouse gas emissions from feedyard and dairy pen surfaces, retention ponds, lagoons. 2C. Identify, verify, validate process-based models of ammonia and greenhouse gas emissions for beef cattle feedyards and dairies. 2D. Determine effects of pen surface amendments on ammonia emissions from feedyard and dairy pen surfaces, retention ponds, lagoons. 2E. Determine methane production potential of manure from cattle fed steam-flaked corn and distiller's grains based diets. Obj. 3. Isolate, identify, and characterize microbial strains and consortia that are capable of efficiently producing hydrogen and/or electricity from feedyard manures while also reducing pathogen loads. 3A. Identify microorganisms that are electricigens or microbial consortia that can act as electricigens that are present in either beef or dairy confined animal feeding operations. 3B. Determine potential power output of identified electricigens-microbial consortia in low- and high-power fuel cells using various types and forms of manure fuels. 3C. Evaluate microbial consortia-bioreactor designs for efficient generation of hydrogen from manure wastes. 3D. Evaluate influence of various methods of processing manure wastes for use as fuel sources on survival of zoonotic agents, antibiotic resistant gene complexes.
1b. Approach (from AD-416):
Experimental objectives are accomplished through a combination of cooperative,multidisciplinary studies that extend from basic laboratory-scale experiments to practical field experiments. Lab-scale and research feedlot-scale studies are used to determine how chemical, physical and dietary factors affect nutrient losses and atmospheric emissions and for initial evaluation of potential abatement measures. Larger field studies will be used to determine the atmospheric losses under practical conditions in the Southern Great Plains of the United States. Laboratory-scale studies will examine the feasibility of producing electricity with microbial fuel cells that use feedlot and/or dairy manures as sources of fuel and microbes.
3. Progress Report:
Our research progressed on three closely interrelated tracks that corresponded to major objectives: determine the effects of cattle nutrition and diet on emissions of ammonia and greenhouse gases (Objective 1); quantify emissions of ammonia and greenhouse gases from beef and dairy cattle production (Objective 2A); and develop, evaluate, and improve mathematical models that predict or estimate emissions (Objectives 2B-2D). Elimination of the renewable energy component of the project plan and associated scientist vacancy caused Objective 3 to be no longer applicable. Redirected research efforts have expanded the scope of Objective 1 to include research with new tools such as respiration calorimetry and Greenfeed technology to explore the links between cattle nutrition in both high-concentrate and high-forage diets and greenhouse gases. New directions in Objective 2 include investigations of grazing cattle and greenhouse gases, and refinement and improvement of computer-based predictive tools for emissions and nutrient management. Cattle Nutrition. (1) Adding supplemental protein to low quality forage diets increases forage intake and digestion, but effects on greenhouse gas production are uncertain. Experiments were conducted to develop ways to reduce greenhouse gas production in beef cattle consuming low-quality hay or native grasses. In one experiment, a low protein hay diet fed to steers contained either no added protein, or cottonseed meal, or dried distillers grains added to meet the cattle protein requirement. Providing a protein supplement increased forage intake by 35% and increased emissions of carbon dioxide and methane by 11% and 12%, respectively. However, as a percentage of the total energy consumed, steers receiving either protein supplement had 25% lower methane emissions compared to the group receiving no added protein. Supplemental protein also shifted rumen fermentation away from methane production and towards useable energy for the animal. In a second experiment, steers were fed increasing levels of supplemental protein from cottonseed meal to meet 0%, 33%, 66%, 100%, or 133% of the nutritional protein requirement. Supplemental protein increased forage intake and decreased methane emissions when protein was 133% of required protein. These studies suggest that supplementing protein to beef cattle consuming low quality forage will increase forage intake and animal productivity and lower methane production as a fraction of energy intake. (2) Two respiration calorimetry studies were conducted to determine the effects of corn flaking intensity and wet distillers grains on energy metabolism and greenhouse gas emissions from finishing cattle; and to determine associative effects between grain processing and wet distillers grains on energy metabolism and greenhouse gas emissions from finishing cattle. Data are currently being statistically analyzed and the manuscripts written. (3) Through cooperative agreements with West Texas A&M University and Texas A&M AgriLife Research we are conducting a study to evaluate the effects of grain source and solubles additions on the performance of finishing beef cattle. (4) We compiled a comprehensive, multi-disciplinary, state-of-the-science review of feedyard nitrogen sustainability. This review provided current and accurate information for producers, regulatory agencies, and the general public, and provided direction for research scientists involved in the study of livestock production and environmental quality. The review will be available to members of a major stakeholder group and the public and will be distributed as fact sheets and published journal articles. Quantify Emissions. (5) Ammonia emissions from the open lot of a 3500-head commercial dairy were quantified. Open path lasers measured atmospheric ammonia concentration, sonic anemometers characterized turbulence, and inverse dispersion analysis was used to quantify emissions. Nitrogen loss as ammonia averaged 252 grams per cow per day, which was 41% of the nitrogen fed to cows. A manuscript for this work is in development. (6) Grazing cattle are responsible for most methane produced by beef cattle. We collaborated on a multi-year, multi-institutional project to understand the effects of grazing cattle on greenhouse gases and the resilience of grazing systems to climate change. A novel pasture-scale experimental system that employed multiple scanning open path methane lasers and that tracked grazing cattle using global positioning satellites was deployed during a two-week-long intensive field campaign coordinated with Agricultural Research Service scientists at El Reno, Oklahoma. Processing of the collected data is underway. (7) The Global Research Alliance (GRA) is an international collaboration with the goal of coordinating international research efforts on greenhouse gases and agriculture. A researcher from Bushland, Texas, served as North American coordinator for the Grazing Research Network of the GRA. A literature review of the greenhouse gas mitigation potential of North American grazing lands was compiled to support the objectives of the group. (8) Technologies and management are needed to reduce feedyard ammonia losses. Laboratory studies were conducted to evaluate how zeolite added to manure affected ammonia volatilization. Zeolite applied at 0.5% reduced ammonia losses by 19%, but results were highly variable. Model Emissions. (9) Little is known about factors controlling the emission of the greenhouse gases nitrous oxide and methane from manure. A comprehensive database was developed to statistically evaluate how climate and manure characteristics influence the rate of nitrous oxide and methane production. These data will be used to develop empirical models to improve predictions of manure-derived nitrous oxide and methane from feedyards. (10) We evaluated several statistical models that predict methane loss from cattle based on dietary factors using a database of methane emissions from a commercial beef cattle feedyard. We found that statistical models that incorporated the percentage of forage in diets, dry matter intake, and diet fat content predicted methane loss best, within -11 to +25% of measured methane loss. A ruminal process model consistently overestimated methane loss on average by 21%, suggesting that further refinement of the ruminal model is needed. In early 2013 the Unit Research Leader was named the Acting Laboratory Director of the CPRL and in early 2014 was officially named the Laboratory Director. Over the past 3 years the RL has served on a number of influential writing teams including: 1) writing team funded through the USDA-Office of the Chief Economist-Climate Change Office to develop a "tool" for livestock producers to use to predict greenhouse gas emissions from their operations; and 2) on the National Research Council panel to revise the publication "Nutrient Requirements of Beef Cattle." A new Research Chemist was added to the scientific staff in early 2014. Two scientists in the Unit are investigators on a USDA-NIFA-CAP grant titled "Resilience and vulnerability of beef cattle production in the Southern Great Plains under changing climate, land use and markets" that entered its second (of 5) year late in 2014. A post doc has been hired through an agreement with the Oak Ridge Institute of Science and Education (ORISE) to conduct studies on dietary and management factors controlling and mitigating greenhouse gas emission from beef cattle fed high roughage diets.
1. Improved computer tools to estimate ammonia emissions from beef cattle feedyards. Computer tools called process models that can estimate ammonia emissions or predict emissions in different production scenarios are available, but not evaluated for beef cattle production in open lot feedyards. Ammonia emissions will be regulated by the US EPA in the near future; however, the EPA currently does not have a good model to estimate ammonia emissions or to estimate the effects of management strategies on ammonia emissions from agricultural operations. Agricultural Research Service scientists at Bushland, Texas, collaborated with ARS researchers at State College, Pennsylvania, to evaluate and improve the Integrated Farm Systems Model (IFSM) for estimating feedyard ammonia emissions. The manure nitrogen component of the model was improved to better represent feedyard conditions, and the new version of IFSM predicted ammonia emissions from commercial feedyards within 11 to 24% of observed emissions. In contrast, emission predictions based on a constant emission factor used by U.S. Environmental Protection Agency deviated from observed emissions by as much as 79%. Our model has the potential for use by regulators, consultants, and producers to obtain better estimates of ammonia emissions and to estimate how management practices can be changed to influence feedyard ammonia losses.
2. Methane emissions from a beef cattle feedyard. Methane is an important greenhouse gas with increasing atmospheric concentration; livestock contribute about 2% of the U.S. methane emissions, with most of that emitted by cattle. Agricultural Research Service scientists at Bushland, Texas, monitored methane emissions at a commercial feedyard in Texas and found that cattle fed a finishing diet based on steam-flaked corn lost from 71 to 130 grams of methane per animal daily. The methane conversion factor (Ym: the percentage of energy consumed lost as methane) ranged from 2.8% to 3.2%, and averaged 3.0%, which is the same as the Ym value recommended from feedlot cattle by the Intergovernmental Panel on Climate Change (IPCC) but lower than the Ym value currently recommended by the U.S. Environmental Protection Agency (EPA; 3.9%). Methane conversion factors and methane emission factors are important values used by the U.S. EPA and the IPCC to estimate methane produced by cattle and to develop national inventories of methane. Results from this research can be used to refine the values used to estimate cattle methane emissions in national greenhouse gas inventories.
3. Characteristics of feedyard manure. Gaseous emissions from feedyard manure depend on characteristics of manure, such as source, composition, and the associated microbial community. Agricultural Research Service scientists at Bushland, Texas, headed a collaborative project with ARS researchers at New Orleans, Louisiana, and Orono, Maine, and colleagues at West Texas A&M University in Canyon, Texas, that used advanced laboratory techniques to characterize the properties of feedyard manure organic matter. Researchers chemically analyzed manure samples collected from cattle pens, manure stockpiles, settling basins, and a retention pond at a typical commercial feedyard in the Texas Panhandle. They found that as manure organic matter moved through the feedyard system from the animal to the pen surface, to stockpiles or retention ponds, it lost up to 98% of the soluble carbon and nitrogen. These soluble forms of carbon and nitrogen are readily available to microbes that produce gases of environmental concern (greenhouse gases, odors, ammonia, etc.). The chemical and physical characteristics of the manure organic matter changed as the manure aged, resulting in a product that was more resistant to microbial decomposition, had a lower fertilizer (i.e., nitrogen) value, and had a lower gas production potential. These results will be used to refine whole-farm process-based models that predict microbial growth, manure fertilizer value, and gaseous emissions from different feedyard sources.
Waldrip, H., He, Z., Todd, R.W., Hunt, J.F., Rhoades, M.B., Cole, N.A. 2014. Characterization of organic matter in beef feedyard manure by Ultraviolet-Visible and Fourier transform infrared spectroscopies. Journal of Environmental Quality. 43:690-700.
He, Z., Olk, D.C., Waldrip, H.M. 2014. Soil amino compound and carbohydrate contents influenced by organic amendments. In: He, Z., Zhang, H., editors. Applied Manure and Nutrient Chemistry for Sustainable Agriculture and Environment. Amsterdam, the Netherlands: Springer. p. 69-82.
Acosta Martinez, V., Waldrip, H. 2014. Soil enzyme activities as affected by manure types, application rates and management practices. In: He, Z. and Zhang, H., editors. Applied Manure and Nutrient Chemistry for Sustainable Agriculture and Environment. New York, NY: Springer Science+Business Media Dordrecht. p. 99-122.
He, Z., Cao, X., Mao, J., Ohno, T., Waldrip, H.M. 2013. Analysis of carbon functional groups in mobile humic acid and recalcitrant calcium humate extracted from eight US soils. Pedosphere. 23(6):705-716.
Ro, K.S., Stone, K.C., Johnson, M.H., Hunt, P.G., Flesch, T., Todd, R.W. 2014. Optimal sensor locations for the backward Lagrangian stochastic technique in measuring lagoon gas emission. Journal of Environmental Quality. DOI: 10.02134/jeq2013.05.0163.
Ponce, C., Brown, M.S., Osterstock, J.B., Cole, N.A., Lawrence, T.E., Soto-Navarro, S.A., MacDonald, J., Maxwell, C. 2014. Effects of wet distillers grains with solubles on visceral organ mass, trace mineral status, and polioencephalomalacia biomarkers by individually-fed cattle. Journal of Animal Science. 92:4034-4046.
Waldrip, H., Acosta Martinez, V. 2014. Phoshatase activities and their effects on phosphorus availability in soils amended with livestock manures. In: He, Z., Zhang, H., editors. Applied Manure and Nutrient Chemistry for Sustainable Agriculture and Environment. New York, NY: Springer Science+Media Dordrecht. p. 123-140.
Waldrip, H., Rotz, C.A., Hafner, S.D., Todd, R.W., Cole, N.A. 2014. Process-based modeling of ammonia emission from beef cattle feedyards with the integrated farm systems model. Journal of Environmental Quality. 43:1159-1168.
Todd, R.W., Cole, N.A., Waldrip, H. 2014. Methane emissions from a beef cattle feedyard during winter and summer on the southern High Plains of Texas. Journal of Environmental Quality. 43:1125-1130.