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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Livestock Nutrient Management Research » Research » Research Project #419829


Location: Livestock Nutrient Management Research

2015 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:
The project transferred to bridging project #3090-31630-004-00D in June 2015. Research remained focused on the objectives to: 1) determine the effects of cattle nutrition and diet on emissions of ammonia and greenhouse gases; 2) quantify emissions of ammonia and greenhouse gases from beef and dairy cattle production; and 3) develop, evaluate and improve mathematical models that predict or estimate emissions. Efforts in FY15 led to 4 scientific publications, 2 book chapters and 4 peer-reviewed manuscripts. In addition, multiple presentations were given at scientific meetings. Two respiration calorimetry studies were conducted in FY15 to: a) evaluate the effects of energy supplementation on energy metabolism and methane production of cattle fed high quality wheat forage; and b) determine the effects of excessive protein intake on the energy metabolism of cattle fed finishing diets. Four studies were conducted using an automated system to measure enteric methane emissions from cattle fed low quality (4% protein hay) and high quality (spring native pasture and wheat pasture) forages; with or without supplementation. Results from 4 studies will be reported at a scientific meeting in July 2015. We further refined a pasture-scale measurement system that uses multiple scanning open path methane lasers and that tracked grazing cattle using global positioning satellites in FY15 to measaure greenhouse gas emissions. We collaborated with Texas A&M AgriLife Research (TALR) to apply the system to measure methane from stocker steers grazing on wheat pasture during a three-month winter/spring trial. Data collected from last summer's intensive field campaign at the ARS Grazinglands Research Laboratory as part of the NIFA-USDA CAP grant will be reported at professional meetings in November 2015. A system to evaluate the sensitivity of a dispersion model was developed and controlled release experiments were conducted. Research in FY15 focused on better understanding the factors related to emissions of ammonia and greenhouse gases from feedyard manure. Through lab and field studies, we are working to: 1) develop empirical models to predict methane and nitrous oxide emissions from beef cattle manure, and 2) improve existing process-based models for predicting ammonia and greenhouse gas emissions. Because little is known about factors controlling manure nitrous oxide and methane emissions, a comprehensive database is being developed to statistically evaluate how climate and manure characteristics influence the carbon and nutrient transformations related to greenhouse gas emissions. Preliminary field evaluations showed that average hourly fluxes of nitrous oxide and methane from cattle pens in commercial feedyards were 1.1 and 1.9 milligrams per square meter, respectively; however, these emissions were highly variable. Statistical evaluations showed that nitrous oxide emission was positively correlated to nitrate and water concentrations, and negatively related to concentrations of dissolved carbon and nitrogen. The composition of organic matter in manure was related to greenhouse gas emissions, where nitrous oxide production tended to be reduced when the organic matter was more stabilized, as evidenced using ultraviolet-visible spectroscopy. Based on these data, empirical models were developed to predict feedyard nitrous oxide emissions based on nitrate and dissolved carbon concentrations, water content, environmental temperature, and composition of dissolved organic matter. Evaluation of these models against measured emissions showed that they were 70% to 86% accurate at predicting manure-derived nitrous oxide losses. However, no meaningful correlations between methane emissions and the investigated variables were found, and this is an area that requires further study. Laboratory incubation studies are being conducted to investigate greenhouse gas emissions and nutrient transformations in soil and feedyard manure under controlled conditions, where temperature, water content, nitrogen concentration and other factors can be directly manipulated. Grants under which some of the research was conducted included National Cattlemen's Beef Association ($12,410, review of feedyard N), and NIFA Grazing CAP (cattle diet and grazing emissions work, $244,772 in FY15). The NIFA Grazing CAP project is a multi-year, multi-institutional effort to understand the effects of grazing cattle on greenhouse gases and the resilience of grazing systems to climate change. We are in year three of its implementation. Over this project’s 5-year life the research addressed issues related to the sustainability of beef and dairy industries throughout the United States, with special emphasis on production systems of the southern High Plains. Results vary in scale from the regional industries to individual animals and/or pens in a feedlot or dairy. At the regional industry scale, results comparing cattle fed on steam-flaked corn versus dry rolled corn indicated that life cycle analysis of these practices requires not only analyses of the energy input of feed processing but data on how cattle utilize the nutrients in the different feeds both in terms of efficiency of feed utilization and greenhouse gas production. At smaller scales of farms, pens and animals, research focused primarily on nitrogen utilization and losses, and methane production. Using results from 50 beef cattle diets, nitrogen excretion in feces and urine was positively related to nitrogen and crude protein intake, indicating that feed has a large impact on nitrogen losses. The properties of manure changes as it matures and moves through a feedlot, but in general it tends to lose carbon and nitrogen with time. Although many nitrogen compounds are excreted by cattle, ammonia draws particular attention because of its potential negative environmental effects and probable regulations of emissions by U.S. Environmental Protection Agency (USEPA). Scientists in this project published an extensive review of the literature that found on average approximately 15% of the fed nitrogen is retained by cattle, while approximately 50% of the fed nitrogen is lost as ammonia. A hallmark experiment confirmed these findings. The team measured ammonia emissions from two commercial feedlots over two years. On average, 52 to 59% of the fed nitrogen was lost as ammonia. In the absence of any other information, a beef cattle feeder could estimate feedyard ammonia emission as 88 pounds per head per year, which is three times greater than the emission factor used by USEPA. Southern High Plains dairy cows are typically housed in large open lots and it was found that the open lot was the source of almost all dairy ammonia emissions, with over 40% of the fed nitrogen lost as ammonia during summer. This contrasted with much lower ammonia losses found in closed barn dairy housing systems, and pinpointed where mitigation measures would be most effective. The ammonia measurements from the two feedlots indicated that crude protein of the diet and air temperature were important factors affecting ammonia losses. Ammonia emissions increased as temperature and diet crude protein increased. The extensive data set and observations of the effects of temperature and dietary protein led to improved models to predict ammonia emissions from fed beef operations. The ammonia emissions predicted by the Integrated Farms Systems Model differed from observed values by as much as 79% prior to modifications. Once this model was modified to account for air temperature and dietary protein, results from the revised Integrated Farms Systems Model were within 20% of observed values. Another model called Manure-DNDC predicted ammonia emissions that were close to those observed at the two feedlots. Feed composition strongly affects ammonia emissions with steam-flaked corn diets producing less ammonia, while more emissions occur with diets higher in distiller’s grains. Methane is a greenhouse gas of particular importance because of its contribution to global warming and climate change. Cattle production contributes about 2% of the methane emissions in the U.S. Most of the methane from cattle is produce by enteric fermentation in the rumen and then expelled through the mouth. Results indicated that beef cattle on a steam-flaked corn diet produced about 0.2 pounds of enteric methane per head per day. This level of enteric methane production corresponded to approximately 3% of calorie intake, which is similar to that recommended by the Intergovernmental Panel on Climate Change for feedyard cattle on high quality diets. Changes in diet appear to affect enteric methane production with distiller’s grain and dry rolled corn diets producing 20-30% greater enteric methane than steam-flaked corn diets. Data on enteric methane production helped to increase the accuracy of a model to predict methane emissions from feed intake, dietary fat, corn processing method and dietary grain concentrations. Methane production from dairy lagoons can also be significant. Research results indicated that methane production from uncovered dairy lagoons averaged 0.5 pounds of methane per dairy cow per day. Two other properties of animal waste that are of concerns are odors and phosphorus. Odors tended to be greater from manure of cattle fed diets higher in starch and odors from sulfur containing compounds were greater when cattle were fed distiller’s grains. When comparing manure from organic dairies to conventional dairies, it was observed that the carbon concentrations of manure from organic dairies is higher and this causes the phosphorus to be less available to plants as a fertilizer nutrient. The accomplishments of this project contributed to advances of ARS National Program 214, Agricultural and Industrial Byproducts. The accomplishments also contributed to ARS National Program 212, Climate Change, Soils and Emissions, and National Program 101, Animal Food Production.

4. Accomplishments
1. Management and cattle diet influence nitrogen sustainability of beef cattle feedyards. Sustainable beef production systems must efficiently feed nitrogen with minimal losses to the environment from the manure produced by cattle. USDA-ARS researchers at Bushland, Texas conducted a comprehensive review of the state of the science to evaluate how manure management, weather, and cattle diets influenced nitrogen transformations and gaseous ammonia losses from feedyards. Key findings included that only about 15% of the fed nitrogen remained in animal tissue and about 50% of fed nitrogen was lost to the atmosphere as ammonia. Ammonia production and volatilization was strongly influenced by both cattle diet and environmental conditions; however, dietary manipulation may be the most promising means of improving feedyard nitrogen efficiency. This review provided current and accurate information for cattle producers and regulatory agencies and provided direction for further research for scientists involved in the study of cattle production and environmental quality.

2. Surface-applied zeolite mitigates feedyard ammonia losses. Ammonia lost from beef cattle feedyards can negatively impact the environment and decrease the fertilizer value of manure; cost-effective methods are needed to reduce its loss. Zeolite, a porous, natural aluminosilicate mineral that can capture ammonium, has potential as an amendment to reduce ammonia losses from feedyard pens. Researchers with USDA-ARS in Bushland, Texas evaluated the effects of zeolite on ammonia emissions from manure collected at commercial feedyards in the Texas Panhandle. Lab studies showed that ammonium retention by zeolite was rapid. As little as 0.5% zeolite increased ammonium retention by up to 19%, but specific zeolite properties influenced its effectiveness. This work showed the potential of zeolite to mitigate ammonia losses but further studies are needed to assess the cost:benefit of zeolite application at commercial feedyards.

3. Ammonia emissions from an open lot dairy. Excessive ammonia in the environment can degrade sensitive ecosystems and contribute to formation of unhealthy particles in the atmosphere. Ammonia emissions from closed housing dairies have been extensively studied, but less is known about emissions from open lot systems more common on the Southern Plains. Agricultural Research Service researchers at Bushland, Texas found that ammonia emissions from a New Mexico open lot dairy during summer were much greater than emissions from closed housing systems and that the source of most emissions was the open lot surface; 43% of the nitrogen fed at the dairy was lost as ammonia. Careful management of manure is critical to reduce ammonia emissions and this research highlighted the ammonia source areas in open dairies where mitigation would be most effective.

4. Improved process models to estimate feedyard and diary ammonia and nitrous oxide emissions. Ammonia and nitrous oxide are forms of reactive nitrogen that can have negative effects on the environment. Atmospheric ammonia contributes to particulate formation that degrades air quality, whereas nitrous oxide is a potent greenhouse gas that contributes to global warming. Climate and management strongly influence these emissions, making them very difficult to estimate in diverse open lot beef and dairy cattle facilities. USDA-ARS researchers at University Park, Pennsylvania, Kimberly, Idaho, and Bushland, Texas worked together to improve the Integrated Farm System Model (IFSM) for predicting ammonia and nitrous oxide emissions from Texas feedyards and open lot dairies in Idaho. The revised IFSM (ver. 4.1) contains more appropriate information about manure properties and decomposition than the previous version (ver. 4.0). Model predictions for ammonia showed from 56 to 92% agreement with measured daily emissions. The IFSM also predicted nitrous oxide emissions from Idaho dairies with 64% to 80% agreement. This work showed that IFSM is an effective tool to estimate emissions from open lot cattle facilities and could help evaluate how management and climate affect the sustainability of beef and dairy production systems.

5. Modern techniques monitor decomposition in beef cattle feedyard manure. Beef cattle manure quality changes as it ages, affecting its fertilizer value; however, these changes during decomposition have not been quantified. USDA-ARS researchers in Bushland, Texas and New Orleans, Louisiana collected freshly excreted manure, stockpiled pen manure, runoff settling basin sediment, and retention pond sediment from a commercial feedyard in the Texas Panhandle. These researchers used multiple modern spectroscopic techniques and identified changes as manure aged during its on-farm life cycle. Recently excreted manure contained high concentrations of readily available carbon and nutrients. Fats, lipids and proteins were broken down quickly and the organic matter in older manures was more stabilized that that which was more recently excreted. This work showed that material from different feedyard sources could have differential effects on soil fertility and potential for environmental degradation.

Review Publications
Waldrip, H., Todd, R.W., Cole, N.A. 2015. Can surface-applied zeolite reduce ammonia losses from feedyard manure? A laboratory study. Trans.ASABE 58(1):137-145.

Waldrip, H., Cole, N.A., Todd, R.W. 2015. Nitrogen sustainability and beef cattle feedyards: introduction and influence of pen surface conditions and diet. The Professional Animal Scientist 2015. 31:89-100 doi:10.15232/pas.2014-01361

Todd, R.W., Cole, N.A., Hagevoort, R., Casey, K.D., Auvermann, B.W. 2015. Ammonia losses and nitrogen partitioning at the southern High Plains open lot dairy. Atmospheric Environment. 110:75-83

He, Z., Waldrip, H. 2015. Composition of whole and water extractable organic matter of cattle manure affected by management practices. Soil Science Society of America Special Publication, Madison, WI. Book Chapter. 382(2015):41-60. doi:10.2136/sssaspecpub62.2014.0034.