USDA-NRCS and the National Air Quality Site Assessment Tool (NAQSAT) for Livestock and Poultry Operations

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The National Air Quality Site Assessment Tool (NAQSAT) was developed as a first-of-its-kind tool to help producers and their advisors assess the impact of management on air emissions from livestock and poultry operations and identify areas for potential improvement related to those air emissions.

What did we do?

In 2007, several land-grant universities, with leadership from Michigan State University, began developing NAQSAT under a USDA-NRCS Conservation Innovation Grant (CIG). The initial tool included beef, dairy, swine, and poultry operations. A subsequent CIG project, with leadership from Colorado State University, made several enhancements to the tool, including adding horses to the species list. In 2015, USDA-NRCS officially adopted NAQSAT as an approved tool for evaluating air quality resource concerns at livestock and poultry operations. USDA-NRCS also contracted with Florida A&M University in 2015 to provide several regional training workshops on NAQSAT to NRCS employees. Six training workshops have been completed to date (Raleigh, NC; Modesto, CA; Elizabethtown, PA; Lincoln, NE; Richmond, VA; and Yakima, WA) with assistance from multiple NAQSAT development partners. Additionally, USDA-NRCS revised its comprehensive nutrient management plan (CNMP) policy in October 2015 to make the evaluation of air quality resource concerns mandatory as part of CNMP development.

Snippet from website of the National Air Quality Site Assessment Tool

Group photo of team in field

Zwicke in class lecturing

Zwicke and group in animal housing facility

What have we learned?

NAQSAT has proven to be a useful tool for bench-marking the air emissions impacts of current management on confinement-based livestock and poultry operations. In the training sessions, students have been able to complete NAQSAT runs on-site with the producer or producer representative via tablet or smartphone technologies. Further classroom discussion has helped to better understand the questions and answers and how the NAQSAT results can feed into the USDA-NRCS conservation planning process. Several needed enhancements and upgrades to the tool have been identified in order to more closely align the output of the tool to USDA-NRCS conservation planning needs. NAQSAT has also proven to be useful for evaluating the air quality resource concern status of an operation in relation to the CNMP development process.

Future Plans

It is anticipated that the identified needed enhancements and upgrades will be completed as funding for further NAQSAT development becomes available. Additionally, as use of NAQSAT by USDA-NRCS and our conservation planning and CNMP development partners expands, additional training and experience-building opportunities will be needed. The NAQSAT development team has great geographic coverage to assist in these additional opportunities.

Corresponding author, title, and affiliation

Greg Zwicke, Air Quality Engineer – Air Quality and Atmospheric Change Team, USDA-NRCS

Corresponding author email

Other authors

Greg Johnson, Air Quality and Atmospheric Change Team Leader, USDA-NRCS; Jeff Porter, Animal Nutrient and Manure Management Team Leader, USDA-NRCS; Sandy Means, Agricultural Engineer – Animal Nutrient and Manure Management Team, USDA-NRCS

Additional information


C.E. Meadows Endowment, Michigan State University

Colorado Livestock Association

Colorado State University

Florida A&M University

Iowa Turkey Federation

Iowa Pork Producers

Iowa Pork Industry Center

Iowa State University

Iowa State University Experiment Station

Kansas State University

Michigan Milk Producers Association

Michigan Pork Producers Association

Michigan State University

Michigan State University Extension

National Pork Board

Nebraska Environmental Trust

Oregon State University

Penn State University

Purdue University

Texas A&M University

University of California, Davis

University of Georgia

University of Georgia Department of Poultry Science

University of Idaho

University of Maryland

University of Maryland Department of Animal and Avian Sciences

University of Minnesota

University of Missouri

University of Nebraska


Virginia Tech University

Washington State University

Western United Dairymen

Whatcom County (WA) Conservation District

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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

Talking Climate with Animal Agriculture Advisers

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The Animal Agriculture in a Changing Climate (AACC) project was established to leverage limited Extension expertise across the country in climate change mitigation and adaptation, with the goal of building capacity among Extension professionals and other livestock advisers to address climate change issues.

What did we do? 

The Animal Agriculture in a Changing Climate project team created a suite of educational programs and products to build capacity across the United States. Key products of the project:

  • Online courses: 363 participants registered with a 35% completion rate (Whitefield et al., JOE, 2016)
  • National and regional symposia and workshops: 11 face-to-face conferences with approximately 1,350 attendees.
  • Website: Over 5,900 users with over 21,100 total views. Project videos have received nearly 8,900 views.
  • Social media: AACC weekly blog (990 subscribers); daily Southeast Climate Blog (38,506 site visits); regional newsletters (627 subscribers); Facebook & Twitter (280 followers)
  • Ready-to-use videos, slide sets, and fact sheets
  • Educational programming: 390 presentations at local, regional, and international meetings
  • Collaboration with 14 related research and education projects

What have we learned? 

A survey was sent out to participants in any of the project efforts, in the third year of the project and again in year five. Overall, participants found the project resources valuable, particularly the project website, the online course, and regional meetings. We surveyed two key measures: abilities and motivations. Overall, 60% or more of respondents report being able or very able to address all eight capabilities after their participation in the AACC program. A sizeable increase in respondent motivation (motivated or very motivated) existed after participation in the program, particularly for helping producers take steps to address climate change, informing others about greenhouse gases emitted by agriculture, answering client questions, and adding new information to programs or curriculum.

The first challenge in building capacity in Extension professionals was finding key communication methods to engage them. Two key strategies identified were to: 1) start programming with a discussion of historical trends and agricultural impacts, as locally relevant as available, and 2) start the discussion around adaptation rather than mitigation. Seeing the changes that are already apparent in the climatic record and how agriculture has adapted in the past and is adapting to more recent weather variability and climatic changes often were excellent discussion starters.

Another challenge was that many were comfortable with the science, but were unsure how to effectively communicate that science with the sometimes controversial discussions that surround climate change. This prompted us to include climate science communication in most of the professional development opportunities, which were then consistently rated as one of the most valuable topics.

Future Plans    

The project funding ended on March 31, 2017. All project materials will continue to be available on the LPELC webpage.

Corresponding author, title, and affiliation        

Crystal Powers, Extension Engineer, University of Nebraska – Lincoln

Corresponding author email

Other authors   

Rick Stowell, University of Nebraska – Lincoln

Additional information


Thank you to the project team:

Rick Stowell, Crystal Powers, and Jill Heemstra, University of Nebraska – Lincoln

Mark Risse, Pam Knox, and Gary Hawkins, University of Georgia

Larry Jacobson and David Schmidt, University of Minnesota

Saqib Mukhtar, University of Florida

David Smith, Texas A&M University

Joe Harrison and Liz Whitefield, Washington State University

Curt Gooch and Jennifer Pronto, Cornell University

This project was supported by Agricultural and Food Research Initiative Competitive Grant No. 2011-67003-30206 from the USDA National Institute of Food and Agriculture.


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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

Aeration to Improve Biogas Production by Recalcitrant Feedstock

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Why aerate biogas digesters?

Most agricultural waste is largely composed of polymers such as lignin and complex carbohydrates that are slowly or nearly completely non-degradable in anaerobic environments. An example of such a waste is chicken litter in which wood chips, rice hulls, straw and sawdust are commonly employed bedding materials.  This makes chicken litter a poor candidate for anaerobic digestion because of inherently poor digestibility and, as a consequence, low gas production rates.

Previous studies, however, have shown that the addition of small amounts of air to anaerobic digestates can improve degradation rates and gas production. These studies were largely performed at laboratory-scale with no provision to keep the added air within the anaerobic sludge.

What Did We Do?

Picture of 4 digesters with sprayer tanksFour digesters were constructed out of 55 gallon sprayer tanks. The digestate was 132 L in volume with a dynamic headspace of 76 L. At the bottom of each tank a manifold was constructed from ½” PVC pipe in an “H” configuration and with a volume of approximately 230 mL. The bottom of the manifold had holes drilled in it to allow exchange with the sludge. Tanks were fed 400 g of used top dressing chicken litter (wood shaving bedding) obtained from a local producer (averaging 40% moisture and 15% ash) in 2 L of water through a port in the tank [labeled “1” in figure]. Two hundred mL of air were fed to the manifold through a flow meter [2] 0, 1, 4, or 10 times daily in 15-minute periods at widely spaced intervals by means of an air pump and rotary timer [4]. A gas port [3] at the top of the tank allowed for sampling and led to a wet tip flow meter ( to measure gas production. Digestate samples were taken out of a side port [5] for measurement of water quality and dissolved gases and overflow was discharged from the tank by means of a float switch wired in line with a ½” PVC electrically actuated ball valve.

Seven dried and weighed tulip poplar disks were added to each tank at the beginning of the experiment. At the end of the experiment, the disks were cleaned and dried for three days at 105 0C before re-weighing. Dissolved and headspace gases were measured on a gas chromatograph equipped with FID, ECD, and TCD detectors. Water quality was measured by standard APHA methods.

What Have We Learned?

Graph of chemical oxygen demand per liter and graph of liters of biogas per day

Adding 800 mL of air daily increased biogas production by an average of 73.4% compared to strictly anaerobic digestate. While adding 200 mL of air daily slightly increased gas production, adding 2 L per day decreased gas production by 16.7%.

Aerating the sludge improved chemical oxygen demand (COD) with the greatest benefit occurring at 2,000 mL added air per day. As noted, however, this decreased gas production in the control indicating toxicity to the anaerobic sludge.

The experiment was stopped after 148 days. When the tanks were opened, there was widespread fungal growth both on the surface of the digestate and the wood disks in the aerated tanks [left], whereas non-aerated tanks showed little evidence of fungal growth [right]. While wood disks subjected to all treatments lost significant mass (t-test, α=0.05), disks in the anaerobic tank lost the least amount of weight on average (6.3 g) while all other treatments lost over 7 g weight on average.

Picture of widespread fungal growth on the surface of the digestate and the wood discs in aerated tanks

Future Plans

Research on other feedstocks and aeration regimes are being conducted as are 16s and 18s community analyses.

Chart of grams dry weight pre experiment and post experiment

Corresponding author (name, title, affiliation)

John Loughrin, Research Chemist, Food Animal Environmental Research Systems, USDA-ARS, 2413 Nashville Rd. B5, Bowling Green, KY 42104

Corresponding author email address

Other Authors

Karamat Sistani, Supervisory Soil Scientist, Food Animal Environmental Research Systems. Nanh Lovanh, Environmental Engineer, Food Animal Environmental Research Systems.

Additional Information…


We thank Stacy Antle and Mike Bryant (FAESRU) and Zachary Berry (WKU Dept. of Chemistry) for technical assistance.

Poultry Mortality Freezer Units: Better BMP, Better Biosecurity, Better Bottom Line.

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Why Tackle Mortality Management?  It’s Ripe for Revolution.

The poultry industry has enjoyed a long run of technological and scientific advancements that have led to improvements in quality and efficiency.  To ensure its hard-won prosperity continues into the future, the industry has rightly shifted its focus to sustainability.  For example, much money and effort has been expended on developing better management methods and alternative uses/destinations for poultry litter.

In contrast, little effort or money has been expended to improve routine mortality management – arguably one of the most critical aspects of every poultry operation.  In many poultry producing areas of the country, mortality management methods have not changed in decades – not since the industry was forced to shift from the longstanding practice of pit burial.  Often that shift was to composting (with mixed results at best).  For several reasons – improved biosecurity being the most important/immediate – it’s time that the industry shift again.

The shift, however, doesn’t require reinventing the wheel, i.e., mortality management can be revolutionized without developing anything revolutionary.  In fact, the mortality management practice of the future owes its existence in part to a technology that was patented exactly 20 years ago by Tyson Foods – large freezer containers designed for storing routine/daily mortality on each individual farm until the containers are later emptied and the material is hauled off the farm for disposal.

Despite having been around for two decades, the practice of using on-farm freezer units has received almost no attention.  Little has been done to promote the practice or to study or improve on the original concept, which is a shame given the increasing focus on two of its biggest advantages – biosecurity and nutrient management.

Dusting off this old BMP for a closer look has been the focus of our work – and with promising results.  The benefits of hitting the reset button on this practice couldn’t be more clear:

  1. Greatly improved biosecurity for the individual grower when compared to traditional composting;
  2. Improved biosecurity for the entire industry as more individual farms switch from composting to freezing, reducing the likelihood of wider outbreaks;
  3. Reduced operational costs for the individual poultry farm as compared to more labor-intensive practices, such as composting;
  4. Greatly reduced environmental impact as compared to other BMPs that require land application as a second step, including composting, bio-digestion and incineration; and
  5. Improved quality of life for the grower, the grower’s family and the grower’s neighbors when compared to other BMPs, such as composting and incineration.

What Did We Do?

We basically took a fresh look at all aspects of this “old” BMP, and shared our findings with various audiences.

That work included:

  1. Direct testing with our own equipment on our own poultry farm regarding
    1. Farm visitation by animals and other disease vectors,
    2. Freezer unit capacity,
    3. Power consumption, and
    4. Operational/maintenance aspects;
  2. Field trials on two pilot project farms over two years regarding
    1. Freezer unit capacity
    2. Quality of life issues for growers and neighbors,
    3. Farm visitation by animals and other disease vectors,
    4. Operational and collection/hauling aspects;
  3. Performing literature reviews and interviews regarding
    1. Farm visitation by animals and other disease vectors
    2. Pathogen/disease transmission,
    3. Biosecurity measures
    4. Nutrient management comparisons
    5. Quality of life issues for growers and neighbors
  4. Ensuring the results of the above topics/tests were communicated to
    1. Growers
    2. Integrators
    3. Legislators
    4. Environmental groups
    5. Funding agencies (state and federal)
    6. Veterinary agencies (state and federal)

What Have We Learned?

The breadth of the work at times limited the depth of any one topic’s exploration, but here is an overview of our findings:

  1. Direct testing with our own equipment on our own poultry farm regarding
    1. Farm visitation by animals and other disease vectors
      1. Farm visitation by scavenger animals, including buzzards/vultures, raccoons, foxes and feral cats, that previously dined in the composting shed daily slowly decreased and then stopped entirely about three weeks after the farm converted to freezer units.
      2. The fly population was dramatically reduced after the farm converted from composting to freezer units.  [Reduction was estimated at 80%-90%.]
    2. Freezer unit capacity
      1. The test units were carefully filled on a daily basis to replicate the size and amount of deadstock generated over the course of a full farm’s grow-out cycle.
      2. The capacity tests were repeated over several flocks to ensure we had accurate numbers for creating a capacity calculator/matrix, which has since been adopted by the USDA’s Natural Resources Conservation Service to determine the correct number of units per farm based on flock size and finish bird weight (or number of grow-out days) in connection with the agency’s cost-share program.
    3. Power consumption
      1. Power consumption was recorded daily over several flocks and under several conditions, e.g., during all four seasons and under cover versus outside and unprotected from the elements.
      2. Energy costs were higher for uncovered units and obviously varied depending on the season, but the average cost to power one unit is only 90 cents a day.  The total cost of power for the average farm (all four units) is only $92 per flock.  (See additional information for supporting documentation and charts.)
    4. Operational/maintenance aspects;
      1. It was determined that the benefits of installing the units under cover (e.g., inside a small shed or retrofitted bin composter) with a winch system to assist with emptying the units greatly outweighed the additional infrastructure costs.
      2. This greatly reduced wear and tear on the freezer component of the system during emptying, eliminated clogging of the removable filter component, as well as provided enhanced access to the unit for periodic cleaning/maintenance by a refrigeration professional.
  2. Field trials on two pilot project farms over two years regarding
    1. Freezer unit capacity
      1. After tracking two years of full farm collection/hauling data, we were able to increase the per unit capacity number in the calculator/matrix from 1,500 lbs. to 1,800 lbs., thereby reducing the number of units required per farm to satisfy that farm’s capacity needs.
    2. Quality of life issues for growers and neighbors
      1. Both farms reported improved quality of life, largely thanks to the elimination or reduction of animals, insects and smells associated with composting.
    3. Farm visitation by animals and other disease vectors
      1. Both farms reported elimination or reduction of the scavenging animals and disease-carrying insects commonly associated with composting.
    4. Operational and collection/hauling aspects
      1. With the benefit of two years of actual use in the field, we entirely re-designed the sheds used for housing the freezer units.
      2. The biggest improvements were created by turning the units so they faced each other rather than all lined up side-by-side facing outward.  (See additional information for supporting documentation and diagrams.)  This change then meant that the grower went inside the shed (and out of the elements) to load the units.  This change also provided direct access to the fork pockets, allowing for quicker emptying and replacement with a forklift.
  3. Performing literature reviews and interviews regarding
    1. Farm visitation by animals and other disease vectors
      1. More research confirming the connection between farm visitation by scavenger animals and the use of composting was recently published by the USDA National Wildlife Research Center:
        1. “Certain wildlife species may become habituated to anthropogenically modified habitats, especially those associated with abundant food resources.  Such behavior, at least in the context of multiple farms, could facilitate the movement of IAV from farm to farm if a mammal were to become infected at one farm and then travel to a second location.  …  As such, the potential intrusion of select peridomestic mammals into poultry facilities should be accounted for in biosecurity plans.”
        2. Root, J. J. et al. When fur and feather occur together: interclass transmission of avian influenza A virus from mammals to birds through common resources. Sci. Rep. 5, 14354; doi:10.1038/ srep14354 (2015) at page 6 (internal citations omitted; emphasis added).
    2. Pathogen/disease transmission,
      1. Animals and insects have long been known to be carriers of dozens of pathogens harmful to poultry – and to people.  Recently, however, the USDA National Wildlife Research Center demonstrated conclusively that mammals are not only carriers – they also can transmit avian influenza virus to birds.
        1. The study’s conclusion is particularly troubling given the number and variety of mammals and other animals that routinely visit composting sheds as demonstrated by our research using a game camera.  These same animals also routinely visit nearby waterways and other poultry farms increasing the likelihood of cross-contamination, as explained in this the video titled Farm Freezer Biosecurity Benefits.
        2. “When wildlife and poultry interact and both can carry and spread a potentially damaging agricultural pathogen, it’s cause for concern,” said research wildlife biologist Dr. Jeff Root, one of several researchers from the National Wildlife Research Center, part of the USDA-APHIS Wildlife Services program, studying the role wild mammals may play in the spread of avian influenza viruses.
    3. Biosecurity measures
      1. Every day the grower collects routine mortality and stores it inside large freezer units. After the broiler flock is caught and processed, but before the next flock is started – i.e. when no live birds are present,  a customized truck and forklift empty the freezer units and hauls away the deadstock.  During this 10- to 20- day window between flocks biosecurity is relaxed and dozens of visitors (feed trucks, litter brokers, mortality collection) are on site in preparation for the next flock.
        1. “Access will change after a production cycle,” according to a biosecurity best practices document (enclosed) from Iowa State University. “Empty buildings are temporarily considered outside of the [protected area and even] the Line of Separation is temporarily removed because there are no birds in the barn.”
    4. Nutrient management comparisons
      1. Research provided by retired extension agent Bud Malone (enclosed) provided us with the opportunity to calculate nitrogen and phosphorous numbers for on-farm mortality, and therefore, the amount of those nutrients that can be diverted from land application through the use of freezer units instead of composting.
      2. The research (contained in an enclosed presentation) also provided a comparison of the cost-effectiveness of various nutrient management BMPs – and a finding that freezing and recycling is about 90% more efficient than the average of all other ag BMPs in reducing phosphorous.
    5. Quality of life issues for growers and neighbors
      1. Local and county governments in several states have been compiling a lot of research on the various approaches for ensuring farmers and their residential neighbors can coexist peacefully.
      2. Many of the complaints have focused on the unwanted scavenger animals, including buzzards/vultures, raccoons, foxes and feral cats, as well as the smells associated with composting.
      3. The concept of utilizing sealed freezer collection units to eliminate the smells and animals associated with composting is being considered by some government agencies as an alternative to instituting deeper and deeper setbacks from property lines, which make farming operations more difficult and costly.

Future Plans

We see more work on three fronts:

  • First, we’ll continue to do monitoring and testing locally so that we may add another year or two of data to the time frames utilized initially.
  • Second, we are actively working to develop new more profitable uses for the deadstock (alternatives to rendering) that could one day further reduce the cost of mortality management for the grower.
  • Lastly, as two of the biggest advantages of this practice – biosecurity and nutrient management – garner more attention nationwide, our hope would be to see more thorough university-level research into each of the otherwise disparate topics that we were forced to cobble together to develop a broad, initial understanding of this BMP.

Corresponding author (name, title, affiliation)

Victor Clark, Co-Founder & Vice President, Legal and Government Affairs, Farm Freezers LLC and Greener Solutions LLC

Corresponding author email address

Other Authors

Terry Baker, Co-Founder & President, Farm Freezers LLC and Greener Solutions LLC

Additional Information

Farm Freezer Biosecurity Benefits

One Night in a Composting Shed

Transmission Pathways

Avian flu conditions still evolving (editorial)

USDA NRCS Conservation fact sheet Poultry Freezers When fur and feather occur together: interclass transmission of avian influenza A virus from mammals to birds through common resources

How Does It Work? (on-farm freezing)

Influenza infections in wild raccoons (CDC)

Collection Shed Unit specifications

Collection Unit specifications

Freezing vs Composting for Biosecurity (Render magazine)

Manure and spent litter management: HPAI biosecurity (Iowa State University)


Bud Malone, retired University of Delaware Extension poultry specialist and owner of Malone Poultry Consulting

Bill Brown, University of Delaware Extension poultry specialist, poultry grower and Delmarva Poultry Industry board member

Delaware Department of Agriculture

Delaware Nutrient Management Commission

Delaware Office of the Natural Resources Conservation Service

Maryland Office of the Natural Resources Conservation Service

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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

Using Wet Scrubber to Reduce Ammonia Emission from Broiler Houses

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Research on mitigating the effects of animal feeding operations (AFOs) on air quality in the US has made great strides in recent years. Development of cost-effective air emission mitigation and assessing the effectiveness of these technologies is urgently needed to improve our environmental performance and to help producers address increasing regulatory pressures. Scrubbers have been shown to be a powerful tool in reducing ammonia (NH3), dust and odor emissions. An affordable two-stage acid scrubber was developed by USDA ARS for treating exhaust air and can easily be installed onto the exhaust fans of existing poultry facilities. A field project was conducted to evaluate the efficiency of the acid scrubber under field conditions on three broiler farms, two located in Delaware (DE) and one located in Pennsylvania (PA).

What did we do? 

The two-stage scrubbers were installed on the minimum fans of three farms that were using different practices and settings. One farm used 36” minimum fans and reused existing litter throughout the project while an organic farm used a 36” minimum fan, but used new bedding materials for every flock. The third scrubber was installed on a research farm with a 24” minimum fan and used litter. Sodium bisulfate was used as the acid agent. Ammonia concentration and airflow rate through each fan were continuously measured. Scrubber liquid samples were analyzed to calculate the efficiency of each scrubber. Acid, water and electricity consumption of each scrubber were recorded over multiple flocks and seasons.

What have we learned?              

The mean NH3 capturing efficiencies of the three scrubbers for the three sites were 31.3, 34.3 and 11.0 %, respectively. The low efficiency (11%) of one scrubber was due to high NH3 emission rate and inadequate acid solution in the scrubber (the solution at this site was checked and replaced weekly whereas the solution at the other two sites were checked daily). For every kg NH3 captured, the average water, sodium bisulfate and electricity consumption at the three sites were 0.23 m3, 15.10 kg and 43.74 kWh, respectively.

Future Plans 

Based on the field experiences of running the three scrubbers, several recommendations are suggested: 1) increase fan run time to compensate for air flow loss due to high pressure drop, 2) add insulation on drain valves, 3) heat fresh water line and add a heater in pump boxes, 4) clean dust scrubber at least twice per flock for houses with used litter, 5) replace acid solution more frequently toward end of the flock for best performance, 6) add a storage tank for spent liquid if the growers do not have crops or pasture to apply to, and 7) add an automatic acid dosing system to reduce labor requirement and improve scrubber performance.

Corresponding author, title, and affiliation        

Hong Li, Assistant Professor, University of Delaware

Corresponding author email

Other authors   

Chen Zhang, Philip Moore, Michael Buser, Cathleen J. Hapeman, Paul Patterson, Gregory Martin, Jerry Martin

Additional information              

Zhang, Chen, Hong Li , Philip A Moore , Michael Buser, Cathleen J. Hapeman, Paul Patterson, Gregory Martin. 2016. ASABE Annual International Conference. Paper number 2461008; Orkando,Florida, July 17 – July 20.


This study was partially supported by funds from USDA-NRCS Conservation Innovation Grant Program (Award No. NRCS 69-3A75-12-244), University of Delaware, Penn State University, Oklahoma State University, University of Maryland, and USDA-ARS. The cooperation and assistance of the collaborating producer is also acknowledged.


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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

Ethnobotanical Control of Odor in Urban Poultry Production: A Review


Urban agriculture has been growing as the movement of population to the urban centers is increasing. According to FAO (2008), by 2030 majority of the population in sub sahara Africa (SSA) would be living in the urban area. Pollution from animal manure is a global concern and is much more acute and serious in countries with high concentrations of animals on a limited land base for manure disposal (Roderick, Stroot and Varel, 1998), this is the case with urban livestock production. Environmental pollution and odor complaints related to animal production have increased dramatically during the past decade (Ernest and Ronald, 2004). These odors potentially interfere with quality and enjoyment of life (Mauderly, 2002 and Albert, 2002). According to Pfost, Fulhage and Hoehne, 1999, odor complaints are more common when the humidity is high and the air is still or when the prevailing breezes carry odors toward populated areas. Inspite of the role that urban agriculture can play in pursuing the Millennium Development Goals, more specifically those, related to poverty reduction, food security, and environmental sustainability, odor from livestock still remains a major obstacle to future development. According to Obayelu 2010 there has been public’s increasing intolerance of livestock odors, hence the need to find solutions which will be ecosystem friendly. This paper will review some methods of odor control focusing on natural solutions to this problem.

What did we do?

For an odor to be detected downwind, odorous compounds must be: (a) formed, (b) released to the atmosphere, and (c) transported to the receptor site. These three steps provide the basis for most odor control. If any one of the steps is inhibited, the odor will diminish. (Chastain, 2000)

There are four general types of compounds for odor control: (1) masking agents that override the offensive odors, (2) counteractants that are chemically designed to block the sensing of odors, (3) odor absorption chemicals that react with compounds in manure to reduce odor emission, and (4) biological compounds such as enzymatic or bacterial products that alter the decomposition so that odorous compounds are not generated (Chastain, 2000). Some of these compounds are added directly to the manure while others are added to the feed. Yucca schidigera is a natural feed additive for livestock and poultry used to control odors, ammonia and other gas emissions, which can be detrimental to livestock performance. Essential oils are being promoted as effective and safe antimicrobial or antiviral (disinfectant) agents that also act as masking agents in the control of odor examples are thymol and carvacrol. Natural zeolite, clinoptilolite (an ammonium-selective zeolite), has been shown t o enhance adsorption of volatile organic compounds and odor emitted from animal manure due to its high surface area. Cai et al. (2007) reported reduction >51% for selected offensive odorants (i.e. acetic acid, butanoic acid, iso-valeric acid, dimethyl trisulfide, dimethyl sulfone, phenol, indole and skatole) in poultry manure with a 10% zeolite topical application. Treatment of broiler litter with alum was originally developed to reduce the amount of soluble phosphorous in poultry litter. However, it was also observed that using alum reduced the pH of the litter to below 6.5, and as a result, reductions in ammonia emissions from the litter have been observed.

Amendment of manure with alkaline materials such as cement kiln dust, lime, or other alkaline by-products can increase the pH to above 12.0, which limits the vast majority of microbialactivity, including odor producing microorganisms (Veenhuizen and Qi, 1993, Li et al., 1998). The effect of the addition of lime and other ONAs that alter the pH and moisture content of the waste and bedding requires further scientific research (McGahan, et al., 2002).

Dust particles can carry gases and odors. Therefore, dust control in the buildings can reduce the amount of odor carried outside. Management practices that can greatly reduce the amount of dust in poultry buildings are Clean interior building surfaces regularly, Reduce dust from feed, this can be by addition of oil to dry rations, proper and timely maintenance of feeders, augers, and other feed handling equipment. Also managing the relative humidity (RH) in poultry houses. Planting just three rows of trees around animal farms has also been proven to cut nuisance emissions of dust, ammonia, and odors from poultry houses. The use of tress around livestock facilities to mitigate odour and improve air quality has been recently reviewed by Tyndall and Colletti (2000). They concluded that trees have the potential to be an effective and inexpensive odor control technology particularly when used in combination with other odour control methods. Trees ameliorate odours by dilutio n of odour, encourage dust and aerosol deposition by reducing wind speeds, physical interception of dust and aerosols, and acting as a sink for chemical constituents of odour.

What have we learned?

The use of indigenous microorganisms for odor reduction related to livestock is being promoted under Natural farming, in this instance cultured mixtures of microorganisms consisting mainly of lactic acid bacteria, purple bacteria and yeast are used. This is already made into commercial product and marketed as effective microorganism activated solution (EMAS).

Interestingly, there is paucity of information on ethnobotanicals that are useful for odour control. Most literatures on ethnobotany focused of treatment and control of animal diseases but not on traditional control of the environment of livestock. As scientists are still working hard to develop chemical or biological additives which will eliminate or reduce odors associated with poultry wastes there is the need to survey traditional livestock owners for information that can serve for development of effective,inexpensive, efficient and suitable agent for odor control in poultry management.

Corresponding author, title, and affiliation

Oyebanji Bukola, Department of Animal Sciences, Obafemi Awolowo University, Ile-Ife, Nigeria

Corresponding author email


Albert, H. (2002) Outdoor Air Quality. Livestock Waste Facilities Handbook, Midwest Plan Service (MWPS),
Iowa State University in Ames, Iowa. Volume 18, section 3 Page 96.

Cai, L., Koziel, J.A., Liang, Y., Nguyen, A.T., and H. Xin. 2007. Evaluation of zeolite for
control of odorants emissions from simulated poultry manure storage. J. Environ. Qual.

Chastain, J.P., and F.J. Wolak. 2000. Application of a Gaussian Plume Model of Odor
Dispersion to Select a Site for Livestock Facilities. Proceedings of the Odors and VOC
Emissions 2000 Conference, sponsored by the Water Environment Federation, April 16-19,
Cincinnati, OH., 14 pages, published on CD-ROM.

Ernest, F.B and Ronald, A.F.(2004) An Economic Evaluation of Livestock Odor Regulation Distances.
Journal of Environmental Quality, Volume 33, November–December 2004

FAO 2008. Urban agriculture for sustainable poverty alleviation and food security. FAO Rome

Mauderly, J.L. (2002) Health Effects of Mixtures of Air Pollutants. Air Quality and Health: State of the Science, Proceedings of the Clean Air Strategic Alliance Symposium, Red Deer, Alberta, Canada, June 3-4, 2002.

McGahan. E, Kolominska, C Bawden, K. and Ormerod. R (2002). Strategies to reduce odour emissions from Meat chicken farms Proceedings 2002 Poultry Information Exchange

Pfost, D. L., C. D. Fulhage, and J. A. Hoehne (1999) Odors from livestock operations: Causes and possible cures. Outreach and Extension Pub. # G 1884. University of MissouriColumbia.

Obayelu, A. E 2010. Assessment Of The Economic And Environmental Effects Of Odor Emission From Mechanically Ventilated Livestock Building In Ibadan Oyo State Nigeria. International Journal of science and nature VOL. 1(2) 113-119

Tyndall, J. and J. Colletti. 2000. Air quality and shelterbelts: Odor mitigation and livestock production a literature review. Technical report no. 4124-4521-48-3209 submitted to USDA, National Agroforestry Center, Lincoln, NE.

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. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

Practical Use and Application of the Poultry Carbon Footprint Calculation Tool

Why Study Carbon Footprint on Poultry Farms?*          

The poultry industry is a major part of the agricultural industry in the United States, and an awareness of the carbon footprint of the industry is important for future growth and development. With carbon footprint estimated to be as high as 18% of total Green House Gas (GHG) emissions, changes in U.S. animal production systems will be a component in mitigating the impacts of the industry on climate change. Changes in GHG emissions from the poultry industry can be achieved only if the industry knows the levels of greenhouse gas emissions contributed as a result of poultry production.

What did we do? 

The Poultry Carbon Footprint Calculation Tool (PCFCT) was developed and designed specifically for poultry production farms. The tool can be used to estimate the greenhouse gas (GHG) emissions from pullet, breeder and broiler grow-out farms. While several life-cycle assessments have been completed for the production of poultry meat, there is no industry specific carbon footprint calculation tool available for the production phase of the poultry industry and since the poultry farmer only has control over the activities that take place on his farm, he can only make reductions of emissions at the farm-gate level. It is therefore important that a tool such as the PCFCT is available to deal with the farm level emissions.

The GHGs that are assessed are carbon dioxide, nitrous oxide and methane which are the gases of major concern in agriculture. The specific objectives of this study was to develop a computer-based, user-friendly calculation tool to assess greenhouse gas emissions from poultry farms and also to identify abatement strategies in on-farm management practices to reduce the footprint on farms. The user friendly PCFCT is an Excel spreadsheet into which the user will enter farm data to calculate the annual carbon footprint (Figure 1). The research included an assessment of the carbon footprint of test farms under industry management standards with focus placed on management practices and farm-expense data, particularly with regard to expenditures for energy-intensive inputs such as electricity and fuel which are the largest contributors to GHG emissions for poultry farms. This was used to identify potential areas of change.

The calculation tool was developed and then used to estimate the emissions from 30 test farms from three poultry companies in three different regions in Georgia.

What have we learned? 

We observed that the major sources of greenhouse gas that are emitted on poultry production farms were from gas use and manure management. Based on these observations, the tool was then equipped to recommend improvements to the farm, which would in turn show the user potential reductions in GHG emissions and cost savings if the recommended improvements were implemented. The results from the study showed that there were significant differences in emissions from mechanical sources and electricity use between the southern region and the northern and central regions of the state (Table 1). The differences observed could be a result of; climatic differences, the dead bird disposal methods and also the duration of time the flock is kept on the farm.

Table 1. Average Farm Emissions from three Broiler Complexes located in three different regions.

The tool is also very useful for record keeping as it is designed with a printable inventory which will allow users to track and compare their emissions from year to year. It is also equipped with bar charts to show the user their current emissions compared to projected emissions if they apply the recommended changes. A second graph shows the percentage of emission from each source.

Future Plans    

The tool will be made available on the departmental website ( for poultry producers, poultry company environmental personnel and extension personnel to utilize. Articles relevant to the subject will also be made available to users of the tool. Other future plans include incorporation of other segments of the industry (layer and turkey) into the tool.


Claudia Dunkley, Ext. Poultry Scientist

Brian Fairchild, Ext. Poultry Scientist, Casey Ritz, Ext. Poultry Scientist, Brian Kiepper, Ext. Poultry Scientist, John Worley, Ext. Engineer

Additional information        

C. S. Dunkley, University of Georgia, 2360 Rainwater Rd., Tifton, GA 31793-0478


Funded by US Poultry & Egg Association

Figure 1. The PCFCT Interface page showing areas where farm data will be inputted, recommendations can be tried and an inventory showing the emissions and projections based on recommendations can be seen.

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. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

Small Scale Poultry Production Curriculum Materials

One of the most noticeable trends in agriculture is the increase in beginning farmers, small farms and especially in small-scale poultry. Everything from a few backyard chickens to 4-H projects and farms with several hundred hens or broilers all can be considered “small”. Just because a flock is small, does not mean that we can ignore areas like stewardship, efficient production, safe handling, and rules that apply to your farm.

Materials for Teachers and Extension Staff

The following materials were developed for teachers and educators to use in their classrooms and programs. The target age range is high school, jr. college and beginning farmer groups.

Download a .zip file containing all of the above files (videos need to be downloaded separately due to file size restrictions)

Video: Raising Poultry for Profit: Small-Scale Production

Download a copy of this video (.MP4 format; 73 MB)

If you prefer to play shorter video clips, this has been released as four separate parts:

Preview Presentation Slides: Small Scale Poultry


Contact Person for this Module: Martha Sullins, Colorado State University

Authors and Reviewers:

•Blake Angelo, Colorado State University Extension, Urban Agriculture
•Dr. Jack Avens, CSU Food Science and Human Nutrition
•Thomas Bass, Montana State University Extension, Livestock Environment Associate Specialist
•Dr. Marisa Bunning, CSU Food Science and Human Nutrition
•Emily Lockard, CSU Extension, Livestock
•Dea Sloan, CSU Agricultural and Resource Economics
•Martha Sullins, CSU Extension, Agriculture and Business Management
•Dr. Dawn Thilmany, CSU Agricultural and Resource Economics
•Heather Watts, CSU Agricultural and Resource Economics
•Wendy White, Colorado Department of Agriculture
•David Weiss, CSU Agricultural and Resource Economics

Building Environmental Leaders in Animal Agriculture (BELAA) is a collaborative effort of the National Young Farmers Educational Association, University of Nebraska-Lincoln, and Montana State University. It was funded by the USDA National Institute for Food and Agriculture (NIFA) under award #2009-49400-05871. This project would not be possible without the Livestock and Poultry Environmental Learning Center and the National eXtension Initiative, National Association of County Ag Agents (NACAA), National Association of Agriculture Education (NAAE), Farm Credit Services of America, American Registry of Professional Animal Scientists (ARPAS), and Montana FFA Association.

Supporting Small-Scale Poultry and Livestock Businesses

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Why Work With Small Poultry and Livestock Operations?

Understand the business planning and development issues confronting small-scale livestock and poultry producers.

What Did We Do?

Colorado State University has been building educational programming to benefit small-scale crop and livestock producers across the state since 2007.  The Colorado Building Farmers and Ranchers program uses a classroom, experiential learning and community-building approach to help smaller-scale and new agricultural producers build their businesses in a profitable, safe and sustainable manner. To date, we have graduated more than 300 producers, 65% of whom have completed business plans to expand or develop their agricultural business. These producers are primarily characterized by their focus on direct marketing, and many are located relatively close to urban areas; locations that provide both marketing opportunities as well as production constraints. The classroom education takes place over 8 weeks and helps producers build sustainable business plans, and develop a network of producers and technical assistance providers (e.g. NRCS, FSA, county planning staff).  Topics covered include developing a production plan, recordkeeping, pricing, risk management, and on-farm food safety.  In addition, since small-scale livestock production is a more complex business model, we have built a curriculum that guides producers through all the business planning considerations necessary to start and operate a profitable livestock operation: from acquiring poultry, sheep or goats, to health and environmental issues, to processing and creating a unique market niche.

What Have We Learned?

Given that smaller or more diversified poultry and small ruminant operations may be trying to maintain a greater number of enterprises on one farm or operation, it may be more difficult for those producers to stay on top of good management practices, as well as any requirements necessary to remain in good standing with local government and marketing partners. For example, these small-scale operations may be maintained on a limited number of acres, thus requiring very careful land and animal management.  Additionally, many smaller-scale operations are located in areas where agriculture is not the primary land use.  Such operations may be in the urban-rural interface, the suburbs or even in towns or cities.  The research for this curriculum provided a basic overview of production, management and marketing considerations and opportunities for smaller-scale poultry and small ruminant production, and a means to discuss the relationship between resource stewardship and long-term business viability. We examined, in particular, emerging niche market opportunities and some of the costs and benefits inherent to pursuing those newer markets, finding that the costs and management skills required make it extremely difficult to operate a commercially viable small-scale livestock business in an urban area.

Future Plans

Next steps involve developing enterprise budgets with different numbers of poultry and small ruminants to understand the point at which these businesses become financially viable. This is important for helping prospective new livestock enterprises to truth their business plans, based on realistic assumptions.

Raising Poultry for Profit Video

Raising Sheep and Goats for Profit Video


Martha Sullins, Extension Regional Specialist, Colorado State University Extension,

Additional Information


David Weiss and Dawn Thilmany (Department of Agricultural and Resource Economics, CSU), Blake Angelo (Urban Ag Educator, Denver/Jefferson Counties, CSU Extension),  Marisa Bunning (Department of Food Science and Human Nutrition, CSU); Thomas Bass (Montana State University).

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.

Staying Ahead of the Curve: How Farmers and Industry Are Responding to the Issue of Climate Change

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Why Is This Topic Important?

Several farmers, ranchers, and industry groups are leading the way on the issue of climate change. 

What Will Be Learned In This Presentation?

These panelists will share how their farm or industry is responding to climate change, what factors are driving their decision to make changes, and the impact of climate change on long-term planning. This moderated session will encourage audience questions and facilitate exchange of ideas on how the agriculture industry can meet this challenge.


David Smith, Southwest Region Coordinator Animal Agriculture and Climate Change Project, Texas A&M University and Liz Whitefield, Western Region Coordinator, Washington State University

  • Jamie Burr –  Tyson Foods, Chair National Pork Board Environment Committee
  • Abe Collins – cattle grazier, Cimarron Farm, Regenerative Farmscaping consultant, Board Member Soil Carbon Coalition
  • Paul Helgeson – Sustainability Director with Gold’n Plump Chicken
  • Bryan Weech, Director Livestock & MTI Commodity Lead, World Wildlife Fund
  • Andy Werkoven – dairyman and anaerobic digester co-owner, Werkhoven Dairy Inc., 2012 winner of US Dairy Sustainability Award