Pig House Research Articles

Computational fluid dynamics evaluation of pig house ventilation systems for improving the internal rearing environment

Due to the cold stress experienced by pigs, and the increased energy load during winters and the changes from winter to spring and summer to autumn, it is difficult to provide sufficient ventilation in pig houses. These factors can result in a poor internal environment. Therefore, fundamental measures to increase the ventilation rate and a corresponding analysis of the effects were needed to improve internal rearing environment. Due to the characteristics of invisible air, it was difficult to analyse the aerodynamic characteristics inside a pig house by field experiment. Computational fluid dynamics (CFD) has been used to overcome such limitations for the last 30 years. In this study, environmental monitoring (air temperature, humidity, etc.) in a commercial pig house were conducted to identify environmental problems. After this, CFD validated models were designed and evaluated to find effective solutions, by changing the conditions of the pig house air inlets and outlets (air buffer space, inlet duct, and exhaust fan). Compared with the conventional ventilation system of the experimental pig house, adjusting the hole spacing of the inlet duct and installing a roof–chimney exhaust fan did not significantly improve the rearing environment. However, when an air buffer space was installed just before the location of the inlet on the sidewall, the air temperature flowing through the air buffer space increased making it possible to supply more than twice the external air to the pig house, while maintaining the air temperature distribution at the height of the animal-occupied zone.

Evaluation of a Cost-Effective Ammonia Monitoring System for Continuous Real-Time Concentration Measurements in a Fattening Pig Barn.

Ammonia (NH3) emission is one of the major environmental issues in livestock farming. Gas measurements are required to study the emission process, to establish emission factors, and to assess the efficiency of emission reduction techniques. However, the current methods for acquiring reference measurements of NH3 are either high in cost or labor intensive. In this study, a cost-effective ammonia monitoring system (AMS) was constructed from a commercially-available gas analyzing module based on tunable diode laser absorption (TDLA) spectroscopy. To cope with the negative measurement biases caused by differing inlet pressures, a set of correction equations was formulated. Field validation of the AMS on NH3 measurement was conducted in a fattening pig barn, where the system was compared to a Fourier-transform infrared (FTIR) spectroscopy analyzer. Under two test conditions in a fattening pig barn, the absolute error of the AMS measurements with respect to the average obtained values between the AMS and the FTIR was respectively 0.66 and 0.08 ppmv, corresponding to 5.9% and 0.5% relative error. Potential sources of the measurement uncertainties in both the AMS and FTIR were discussed. The test results demonstrated that the AMS was capable of performing high-quality measurement with sub-ppm accuracy, making it a promising cost-effective tool for establishing NH3 emission factors and studying NH3 emission processes in pig houses.

Fine particulate matter from pig house induced immune response by activating TLR4/MAPK/NF-κB pathway and NLRP3 inflammasome in alveolar macrophages

Fine particulate matter (PM2.5) from livestock houses is harmful not only to the health and welfare of animals but also to the farmers working inside. As an important pollution source in the atmosphere environment, PM2.5 can threaten public health. PM2.5 collected from nursery pig house was studied. It included particulates of various morphologies, and the concentration of endotoxin was as high as to 681.80 EU/mg. To investigate the ability of PM2.5 from the nursery pig house to induce an immune response, porcine alveolar macrophages 3D4/21 cells were studied. The results showed that PM2.5 can induce cell death, ROS production and inflammatory cytokines release (IL-1β, IL-18, TNF-α and COX-2) by activating TLR4/MyD88 pathway and NLRP3 inflammasome. Furthermore, the downstream signaling pathways of TLR4/MyD88, MAPK and NF-κB, participated in NLRP3 inflammasome activation. To further study the role of endotoxin present in PM2.5 and the oxidative stress induced by PM2.5, polymyxin B (PMB) and N-acetylcysteine (NAC) were used to neutralize the effect of the endotoxin and inhibit the production of ROS, respectively. The results showed endotoxin and ROS played important roles in PM2.5-induced immune response. This study suggests that PM2.5 from pig house is a significant risk for immune response in alveolar macrophages.

English

Local pig production is of economic, nutritional and socio-cultural importance to livelihoods in Ghana. Data was collected from 176 local pig farmers in four regions of Ghana using pretested structured questionnaire. Majority of the farmers interviewed were males over 30 years and kept crossbred pigs (64%) with income (95%) as their main motivation. In terms of housing of pigs, most farmers use sheds (39%), about a third had permanent structures (34%), whilst the rest (22%) use stalls with a few keeping their animals in their yards (2%) or having no housing facility (2%) at all. Growth rate of pigs was a relatively important trait (49%) for the farmers compared to aesthetic traits like coat colour or ear orientation. Majority of the farmers (90%) acquired their breeding stock from family, friends and the open market with only 10% acquiring breeding stock from government breeding stations. Local pig production in the study area was characterised as semi-intensive with significant opportunities for stakeholders to make interventions for improvement through provision of improved breeds, housing, feeding and veterinary care. Key words: Food security, farmer education, pig production, sustainable breeding programmes.

Effects of Environmental Enrichment on Pig Welfare-A Review.

Simple SummaryThe legislation regarding pig housing systems states that environmental enrichment needs to be provided for group-housed pigs. Moreover, the materials used for improving animal housing are categorised as optimal, suboptimal, and of marginal interest. Straw has been considered as the optimal solution for pig housing, however there are some limitations in using it in a large amount. Therefore, other materials, objects, and toys have been used as enrichment in pig maintenance. Understanding how various enrichments influence animal welfare seems to be an important key to elaborating the best methods of improvement. This review presents new literature references regarding environmental enrichment for suckling piglets, weaning piglets, and fattening pigs.Good husbandry conditions on farms is of key importance for assuring animal welfare. One of the most important legal documents regulating the rules of maintaining pigs is the Directive 2008/120/EC, which states that group-housed pigs should have access to litter or other materials that provide exploration and occupation. Released in 2016, the Commission Recommendation (EU) 2016/336 on the application of the Council Directive 2008/120/EC characterizes the various categories of materials that may be used to improve animal welfare. According to the document, straw is considered as an optimal material for pig housing, however, materials categorized as suboptimal (e.g., wood bark) and materials of marginal interest (e.g., plastic toys) are often used in practice and scientific research. As such, the aim of this paper is to review and systematize the current state of knowledge on the topic of the impact of environmental enrichment on pig welfare. This article raises mainly issues, such as the effectiveness of the use of various enrichment on the reduction of undesirable behavior—tail biting; aggression; and stereotypies at the pre-weaning, post-weaning, and fattening stage of pig production.

Long-term microbial community dynamics at two full-scale biotrickling filters treating pig house exhaust air.

SummaryIn this study, the microbial community structure of two full‐scale biotrickling filters treating exhaust air from a pig housing facility were evaluated using 16S metabarcoding. The effect of inoculation with activated sludge of a nearby domestic waste water treatment plant was investigated, which is a cheap procedure and easy to apply in practice. The study was performed at a three‐stage and a two‐stage full‐scale biotrickling filter; of which, only the latter was inoculated. Both biotrickling filters evolved towards a rather similar community over time, which differed from the one in the activated sludge used for inoculation. However, the bacterial population at both biotrickling filters showed small differences on the family level. A large population of heterotrophic bacteria, including denitrifying bacteria, was present in both biotrickling filters. In the non‐inoculated biotrickling filter, nitrite‐oxidizing bacteria (NOB) could not be detected, which corresponded with the incomplete nitrification leading to high nitrite accumulation observed in this system. Inoculation with the wide spectrum inoculum activated sludge had in this study a positive effect on the biotrickling filter performance (higher ammonia removal and lower nitrous oxide production). It could thus be beneficial to inoculate biotrickling filters in order to enrich NOB at the start‐up, making it easier to keep the free nitrous acid concentration low enough to not be inhibited by it.

Analyse zootechnique et économique des systèmes d’élevage de porcs en Casamance (Sénégal)

Afin de mieux cerner les caractéristiques zootechniques et économiques de l’élevage de porc, une étude diagnostique a été conduite de mars à juin 2016 auprès de 324 élevages porcins, sous forme d’enquêtes transversales et rétrospectives dans les trois régions de la Casamance au Sud Sénégal. Les résultats ont montré que l’élevage porcin était pratiqué à la fois par des hommes et des femmes mariés et instruits. Ils étaient majoritairement des ethnies Diola, Mancagne et Balante et associaient l’élevage à l’agriculture, à l’activité privée ou au commerce. Ils évoluaient dans trois systèmes d’élevage différents (traditionnel, semi-intensif ou intensif), avec une nette prédominance du système traditionnel (85,5 % des élevages). Ce dernier était caractérisé par des porcheries traditionnelles améliorées (51,1 %) ou des abris de fortune (28,4 %), où étaient surtout élevés les porcs de race locale (90,4 % des exploitations). La taille moyenne du cheptel était de 19,2 ± 20,1 porcs. Dans 97 % des cas les éleveurs nourrissaient les animaux à partir de déchets de cuisine et de sous-produits agricoles et agro-industriels. L’âge moyen de mise à la reproduction était de 7,6 ± 1,8 mois et la taille moyenne de la portée était de 7,4 ± 2,2 porcelets. Ce sous-secteur d’élevage a un réel potentiel de réduction de la pauvreté car il génère selon les systèmes des revenus nets de 5435 à 7566 FCFA par porc engraissé par an. Néanmoins, le manque de formation des éleveurs, les habitats porcins inadaptés, les contraintes alimentaires et sanitaires restent les principaux facteurs handicapant l’essor de l’élevage porcin dans cette région. Il serait utile de trouver des voies alternatives d’amélioration des conditions d’habitat, d’alimentation et de suivi sanitaire des porcs, accompagnées d’une meilleure organisation et d’un renforcement de capacité des producteurs et des autres acteurs de la filière porcine.

Development of ammonia mass transfer coefficient models for the atmosphere above two types of the slatted floors in a pig house using computational fluid dynamics

Ammonia emissions from animal production systems are a concern due to their potential adverse effects on the environment. It is important for governments to adjust their policies to control ammonia emissions from animal production. To evaluate and quantify emission factors, process-based modelling is a cost-effective procedure, particularly due to the complex and diverse transfer chains. During the modelling process, ammonia mass transfer coefficient is one of the key parameters to be determined. However, inconsistencies are found in widely used expressions for mass transfer coefficients in ammonia volatilization models. This study used CFD simulations to derive the mass transfer coefficients above metal and concrete slatted floor in an experimental pig houses with 12 full-scale pig pens. Five ammonia mass transfer coefficient models were selected for comparison with the models derived from CFD simulations. It was noticed that the models derived from wind tunnel/flux chamber experiments usually predicted lower values of ammonia mass transfer coefficients compared to the models developed from full-scale measurements and/or numerical modelling. Care is needed to extrapolate the relationships developed under controlled laboratory conditions to the commercial barns. The results indicated also that the ammonia mass transfer coefficient relies heavily on the airflow patterns which could be affected by the ventilation systems, location of the inlet and outlets, internal partitions, floor types etc.. This makes it very difficult to present a universal ammonia mass transfer coefficient model for pig houses.

Optimisation of bioscrubber systems to simultaneously remove methane and purify wastewater from intensive pig farms.

The use of bioscrubber is attracting increasing attention for exhaust gas treatment in intensive pig farming. However, the challenge is to improve the methane (CH4) removal efficiency as well as the possibility of pig house wastewater treatment. Three laboratory-scale bioscrubbers, each equipped with different recirculation water types, livestock wastewater (10-times-diluted pig house wastewater supernatant), a methanotroph growth medium (10-times-diluted), and tap water, were established to evaluate the performance of CH4 removal and wastewater treatment. The results showed that enhanced CH4 removal efficiency (25%) can be rapidly achieved with improved methanotrophic activity due to extra nutrient support from the wastewater. The majority of the CH4 was removed in the middle to end part of the bioscrubbers, which indicated that CH4 removal could be potentially optimised by extending the length of the reactor. Moreover, 52-86% of the ammonium (NH4+-N), total organic carbon (TOC), and phosphate (PO43--P) removal were simultaneously achieved with CH4 removal in the present study. Based on these results, this study introduces a low-cost and simple-to-operate method to improve CH4 removal and simultaneously treat pig farm wastewater in bioscrubbers.

Cough sound analysis to assess air quality in commercial weaner barns

The respiratory health and comfort of animals are closely associated with the air quality of their living environment. The aim of the present work is to identify the relationship between animal sounds and air quality of their living environment. Cough sounds of 84 weaners and four important aerial factors (i.e., air temperature, relative humidity, ammonia concentration, and dust concentration) were measured. The resulting power spectral density (PSD) showed a significant difference in cough sounds from weaners under different air qualities. Moreover, the developed recognition algorithm, using mel frequency cepstrum coefficients (MFCCs), principal component analysis (PCA), and support vector machine (SVM), provided an average recognition rate of 95% for sound samples collected in different pig houses. The results indicate that the cough sound analysis can provide qualitative information about the situation of the air quality in commercial livestock buildings.

A quantitative risk assessment for human Taenia solium exposure from home slaughtered pigs in European countries

BackgroundTaenia solium, a zoonotic tapeworm, is responsible for about a third of all preventable epilepsy human cases in endemic regions. In Europe, adequate biosecurity of pig housing and meat inspection practices have decreased the incidence of T. solium taeniosis and cysticercosis. Pigs slaughtered at home may have been raised in suboptimal biosecurity conditions and slaughtered without meat inspection. As a result, consumption of undercooked pork from home slaughtered pigs could pose a risk for exposure to T. solium. The aim of this study was to quantify the risk of human T. solium exposure from meat of home slaughtered pigs, in comparison to controlled slaughtered pigs, in European countries. A quantitative microbial risk assessment model (QMRA) was developed and porcine cysticercosis prevalence data, the percentage of home slaughtered pigs, meat inspection sensitivity, the cyst distribution in pork and pork consumption in five European countries, Bulgaria, Germany, Poland, Romania and Spain, were included as variables in the model. This was combined with literature about cooking habits to estimate the number of infected pork portions eaten per year in a country.ResultsThe results of the model showed a 13.83 times higher prevalence of contaminated pork portions from home slaughtered pigs than controlled slaughtered pigs. This difference is brought about by the higher prevalence of cysticercosis in pigs that are home raised and slaughtered. Meat inspection did not affect the higher exposure from pork that is home slaughtered. Cooking meat effectively lowered the risk of exposure to T. solium-infected pork.ConclusionsThis QMRA showed that there is still a risk of obtaining an infection with T. solium due to consumption of pork, especially when pigs are reared and slaughtered at home, using data of five European countries that reported porcine cysticercosis cases. We propose systematic reporting of cysticercosis cases in slaughterhouses, and in addition molecularly confirming suspected cases to gain more insight into the presence of T. solium in pigs and the risk for humans in Europe. When more data become available, this QMRA model could be used to evaluate human exposure to T. solium in Europe and beyond.

Extraction efficiency of odorous compounds during a winter and summer period for partial pit ventilation in pig houses with diffuse ceiling inlet and wall inlets

Partial pit ventilation is a strategy to concentrate a large part of the air pollutants from pig houses in a small part of the ventilation air that can be treated by an air cleaner. In this study, the effect of partial pit ventilation on odorant emissions from two experimental pig houses (32 pigs in each) with two different ventilation inlet systems (diffuse ceiling inlet and wall inlet) was evaluated in two seasons (winter and summer). The emission of ammonia and odorants was measured by proton-transfer-reaction mass spectrometry. At a set point of 10% of the maximum total ventilation, the pit ventilation air contained on average 20 to 50% by mass of the different odorants in summer. In winter, when the pit ventilation exceeds 10% of the ventilation rate, it contained 30 to 65% of the various odorants. The effect of increasing the percentage of pit ventilation (10, 20 and 30%) was tested under summer conditions. This resulted in increasing pit extraction efficiency for both inlet systems and all odorants. In the wall inlet system, it also led to an increase in total emission of most compounds, while in the diffuse ceiling inlet system this was only the case for some compounds. In conclusion, the diffuse inlet system seems more favourable for pit ventilation, with generally higher pit extraction efficiencies for important odorants and a lower tendency for higher emission with increasing pit ventilation percentage.

Dynamic Heat Flux Measurements from Finishing Pigs

Abstract. Animal heat production and transfer data needs updating as genetics evolve, and newer technology provides alternative settings for collecting heat flux measurements. The project objective was to use heat flux sensors to measure the postural (resting, standing) effects on heat flux from finishing pigs, and compare estimated tissue resistance and sensible heat production based on these measurements to literature values. We measured heat flux from 12 individually housed active barrows with average (±SD) weight ranges of 95.6±15.5 kg and 111±13.9 kg, for Trials 1 and 2, respectively. We affixed heat flux sensors to the shaved areas on the right and left sides and rumps of the pigs to collect heat flux measurements every minute over a 6-h period during each trial. An overhead video camera system recorded pig behavior and positioning within each pen throughout the trials. Heat flux measurements showed rapid heat loss between a pig and floor when the pig lies on a cooled surface, but the heat flux starts to decrease almost immediately to steady state levels. When standing, the average heat flux from the rear of the pigs (124±8 W m-2) was greater than the heat flux from the sides of the animal (117±8 W m-2) (p<0.05, n=24). A linear regression model (R2=0.2735, n=24) with an intercept of 143 W m-2, suggests the heat flux decreases 0.25 W m-2 for each 1 kg increase in pig mass. Tissue resistance estimates from these heat flux measurements are approximately 60% of tissue resistance model estimates from the 1990’s. The heat flux data translate to sensible heat production estimates of 1.8 W kg-1, within the range of calorimeter-based estimates from recent literature. Keywords: Heat transfer model, Pigs, Pig housing, Tissue resistance.

Relation between energy use and indoor thermal environment in animal husbandry: a case study

Climate control is of the foremost importance in structures for intensive animal rearing because many animals (e.g. pigs and broilers) tolerate a small range of climate conditions (mainly air temperature and relative humidity) that may differ considerably from the outdoor environment. For this reason, the indoor climate in the majority of structures for animal husbandry is guaranteed by HVAC systems. On the one hand, the use of mechanical systems makes it possible to avoid production risks due to the unpredictability of the outdoor weather conditions and to maximize the feed efficiency, with positive effects on both the animal welfare and farm profit. On the other hand, the use of HVAC entails not negligible thermal and electrical energy consumptions. In literature, few data about the real thermo-hygrometric conditions and energy consumption of animal houses are present. In this work (in the framework of the EPAnHaus – Energy Performance certification of Animal Houses –project), the results obtained from a long-term monitoring campaign in two growing-finishing pig houses are presented. The performed measurements concerned environmental parameters and electrical power that were acquired during two production cycles (warm and cool seasons). For the environmental monitoring, both the buildings were equipped with temperature and relative humidity sensors embedded in portable data loggers (10 minutes logging time) that were placed in various spots inside the houses. Outdoor data were obtained through a weather station located near the test site. Concerning the energy monitoring, power transducers connected to portable data loggers (10 seconds logging time) were placed in the electric panel of each house to log the electrical energy consumptions due to ventilation, lighting and automatic feeding. The acquired data were used for carrying out analysis concerning the indoor thermal environment, its characterization in relation with the animal welfare, the electrical energy uses and the existing relations between all these aspects. The obtained data were used to evaluate the effectiveness of the HVAC system in guaranteeing the adequate indoor climate conditions (avoiding heat/cold stress conditions) and to identify electrical energy uses.

Behavioural response of crossbred (Landrace × Desi) pigs under different floor space allowances

Present investigation was carried out to study the behaviour of pigs at 33 and 50% reduced floor space allowances in relation to Indian standards (IS: 3916-1966) for housing of pigs. Crossbred (Landrace × Desi) barrows (36) were reared with 3 different floor space allowances (n = 4 (group size) × 3 (replications) = 12 each) i.e. group TIS (control) had floor space allowance as per Indian standards, while T2/3 and T1/2 treatment groups had 33 and 50% reduced floor space allocation per pig. Accordingly, during weaner (6–14 weeks), grower (15–22 weeks) and finisher (23–28 weeks) stages, 3 different floor spaces were provided. During each growth stage (weaner/grower/ finisher), activities of each unit (consisting of 4 animals) were recorded thrice in sessions of 2 consecutive hours (an hour before (preprandial) and after (prandial and postprandial) offering of second meal in afternoon). Total time spent in agonistic activities did not differ among the groups. However, parallel pressing agonistic activity was more in T1/2 group during grower and finisher stages at prandial and postprandial time while in TIS group during weaner stage at preprandial time. Time spent resting was higher in TIS group at prandial and postprandial time during weaner stage while it was higher in T2/3 group during grower stage. Exploratory activities and social interactions were maximum in T2/3 group during weaner and finisher stages and differed significantly from T1/2 group. From behavioural response, it can be concluded that suitable floor space allowance should lie in between 33 to 50% reduction in relation to IS specifications.

Effect of ventilation settings on ammonia emission in an experimental pig house equipped with artificial pigs

The aim of this study was to compare the impact of 3 ventilation set-point temperatures (Tset = 21, 23 & 25 °C) on indoor climate and NH3 emission, using 2 pig compartments with underfloor air distribution (UFAD) and equipped with artificial pigs. The artificial pigs consisted of mock-up pigs to simulate heat production and a spraying installation to mimic pig urination by applying urea solution onto the fully slatted pen floors in the test compartments. The study identified ground channel temperature (TGC) as a key factor affecting NH3 emission (P

Reservoirs and Transmission Pathways of Resistant Indicator Bacteria in the Biotope Pig Stable and along the Food Chain: A Review from a One Health Perspective

The holistic approach of “One Health” includes the consideration of possible links between animals, humans, and the environment. In this review, an effort was made to highlight knowledge gaps and various factors that contribute to the transmission of antibiotic-resistant bacteria between these three reservoirs. Due to the broad scope of this topic, we focused on pig production and selected “indicator bacteria”. In this context, the role of the bacteria livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) and extended spectrum beta-lactamases carrying Escherichia coli (ESBL-E) along the pig production was particularly addressed. Hotspots of their prevalence and transmission are, for example, pig stable air for MRSA, or wastewater and manure for ESBL-E, or even humans as vectors in close contact to pigs (farmers and veterinarians). Thus, this review focuses on the biotope “stable environment” where humans and animals are both affected, but also where the end of the food chain is not neglected. We provide basic background information about antibiotics in livestock, MRSA, and ESBL-bacteria. We further present studies (predominantly European studies) in tabular form regarding the risk potentials for the transmission of resistant bacteria for humans, animals, and meat differentiated according to biotopes. However, we cannot guarantee completeness as this was only intended to give a broad superficial overview. We point out sustainable biotope approaches to try to contribute to policy management as critical assessment points in pig housing conditions, environmental care, animal health, and food product safety and quality as well as consumer acceptance have already been defined.

Indoor distribution characteristics of airborne bacteria in pig buildings as influenced by season and housing type.

ObjectiveA concentration of airborne bacteria generated from swine houses is recognized to be relatively higher than other work places and it is essential to optimally manage it to prevent farmers’ respiratory diseases. This study was conducted to assess the distribution characteristics of airborne bacteria in swine houses located at South Korea.MethodsA total 27 pig buildings of the enclosed type operated with mechanical ventilation system by a side wall fan and deep-pit manure system with slats were surveyed. Air samples were collected at 1.0 m above the middle floor in pig housing room. A six-stage viable particulate cascade impactor was used to identify the distribution of the sizes of particles in diameter.ResultsSeasonal mean levels of airborne bacteria in the housing rooms of gestation/farrowing pigs, nursery pigs and growing/fattening pigs were 3,428(±1,244) colony forming unit (cfu)/m3, 8,325(±3,209) cfu/m, and 13,254(±6,108) cfu/m3 for spring; 9,824(±2,157) cfu/m3, 18,254(±5,166) cfu/m3, and 24,088(±9,274) cfu/m3 for summer; 1,707(±957) cfu/m3, 4,258 (±1,438) cfu/m3, and 8,254(±2,416) cfu/m3 for autumn; and 2,322(±1,352) cfu/m3, 6,124(±1,527) cfu/m3 and 12,470(±4,869) cfu/m3 for winter, respectively.ConclusionConcentrations of airborne bacteria according to pig housing type were highest in growing/fattening housing room followed by nursery housing room and gestation/farrowing housing room. In terms of seasonal aspect, the pig building showed the highest levels of airborne bacteria in summer followed by spring, winter and autumn. The respirable airborne bacteria which are ranged between 0.6 and 4.7 μm accounted for approximately 60% compared to total airborne bacteria regardless of pig housing type.

Thermal environment sensor array: Part 2 applying the data to assess grow-finish pig housing

Current thermal environment (TE) assessment techniques for controlling livestock and poultry facilities often solely use dry-bulb temperature (Tdb) and occasionally relative humidity (RH) as assessment parameters. The TE sensor array (TESA; Part 1) provides the opportunity to simultaneously quantify Tdb, RH, airspeed, and black globe temperature, but there are no existing methods incorporating these additional TE parameters to accurately assess the TE based on the thermal demands of the animal. Hence, the goal of Part 2 of this series was to develop a technique for evaluating the TE as a function of mean body temperature difference from thermally comfortable (ΔTb) using body mass, Tdb, RH, and airspeed inputs. Multiple regression analysis of the simulated data from the mechanistic thermal balance model for group-housed growing pigs was used to develop the Housed Swine Heat Stress Index (HS2I), which scales impact of the TE from 0 (thermally comfortable) to 10 (severe heat stress). Further, a wetted skin adjustment parameter was included to enable analysing TE with sprinklers. Simulated and predicted ΔTb agreed well without wetted skin (R2 = 0.98; RMSE = 0.061 °C) and with wetted skin (R2 = 0.97; RMSE = 0.054 °C). The HS2I was applied to assess the spatiotemporal TE data collected by TESA in the commercial grow-finish facility presented in Part 1. HS2I can be used to evaluate the potential impact of the TE in existing facilities and as a design tool to explore different ventilation and cooling strategies.

Sources and pollution characteristics of antibiotic resistance genes and conditional pathogenic bacteria in concentrated swine feeding operation.

Air in concentrated animal feeding operations contains antibiotic resistance genes and airborne pathogens, with potential threat to human and animal health. In this study, air was sampled in the living area, outside, and inside of a fattening pig house in a pig farm for 24 and 48 hours. Feedstuffs, drinking water additives, and feces in the pig house were collected. Three kinds of antibiotic resistance genes (macrolide, β-lactam, and tetracycline) and seven pathogenic microorganisms (Campylobacter, Clostridium perfringens, Enterococcus, Escherichia coli, Yersinia enterocolitica, Staphylococcus spp., and Streptococcus suis) were detected by polymerase chain reaction (PCR). Six genes with high detection rates were selected, with their concentrations being determined by real-time quantitative PCR (qPCR). Results showed that three macrolide and two tetracycline resistance genes were detected in all air samples. Enterococcus, Escherichia coli, Yersinia enterocolitica, and Staphylococcus spp. were detected in air samples and drinking water additive. The concentrations of most target genes were above 104 copies·m-3. The gene concentrations near the pig house were much higher than those in the living area. Main sources of antibiotic resistance genes and pathogens in the air were pig manure and drinking water additive. Sampling time of 24 h in the pig farm met the requirements for PCR detection. Sampling time of 48 h had a higher sampling efficiency than that of 24 h in the living area of the pig farm, whereas sampling time of 24 h was more appropriate than that of 48 h in high bioaerosol concentration area such as the pig house.