Swine Buildings Research Articles

Development and Validation of Low-Cost Indoor Air Quality Monitoring System for Swine Buildings.

The optimal indoor environment is associated with comfortable temperatures along with favorable indoor air quality. One of the air pollutants, particulate matter (PM), is potentially harmful to animals and humans. Most farms have monitoring systems to identify other hazardous gases rather than PM due to the sensor cost. In recent decades, the application of environmental monitoring systems based on Internet of Things (IoT) devices that incorporate low-cost sensors has elevated extensively. The current study develops a low-cost air quality monitoring system for swine buildings based on Raspberry Pi single-board computers along with a sensor array. The system collects data using 11 types of environmental variables along with temperature, humidity, CO2, light, pressure, and different types of gases, namely PM1, PM2.5, and PM10. The system is designed with a central web server that provides real-time data visualization and data availability through the Internet. It was tested in actual pig barns to ensure stability and functionality. In addition, there was a collocation test conducted by placing the system in two different pig barns to validate the sensor data. The Wilcoxon rank sum test demonstrates that there are no significant differences between the two sensor datasets, as all variables have a p-value greater than 0.05. However, except for carbon monoxide (CO), none of the variables exhibit correlation exceeding 0.5 with PM concentrations. Overall, a scalable, portable, non-complex, low-cost air quality monitoring system was successfully developed within a cost of USD 94.

Hunting for a viral proxy in bioaerosols of swine buildings using molecular detection and metagenomics

There are limited biosecurity measures directed at preventing airborne transmission of viruses in swine. The effectiveness of dust mitigation strategies such as oil sprinkling, to decrease risk of airborne virus transmission are unknown. Metagenomics and qPCR for common fecal viruses were used to hunt for a ubiquitous virus to serve as a proxy when evaluating the efficiency of mitigation strategies against airborne viral infectious agents. Air particles were collected from swine buildings using high-volume air samplers. Extracted DNA and RNA were used to perform specific RT-qPCR and qPCR and analyzed by high-throughput sequencing. Porcine astroviruses group 2 were common (from 102 to 105 genomic copies per cubic meter of air or gc/m3, 93% positivity) while no norovirus genogroup II was recovered from air samples. Porcine torque teno sus virus were detected by qPCR in low concentrations (from 101 to 102 gc/m3, 47% positivity). Among the identified viral families by metagenomics analysis, Herelleviridae, Microviridae, Myoviridae, Podoviridae, and Siphoviridae were dominant. The phage vB_AviM_AVP of Aerococcus was present in all air samples and a newly designed qPCR revealed between 101 and 105 gc/m3 among the samples taken for the present study (97% positivity) and banked samples from 5- and 15-year old studies (89% positivity). According to the present study, both the porcine astrovirus group 2 and the phage vB_AviM_AVP of Aerococcus could be proxy for airborne viruses of swine buildings.

82. Evaluating the effectiveness of aerogeothermy in filtering and conditioning the air entering swine buildings

82. Evaluating the effectiveness of aerogeothermy in filtering and conditioning the air entering swine buildings

Prediction of drinking water requirements by applying statistical and machine learning models in growing-finishing stage of pigs

Effective monitoring and management of drinking water in swine buildings is a crucial aspect for promoting pigs' health and productivity. Therefore, this study aimed to quantify and model drinking water intake (DWI) in growing-finishing pigs by providing them with three concentrated diets in experimental pig barns. Two independent experiments were conducted in three experimental barns between 2021 and 2022. One statistical (multiple linear regression) and four machine learning algorithms (elastic net, random forest regression, support vector regression, and multilayer perceptron) were employed, with feed intake (FI), mass of pigs (MP), pigs' body temperature (PBT), room temperature (RT), CO2 concentration (RCO2), and temperature-humidity index (RTHI) as input parameters. The results revealed that pigs with a body mass of 30 to 60 kg consumed approximately 3.58 L of drinking water and 2.10 kg of concentrated diet per day. Additionally, strong positive correlations were observed between MP, FI, and DWI (correlation coefficient (r) > 90) during both experimental periods. The findings indicated that the random forest regression algorithm performed the best, explaining over 90% and 80% of the observed and predicted data during the training and testing phases, respectively. However, during the testing phase, the multiple linear regression methods performed the worst (R2 < 0.79 and RMSE > 0.89 L pig−1 day−1) when compared to the other models. Sensitivity analysis indicated that among all the variables, MP had the greatest impact on predicting DWI, followed by FI, RCO2, RTHI, and RT. The study concluded that random forest regression could predict DWI precisely, which can assist pig farmers in enhancing their water monitoring capabilities and promptly assessing the availability of drinking water.

167 Modulation of the Innate Immune Response to Lipopolysaccharide Through Ghrelin Administration in Weaned Pigs

Abstract Ghrelin is a hormone produced in the gastrointestinal tract that is known to stimulate feed intake. However, recent evidence suggests ghrelin may have a role in inflammation reduction. Therefore, this study was designed to determine whether repeated ghrelin administration before and following an inflammatory challenge would alter the innate immune response. Weaned pigs (n = 36; 21 d of age) were transported to the Swine Building of the Livestock Issues Research Unit where they were housed in individual pens in an environmentally controlled room. Pigs had ad libitum access to water and a starter ration. On d -7 (3 days post arrival), pigs were fitted with temperature loggers within the intraperitoneal cavity (IP) or subcutaneously between the abdomen and the hind leg (Flank). On d -3, pigs were fitted with jugular vein catheters to allow for serial blood collection. Pigs were balanced by body weight measured following cannulation and assigned to 1 of 2 treatments: 1) Ghrelin: administered human ghrelin (5 µg/kg BW iv) every 12 h from -48 to 36 h relative to LPS administration at 0 h; 2) Control: administered saline at previously mentioned time points. Blood samples were collected at -48, -36, -24, -12, -2, -1, 0, 1 2, 3, 4, 5, 6,2, 24, 36 and 48 h relative to LPS administration. After collection of the 48-h sample, pigs were humanely euthanized, and samples of the jejunum and ileum were collected for histology. Pigs administered ghrelin gained more body weight (P = 0.04) compared with Control pigs after initiation of ghrelin administration. There was a treatment × time interaction (P = 0.03) for Flank temperature where Ghrelin pigs had greater body temperature at 0, 2, 4 and 48 h post-LPS challenge. Neutrophil and basophil concentrations and the neutrophil:lymphocyte ratio were reduced (P ≤ 0.04) in Ghrelin pigs compared with Control pigs. Additionally, there was a treatment × time interaction for eosinophil concentration (P = 0.03), where concentrations were reduced in Ghrelin pigs compared with Control pigs at 0 and 36 h post-LPS challenge. There were treatment × time interactions for serum concentrations of tumor necrosis factor-alpha, Interferon-gamma, granulocyte-macrophage-colony stimulating factor, and Interleukin-4 (P ≤ 0.04), with greater concentrations observed in Ghrelin compared with Control pigs. However, there was no effect of ghrelin administration on cortisol concentrations (P = 0.38). In the ileum, Ghrelin pigs had greater villi length, and reduced villus blunting score, lacteal dilation score, and lamina propria eosinophil count compared with Control pigs (P ≤ 0.04). Data from this study suggests ghrelin may provide some protection against endotoxin-induced inflammation in the ileum, while increasing basal concentrations of cytokines. Further research is necessary to fully understand the impact of ghrelin on the inflammatory response in weaned pigs.

Identified factors and predicted unidentified-factors affecting ammonia emissions from a swine building

Large variabilities in ammonia (NH3) released from animal manure and emitted from different livestock buildings were frequently reported, but the factors influencing the emissions were not sufficiently investigated. In this paper, continuously monitored data of NH3 emissions and other relevant environmental variables under controlled conditions in a 12-room experimental swine building for a 155-d complete wean-to-finish cycle were studied. Measurement data mining was conducted at both spatial and temporal dimensions using panel data analysis with heterogeneous time trends. The pig diet, total pig weight, and the pit air temperature were identified as the major influencing factors for the variabilities by using multivariate linear regression. Two unidentified factors that imposed substantial influences on the NH3 emission variabilities were predicted. They were most possibly related to variations in microenvironment and microbial activity inside the manure in the pit. The results suggest necessary future research to identify physical properties of the new NH3 emissions factors in microbiological and biochemical processes.

A Test of Social Cognitive Theory to Increase Hearing Protection Use in Swine Buildings.

Farming ranks among the top occupations for which workers are at risk for noise-induced hearing loss (NIHL), an irreversible yet preventable condition. Hearing Protection Devices (HPDs) (i.e., earmuffs and ear plugs) are effective at preventing expo- sure to noise; however, few farmers report consistent use. The purpose of this study was to test an intervention based on Social Cognitive Theory with interactive smartphone technology to increase the use of HPDs among swine facility workers. A pilot, quasi-experimental study was implemented among 72 younger adult swine workers. Participants were randomly assigned to one of three groups. Group 1 received HPDs (e.g., earmuffs and ear plugs). Group 2 received the same HPDs as Group 1 and was also instructed to use a smartphone application to track their use of hearing protection for 60 days. Group 3 received the HPDs and instructions on using a smartphone app for tracking the use of hearing protection and setting daily goals for hearing protection use. Use of hearing protection was assessed via an online survey prior to the intervention (i.e., "baseline"), immediately after the post-intervention, and at a 3-month follow-up. Compared to baseline use, all three groups reported increased use of hearing protection immediately post-intervention. However, this increase was not maintained at a 3-month follow-up for two of the study groups. Group 3 (HPD, tracking, and goal-setting app) showed the greatest increase in the use of HPDs from baseline to immediate post-intervention; however, Group 1 (HPD only) showed the greatest sustained increase from baseline to the 3-month follow-up. Modifying the environment by supplying HPDs was effective in increasing HPD use among swine facility workers. Improving access to hearing protection devices alone may lead to sustained changes in behavior.

Real-Time Monitoring of Environmental Parameters in a Commercial Gestating Sow House Using a ZigBee-Based Wireless Sensor Network

Significant intensification in livestock farming has become prevalent to meet the increasing meat production demand, resulting in a higher density of pigs in relatively small areas in a commercial swine building. The subsequent challenges of maintaining the quality of both routine management and environmental comfort of pigs to minimize the loss of both pigs’ health and welfare can be attained by implementing autonomous monitoring and intelligent management decisions based on precision livestock farming (PLF). A three-layer wireless sensor network (WSN) based on ZigBee technology has been devised to monitor four environmental parameters in real-time, namely: temperature, relative humidity, concentrations of carbon dioxide and ammonia in a commercial gestating sow house. The overall packet loss rate of the WSN system which reported 16,371 records from its 41 indoor slave nodes in a 10-min interval for three consecutive days was 4%. The carbon dioxide sensors had an average outlier rate of 6.5% after a series of preprocessing procedures. The spatial and temporal characteristics showed that the carbon dioxide level exceeded the limit of 2700 mg/m3 twice during both 07:00–08:00 and 14:00–15:00. Besides, the overall NH3 concentration in the swine building was maintained in a relatively low-level range with a maximum of less than 8 mg/m3. In sum, the real-time monitoring and timely intervention of microclimate in this commercial gestating sow house can be achieved by deploying this WSN system, thereby making it possible to provide an intelligent decision on precise management of livestock automatically.

Machine Learning-Based Microclimate Model for Indoor Air Temperature and Relative Humidity Prediction in a Swine Building.

Simple SummaryIndoor air temperature (IAT) and indoor relative humidity (IRH) are the prominent microclimatic variables. Among other livestock animals, pigs are more sensitive to environmental equilibrium; a lack of favorable environment in barns affects the productivity parameters such as voluntary feed intake, feed conversion, heat stress, etc. Machine learning (ML) based prediction models are utilized for solving various nonlinear problems in the current decade. Meanwhile, multiple linear regression (MLR), multilayered perceptron (MLP), random forest regression (RFR), decision tree regression (DTR), and support vector regression (SVR) models were utilized for the prediction. Typically, most of the available IAT and IRH models are limited to feed the animal biological data as the input. Since the biological factors of the internal animals are challenging to acquire, this study used accessible factors such as external environmental data to simulate the models. Three different input datasets named S1 (weather station parameters), S2 (weather station parameters and indoor attributes), and S3 (Highly correlated values) were used to assess the models. From the results, RFR models performed better results in both IAT (R2 = 0.9913; RMSE = 0.476; MAE = 0.3535) and IRH (R2 = 0.9594; RMSE = 2.429; MAE = 1.47) prediction with S3 input datasets. In addition, it has been proven that selecting the right features from the given input data builds supportive conditions under which the expected results are available.Indoor air temperature (IAT) and indoor relative humidity (IRH) are the prominent microclimatic variables; still, potential contributors that influence the homeostasis of livestock animals reared in closed barns. Further, predicting IAT and IRH encourages farmers to think ahead actively and to prepare the optimum solutions. Therefore, the primary objective of the current literature is to build and investigate extensive performance analysis between popular ML models in practice used for IAT and IRH predictions. Meanwhile, multiple linear regression (MLR), multilayered perceptron (MLP), random forest regression (RFR), decision tree regression (DTR), and support vector regression (SVR) models were utilized for the prediction. This study used accessible factors such as external environmental data to simulate the models. In addition, three different input datasets named S1, S2, and S3 were used to assess the models. From the results, RFR models performed better results in both IAT (R2 = 0.9913; RMSE = 0.476; MAE = 0.3535) and IRH (R2 = 0.9594; RMSE = 2.429; MAE = 1.47) prediction among other models particularly with S3 input datasets. In addition, it has been proven that selecting the right features from the given input data builds supportive conditions under which the expected results are available. Overall, the current study demonstrates a better model among other models to predict IAT and IRH of a naturally ventilated swine building containing animals with fewer input attributes.

Ozone treatment in a wind tunnel for the reduction of airborne viruses in swine buildings

Ozone is effective against bacteria and viruses although its influence over bioaerosols is understudied and could be useful particularly in agricultural buildings such as swine confinement buildings. Ozone treatment of air within ventilation plenum could be applied for biosecurity purposes during the quarantine of incoming animals. In this study, a bacteriophage (PhiX174) was used as a surrogate for eukaryotic viruses in nebulization experiments inside a wind tunnel to study the factors that affect ozone’s efficacy to reduce the virus. A tunnel system was installed in the workshop of a swine building with controlled relative humidity (40% and 80%), ozone concentration (0, 0.3, 0.6, 0.9, 1.2, 1.5, and 1.8 ppm), and exposure time (up to approximately 6 min) of PhiX174 nebulized. Although there was no effect of ozone on phage genomes, culturable phages were inactivated. There was a reduction of PhiX174 infectious ratios with increasing ozone concentrations and stronger effects of ozone observed at 80% relative humidity. The data suggests the potential success of a wind tunnel and ozone air treatment to control infectious viruses emitted from swine barns or quarantine buildings.Copyright © 2020 American Association for Aerosol Research

Quantification of Site Layout and Filter Characteristics on Primary Filter Airflow Reduction on Commercial Swine Sites in Iowa

Fresh air intake filtration is used on commercial swine breeding-gestation-farrowing farms to reduce the frequency of airborne infectious agents. For swine producers, porcine reproductive and respiratory syndrome virus (PRRSV), influenza A virus and Mycoplasma hyopneumoniae are considered the most economically challenging airborne pathogens. Reduced frequency of disease outbreaks has been attributed to retrofitting existing systems with filtration. Economic analysis of operating costs includes energy use, maintenance and replacement of filters. Filter replacement, the largest operational cost, is dependent on filter lifespan. However, limited data is available on filter lifespan and the rate of airflow reduction during the high dust-loading periods typically encountered for filtered swine building ventilation systems. Therefore, the objectives of this study were (1) estimate the average primary filter airflow reduction per day, (2) identify the impact of factors related to site layout, filter characteristics and weather on airflow reduction rates of filters in positive-pressure ventilated buildings and (3) determine methods for reducing average primary filter airflow reduction rate per day during row-crop harvest season. Both filter brand and the installed orientation of the filter significantly (p = 0.0314, p = 0.0419, respectively) impacted airflow reduction rates. All site layout factors were significant (driveway side, p = 0.001; dormer orientation, p = 0.0001; and dormer configuration, p = 0.0001). The materials tested significantly reduced the airflow reduction rate during row-crop harvest. The information obtained in this study will aid producers when planning for filtration, highlight details relevant to the purchase and installation of filters, identify factors that affect filter lifespan and identify methods for improving filter lifespan.

Concentrations and Distributions of Airborne Bacteria Inside and Downwind of a Growing Swine Building in China

Abstract. Bioaerosols from concentrated animal feeding operations (CAFOs) pose potential adverse effects on the health and well-being of animals, workers, and the general public. Consequently, the topic of characterizing and mitigating bioaerosols associated with CAFOs continues to draw attention as the scale of animal production increases, especially in developing countries. This study was conducted to quantify indoor and downwind concentrations of airborne bacteria, including total bacterial count (TBC), , , and , of a mechanically ventilated growing swine barn (210-head capacity) in suburban Beijing, China. The results revealed that the indoor airborne bacterial levels averaged 1.96 × 104 ±3.08 × 103 colony forming units (CFU) m-3 for TBC, 2.29 × 103 ±5.04 × 102 CFU m-3 for , 1.44 × 104 ±1.59 × 103 CFU m-3 for , and 9.16 × 103 ±1.11 × 103 CFU m-3 for . The airborne microbe concentrations decreased with distance downwind of the swine barn. Specifically, at 10 m downwind, concentration decreased by more than 60%, while the other microorganisms decreased by 30% to 40%. All the bioaerosol microbes decreased by 55% to 70% at 30 m downwind. The relationships between the airborne bacterial concentration and downwind distance were depicted graphically and through linear regression equations. Keywords: Bioaerosols, Emissions, Intensive swine production, Microorganisms.

Electrodisinfection of real swine wastewater for water reuse

Swine production generates large volumes of wastewater, rich in organic matter, nutrients and pathogens. Electrodisinfection is used to remove organic matter and nutrients from animal wastewater, but its effectiveness on pathogens inactivation has not been studied using real swine wastewater. Therefore, we evaluated the efficiency of electrodisinfection on pathogens reduction using real swine wastewater. For that, we tested the effect of pH and current density, using iron and aluminum electrodes. Results show a 99.99% reduction of Escherichia coli when electrodisinfection was performed during 60 min at pH 3.0 and current density of 44 mA cm−2 using iron or aluminum electrodes. The liquid fraction obtained after electrodisinfection can be reused for cleaning swine buildings, thus avoiding the use of potable water.

Enterobacteria associated with houseflies (Musca domestica) as an infection risk indicator in swine production farms

Houseflies (Musca domestica) spend part of their life development on animal or human manure. Manure is high in pathogenic microbes; thus, houseflies have been known as a mechanical vector for various important zoonotic diseases. Therefore, the present study showcases captured houseflies from intensive swine production regions (which are areas of high manure concentration) in Southern Brazil, and analyses their bodies’ to the presence of Escherichia coli and Salmonella sp. and the sensitivity of these bacteria to various antibiotics. Additionally, Quantitative Microbiology Risk Assessment was performed simulating the contamination of lettuce by flies' bacteria and subsequent lettuce consumption by an adult human being. Houseflies were captured in swine buildings and farm houses from five farms. E. coli quantification values ranged from 104 to 106 CFU/20 flies, and all sampling sites had positive results from bacteria presence in the collected houseflies. On the other hand, Salmonella sp. presence was observed in only three farms, where the quantification ranged from 102 to 105 CFU/20 flies. The bacteria showed to be resistant to at least two from the four tested antibiotics (ampicillin, Cefalotin, Ciprofloxacin and Norfloxacin) antibiotics used in human or veterinary medicine. Infection probability analyses showed risk of human infection by E.coli, indicating possible transmission of zoonotic pathogens through flies. In this context, it was possible to conclude that there is a need for flies control, especially in swine farms where zoonotic pathogens can be abundant, to minimize the health impact of the vectorization of enteric bacteria.

Hydrogen sulfide emissions from a swine building affected by dietary crude protein

Hydrogen sulfide (H2S) is a toxic air pollutant at animal facilities; but the understanding of its generation and emission processes has been limited. This paper studied H2S emissions during a complete cycle of wean–finish pigs from a research building, where 12 pig rooms were divided into three groups that were fed with standard feed (control), and 2.1–3.8% (T1) and 4.4–7.8% (T2) reduced dietary crude protein (CP) feed. The group cycle mean H2S emission rates were 4.0 ± 2.9, 4.3 ± 3.2, and 5.4 ± 4.0 g d−1 AU−1 (Animal Unit = 500 kg live mass), respectively, for the control, T1, and T2 groups. Emissions of H2S were promoted by 10.0 and 36.7%, respectively, for the T1 and T2 groups (p < 0.001), although large variabilities existed in the emissions from different rooms within the same groups. The enhanced H2S emissions from the T1 and T2 groups were related to the reduced manure pH and were possibly affected through a number of pathways, which could involve volatile fatty acids and nitrogen concentrations, and microbial activities in manure.

Fuzzy comprehensive evaluation of multiple environmental factors for swine building assessment and control

In confined swine buildings, temperature, humidity, and air quality are all important for animal health and productivity. However, the current swine building environmental control is only based on temperature; and evaluation and control methods based on multiple environmental factors are needed. In this paper, fuzzy comprehensive evaluation (FCE) theory was adopted for multi-factor assessment of environmental quality in two commercial swine buildings using real measurement data. An assessment index system and membership functions were established; and predetermined weights were given using analytic hierarchy process (AHP) combined with knowledge of experts. The results show that multi-factors such as temperature, humidity, and concentrations of ammonia (NH3), carbon dioxide (CO2), and hydrogen sulfide (H2S) can be successfully integrated in FCE for swine building environment assessment. The FCE method has a high correlation coefficient of 0.737 compared with the method of single-factor evaluation (SFE). The FCE method can significantly increase the sensitivity and perform an effective and integrative assessment. It can be used as part of environmental controlling and warning systems for swine building environment management to improve swine production and welfare.

PRODUCTION, MANAGEMENT AND THE ENVIRONMENT SYMPOSIUM: Measurement and mitigation of reactive nitrogen species from swine and poultry production.

Reactive nitrogen (Nr) species include oxides of nitrogen [N; nitric oxide, nitrogen dioxide and nitrous oxide (NO)], anions (nitrate and nitrite), and amine derivatives [ammonia (NH), ammonium salts and urea]. Of the different Nr species, air emissions from swine and poultry facilities are predominantly NH followed by NO. Excreta emissions are NH, ammonium ions, and urea with trace amounts of nitrate and nitrite. Farm systems and practices that handle manure as a wet product without pH modification favor almost exclusive NH production. Systems and practices associated with dry manure handling and bedded systems emit more NH than NO. Results from a turkey grow-out study estimated that just under 1% of consumed N was emitted as NO from housing, compared with just under 11% emitted as NH. Despite generally less NO emissions from animal housing compared with crop field emissions, NO emissions from housing are often greater than estimated. Lagoon systems emit more NO than either slurry or deep pit swine systems. Deep pit swine buildings emit only one-third the NO that is emitted from deep bedded swine systems. Laying hen, broiler chicken, and turkey buildings emit over 4 times as much NO as swine housing, on a weight-adjusted basis. Critical control points for mitigation center on: 1) reducing the amount of N excreted and, therefore, excreted N available for loss to air or water during housing, manure storage, or following land application of manures; 2) capturing excreted N to prevent release of N-containing compounds to air, water, or soil resources; or 3) conversion or treatment of N-containing compounds to non-reactive N gas.

Assessment of Interventions to Improve Air Quality in a Livestock Building.

This study examined the effectiveness of engineering controls to reduce contaminant concentrations in a swine farrowing room during winter in the U.S. Midwest. Over two winters, changes in air quality were evaluated following installation of a 1700 m3 h-1 (1000 cfm) recirculating ventilation system to provide 5.4 air exchanges per hour. This system incorporated one of two readily available dust control systems, one based on filtration and the other on cyclonic treatment. A second treatment evaluated reductions in carbon dioxide (CO2) associated with replacement of standard, unvented gas-fired heaters with new vented heaters, installed between the two winter test periods. The concentrations of carbon monoxide and hydrogen sulfide were negligible in the test room. Although concentrations of ammonia increased over each winter test period, the increase was unrelated to increased air movement from the new recirculating ventilation system. The dust concentrations were significantly reduced by the ventilation system for both inhalable dust (23% to 44% with filtration, 33% with cyclone) and respirable dust (32% with filtration, 20% with cyclone), significant (p 0.024) for all except respirable dust using the cyclone (p = 0.141). The filtration unit is recommended to improve livestock building air quality because it was more effective than the cyclone unit at reducing respirable dust. Carbon dioxide concentrations were significantly lower with vented heaters (mean = 1400 ppm, SD = 330 ppm) compared to unvented heaters (mean = 2480 ppm, SD = 160 ppm). A 940 ppm reduction in CO2 was attributed to the use of the vented heater, after accounting for differences in outdoor temperatures and animal housing over both test periods. The benefits of readily available technology to significantly reduce concentrations of dust and CO2 demonstrates useful control options to improve air quality in swine buildings.

Spraying of swine buildings with lemon grass (&lt;em&gt;Cymbopogon citratus&lt;/em&gt;) essential oil does not produce blood absorption in swine

&lt;p align="left"&gt;&lt;em&gt;Cymbopogon citratus &lt;/em&gt;(Lemon grass)&lt;em&gt; &lt;/em&gt;essential oils have been used in swine buildings to reduce the offensive odor emanating from swine buildings. The present study was designed to investigate plasma residues of citral which is a major constituent of the essential oils of &lt;em&gt;Cymbopogon citratus. &lt;/em&gt;&lt;/p&gt;&lt;p align="left"&gt;An HPLC method was established, validated and used for the determination of citral in swine plasma harvested from blood samples taken at the 14&lt;sup&gt;th&lt;/sup&gt;, 21&lt;sup&gt;st&lt;/sup&gt; and 28&lt;sup&gt;th&lt;/sup&gt; day after spraying swine buildings with the 3% Lemon grass essential oil. Thereafter, analysis of the sample was&lt;em&gt; &lt;/em&gt;conducted&lt;em&gt; &lt;/em&gt;using HP ODS Hypersil column (200 × 4.6 mm, 5 µm) with a mobile phase consisting of methanol and 0.5% acetic acid; and a flow rate of 1mL/ min. The method was validated for parameters such as accuracy, precision, linearity and detection limits. Plasma spiked with standard citral (95%) revealed two chromatograms with retention times of about 10.7 and 12.2 minutes. The calibration curves for the citral isomers were found to be linear in the tested concentration ranges and mean recoveries wre 101% and 99.17%. This method was used to determine the residues of citral in swine plasma pretreated with methanol.&lt;em&gt; &lt;/em&gt;Surprisingly, there was no any detectable level of citral in swine plasma within the 28 days of exposure.&lt;/p&gt;&lt;p align="left"&gt;spraying of swine buildings with essential oils of lemon grass oil does not cause plasma residues of citral.&lt;/p&gt;&lt;p align="left"&gt; &lt;/p&gt;

Mitigation of Multiple Air Emissions from Swine Buildings Using Corn Cob Biofilters

<abstract> <b><sc>Abstract.</sc></b> Biofiltration is a proven method to reduce odor and gas emissions from swine buildings and manure storage units. Biofilter media selection and moisture content fluctuations significantly influence biofilter performance. The purpose of this study was to test corn cobs as an alternative biofilter media because wood chips may become less available in the future due to the spread of emerald ash borer disease. In addition, a naturally occurring adsorbent (diatomaceous shale) was tested as an additive to manage biofilter media moisture content. Five 1 m x 1 m x 1 m biofilter cells were built to treat pit fan exhaust air from a swine finishing barn. A semi-continuous sampling system was used to measure the biofilters‘ inlet and outlet gas concentrations. Results showed that all of the biofilters were effective, reducing H₂S emissions on average by 7.3% to 50.1% and reducing NH₃ emissions on average by 9.8% to 86.3%. The corn cobs were less dense and more porous than the wood chips and had lower pressure drop per unit depth. Adding 15% diatomaceous shale to the corn cobs helped manage media moisture and improved H₂S and NH₃ reduction efficiencies. However, after 16 months of media aging, high levels of N₂O generation were observed during two sampling days. The estimated media cost with 15% diatomaceous shale was $0.52 per m³ h^-1 ($0.89 per cfm) of air treated. The corn cobs cost (100% corn cob biofilter) was $0.03 per m³ h^-1 ($0.05 per cfm) of air treated.