Much of the greenhouse gases (GHG) generated from the poultry industry is primarily from feed production. The poultry producer does not have control over the production and distribution of the feed used on the farm. However, they can control other emissions that occur on the farm such as emissions from the utilization of fossil fuels and from manure management. A series of studies were conducted to evaluate on-farm greenhouse gas emissions from broiler, breeder and pullets houses in addition to an in-line commercial layer complex. Data was collected from distributed questionnaires and included; the activity data from the facility operations (in the form of fuel bills and electricity bills), house size and age, flock size, number of flocks per year, and manure management system. Emissions were calculated using GHG calculation tools and emission factors from IPCC. The carbon dioxide, nitrous oxide and methane emissions were computed and a carbon footprint was determined and expressed in tonnes carbon dioxide equivalents (CO2e).
The results from the study showed that about 90% of the emissions from the broiler and pullet farms were from propane and diesel gas use, while only 6% of the total emissions from breeder farms were from propane and diesel gas use. On breeder farms, about 29% of GHG emissions were the result of electricity use while the pullet and broiler farms had only 3% emissions from electricity use. Emissions from manure management in the layer facility were responsible for 53% of the total emission from the facility, while electricity use represented 28% of the total emissions. The results from these studies identified the major sources of on-farm of GHG emissions. This will allow us to target these areas for abatement and mitigation strategies.
Why Study Greenhouse Gases on Poultry Farms?
Human activities, including modern agriculture, contribute to greenhouse gas (GHG) emissions (IPCC, 1996). Agriculture has been reported to be responsible for 6.3% of the GHG emissions in the U.S., of this 53.5% were a result of animal agriculture. Of the emissions from animal agriculture, poultry was responsible for only 0.6%. Much of the CO2e that is generated from the poultry industry is primarily from feed production, the utilization of fossil fuels and manure management (Pelletier, 2008; EWG, 2011). While the poultry producer does not have control over the production of the feed that is used on the farm, there are other GHG emissions that occur on the farm that are under their control. These emissions may be in the form of purchased electricity, propane used for heating houses and incineration of dead birds, diesel used in farm equipment which includes generators and emissions from manure management.
What Did We Do?
A series of studies were conducted to examine the GHG emissions from poultry production houses and involved the estimation of emissions from; broiler grow-out farms, pullet farms, breeder farms from one commercial egg complex. Data collection included the fuel and electricity bills from each farm, house size and age, flock size and number of flocks per year and manure management. The GHG emissions were evaluated using the IPCC spreadsheets with emission factors based on region and animal type. We separated the emissions based on their sources and determined that there were two main sources, 1. Mechanical and 2. Non-mechanical. After we determined the sources, we looked at what contributed to each source.
What Have We Learned?
When all GHG emissions from each type of operation was evaluated, the total for an average broiler house was approximately 847 tonnes CO2e/year, the average breeder house emission was 102.56 tonnes CO2e/year, pullet houses had a total emission of 487.67 tonnes CO2e/year, and 4585.52 CO2e/year from a 12 house laying facility. The results from this study showed that approximately 96% of the mechanical emissions from broiler and pullet houses were from propane (stationary combustion) use while less than 5% of these emissions from breeder houses were from propane use. The high emission from propane use in broiler and pullet houses is due to heating the houses during brooding and cold weather. Annual emissions from manure management showed that layer houses had higher emissions (139 tonnes CO2e/year) when compared to breeder houses (65.3 tonnes CO2e/year), broiler houses (59 tonnes CO2e/year) and pullet houses (61.7tonnesCO2e/year). Poultry reared in management systems with litter and using solid storage has relatively high N2O emissions but low CH4 emissions.We have learned that there is variability in the amount of emissions within each type of poultry production facility regardless of the age or structure of houses and as such reduction strategies will have to be tailored to suit each situation. We have also learned that the amount of emissions from each source (mechanical or non-mechanical) depends on the type of operation (broiler, pullet, breeder, or layer).
Future Plans
Abatement and Mitigation strategies will be assessed and a Poultry Carbon Footprint Calculation Tool is currently being developed by the team and will be made available to poultry producers to calculate their on-farm emissions. This tool will populate a report and make mitigation recommendations for each scenario presented. Best management practices (BMP) can result in improvements in energy use and will help to reduce the use of fossil fuel, specifically propane on the poultry farms thereby reducing GHG emissions, we will develop a set of BMP for the poultry producer.
Authors
Claudia. S. Dunkley, Department of Poultry Science, University of Georgia; cdunkley@uga.edu
Brian. D. Fairchild, Casey. W. Ritz, Brian. H. Kiepper, and Michael. P. Lacy, Department of Poultry Science, University of Georgia
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
Many of today’s high school students have little insight into the basic day-to-day operational decisions and challenges faced by Agricultural producers. Therefore, there is a need for the development of ag-centric and dynamic educational material. Furthermore; there is an even greater need to provide high-school instructors with innovative classroom materials and instructional tools that are conducive to the structured conveyance of ag principles. Targeting the need for these innovative ag educational materials within Arkansas classrooms, this project presents an dynamic lab activity with emphasis on introductory level subject matter about Arkansas swine production systems and the related greenhouse gas emissions. Due to the particular nature of the subject matter, the activity materials were crafted into two complementary products for practicality. The first product is a compilation of swine production reference materials including: terminology and layman definitions of Arkansas swine management strategies and the basic dynamics of greenhouse gasses (CO2, N2O, CH4) as they relate to swine production. The second product is a scenario based critical thinking exercise, implemented from a manipulative decision-tree platform.
Purpose
Educate students within the state of Arkansas about the various management systems intrinsic to swine production operations within their state.
Provide students insight into the management obstacles that Arkansas swine producers are challenged with through balancing Carbon footprints, economic resources, natural resources, and legal compliance with production profitability and productivity
What Did We Do?
This project presents an dynamic lab activity with emphasis on introductory level subject matter about Arkansas swine production systems and the related greenhouse gas emissions. The activity materials were crafted into two complementary products for practicality. The first product is a compilation of swine production reference materials including: terminology and layman definitions of Arkansas swine management strategies and the basic dynamics of common greenhouse gasses (CO2, N2O, CH4) as they relate to this activities scope of swine production. The reference material serves as both an introduction to basic ideas and practices native to swine production and GHGs, and as a guide which aids the students in completion of the second product (lab activity).
The second product is a scenario based critical thinking exercise, implemented from a manipulative decision-tree platform. Flashcards are used to represent three specific swine management systems using a three tier hierarchy. This hierarchy is distinguished by the allocation of Categories, Components, and Options. The “Categories” are the designated ranking class and will represent three major swine production management systems: Housing Management, Waste Management, and Feed Management. The “Components’ are the first sub-order class, and are used to represent various functions/considerations that comprise each “Category” of production system. The “Options” class holds the lowest position within the hierarchy and represents the different configurations/settings for the individual “Components”. For the context of this exercise the students will act as consultants hired by a producer to design the three management systems (via the flashcards) to “best match” the producer’s desired specifications, as defined within by a supplied catalog of unique scenarios.
Graphical reference to the hierarchical structure of the manipulatives used within this project’s lab activity.
Future Plans
Implementation of this project’s developed lab-activity within Arkansas’ high school classrooms via the Arkansas Farm Bureau supported (Ag-In-the-Classroom) program.
Authors
Szymanski “Rick” Fields II, Program Associate, Biological and Agricultural Engineering, University of Arkansas Division of Agriculture Extension rfields@uaex.edu
Karl VanDevender, Professor-Engineer, Biological and Agricultural Engineering, University of Arkansas Division of Agriculture Extension
This is a NIFA funded project (Proposal # 2010-04269; Title of Proposal “Integrated Resource Management Tool to Mitigate the Carbon Footprint of Swine Produced in the U.S”)
Special thanks to Donna VanDevender (High School Science Teacher-Bauxite Arkansas) for her insight into the development of the materials and for providing the opportunity to conduct trial runs of the lab-activity.
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
Soil microbial communities have been proposed as indicators of soil quality due to their importance as drivers of global biogeochemical cycles and their sensitivity to management and climatic conditions. Despite the importance of the soil microbiota to nutrient transformation and chemical cycling, physio-chemical properties rather than biological properties of soils are traditionally used as measures of environmental status. In general, much is unknown regarding the effect of management fluctuations on important functional groups in soils systems (i.e., methanogens, nitrifiers and denitrifiers). It is only recently that it has been possible, through application of sophisticated molecular microbiological methods, to sensitively and specifically target important microbial populations that contribute to nutrient cycling and plant health present at the field-scale and in differentially managed soil systems.
Fig. 1. Swine slurry surface application.
In this study, quantitative, real-time PCR (qPCR) was used to quantify changes in denitrifiers (narG) and methanogens (mcrA) in agricultural soils with three different swine effluent application methods including surface application, direct injection, and application in combination with soil aeration. Results show that concentrations of bacteria were high in all treatments (2.9 ± 1.4 X 109 cells per gram of soil); about 25% higher than in controls with no slurry added. Concentrations of methanogens and denitrifiers were slightly higher (around 50%) when slurry was applied by injection or aeration (5.3 ± 2.4 X 107 cells and 2.8 ± 1.8 X 107 cells per gram of soil, respectively) as compared to no till (2.4 ± 1.6 X 107 cells and 1.6 ± 1.0 X 107 cells per gram of soil, respectively).
These results suggest that application method has little influence on concentrations of functional groups of microorganisms. These results will be discussed in light of results of GHG sampling conducted during the same study.
Fig. 2. Swine slurry application by direct injection.
Why Study Greenhouse Gases and the Manure-Soil Interaction?
Although agricultural production has been identified as a significant source of green house gas (GHG) emissions, relatively little scientific research has been conducted to determine how manure management strategies effect GHG production upon land application. Even fewer studies have taken into consideration the microorganisms associated with applied manures. Microbial communities are responsible for nutrient transformation and chemical cycling in soil systems and many important functional groups (i.e., methanogens, nitrifiers and denitrifiers) are extremely sensitive to environmental management and climate conditions. The goal of this study was to evaluate how swine slurry land application methods effect microbial communities associated with nitrogen cycling and GHG production.
Fig. 3. Swine slurry application in combination with soil aeration.
What Did We Do?
We used molecular microbial methods to quantify changes in nitrifiers (amoA), denitrifiers (nirK, nosZ and narG) and methanogens (mcrA) in agricultural soils receiving swine slurry applied by (A) surface application (Fig. 1) (B) direct injection (Fig. 2) or (C) application in combination with soil aeration (Fig. 3). Soil samples were taken from triplicate plots 13 days after effluent application.
Above – Fig. 4. Concentration of methanogens (mcrA) and nitrate reducing bacteria (narG) as measured by quantitative, real-time PCR analysis of targeted genes (in parentheses). Swine slurry was applied by three methods surface, direct injection (Inj) or in combination with aeration (Aer). Chemical fertilizer (Fert) and plots with no fertilizer (Control) were also included. Initial slurry was removed before application. Cells in soils from plots with surface applied slurry were sampled at two depths (1.3 cm and 5.1 cm). Error bars represent the standard deviation of triplicate plot samples.
Below – Fig. 5. Concentration of nitrifying bacteria or archaea as measured by quantitative, real-time PCR analysis of the amoA specific for each group. Swine slurry was applied by three methods surface, direct injection (Inj) or in combination with aeration (Aer). Chemical fertilizer (Fert) and plots with no fertilizer (Control) were also included. Initial slurry was removed before application. Cells in soils from plots with surface applied slurry were sampled at two depths (1.3 cm and 5.1 cm). Error bars represent the standard deviation of triplicate plot samples.
What Have We Learned?
Sampling cell concentrations at different soil depths (1.3 cm or 5 cm) from plots with surface applied slurry significantly influenced results (Fig. 4, Fig. 5 and Fig 6).
Slurry applied by any method significantly increased (7 logs) concentrations of nitrate reducing bacteria and methanogens (Fig 4). Methanogens were present in the slurry while nitrate reducers were not measurable in slurry or control plots.
Nitrifying bacteria significantly increased in concentration after slurry addition (i.e. 7, 31, 2 and 68 times higher than control plots for slurry applied by injection, aeration or surface application (1.3 cm and 5 cm), respectively); concentrations of nitrifying archaea did not change from initial levels after slurry addition (Fig. 5).
Concentrations of bacteria, fungi and denitrifiers on plots with slurry applied were two to nine times higher than concentrations in controls with no slurry (Fig. 6).
Future Plans
Findings from this study underscore the importance of measuring both microbial populations and gas production when evaluating the impact of manure application on emissions. Emission data provided important information about the kind and rate of GHG emissions (see reference below for details; Sistani et al (2011) Soil Sci. America J. 74(2): 429-435). However, microbial analyses showed that select groups of nitrifiers and denitrifiers (but not all groups) were affected by manure application. Findings from microbial analyses will be the basis for development of future studies to target and manipulate specific microbial populations in ways that inhibit their ability to produce GHG.
Fig. 6. Change in concentration of targeted population in each treatment relative to that in the control with no slurry or fertilizer added. Concentrations of bacteria (16S RNA gene), fungi (18S RNA gene), nitrite reducing bacteria (nirK) or nitrous oxide reducing bacteria (nosZ) were measured by quantitative, real-time PCR analysis of targeted genes (in parentheses). Swine slurry was applied by three methods surface, direct injection (Inj) or in combination with aeration (Aer). Chemical fertilizer (Fert) and plots with no fertilizer (Control) were also included. Initial slurry was removed before application. Cells in soils from plots with surface applied slurry were sampled at two depths (1.3 cm and 5.1 cm). Error bars represent the standard deviation of triplicate plot samples.
Authors
Dr. Kimberly Cook, Research Microbiologist, USDA Agricultural Research Service, kim.cook@ars.usda.gov
Dr. Karamat Sistani, Research Soil Scientist, USDA Agricultural Research Service
Sistani, K.R., Warren, J.G., Lovanh, N.C., Higgins, S., Shearer, S. 2010. Green House Gas Emissions from Swine Effluent Applied to Soil by Different Methods. Soil Sci. America J. 74(2): 429-435.
Acknowledgements
We would like to thank Jason Simmons and Rohan Parekh for valuable technical assistance. This research is part of USDA-ARS National Program 214: Agricultural and Industrial By-products
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
The use of wet distiller’s grains with solubles (WDGS) in feedlot diets has increased as a result of the growing U.S. ethanol industry. However, few studies have evaluated the use of WDGS in finishing diets based on steam-flaked corn (SFC), the processing method used extensively in the Southern Great Plains. The effects of corn processing method and WDGS on enteric methane (CH4) production, carbon dioxide (CO2) production and energy metabolism were evaluated in two respiration calorimetry studies. In Exp. 1, the effects of corn processing method (SFC or dry rolled corn – DRC) and WDGS inclusion (0 or 30% of diet dry matter- DM) were studied using a 2 x 2 factorial arrangement of treatments and four Jersey steers in a 4 x 4 Latin square design. In Exp. 2, the effects of WDGS inclusion rate (0, 15, 30, or 45% of diet DM) on CH4 and CO2 production were measured in a 4 x 4 Latin square design. Results indicate that cattle consuming SFC-based diets produce less enteric CH4 and retain more energy than cattle fed DRC-based diets. When dietary fat levels were held constant, dietary inclusion of WDGS at 15% of diet DM did not affect enteric CH4 production, WDGS inclusion at 45% of diet DM significantly increased enteric CH4 production and WDGS inclusion at 30% of diet DM had variable effects on enteric CH4 production.
Purpose
Our objectives were to determine the effects of corn processing method and WDGS inclusion rate on enteric methane losses from finishing cattle using respiration calorimetry.
What Did We Do?
Steer in open circuit respiration calorimetry chamber.
Eight steers were used in two studies. In each study steers were fed one of four diets at 2 x maintenance energy requirements in a 4 x 4 Latin square design. Each period of the Latin squares included a 16 d adaptation period followed by 5 days of total fecal and urine collection and measurement of gas exchange in respiration chambers. In Experiment 1 dietary treatments consisted of corn processing method (steam flaked -SFC or dry rolled -DRC) and WDGS inclusion rate (0 or 30% of DM). All diets were balanced for ether extract. In Exp. 2, cattle were fed SFC-based diets containing 0, 15, 30 or 45% WDGS (DM basis). The calorimetry system consisted of 4 chambers with an internal volume of 6500 L. Outside air was pulled through chambers using a mass flow system. Gas concentrations were determined using a paramagnetic oxygen analyzer and infrared methane and carbon dioxide analyzers (Sable Systems, Las Vegas, NV) Data were statistically analyzed using the Mixed procedure of SAS.
What Have We Learned?
In Exp. 1. no iteractions between grain processing method and WDGS inclusion were detected (P> 0.47). Cattle fed DRC-based diets had greater (P< 0.05) CH4 production (L/steer, L/kg of DMI, % of gross energy intake, and % of digestible energy intake) than cattle fed SFC-based diets probably the result of differences in ruminal fermentation and ruminal pH. Methane losses as a proportion of GE intake (2.47 and 3.04 for SFC and DRC-based diets, respectively) were similar to previous reports and to IPCC (2006) values but were somewhat lower than EPA (2012) values. Grain processing method did not affect CO2 production (13 to 14 Kg/d). WDGS inclusion rate did not affect CH4 or CO2 production. In Exp. 2, CH4 production (L/d) increased quadratically (P = 0.03) and CH4 production as L/kg of DMI and as a proportion of energy intake increased linearly (P < 0.01) with increasing concentrations of WDGS in the diet. Feeding WDGS did not affect (P > 0.23) total CO2 production. Conclucions: Our results indicate that cattle consuming DRC-based finishing diets produce approximately 20% more enteric CH4 than cattle fed SFC-based diets. When WDGS comprised 30% or less of the diet and diets were similar in total fat content, feeding WDGS had little effect on enteric CH4 but when fed at higher inclusion rates enteric CH4 production was increased by approximately 40%.
Future Plans
Over 80% of the enteric methane emissions of the U.S. beef cattle herd are produced by cows, calves, and yearling on pasture. Therefore, additional research will study the effects of supplementation strategies and forage quality on enteric methane production by cattle.
Authors
N. Andy Cole; Research Animal Scientist/Research Leader; USDA-ARS-CPRL, Bushland, TX andy.cole@ars.usda.gov
Kristin E. Hales, Research Animal Scientist, USDA-ARS-MARC, Clay Center, NE
Richard W. Todd, Research Soil Scientist, USDA-ARS-CPRL, Bushland, TX
Ken Casey, Associate Professor, Texas AgriLife Research, Amarillo, TX
Jim C. MacDonald, Associate Professor, Dept. of Animal Science, Univ. of NE, Lincoln
Additional Information
Hales, K. E. , N. A. Cole, and J. C. MacDonald. 2013. Effects of increasing concentrations of wet distillers grains with solubles in steam-flaked corn-based diets on energy metabolism, carbon-nitrogen balance, and methane emissions of cattle. J. Anim. Sci. (in press)
Hales, K. E. , N. A. Cole, and J. C. MacDonald. 2012. Effects of corn processing method and dietary inclusion of wet distillers grains with solubles on energy metabolism, carbon-nitrogen balance, and methane emissions of cattle. J. Anim. Sci. 90:3174-3185.
Acknowledgements
Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA. USDA is an equal opportunity provider and employer.
We wish to thank USDA-NIFA for partial funding through Project # TS-2006-06009 entitled “Air Quality: Odor, Dust and Gaseous Emissions from Concentrated Animal Feeding Operations in the Southern Great Plains”
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
A new method was used at the Ag 450 Farm Iowa State University (41.98N, 93.65W) from October 24, 2012 through December 14, 2012 to assess GHG emission from land-applied swine manure on crop land. Gas samples were collected daily from four static flux chambers. Gas method detection limits were 1.99 ppm, 170 ppb, and 20.7 ppb for CO2, CH4 and N2O, respectively. Measured gas concentrations were used to estimate flux using four different models, i.e., (1) linear regression, (2) non-linear regression, (3) non-equilibrium, and (4) revised Hutchinson & Mosier (HMR). Sixteen days of baseline measurements (before manure application) were followed by manure application with deep injection (at 41.2 m3/ha), and thirty seven days of measurements after manure application.
Static flux chamber (pictured) method was developed to measure greenhouse gas emissions from land-applied swine manure from a corn-on-corn system in central Iowa in the Fall of 2012. Gas samples were collected in vials and transported to the Air Quality Laboratory at Iowa State University campus.
Why Study Greenhouse Gases and Land Application of Swine Manure?
Assessment of greenhouse gas (GHG) emissions from land-applied swine manure is needed for improved process-based modeling of nitrogen and carbon cycles in animal-crop production systems.
What Did We Do?
We developed novel method for measurement and estimation of greenhouse gas (CO2, CH4, N2O) flux (mass/area/time) from land-applied swine manure. New method is based on gas emissions collection with static flux chambers (surface coverage area of 0.134 m^2 and a head space volume of 7 L) and gas analysis with a GC-FID-ECD.
Baseline (post tilling) greenhouse gas (GHGs) emissions monitoring was followed with swine manure application in the Fall of 2012 (pictured) and about 10 weeks of post-application monitoring of GHGs.
New method is also applicable to measure fluxes of GHGs from area sources involving crops and soils, agricultural waste management, municipal, and industrial waste. New method was used at the Ag 450 Farm Iowa State Univeristy (41.98 N, 93.65 W) from October 24, 2012 through December 14, 2012 to assess GHG emission from land-applied swine manure on crop (corn on corn) land. Gas samples were collected daily from four static flux chambers. Gas method detection limits were 1.99 ppm, 170 ppb, and 20.7 ppb for CO2, CH4, and N2O, respectively.
What Have We Learned?
Measured gas concentrations were used to estimate flux using four different mathematical models, i.e., (1) linear regression, (2) non-linear regression, (3) non-equilibrium, and (4) revised Hutchinson & Mosier (HMR). Sixteen days of baseline measurements (before manure application) were followed by manure application with deep injection (at 41.2 m3/ha), and thirty seven days of measurements after manure application. Preliminary net cumulative flux estimates ranged from 115,000 to 462,000 g/ha of CO2, -4.65 to 204 g/ha of CH4, and 860 to 2,720 g/ha N2O. These ranges are consistent with those reported in literature for similar climatic conditions and manure application method.
Greenhouse gases (GHGs) were analyzed in the Air Quality Laboratory (ISU) using dedicated GHGs gas chromatograph. The picture above shows an example of gas sample analysis for CO2, GH4 and N2O. Each ‘peak’ represents one of the tagget GHGs. Gas concentrations were used in a mathematical model to estimate GHG flux (mass emitted/area/time).
Future Plans
Spring 2013 measurements of GHG flux from land-applied swine manure are planned. The spring study will follow the protocols developed for the Fall 2012 season. Estimates of the Spring and Fall GHG flux will be used to develop GHG emission factors for emissions from swine manure in Midwestern corn-on-corn systems. Emission factors will be compared with literature data.
Authors
Dr. Jacek Koziel, Associate Professor, Iowa State University Department of Agricultural and Biosystems Engineering koziel@iastate.edu
Devin Maurer, Research Associate, Iowa State University Department of Agricultural and Biosystems Engineering
Kelsey Bruning, Undergraduate Research Assistant, Iowa State University Department of Civil, Construction and Environmental Engineering
Tanner Lewis, Undergraduate Research Assistant, Iowa State University Department of Agricultural and Biosystems Engineering
Danica Tamaye, Undergraduate Research Assistant, University of Hawaii College of Agriculture, Forestry, and Natural Resource Management
William Salas, Applied Geosolutions
Acknowledgements
We would like to thank the National Pork Board for supporting this research.
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
In recent years, processing agricultural by-products to produce energy has become increasingly attractive due to several reasons: centralized availability of low cost by-products, avoiding the fuel vs. food debate, reduction of some associated environmental impacts, and added value that has the potential to generate additional income for producers. Anaerobic digestion systems are one waste-to-energy technology that has been proven to achieve these objectives. However, investigation on the impacts of anaerobic digestion has focused on defined segments, leaving little known about the impacts that take place across the lifecycle. Current systems within the U.S. are dairy centric with dairy manure as the most widely used substrate and electricity production as the almost sole source for biogas end use. Recently, there is more interest in exploring alternative feedstocks, co-digestion pathways, digestate processing, and biogas end uses. Different operational and design practices raise additional questions about the wide reaching impacts of these decisions in terms of economics, environment, and operational aspects, which cannot be answered with the current state of knowledge.
Why Study the Life Cycle of Anaerobic Digestion?
Waste management is a critical component for the economic and environmental sustainability of the agricultural sector. Common disposal methods include land application, which consumes large amounts of land resources, fossil energy, and produces significant atmospheric GHG emissions. Proof of this is that agriculture accounts for approximately 50% of the methane (CH4) and 60% of the nitrous oxide (N2O) global anthropogenic emissions, being livestock manure one of the major sources of these emissions (Smith et al., 2007). In the last decades, the development of anaerobic digestion (AD) systems has contributed to achieve both climate change mitigation and energy independence by utilizing agricultural wastes, such as livestock manure, to produce biogas. In addition, it has been claimed that these systems contribute to nutrient management strategies by adding flexibility to the final use and disposal of the remaining digestate. Despite these advantages, the implementation of AD systems has been slow, due to the high investment and maintenance costs. In addition, little is still known about the lifecycle impacts and fate and form of nutrients of specific AD systems, which would be useful to validate their advantages and identify strategic and feasible areas for improvement.
The main goal of this study is to quantify the lifecycle GHG emissions, ammonia emissions, net energy, and fate and form of nutrients of alternative dairy manure management systems including land-spread, solid-liquid separation, and anaerobic digestion. As cow manure is gaining an important role within the biofuel research in the pursuit for new and less controversial feedstocks, such as corn grain, the results of this study will provide useful information to researchers, dairy operators, and policy makers.
What Did We Do?
Lifecycle sustainability assessment (LCSA) methods were used to conduct this research, which is focused in Wisconsin. The state has nearly 1.3 million dairy cows that produce approximately 4.7 million dry tons of manure annually and is the leading state for implemented agricultural based AD systems. Manure from a 1,000 milking cow farm (and related maintenance heifers and dry cows) was taken as the base-case scenario. Four main processes were analyzed using the software GaBi 5 (PE, 2012) for the base case: manure production and collection, bedding sand-separation, storage, and land application. Three different manure treatment pathways were compared to the base-case scenario: including a solid-liquid mechanical separator, including a plug-flow anaerobic digester, and including both the separator and the digester. The functional unit was defined as one kilogram of excreted manure since the function of the system is to dispose the waste generated by the herd. A cradle-to-farm-gate approach was defined, but since manure is considered waste, animal husbandry and cultivation processes were not included in the analysis (Fig. 1). Embedded and cumulative energy and GHG emissions associated with the production of material and energy inputs (i.e. sand bedding, diesel, electricity, etc.) were included in the system boundaries; however, the production of capital goods (i.e. machinery and buildings) were excluded.
Figure 1. System boundaries of the base case scenario (land-spread manure) and the three manure treatment pathways: 1) solid-liquid separation, 2) anaerobic digestion, 3) anaerobic digestion and solid-liquid separation.
Global warming potential (GWP) was characterized for a 100-year time horizon and measured in kg of carbon dioxide equivalents (CO2-eq). Characterization factors used for gases other than CO2 were 298 kg CO2-eq for N2O, 25 kg CO2-eq for abiotic CH4 based on the CML 2001 method, and 24 kg CO2-eq for biotic CH4. CO2 emissions from biomass are considered to be different from fossil fuel CO2 emissions in this study; the former recycles existing carbon in the system, while the latter introduces new carbon into the atmosphere. In this context, it will be assumed that CO2 emissions from biomass sources were already captured by the plant and will not be characterized towards GWP[1]. This logic was applied when characterizing biogenic methane as one CO2 was already captured by the plant, therefore, reducing the characterization factor from 25 kg CO2-eq to 24 kg CO2-eq. Even though ammonia (NH3) does not contribute directly to global warming potential, it is considered to be an indirect contributor to this impact category (IPCC, 2006).
Data was collected from different sources to develop lifecycle inventory (LCI) as specific to Wisconsin as possible, in order to maximize the reliability, completeness, and representativeness of the model. The following points summarize some of the data sources and assumptions used to construct the LCI:
Related research (Reinemann et al., 2010): This model provided data about animal husbandry and crop production for dairy diet in Wisconsin.
Manure management survey: The survey, sent to dairy farms in Wisconsin, has the objective of providing information related to manure management practices and their associated energy consumption.
In house experiments: laboratory experiments, conducted at the University of Wisconsin-Madison, provided characterization data about manure flows before and after anaerobic digestion and solid-liquid separation and manure density in relation to total solids (Ozkaynak and Larson, 2012).
Material and energy databases: National Renewable Energy Laboratory U.S. LCI dataset (NREL, 2008), PE International Professional database (PE, 2012), and EcoInvent (EcoInvent Center, 2007), which are built into GaBi 5. The electricity matrix used in this LCA represents the mix of fuels that are part of the electric grid of Wisconsin.
Representative literature review.
Biotic emissions from manure have been cited to be very site specific (IPCC, 2006) and even though the Intergovernmental Panel on Climate Change (IPCC) provides regional emission factors, they are only for CH4 and N2O. Specific GHG emission factors were developed for Wisconsin based on the Integrated Farm System Model (IFSM) (Rotz et al., 2011), and by using key parameters that affect emissions (e.g. temperature, volatile solids, manure management practices) for each stage of the manure management lifecycle.
What Have We Learned?
Emissions are produced from consumed energy and from manure during each stage of the manure management lifecycle. In the base-case scenario, manure storage is the major contributor to GHG emissions. In this scenario, a crust tends to form on top of stored manure due to the higher total solids content when compared to digested manure and the liquid fraction of the separated manure. The formation of this crust affects overall GHG emissions (e.g. crust formation will increase N2O emissions but reduce CH4 emissions). The installation of a digester reduces CH4 emissions during storage due to the destruction of volatile solids that takes place during the digestion process. However, some of the organic nitrogen changes form to ammoniacal nitrogen, increasing ammonia and N2O emissions posterior to storage and land application. Energy consumption increases with both anaerobic digester and separation, but net energy is higher with anaerobic digestion due to the production of on-farm electricity. The nutrient balance is mostly affected by the solid-liquid separation process rather than the anaerobic digestion process.
Future Plans
A comprehensive and accurate evaluation of the lifecycle environmental impacts of AD systems requires assessing the multiple pathways that are possible for the production of biogas, which are defined based on local resources, technology, and final uses of the resulting products. A second goal of this research is to quantify the net GHG and ammonia emissions, net energy gains, and fate of nutrients of multiple and potential biogas pathways that consider different: i) biomass feedstocks (e.g miscanthus and corn stover), ii) management practices and technology choices, and iii) uses of the produced biogas (e.g. compressed biogas for transportation and upgraded biogas for pipeline injection) and digestate (e.g. bedding). This comprehensive analysis is important to identify the most desirable pathways based on established priorities and to propose improvements to the currently available pathways.
Authors
Aguirre-Villegas Horacio Andres. Ph.D. candidate. Department of Biological Systems Engineering, University of Wisconsin-Madison. aguirreville@wisc.edu
Larson Rebecca. Ph.D. Assistant Professor. Department of Biological Systems Engineering, University of Wisconsin-Madison.
Additional Information
Ozkaynak, A. and R.A. Larson. 2012. Nutrient Fate and Pathogen Assessment of Solid Liquid Separators Following Digestion. 2012 ASABE International Meeting, Dallas, Texas, August 2012
References
De Klein C., R. S.A. Novoa, S. Ogle, K. A. Smith, P. Rochette, T. C. Wirth, B. G. McConkey, A. Mosier, and K. Rypdal. 2006. Chapter 11: N2O emissions from managed soils, and CO2 emissions from lime and urea application. In Volume 4: Agriculture, Forestry and Other Land Use. IPCC 2006, 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Prepared by the National Greenhouse Gas Inventories Programme, Eggleston H.S., Buendia L., Miwa K., Ngara T. and Tanabe K. (eds). Published: IGES, Japan.
Ecoinvent Centre.2007. Ecoinvent Eata. v2.0. Ecoinvent Reports No.1-25. Swiss Centre for Life Cycle Inventories. Dübendorf.
National Renewable Energy Laboratory (NREL). 2008. U.S. Life-Cycle Inventory (LCI) Database.
Ozkaynak, A. and R.A. Larson. 2012. Nutrient Fate and Pathogen Assessment of Solid Liquid Separators Following Digestion. 2012 ASABE International Meeting, Dallas, Texas, August 2012
PE International. 2012. Software-systems and databases for lifecycle engineering.
Reinemann D. J., T.H. Passos-Fonseca, H.A. Aguirre-Villegas, S. Kraatz, F. Milani, L.E. Armentano, V. Cabrera, M. Watteau, and J. Norman. 2011. Energy intensity and environmental impact of integrated dairy and bio-energy systems in Wisconsin, The Greencheese Model.
Rotz, C. A., M. S. Corson, D. S. Chianese, F. Montes, S.D. Hafner, R. Jarvis, and C. U. Coiner. 2011. The Integrated Farm System Model (IFSM). Reference Manual Version 3.4. Accessed on Nov, 2012. Available at: http://www.ars.usda.gov/Main/docs.htm?docid=8519
Smith, P., D. Martino, Z. Cai, D. Gwary, H. Janzen, P. Kumar, B. McCarl, S. Ogle, F. O’Mara, C. Rice, B. Scholes, O. Sirotenko. 2007: Agriculture. In Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds)], Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
Acknowledgements
This work was funded by the Wisconsin Institute for Sustainable Agriculture (WISA-Hatch)
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
Dr. Karl VanDevender – University of Arkansas:Cooperative Extension Service and Dr. Brian Richert – Purdue University
Sub-Project Overview
The research and modeling work encompassed by this project offers great potential for assisting researchers, policy makers, and especially farm managers to make informed management and facilities decisions regarding GHG emissions while maintaining production and profitability. However for this potential to be realized the swine production community needs to be aware of both its abilities and availability. To this end existing relationships with the National Pork Board , U.S. Pork Center of Excellence, and eXtension are being enhanced.
The focus audience of this training is technical service providers (professionals, consultants, engineers, nutritionists, extension swine specialist and educators) who are involved in assisting swine producer’s making both strategic and tactical management decisions. The goal is to develop and implement education and outreach programs focused on the interaction between climate and swine science.
Dr. Richert serves as the nutrition domain editor for the US Pork Center of Excellence and US Pork Information Gateway which also serves as the swine domain for National eXtension. Through this relationship with domain editor for the Environmental section, Erin Cortus, we have initiated the rewriting of the factsheet “Pork production and greenhouse gas emissions” and have started authoring a factsheet on “Pork production, what might your carbon footprint be?”
Karl VanDevender, the project liaison with eXtension has a long history with the Livestock and Poultry Environmental Learning Center (LPELC) which has become the eXtension community of practice working in the area of livestock and poultry manure management. In response to the project needs he has transitioned from a topic area leadership role to a member of the LPELC leadership team, alongside other eXtension professionals. This provides the capacity to ensure that the project and LPELC take full advantage of the synergy of multiple funded projects without undesirable duplication of effort and resources.
The benefits of integration of extension efforts with research and education is that more rapid translation of research results into actionable knowledge will be achieved. Frequent team meetings are established to ensure that there is continual interaction and information exchange.
The working relationship between our project’s Extension component and the LPELC has helped facilitate the recent production of the webcast “Life Cycle Assesment Modeling for the Pork Industry“, which overviews the LCA goals and provides details in the sub-project areas dealing with concepts and research of feed management. Our project will also be hosting a special session featuring project leads during the LPELC hosted Waste to Worth: Spreading Science and Solutions conference in Denver Colorado, April 2013. The special session will feature a showcasing of the project’s individual and collective works; topics discussed will include: LCA concepts, research and modeling challenges, model results, and economics.
Dr. VanDevender recently published an article in PIG Progress Magazine entitled “A Swine Carbon Footprint Model as a decision aid tool”, in which the efforts of this project were presented. The article stressed the imoportance of continued management of greenhouse gasses in the livestock industry through improvements in efficiencies.
.
Sub-Project Objectives
Developing the necessary system and protocols for sharing and vetting information and educational materials
Strengthening the relationship between this project and eXtension
Development and delivery of information both internally and externally.
Contact Information
Dr. Karl VanDevender kvan@uaex.edu
Phone: (501) 671-2244
Dr. Marty Matlock and Dr. Jennie Popp – University of Arkansas
Sub-Project Overview
A summer research program for undergraduate students has been developed with the focus of carbon footprint mitigation from agriculture. The goal of this USDA REU is to support 10 students each summer for a 10 week period throughout the duration of this project. The REU supported by this project is offered parallel to the National Science Foundation Research Experience for Undergraduates (NSF REU), and students are recruited from the same pool as the NSF REU programs. The REU students are selected through an application process informed by an established recruitment network. We are actively recruiting from under-represented minorities, including: Native Americans, African Americans and Hispanics.
REU Students spend the first week in a skills development workshop where they learn to develop and test hypotheses, analyze data and write reports and manuscripts. They then spend eight weeks working with their faculty mentors, followed by a one week report of results in poster and presentation format.
The expected outcomes of the REU include; inspiring students to continue their education through graduate school, and fostering an interest and competency in agricultural research.
Sub-Project Objectives
To expose undergraduate students to the scientific research process through the steps of developing testable hypotheses, data collection and analysis, and scientific communication in the form of oral presentations and written manuscripts.
Dr. Marty Matlock and Dr. Thomas Costello – University of Arkansas
Sub-Project Overview
Algal biomass offers many advantages over traditional energy crops; algal biomass generates higher yields and requires smaller land area than other energy crops. In addition to biomass production for potential biofuel feedstock generation, algal growth systems can also act as tertiary treatment systems for wastewater. Algal growth can dramatically reduce nitrogen and phosphorus from wastewater. Unlike conventional open pond and photo-bioreactor systems, periphytic systems (e.g., algal turf scrubbers) generally involve the polyculture of micro-algae, which does not require specialized conditions. While algal turf scrubber systems are traditionally used for water treatment, they are also capable of generating high biomass yields.
The Algal Nutrient Removal Team has focused on installation of the test bed for the research. This has included construction of a precision graded base for the 20-ft wide by 200-ft long flow way. Our working hypothesis is that operation of an algal flow-way to treat swine manure will remove nutrients, produce a harvestable biomass residue, and add dissolved oxygen which will decrease potential for nitrous oxide emissions (and possibly methane emissions) during manure storage. Wastewater from the swine finisher unit at the University of Arkansas will provide nutrient input to the Algae Flow-way. The flow way will be tested with manure output from pigs fed conventional diets as well as the custom rations intended to reduce manure nitrogen. Impacts on nutrient removal and algal biomass productivity, as a function of diet formulation, will be measured. Nutrient removal will be documented and data collected will be used in the DNDC model to represent the waste treatment performance of the algal systems
Algal growth systems not only provide a method for nutrient removal from animal waste, but also provide biomass production as feedstock for biofuels which can improve the carbon footprint of swine production and other animal production systems in the U.S. This project will provide field scalable data on life cycle impacts of the technology. Design and construct algal turf scrubber concluded in late summer of 2012, and the system is currently undergoing callibrations in preperation for full-scale trials.
Sub-Project Objectives
Measure algal productivity.
Quantify impact of algal nitrogen uptake on swine system GHG emissions.
Dr. Thomas Costello tac@uark.edu
Phone: (479) 575-2847
Solids Separation
Dr. Karl VanDevender – University of Arkansas. Cooperative Extension Service
Sub-Project Overview
Many technologies being considered incorporate some type of manure separation to concentrate manure solids, nutrients, and energy content. An LCA study in Denmark showed that energy recovery (incineration, gasification, and anaerobic digestion) had lower GHG emissions than traditional land application of swine manure. Other studies point to the complexities of manure management system design options in relation to GHG emissions. This portion of the project will quantify the effect of various solid separation approaches on the chemical composition of the manure generated by the feed trials at the University of Arkansas facilities during this project ,and generate the necessary manure solids for the thermo-chemical conversion portion of this project. Design and construct a pilot scale mobile solids separation system (see image below) is currently approaching completion and anticipated to be ready to begin trial calibrations soon.
Sub-Project Objectives
Capture and separation of manure from the UA animal experiments.
This unit contains systems to allow for various combinations of mechanical screen and filter bag separation, with and without chemical treatment; and is designed to operate in a batch mode with a capacity of 1000 gallons per batch.
Determine overall characteristics for the feed trial manure samples to provide additional validation data for the animal physiology sub-model.
Contact Information
Dr. Karl VanDevender kvan@uaex.edu
Phone: (501) 671-2244
Auger Reactor Gasification
Dr. Sammy Sadaka – University of Arkansas. Cooperative Extension Service
Sub-Project Overview
Due to the high moisture content, it is not economical to transport raw swine manure over long distances. As a result, manure is spread on land close to the source at high application rates. The energy content of dry manure is in the range of 12 to 18 GJ/ton, about half that of coal. In recent years, wet and dry gasification of algal biomass has been investigated by several researchers. Fluidized bed and downdraft gasification of algal biomass showed various challenges due to the nature of algae biomass. An auger gasification system (see image below) developed in the University of Arkansas, Bioenergy Laboratory, may help to simplify the air gasification process for this type of biomass. Algal biomass was gasified using the auger system during preliminary tests. Several improvements to the system took place during the first year to ensure smooth operation. Our long-term goal is to provide technology to convert swine manure and/or algal biomass to biofuel via a continuous gasification process. Energy conversion technology could provide a revenue stream of about $23 billion/year to the livestock industry.
Sub-Project Objectives
Modify the existing gasification unit to handle swine manure and/or algal biomass.
Test the performance of the gasifier
Optimize the operating parameters to maximize producer gas quality.
Study the effect of reactor temperature on the process yields (gas, char, and tar), as well as on the process efficiency.
Dr. Charles Maxwell, Dr. Jennie Popp, and Dr. Richard Ulrich – University of Arkansas; Dr. Scott Radcliffe – Purdue University, and Dr. Mark Hanigan – Virginia Tech
Why study crude protein and carbon footprint?
Maximizing feed grade amino acid (FGAA) use and reducing dietary crude protein in swine diets has been shown to dramatically reduce nitrogen excretion in both nursery and growing/finishing swine which could substantially reduce nitrous oxide (N2O) emissions associated with manure management in swine production. The global warming potential of N2O is about 298 times that of CO2 (carbon dioxide). Reducing the crude protein (CP) content of grower and finisher diets has also been repeatedly shown to enhance carcass quality by elevating intramuscular fat. While some crystalline amino acids are already commonly used in pork production the maximum level of CP reduction, in conjunction with the optimum amino acid inclusion rate, has not been sufficiently determined for widespread acceptance by the swine industry.
Project Objectives:
Hypothesis: Reducing dietary CP while maintaining amino acids (AA) at equivalent Standardized Ileal Digestibility (SID) ratios by supplementing feed grade AA will reduce nitrogen (N) excretion and greenhouse gas (GHG) emissions (N2O from manure) without impacting swine performance or carcass yield.
Determine the practical limits of reducing CP in diets of nursery and finishing pigs.
Validate the effectiveness of reduced dietary nitrogen as a mitigation strategy for greenhouse gases.
Provide data for validation of animal physiology model capable of predicting swine performance and relevant manure characteristics (quantity and composition for Manure DNDC).
Compare ME vs. NE formulation strategies on lean tissue deposition and fat accretion.
Determine the impact of dietary amino acid levels on signaling in regulation of tissue growth.
[2014 & 2015 annual reports indicated another objective was added] Estimate manure reductions in N excretion via a N balance trial.
Studies were conducted at multiple sites. One was the University of Arkansas wean-to-finish facilities and the second at the Purdue Swine Environmental Research Building (SERB). See the videos above for more on these facilities). The data generated was utilized in modelling work at Virginia Tech. The model was ultimately incorporated into the Swine Environmental Footprint Calculator.
Nursery Studies
What Did We Do? (Methods or Experimental Design)
Experiment 1
To evaluate maximum replacement of CP with FGAA, 320 weaned pigs were allotted to gender-balanced pens in a wean-to-finish facility (8 pigs/pen). Within blocks, pens were randomly assigned to 1 of 5 dietary treatments. Diets were formulated to maintain constant ME and SID Lys across treatments with SID Lys set at 95% requirement (PIC Nutrient Specification Manual, 2011). Diets were formulated to meet the SID AA ratio recommendations for other indispensable AA (SID) for nursery pigs through the 6th limiting AA (PIC Nutrient Specifications Manual, 2011). For each phase, Ctrl diets were devoid of FGAA, whereas Lys HCl was added in equal increments at the expense of CP (SBM, fish meal [FM], and poultry meal [PM] in phase 1, FM and PM in phase 2, and SBM in phase 3). This formulation procedure resulted in diets that were below the His and Phe/Tyr SID requirement for the highest level of CP reduction. CP and Lys inclusion levels were analyzed. Experiment 2
A second three phase nursery study was conducted with pigs weaned at 21 d to further evaluate limits of CP reduction in nursery diets and compare performance in pigs fed diets based on formulation on an ME vs. NE basis. The study involved 7 pigs/pen and 7 replicates/treatment. Dietary ingredients were similar to those used in experiment 1, except soy protein concentrate was used to replace fish meal. Dietary treatments were: 1), Control diet formulated on an ME basis and with FGAA used to meet the “Trp Set Point” without adding feed grade Trp in phase 1 and 2 and 0.02 % added Trp in phase 3; 2) Diet formulated on an ME basis and to meet the “His Set Point” without added feed grade His; 3) As 2 with diets formulated on a NE basis.
Nursery What Did We Learn (Results)?
Experiment 1
Pigs fed RCP 1, RCP 2, and RCP 3 diets in phase 1, 2 and 3, and for the overall study had similar ADG and BW but growth performance declined for pigs fed RCP 4 diets (Table 5; Quadratic effect, P < 0.01). A similar response was observed in ADFI in all time periods except phase 1 where ADFI was similar among treatments. In phase 1, G:F ratio followed a similar response (Quadratic effect, P < 0.01), but decreased linearly in phase 2 (P < 0.08), 3, and overall (P < 0.01). It should be noted that the RCP 4 diet was below requirement for SID His:Lys and Phe/Tyr:Lys which might explain the decrease in performance. The results of this study establishes that a high inclusion of feed grade Lys at the expense of intact proteins can be fed without decreasing ADG and ADFI except at the highest level of FGAA where the requirement for all IDAA was not met. However, G:F was generally reduced at the higher inclusion rates of FGAA, particularly in phase 3. Experiment 2
No differences were observed in ADG, ADFI, or G:F (Table 6) in any phase or overall in pigs fed diets formulated on an aggressive FGAA inclusion (His Set Point) based on ME (Trt.2) or NE (Trt. 3) compared to pigs fed AA inclusion levels currently used in swine industry (Trt. 1). These results indicate that in nursery pigs, one should be able to use a His Set Point in formulating AA based diets without concern for pig performance.
The previous nursery experiment (Experiment 1; Bass et al., 2013) conducted to evaluate feeding reduced CP diet with the highest levels of FGAA to nursery pigs resulted in poor growth performance, especially G:F ratio in phase 3 and the overall nursery period. In the previous study, experimental diets were formulated to meet the 95% of SID Lys requirement for nursery pigs. Also, RCP 4, which was formulated with the highest level of FGAA, did not meet the His and Phe requirement Lys/NE.
Conclusion
In conclusion, unlike the previous study, growth performance of nursery pigs was not affected by the higher level of FGAA and lower dietary CP. This may be due to different SID His:Lys and SID Phe+Tyr:Lys ratios used in diet formulation or different protein source used in each study. In the second nursery study, all diets were formulated based on 100 % or excess of SID Lys requirement for nursery pigs, and were formulated to meet the His and Phe+Tyr requirement. In addition, soy protein concentrate (SPC) was used in the second study during phase 1 and 2, replacing menhaden fish meal used in nursery study one.
Publications
2013 Midwest American Society of Animal Science (ASAS) meeting (Experiment 1) Abstract P042, page 102
Grow-Finish Studies
What Did We Do? (Methods)
Each experiment was conducted following a five phase grow-finish protocol. Pigs were fed 1 of 4 or 5 diets and 10 ppm of Paylean was fed during the final 3-week finishing phase-Phase 5. During phase 1 through 5, individual pig BW, and pen feed disappearance were measured over each phase to allow calculation of ADG, ADFI and G:F by phase. Tenth rib, ¾ midline back fat measurements and loin muscle area were estimated at study initiation and at the end of each phase via ultrasound to allow estimation of carcass lean gain. When the average of all blocks was 129-134 kg all pigs were individually weighed, tattooed, transported to, and harvested at a commercial pork packing plant according to industry accepted procedures. Longissimus muscle (LM) and fat depths at the 10th rib were measured on-line with a Fat-O-Meater probe and individual hot carcass weight was recorded. Experiment 1
A total of 420 pigs were blocked within gender and randomly allotted to pens with 6 pigs/pen. Within blocks, pens of pigs were randomly assigned to 1 of 5 dietary treatments (7 reps/treatment/gender). Diets were formulated by incrementally increasing levels of Lys with corresponding reductions in CP. Pigs were randomly allotted to the following diets:
Ctrl: Corn-SBM-DDGS diets devoid of FGAA,
RCP 1 (reduced crude protein 1)
RCP 2
RCP3
RCP 4 – was balanced on the requirement of the 7th limiting AA, His (PIC Nutrient Specifications Manual, 2011) which was considered the practical limit of the highest level of RCP because of availability constraints.
RCP 1 to 4 were then formulated to have stepwise and equally spaced increased Lys with corresponding reductions in CP between RCP 1 and 4. Diets 2-4 were supplemented with FGAA as needed to meet AA needs based on AA minimum ratios. Dietary CP and Lys inclusion levels were analyzed.
Diets were formulated to 95% of the average SID Lys requirement for barrows and gilts (PIC Nutrient Specifications Manual, 2011), and exceeded the SID AA/Lys ratio recommendations for other IDAA by 2 percentage points.
Distillers dried grains with solubles (DDGS) were included in all diets at the 20% level, with the exception of phase-5 finishing diets which was devoid of DDGS. Experiment 2
In experiment 1, diets were formulated on an ME basis and as soybean meal was reduced in diets, the calculated Lys/NE decreased which may explain some of the increase in fat deposition in pigs fed ME based diets formulated by decreasing soybean meal and including high levels of FGAA. Therefore, experiment 2 was conducted to establish the efficacy of using a “Set Point SID requirement” of sequentially reducing CP by adding FGAA to meet the SID IDAA/Lys ratio as a means of establishing the practical limits of CP reduction and AA replacement without impacting growth performance, carcass composition or quality in growing and finishing pigs fed NE based RCP diets. Diets were formulated starting with a Ctrl diet that approximates acceptable inclusion levels of FGAA currently used in industry, followed by sequentially formulating three additional dietary treatments, each based on the next limiting AA. Diets in this study were formulated on a constant NE basis within phase. DDGS was included in all diets. The SID His requirement in the highest RCP diet was met in each phase without added feed grade His.
There were a total of 9 replicates/treatment with pigs housed 6 pigs/pen. Sex within pen was balanced. Diets were formulated as in experiment 1 which were:
Treatment 1, Ctrl: Conventional phase 1 through 5 diets that approximates acceptable levels of FGAA currently used in industry. The assumption is that most in the industry are comfortable utilizing feed grade Thr and Met to meet the suggested SID Thr/Lys and Met/Lys ratio in diets formulated to meet the SID Trp/Lys requirement without added feed grade Trp. This is referred to as the Trp Set Point.
Treatment 2, RCP 1: Diets were formulated to meet the next limiting AA. In phase 1 and 5, the next limiting AA was Val while Ile was next limiting in phases 2, 3 and 4. This is referred to as the “Val or Ile Set Point”. Note that neither feed grade Val nor Ile were added in any phase.
Treatment 3, RCP 2: Diets were formulated to meet the next limiting AA. In phase 1 and 5, the next limiting AA was Ile while Val was next limiting in phases 2, 3 and 4. This is referred to as the “Val and Ile Set Point”. Note that feed grade Val but not Ile was added in phases 1 and 5, and Ile but not Val was added in phase 2, 3, and 4.
Treatment 4, RCP 3: Diets were formulated to meet the next (7th) limiting AA, His. This is referred to as the “His Set Point”.
All diets were supplemented with FGAA to meet IDAA recommended levels. Note that feed grade His was not added to any diet.
Grow-Finish Studies – What Did We Learn?
Experiment 1
Body weights of pigs decreased linearly with decreasing dietary CP during phase 1, 2, and 3 (P < 0.01; Table 7). Additionally, BW increased and then decreased quadratically during phase 3 (P = 0.09), 4 (P < 0.04), and 5 (P < 0.01) with BW decreasing significantly in pigs fed RCP 4. When Paylean was included in the Phase 5 diets, barrows fed the Ctrl diet had greater ADG than Ctrl-fed gilts, but RCP 1-, RCP 2-, and RCP 3-fed gilts had greater ADG than their castrated male counterparts (Quadratic gender × reduced CP diet, P = 0.08; Figure 1A) Both ADG and G:F decreased linearly (P ≤ 0.06) during phase 1 and 2. Furthermore, gain efficiency increased 4.6 % in gilts between Ctrl and RCP 2 before decreasing to similar G:F values between Ctrl and RCP 4; however, G:F remained relatively unchanged in barrows across the 5 dietary treatments (Quadratic gender × reduced CP diet, P = 0.04; Figure 1B).
Across the entire feeding trial, ADG increased only 2 % between Ctrl and RCP3, but dropped 6 % between RCP3 and RCP4 (Quadratic, P < 0.01). On the other hand, ADFI tended to decreased linearly (P = 0.09) as CP was reduced in swine diets. Gain efficiency increased 4.6 % in gilts between Ctrl and RCP2 before decreasing to similar values between Ctrl and RCP4; however, G:F remained relatively unchanged in barrows across the 5 dietary treatments (Quadratic gender × reduced CP diet, P = 0.04; Figure 1C).
Reducing dietary CP and optimizing the use of FGAA had limited (P ≥ 0.21) effects on HCW, dressing percentage, or LM depth; however, 10th rib fat depth increased linearly (P < 0.01), and fat free lean percentage at study termination decreased linearly as CP was reduced in swine diets (P < 0.02; Figure 1D). Experiment 2
Effects of dietary treatment (Trt.) indicated that ADG decreased linearly with increasing dietary FGAA in phase 3 (Table 8, P < 0.05), 4 (P < 0.10), 5 (P < 0.01) and overall (P < 0.01). Similarly, ADFI decreased linearly in phase 4 (P < 0.05), 5 (P < 0.01) and overall (P < 0.01) with increasing FGAA. Compared to pigs fed the control diet (Trt. 1), G:F in phase 1 increased in pigs fed increasing levels of FGAA at the lower inclusion rates (Trt. 2 and 3) before decreasing to the control level at the highest level of inclusion (Trt. 4, Quadratic effect, P < 0.05). During phase 3, a small, but significant, decrease in G:F was observed with increasing levels of FGAA (Linear effect, P < 0.05). For the overall study, however, a trend for increased G:F was observed (Linear effect, P < 0.06). BW increased at the end of phase 2 with increasing level of FGAA (Quadratic effect, P < 0.06). However, consistent with ADG, BW decreased with increasing dietary FGAA at the end of phase 3, 4 and 5 (Linear effect, P < 0.05, P < 0.01 and P < 0.01, respectively).
As might be expected based on BW, HCW decreased with increasing inclusion of dietary FGAA (Linear effect, P < 0.01). Tenth rib backfat was lower in pigs fed diets formulated to the Val or Ile Set Point (Trt. 2) or the His Set Point (Trt. 4) when compared to those fed diets formulated to the Val and Ile Set Point (Trt. 3).
Publications – G/F (Trial 1)
2013 Midwest American Society of Animal Science (ASAS) meeting Abstract 0224, page 73 (performance and carcass composition)
2013 Midwest American Society of Animal Science (ASAS) meeting Abstract P027, page 97 (LM – longissimus muscle quality)
Significance. This information is timely since the cost of soybean meal is approaching record levels which make substitution of synthetic amino acids for intact protein more economically feasible.
Nitrogen (N) Balance Study
What Did We Do? (Methods)
Thirty-two barrows were used to evaluate the effect of feeding reduced CP, AA supplemented diets, on nutrient and VFA excretion. Pigs were randomly allotted to the following diets:
Control: Corn-SBM-DDGS diets with no FGAA,
1X reduction in CP,
2X reduction in CP, and
3X reduction in CP. This diet was balanced on the 7th limiting AA in each phase.
Diets 2 and 3 were formulated to have stepwise and equally spaced reductions in CP between diets 1 and 4. Diets 2-4 were supplemented with FGAA as needed to meet AA needs based on NRC 2012 AA minimum ratios. Four nursery phases and 5 grow-finish phases (21d phases) were fed. Pigs were housed in stainless-steel metabolism pens equipped with a nipple waterer and stainless steel feeder. Collections started with nursery phase 3 and during nursery phases pigs were allowed an eight day adjustment period to the diets followed by a 3 d total collection of feces, urine, and orts. During the grow-finish phases, pigs were acclimated to diets for the first 10 d of each phase, and then feces, urine, and orts were collected for 3 days.
Nitrogen Balance – What Did We Learn? (Results)
Overall, from d 14-147 post-weaning ADFI was linearly increased as dietary CP was reduced, but no effect of dietary CP concentration on ADG or G:F (Table 9) was observed. Fecal excretion (DM) tended to respond in a quadratic (P = 0.08) fashion with decreasing fecal excretion (DM) up to 2X reduction in CP, but then increasing in 3X fed pigs. Both DE and ME (kcal/kg) were linearly (P < 0.01) reduced as dietary CP was reduced. The linear (P < 0.01) decrease in N intake for pigs fed reduced CP diets was accompanied by linear (P < 0.01) decreases in both urinary and total N excreted. Nitrogen digestibility (%) linearly decreased (P < 0.01) and N retention linearly (%) increased (P < 0.01) with reductions in dietary CP. Overall, there was a linear (P < 0.03) reduction in fecal ammonium as dietary CP was reduced. Total carbon (C) intake and total fecal C excreted tended (P = 0.06) to respond quadratically with an increase in both C intake and C excretion up to the 1X reduced CP diets, followed by a decrease in C intake and increasing C excretion to the 3X diet creating a linear (P < 0.05) decrease in C digestibility as dietary CP was reduced.
Significance. The ability to add total fecal and urine collections of the nitrogen manipulation diets across all body weights tested at the University of Arkansas before the diets were tested for greenhouse gas emissions at Purdue University improved the estimation of compounds excreted in fresh manure and then the conversion of these excreted nutrients and compounds during storage in typical deep pit manure structures under the swine facilities (as were measured during the Purdue 12 room study). This research project provided data for a critical link between excretion, storage, and land application.
Validating the Nursery, Grow-Finish, and GHG Measurement Studies
Large-scale trials are in progress to validate the nursery and grow-finish trials done at Arkansas. The Purdue facility is scaled more similarly to a commercial production system. Gas measurement and monitoring, and separate manure handling systems for each room allowed direct measurements with which to compare previous estimations.
Treatment structure for the experiment was:
Conventional diet containing ~ 0.15% Lys-HCl
1X reduction in CP with additional synthetic amino acids
2X reduction in CP with additional synthetic amino acids
All diets were supplemented with Ractopamine during the final 3-4 weeks of the trial, and amino acid concentrations were increased based on estimated increases in lean tissue accretion. However, the overall treatment structure will remain the same. The Experiment involved 24 pens of 10 pigs each per treatment, with 8 manure pits/trt, and 4 rooms per trt. Pen was the experimental unit for all growth performance, feed intake, and carcass data. Pit was the experimental unit for manure excretion data and room is the experimental unit for emission data.
Real-time monitoring of air temperatures included relative humidity, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ammonia (NH3), and hydrogen sulfide (H2S). Total suspended particulates were monitored using gravimetric samplers. The emission and animal performance data were significantly more accurate in this replicated, environmentally-controlled building than is possible commercially, yet still simulate commercial conditions.
Manure from each pit was completely removed to outside storage for volume determination, thorough agitation and sampling at the end of each trial. In addition, core manure samples based on a grid system were obtained at the end of each growth phase. Manure volume in each pit was determined at diet phase changes by taking 6 gridded depth measurements between the slatted floor. Manure samples were analyzed for pH, dry matter, ash, total nitrogen (N), ammonium N, phosphorus (P), carbon (C), and sulfur (S). Data defining the relationship between the reduction in dietary CP with a reduction in manure N and other changes in manure characteristics are essential to model development of the impact of this mitigation strategy on GHG emissions. An additional benefit will be defining the limits of this strategy without impacting animal growth performance under conditions where industry stakeholders have input.
Validation study – What did we learn (results)?
Coming Soon! (first half 2016)
Modeling the Data
[See also: Virginia Tech modeling efforts] Current nutritional requirement models for swine are focused on partitioning of dietary energy and amino acids to maintenance, growth, gestation, and lactation. Little focus is placed on predicting nutrient excretion, and thus these models cannot be used to provide inputs to an emissions model. Models that predict excretion of energy, protein, and phosphorus have been developed, but have not been evaluated for the accuracy of predictions; and evaluations that have been undertaken focus on predictions of growth and body composition, not nutrient excretion.
GHG emissions from manure storage facilities can be predicted from manure composition, underscoring the need for a robust animal model capable of predicting both animal performance and nutrient excretion. Prediction of GHG emissions from swine manure requires knowledge of N and volatile solids content, neither of which are provided by current NRC predictions.
Data from the nitrogen mitigation growth and nitrogen excretion studies were utilized in enhancement of an animal model capable of predicting swine performance and excretion of nitrogen, carbon, and volatile solids (inputs required by the DNDC model). The growth model developed by the workers at UC-Davis and the recently released Nutrient Requirements of Swine (NRC) eleventh revised edition will be used as a starting point for model development. Equations describing the response to dietary protein and amino acid additions will be evaluated for accuracy, and the effects of Paylean on animal performance and manure nutrient output will be encoded and tested for accuracy. This work is scheduled to precede and utilize data from the UA trial and literature sources. The model will be further evaluated in the 5th year using the Purdue data set.
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Waste to Worth home | More proceedings….
The research and modeling work encompassed by this project offers great potential for assisting researchers, policy makers, and especially farm managers to make informed management and facilities decisions regarding GHG emissions while maintaining production and profitability. However for this potential to be realized the swine production community needs to be aware of both its abilities and availability. To this end existing relationships with the
A summer research program for undergraduate students has been developed with the focus of carbon footprint mitigation from agriculture. The goal of this USDA REU is to support 10 students each summer for a 10 week period throughout the duration of this project. The REU supported by this project is offered parallel to the National Science Foundation Research Experience for Undergraduates (NSF REU), and students are recruited from the same pool as the NSF REU programs. The REU students are selected through an application process informed by an established recruitment network. We are actively recruiting from under-represented minorities, including: Native Americans, African Americans and Hispanics.
Algal biomass offers many advantages over traditional energy crops; algal biomass generates higher yields and requires smaller land area than other energy crops. In addition to biomass production for potential biofuel feedstock generation, algal growth systems can also act as tertiary treatment systems for wastewater. Algal growth can dramatically reduce nitrogen and phosphorus from wastewater. Unlike conventional open pond and photo-bioreactor systems, periphytic systems (e.g., algal turf scrubbers) generally involve the polyculture of micro-algae, which does not require specialized conditions. While algal turf scrubber systems are traditionally used for water treatment, they are also capable of generating high biomass yields.
Many technologies being considered incorporate some type of manure separation to concentrate manure solids, nutrients, and energy content. An LCA study in Denmark showed that energy recovery (incineration, gasification, and anaerobic digestion) had lower GHG emissions than traditional land application of swine manure. Other studies point to the complexities of manure management system design options in relation to GHG emissions. This portion of the project will quantify the effect of various solid separation approaches on the chemical composition of the manure generated by the feed trials at the University of Arkansas facilities during this project ,and generate the necessary manure solids for the thermo-chemical conversion portion of this project. Design and construct a pilot scale mobile solids separation system (see image below) is currently approaching completion and anticipated to be ready to begin trial calibrations soon.
Maximizing feed grade amino acid (FGAA) use and reducing dietary crude protein in swine diets has been shown to dramatically reduce nitrogen excretion in both nursery and growing/finishing swine which could substantially reduce nitrous oxide (N