The author wishes to acknowledge Alan Kruger, Todd Boman, Shannon Ostdiek, Elaine Berry, and Ferouz Ayadi who assisted with data collection using the simulated bedded packs. The author also recognizes Tami Brown-Brandl and Dale Janssen for their assistance maintaining the environmental chambers.

The study is designed to be conducted over 42 days with weekly data collection. All animal procedures were reviewed and approved by the US Meat Animal Research Center Institutional Animal Care and Use Committee.
1. Constructing Simulated Bedded Packs
<ol>
	<li>Begin with plastic cylinder containers that are 0.42 m high with a 0.38 m diameter. 
	NOTE: In this study, one particular 10-gallon commercial trash container was used (see Table of Materials), but other similar-s...

<ol>
	<li>Doran, B., Euken, R., Spiehs, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hoops+and+mono-slopes:+What+we+have+learned+about+management+and+performance.">Hoops and mono-slopes: What we have learned about management and performance.</a> Feedlot Forum 2010. , 8-16 (2010).</li><li>Andersson, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Performance+of+bedding+materials+in+affecting+ammonia+emissions+from+pig+manure.">Performance of bedding materials in affecting ammonia emissions from pig manure.</a> J. Agric. Engng. Res. 65, 213-222 (1996).</li><li>Jeppsson, K. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Volatilization+of+ammonia+in+deep-litter+systems+with+different+bedding+materials+for+young+cattle.">Volatilization of ammonia in deep-litter systems with different bedding materials for young cattle.</a> J. Agric. Engng. Res. 73, 49-57 (1999).</li><li>Powell, J. M., Misselbrook, T. H., Casler, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Season+and+bedding+impacts+on+ammonia+emissions+from+tie-stall+dairy+barns.">Season and bedding impacts on ammonia emissions from tie-stall dairy barns.</a> J. Environ. Qual. 37, 7-15 (2008).</li><li>Gilhespy, S. L., Webb, J., Chadwick, D. R., Misselbrook, T. H., Kay, R., Camp, V., Retter, A. L., Bason, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Will+additional+straw+bedding+in+buildings+housing+cattle+and+pigs+reduce+ammonia+emissions.">Will additional straw bedding in buildings housing cattle and pigs reduce ammonia emissions.</a> Biosystems Engng. , 180-189 (2009).</li><li>Spiehs, M. J., Woodbury, B. L., Doran, B. E., Eigenberg, R. A., Kohl, K. D., Varel, V. H., Berry, E. D., Wells, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environmental+conditions+in+beef+deep-bedded+mono-slope+facilities:+A+descriptive+study.">Environmental conditions in beef deep-bedded mono-slope facilities: A descriptive study.</a> Trans ASABE. 54, 663-673 (2011).</li><li>Cortus, E. L., Spiehs, M. J., Doran, B. E., Al Mamun, M. R. H., Ayadi, F. Y., Cortus, S. D., Kohl, K. D., Pohl, S., Stowell, R., Nicolai, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Ammonia and hydrogen sulfide concentration and emission patterns for mono-slope beef cattle facilities in the Northern Great Plains. , (2014).</li><li>Spiehs, M. J., Cortus, E. L., Holt, G. A., Kohl, K. D., Doran, B. E., Ayadi, F. Y., Cortus, S. D., Al Mamun, M. R., Pohl, S., Nicolai, R., Stowell, R., Parker, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Particulate+matter+concentration+for+mono-slope+beef+cattle+facilities+in+the+Northern+Great+Plains.">Particulate matter concentration for mono-slope beef cattle facilities in the Northern Great Plains.</a> Trans. ASABE. 57, 1831-1837 (2014).</li><li>Ayadi, F. Y., Cortus, E. L., Spiehs, M. J., Miller, D. N., Djira, G. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ammonia+and+greenhouse+gas+concentrations+at+surfaces+of+simulated+beef+cattle+bedded+manure+packs.">Ammonia and greenhouse gas concentrations at surfaces of simulated beef cattle bedded manure packs.</a> Trans. ASABE. 58, 783-795 (2015).</li><li>Ayadi, F. Y., Spiehs, M. J., Cortus, E. L., Miller, D. N., Djira, G. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physical,+chemical,+and+biological+properties+of+simulated+beef+cattle+bedded+manure+packs.">Physical, chemical, and biological properties of simulated beef cattle bedded manure packs.</a> Trans. ASABE. 58, 797-811 (2015).</li><li>Spiehs, M. J., Brown-Brandl, T. M., Parker, D. B., Miller, D. N., Berry, E. D., Wells, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+bedding+materials+on+concentration+of+odorous+compounds+and+Escherichia+coli+in+beef+cattle+bedded+manure+packs.">Effect of bedding materials on concentration of odorous compounds and Escherichia coli in beef cattle bedded manure packs.</a> J. Environ. Qual. 42, 65-75 (2013).</li><li>Spiehs, M. J., Brown-Brandl, T. M., Parker, D. B., Miller, D. N., Jaderborg, J. P., Diconstanzo, A., Berry, E. D., Wells, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+wood-based+materials+in+beef+bedded+manure+packs:+1.+Effect+on+ammonia,+total+reduced+sulfide,+and+greenhouse+gas+concentrations.">Use of wood-based materials in beef bedded manure packs: 1. Effect on ammonia, total reduced sulfide, and greenhouse gas concentrations.</a> J. Environ. Qual. 43, 1187-1194 (2014).</li><li>Spiehs, M. J., Brown-Brandl, T. M., Berry, E. D., Wells, J. E., Parker, D. B., Miller, D. N., Jaderborg, J. P., Diconstanzo, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+wood-based+materials+in+beef+bedded+manure+packs:+2.+Effect+on+odorous+volatile+organic+compounds,+odor+activity+value,+Escherichia+coli,+and+nutrient+concentration.">Use of wood-based materials in beef bedded manure packs: 2. Effect on odorous volatile organic compounds, odor activity value, Escherichia coli, and nutrient concentration.</a> J. Environ. Qual. 43, 1195-1206 (2014).</li><li>Spiehs, M. J., Brown-Brandl, T. M., Parker, D. B., Miller, D. N., Berry, E. D., Wells, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ammonia,+total+reduced+sulfides,+and+greenhouse+gases+of+pine+chip+and+corn+stover+bedding+packs.">Ammonia, total reduced sulfides, and greenhouse gases of pine chip and corn stover bedding packs.</a> J. Environ. Qual. 45, 630-637 (2016).</li><li>Spiehs, M. J., Berry, E. D., Wells, J. E., Parker, D. B., Brown-Brandl, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odorous+volatile+organic+compounds,+Escherichia+coli,+and+nutrient+concentrations+when+kiln-dried+pine+chips+and+corn+stover+bedding+are+used+in+beef+bedded+manure+packs.">Odorous volatile organic compounds, Escherichia coli, and nutrient concentrations when kiln-dried pine chips and corn stover bedding are used in beef bedded manure packs.</a> J. Environ. Qual. 46, 722-732 (2017).</li><li>Herbert, S., Hashemi, M., Chickering-Sears, C., Weis, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Bedding options for livestock and equine. , (2008).</li><li>Effects of bedding on pig performance. Iowa State Research Farm Progress Reports Available from: <a target="_blank" href="https://lib.dr.iastate.edu/farms_reports/134/">https://lib.dr.iastate.edu/farms_reports/134/</a> (2012)</li><li>Brown-Brandl, T. M., Nienaber, J. A., Eigenberg, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temperature+and+humidity+control+in+indirect+calorimeter+chambers.">Temperature and humidity control in indirect calorimeter chambers.</a> Trans. ASABE. 54, 685-692 (2011).</li><li>Abney, C. S., Vasconcelos, J. T., McMeniman, J. P., Keyser, S. A., Wilson, K. R., Vogel, G. J., Galyean, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+ractophamine+hydrochlodride+on+performance,+rate+and+variation+in+feed+intake,+and+acid-base+balance+in+feedlot+cattle.">Effects of ractophamine hydrochlodride on performance, rate and variation in feed intake, and acid-base balance in feedlot cattle.</a> J. Anim. Sci. 85, 3090-3098 (2007).</li><li>Miller, D. N., Woodbury, B. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+solid-phase+microextraction+chamber+method+for+analysis+of+manure+volatiles.">A solid-phase microextraction chamber method for analysis of manure volatiles.</a> J. Environ. Qual. 35, 2383-2394 (2006).</li><li>Woodbury, B. L., Miller, D. N., Eigenberg, R. A., Nienaber, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+inexpensive+laboratory+and+field+chamber+for+manure+volatile+gas+flux+analysis.">An inexpensive laboratory and field chamber for manure volatile gas flux analysis.</a> Trans. ASABE. 49, 767-772 (2006).</li><li>Koziel, J. A., Spinhirne, J. P., Lloyd, J. D., Parker, D. B., Wright, D. W., Kuhrt, F. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+sample+recovery+of+malodorous+livestock+gases+from+air+sampling+bags,+solid-phase+microextraction+fibers,+Tenax+TA+sorbent+tubes,+and+sampling+canisters.">Evaluation of sample recovery of malodorous livestock gases from air sampling bags, solid-phase microextraction fibers, Tenax TA sorbent tubes, and sampling canisters.</a> J. Air Waste Manag. Assn. 55, 1147-1157 (2005).</li><li>Parker, D. B., Gilley, J., Woodbury, B., Kim, K., Galvin, G., Bartelt-Hunt, S. L., Li, X., Snow, D. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odorous+VOC+emission+following+land+application+of+swine+manure+slurry.">Odorous VOC emission following land application of swine manure slurry.</a> Atmos. Environ. 66, 91-100 (2013).</li><li>Parker, D. B., Koziel, J. A., Cai, L., Jacobson, L. D., Akdeniz, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odor+and+odorous+chemical+emissions+from+animal+buildings:+Part+6.+Odor+activity+value.">Odor and odorous chemical emissions from animal buildings: Part 6. Odor activity value.</a> Trans. ASABE. 55, 2357-2368 (2012).</li><li>Watson, M., Wolf, A., Wolf, N., Peters, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Total+nitrogen.">Total nitrogen.</a> Recommended methods of manure analysis. , 18-24 (2003).</li><li>Wolf, A., Watson, M., Wolf, N., Peters, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digestion+and+dissolution+methods+for+P,+K,+Ca,+Mg,+and+trace+elements.">Digestion and dissolution methods for P, K, Ca, Mg, and trace elements.</a> Recommended methods of manure analysis. , 30-38 (2003).</li><li>Euken, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+survey+of+manure+characteristics+from+bedded+confinement+buildings+for+feedlot+beef+productions:+Progress+report.">A survey of manure characteristics from bedded confinement buildings for feedlot beef productions: Progress report.</a> Animal Industry Report. , (2009).</li><li>Li, L., Li, Q. -. F., Wang, K., Bogan, B. W., Ni, J. -. Q., Cortus, E. L., Heber, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+National+Air+Emission+Monitoring+Study's+southeast+layer+site:+Part+I.+Site+characteristics+and+monitoring+methodology.">The National Air Emission Monitoring Study's southeast layer site: Part I. Site characteristics and monitoring methodology.</a> Trans. ASABE. 56, 1157-1171 (2013).</li></ol>

The frequent addition of urine and feces to the bedded packs is a critical step. We experimented with adding urine and feces just once weekly, but found that the bedded pack developed a crust, which trapped gases inside the pack and was not representative of commercial facilities. The use of fresh feces at the beginning of the study ensures that the bedded packs is inoculated with common bacterial populations found in cattle facilities. It is also important, when adding the urine, to remember to adjust the pH to physiolo...

Beef cattle confinement facilities are a popular housing option in the Midwest and Upper Great Plains. Confinement facilities are more common in this region than the Southern Plains because the region receives more annual precipitation, which creates more feedlot runoff that must be contained. Many producers chose to build mono-slope barns for beef cattle. The primary reasons cited by producers for selecting a mono-slope facility was the ability to schedule labor and manure removal, and improved performance compared to open lot feedlots1. A majority of cattle producers (72.2%) using mono-slope barns maintain a bedded pack for one turn of cattle or longer, using a deep-bedding management system for bedding and waste1. The most common bedding material used is corn stover, although producers report using soybean stubble, wheat straw, corn cobs, and sawdust1. Because of the regional demand for corn stover bedding, many producers were interested in alternative bedding materials that could be used in mono-slope facilities. In addition to economics and animal comfort, producers questioned how the bedding material would impact the environment of the facility, including the production of odorous gases, nutrient composition of the resulting manure/bedding, and presence of pathogens.
Few studies have been conducted to measure air quality resulting from different bedding materials used in livestock housing, with most focusing only on ammonia. Most of the previous evaluations of air quality include on-farm data collection with one or two experimental units per treatments being analyzed at once2,3,4,5. Having limited numbers of experimental units requires the study to be repeated multiple times, thus adding additional variables such as weather conditions, age or stage of production of animals, and perhaps bedding materials produced in different growing seasons.
With no known lab-scaled model to study factors affecting air quality and nutrient composition of the manure/bedding mixture resulting from beef deep-bedded mono-slope facilities, researchers first attempted to utilize commercial cattle facilities using a deep-bedded system6,7,8. Static flux chambers were used to measure NH3 concentrations on the surface of mono-slope deep bedded cattle facilities over an 18 month period6. Two pens in each of two barns were measured. Chopped corn stalks were the preferred bedding material, but wheat straw and soybean stalks were also used for bedding during brief periods of this project. Bedding use ranged from 1.95 - 3.37 kg per animal per day and pen density ranged from 3.22 - 6.13 m2 per animal. Subsequent studies measured ammonia and hydrogen sulfide emissions from the barn7, and particulate matter concentrations outside the barn8. These studies were conducted over a 2 year period using two to four barn locations. The challenge with on-farm data collection is the lack of control that the research has over the system. Producers change cattle diets, move animals from pen to pen, use bedding materials from different sources, and clean and re-bed pens as their production and labor force allows, thus confounding many variables. On-farm research also involves travel expenses and large quantities of experimental treatments (such as bedding material). The objective of this project was to develop a lab-scale model that could be used to study factors affecting air quality and nutrient management in cattle deep-bedded mono-slope facilities.

<table>
	<tbody>
		<tr>
			<td>10 gallon plastic cylinder containers</td>
			<td>Rubbermaid</td>
			<td>Model 2610</td>
			<td>Other similar-sized plastic containers are suitable</td>
		</tr>
		<tr>
			<td>Mass balance</td>
			<td>Any</td>
			<td></td>
			<td>Capable of measuring 0.1 gram</td>
		</tr>
		<tr>
			<td>Electric drill with 1 cm bit</td>
			<td>Any</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Methane analyzer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Model 55i Methane/Non-methane Analyzer</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrogen sulfide analyzer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Model 450i</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonia analyzer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Model 17i</td>
			<td></td>
		</tr>
		<tr>
			<td>Carbon dioxide analyzer</td>
			<td>California Analytical</td>
			<td>Model 1412</td>
			<td></td>
		</tr>
		<tr>
			<td>Nitrous oxide analyzer</td>
			<td>California Analytical</td>
			<td>Model 1412</td>
			<td></td>
		</tr>
		<tr>
			<td>Programmable Logic Relay</td>
			<td>TECO</td>
			<td>Model SG2-020VR-D</td>
			<td></td>
		</tr>
		<tr>
			<td>Stainless steel flux chambers</td>
			<td>Any</td>
			<td></td>
			<td>Constructed using the parts list and directions cited at Woodbury et al., 2006</td>
		</tr>
		<tr>
			<td>Rubber skits</td>
			<td>Any</td>
			<td></td>
			<td>Constructed from flexible rubber material. Cut into squares (61 cm x 61 cm) with 22.9 cm diameter hole in center.&#160;</td>
		</tr>
		<tr>
			<td>pH meter</td>
			<td>Spectrum Technologies</td>
			<td>IQ150</td>
			<td></td>
		</tr>
		<tr>
			<td>thermometer</td>
			<td>Spectrum Technologies</td>
			<td>IQ150</td>
			<td></td>
		</tr>
		<tr>
			<td>Ruler or tape measure</td>
			<td>Any</td>
			<td></td>
			<td>Capable of measuring in cm</td>
		</tr>
		<tr>
			<td>Sorbent tubes</td>
			<td>Markes International</td>
			<td>Tenax TA</td>
			<td></td>
		</tr>
		<tr>
			<td>Pocket pumps</td>
			<td>SKC Inc.</td>
			<td>Series 210</td>
			<td></td>
		</tr>
		<tr>
			<td>Inert sampling line</td>
			<td>Teflon</td>
			<td></td>
			<td>0.64 cm diameter</td>
		</tr>
		<tr>
			<td>Pump</td>
			<td>Thomas</td>
			<td>107 series</td>
			<td>Used to flush air through sample lines</td>
		</tr>
	</tbody>
</table>

lab-scale model to evaluate odor and gas concentrations emitted by deep bedded pack manure

A lab-scaled simulated bedded pack model was developed to study air quality and nutrient composition of deep-bedded packs used in cattle mono-slope facilities. This protocol has been used to effectively evaluate many different bedding materials, environmental variables (temperature, humidity), and potential mitigation treatments that can improve air quality in commercial deep-bedded mono-slope facilities. The model is dynamic and allows researchers to easily collect many chemical and physical measurements from the bedded pack. Weekly measurements, collected over the course of six to seven weeks, allows sufficient time to see changes in air quality measurements over time as the bedded pack matures. The data collected from the simulated bedded packs is within the range of concentrations previously measured in commercial deep-bedded mono-slope facilities. Past studies have demonstrated that 8 - 10 experimental units per treatment are sufficient to detect statistical differences among the simulated bedded packs. The bedded packs are easy to maintain, requiring less than 10 minutes of labor per bedded packs per week to add urine, feces, and bedding. Sample collection using the gas sampling system requires 20 - 30 minutes per bedded pack, depending on the measurements that are being collected. The use of lab-scaled bedded packs allows the researcher to control variables such as temperature, humidity, and bedding source that are difficult or impossible to control in a research or commercial facility. While not a perfect simulation of &#34;real-world&#34; conditions, the simulated bedded packs serve as a good model for researchers to use to examine treatment differences among bedded packs. Several lab-scale studies can be conducted to eliminate possible treatments before trying them in a research or commercial-sized facility.

To date, seven research studies have been published9,10,11,12,13,14,15 using this procedure, with modifications and adjustments made to improve the model and reflect objectives of the specific experiments. This procedure has been used to evaluate the effect o...

Watch this Scientific Journal Video about Lab-Scale Model to Evaluate Odor and Gas Concentrations Emitted by Deep Bedded Pack Manure at JoVE.com

Lab-Scale Model to Evaluate Odor and Gas Concentrations Emitted by Deep Bedded Pack Manure

A protocol has been developed to measure gases, odors, and nutrient composition in lab-scaled bedded manure packs, which can be used to study ways to improve air quality in commercial cattle facilities using deep-bedded manure packs.

A lab-scaled simulated bedded pack model was developed to study air quality and nutrient composition of deep-bedded packs used in cattle mono-slope ...

This method can help answer key questions related to air quality in livestock facilities including the effect of bedding, humidity, temperature, or amendments that are used in bedded livestock facilities. The main advantage of this technique is that it allows factors to be evaluated in a controlled environment and eliminates less effective treatments before conducting research at commercial-sized facilities. Demonstrating the procedure will be Alan Kruger, a technician from my laboratory.For simulator chambers, use plastic cylindrical containers that are 0.42 meters tall and 0.38 meters in diameter which match some 10 gallon trash containers. Start with drilling out six one-centimeter holes around the circumference of the container approximately five centimeters from the top. Space the holes out equally.Then clean out the container and load it with 320 grams of bedding material, followed by 320 grams of fresh cattle feces, and 320 grams of fresh cattle urine. Then stir the mixture together using a five centimeter circumference rod for about 30 seconds. After stirring, wipe the rod clean using an antiseptic disposal wipe or warm soapy water to prevent cross-contamination of microbes.Then record the final mass of the container's contents. Next, place the plastic container in the environmental chamber set to an ambient temperature of 18 to 20 degrees Celsius with a dew point of 12 degrees Celsius. Three times a week, perform maintenance on the bedding packs.For this task, first adjust the pH of thawed urine to 7.4 using sodium hydroxide and keep the urine container capped as often as possible. Next, weigh and record the mass of the bedded pack. Then weigh out 320 grams of thawed cattle feces and 320 grams of thawed urine and add both to the bedded pack.Once per week, also add 320 grams of fresh bedding. Always stir up the mixture for 30 seconds like when it was initially setup before returning the bedded pack simulator to the environmental chamber. Collect samples from the simulated bedded packs weekly prior to maintenance.First, measure the distance from the top of the simulated bedded pack to the top of the plastic container holding the simulated bedded pack. Next, push a metal stake about five centimeters into the middle of the bedded pack. Then thread 0.64 centimeter outer diameter tubing through one of the holes at the top of the simulated bedded pack container.Then inside the simulator, attach a 12.5 centimeter metal stake to the tubing so that the tubing is 1.3 centimeters above the bedded pack surface. Next, place rubber skirts with 22.9 centimeter diameter holes onto the static flux chambers. The skirt functions as a seal.Place the static flux chambers with skirt onto the bedded pack simulators. Now connect the 0.64 centimeter inert tubing to the flux chambers using inert compression fittings. The flux chamber performs the gas sampling and is controlled by a programmable logic relay that controls the solenoid valves, thus the gas flow.To finish preparing the setup, use the pump to flush ambient air through the tubing at a rate of five liters per minute for 30 minutes. To take gas measurements, first open the stopcock on the sample line to draw ambient air from the room into the inert sample lines connected to gas sampling manifold. Now program the relay to pull in ambient air and record measurements for 20 minutes.After 20 minutes, close the stopcock to end the sampling period. Next, program the relay to sample air from the lines connected to the simulators for 20 minutes. Meanwhile, measure the volatile organics in the simulator head space.First, remove the brass storage cap on a preconditioned, stainless steel sorbent tube. Then attach the sorbent tube onto the inlet port on the flux chamber using flexible rubber tubing and attach the other end of the sorbent tube to a vacuum pump. Then pull air into the sorbent tube from the simulator for five minutes for a total sample volume of 0.375 liters.Later, turn off the pump and put away the sorbent tube. Immediately before analyzing the sorbent tube on the gas analysis system, replace the brass storage caps with PTFE analytical caps. Then proceed with the analysis of volatile organics according to the text protocol.This procedure has been used to evaluate the effect of numerous bedding materials in ambient temperature on odor and gas production as well as amendments that can be added to control ammonia emissions. Chemical and physical properties of the bedded packs have been measured in commercial barns as well as in the simulated bedded packs. The procedure produces comparable results to commercial facilities and also has good repeatability amongst the simulated bedded pack studies.To determine if the protocol was a suitable model to supplement expensive on-farm research trials, air quality data was collected from commercial facilities and simulated bedded packs using the described method and older, labor-intensive methods such as the acid trap method. Overall, the measurements were very similar, supporting the use of the described labor-saving method. After watching this video, you should have a good understanding of how to use this lab-scaled model to study factors affecting air quality and nutrient management in livestock facilities using bedding.Following this procedure, you can create lab-scaled models to evaluate many different materials, environmental variables, and mitigation treatments that can improve air quality in commercial livestock facilities. The model is dynamic and allows researchers to easily collect useful measurements.

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Research

JoVE Journal

Environment

6.2K Views.  USDA ARS U.S. Meat Animal Research Center. This method can help answer key questions related to air quality in livestock facilities including the effect of bedding, humidity, temperature, or amendments that are used in bedded livestock facilities. The main advantage of this technique is that it allows factors to be evaluated in a controlled environment and eliminates less effective treatments before conducting research at commercial-sized facilities. Demonstrating the procedure will be Alan Kruger, a technician from my laboratory....