Commercial Swine Farms Research Articles

Noninvasive thermographic evaluation of the thermal condition of piglets in the first month of life

In a commercial swine farm located in Zacoalco de Torres, Jalisco, we carried out an experiment to obtain information regarding environmental temperature effects on the performance of 13 litters of piglets during the first twenty eight days. It was used a Fluke® thermograph to obtain temperature images. Hypothesis was it is possible to establish the effect of heat sources trough thermographic images on the response of the litters. The aim was to evaluate the thermal condition of the piglets in the first twenty eight days of life and their performance until weaning. Piglets were F1 crosses (York x Landrace) x Pietrain. Treatments were minimum, maximum, average and central point temperatures. Variables registered were mortality, weaned piglets, weight of the weaned litters, piglets’ individual weight and number of lactating days. Contribution is that temperatures in the first week have more influence on mortality, weaned piglets, weight of the weaned litters, piglets’ individual weight and number of lactating days, than the ones in the first month.

Noninvasive thermographic evaluation of the thermal condition of piglets in the first month of life

In a commercial swine farm located in Zacoalco de Torres, Jalisco, we carried out an experiment to obtain information regarding environmental temperature effects on the performance of 13 litters of piglets during the first twenty eight days. It was used a Fluke® thermograph to obtain temperature images. Hypothesis was it is possible to establish the effect of heat sources trough thermographic images on the response of the litters. The aim was to evaluate the thermal condition of the piglets in the first twenty eight days of life and their performance until weaning. Piglets were F1 crosses (York x Landrace) x Pietrain. Treatments were minimum, maximum, average and central point temperatures. Variables registered were mortality, weaned piglets, weight of the weaned litters, piglets’ individual weight and number of lactating days. Contribution is that temperatures in the first week have more influence on mortality, weaned piglets, weight of the weaned litters, piglets’ individual weight and number of lactating days, than the ones in the first month.

Development of Tool to Evaluate Pig Flow on Commercial Swine Farms

Development of Tool to Evaluate Pig Flow on Commercial Swine Farms

Effects of Using Farm-Grown Forage as a Component in ad Libitum Liquid Feeding for Pregnant Sows in Group-Housing on Body Condition Development and Performance

When feeding pregnant sows, optimal body condition at birth is sought to avoid the effects of a deviant nutritional condition on health and performance. Various feeding concepts exist but mainly have a restriction in quantity and renunciation of farm-grown forage in common. An ad libitum liquid feeding system based on farm-grown forage in combination with a sow sorting gate (according to body weight—using mechanical scales) was realized on a commercial swine farm. The sorting gate coordinated access to two feeding areas with rations based on whole plant wheat-silage (WPWS) differing in energy content. In this study with a total of 183 pregnant sows, effects of restrictive dry feeding (System I) were compared with ad libitum liquid feeding based on farm-grown forage (System II). Sows were monitored regarding body condition development during pregnancy by measuring body condition score (BCS), body weight (BW), and back fat thickness (BFT) on different time points. Sow and piglet health (vaginal injuries of sows, rectal temperature during the peripartal period, vitality of newborn piglets) and performance data regarding litter characteristics were also recorded. Body condition development of the sows was absolutely comparable. Performance indicators and the course of birth were also similar but with significantly higher scores for piglet vitality in System II (p < 0.05). The tested concept offers opportunities for more animal welfare and sustainability but remains to be further investigated regarding the repertoire of possibly applied farm-grown forage and the effects of the concept in the transit phase of sows.

Potential risk factors for Brachyspira hyodysenteriae, Lawsonia intracellularis and Salmonella spp. infection and their prevalence in commercial swine farms in Thailand

Potential risk factors for Brachyspira hyodysenteriae, Lawsonia intracellularis and Salmonella spp. infection and their prevalence in commercial swine farms in Thailand

A cross-sectional study of the nasal and fecal microbiota of sows from different health status within six commercial swine farms.

BackgroundCull sows are a unique population on swine farms, often representing poor producing or compromised animals, and even though recent studies have reported that the microbiome is associated with susceptibility to diseases, the microbiome of the cull sow population has not been explored. The main objective of this study was to investigate whether there were differences in fecal and upper respiratory tract microbiota composition for groups of sows of different health status (healthy, cull, and compromised/ clinical sows) and from different farms (1 to 6).MethodsSix swine farms were visited once. Thirty individual fecal samples and nasal swabs were obtained at each farm and pooled by five across health status and farm. Samples underwent 16S rRNA gene amplicon sequencing and nasal and fecal microbiota were analyzed using QIIME2 v.2021.4.ResultsOverall, the diversity of the nasal microbiota was lower than the fecal microbiota (p < 0.01). No significant differences were found in fecal or nasal alpha diversity by sow’s health status or by farm. There were significant differences in nasal microbial composition by farm and health status (PERMANOVA, p < 0.05), and in fecal microbiota by farm (PERMANOVA, p < 0.05), but not by health status. Lastly, at the L7 level, there was one differentially abundant taxa across farms for each nasal and fecal pooled samples.DiscussionThis study provided baseline information for nasal and fecal microbiota of sows under field conditions, and results suggest that farm of origin can affect microbial diversity and composition. Furthermore, sow’s health status may have an impact on the nasal microbiota composition.

Antibody responses to porcine reproductive and respiratory syndrome virus, influenza A virus, and Mycoplasma hyopneumoniae from weaning to the end of the finisher stage in fourteen groups of pigs in Ontario, Canada

BackgroundRespiratory diseases are among the most important factors affecting swine farm productivity in Canada. The objectives of this study were to investigate antibody responses to porcine reproductive and respiratory syndrome virus (PRRSV), influenza A virus (IAV), and Mycoplasma hyopneumoniae (M. hyopneumoniae) from weaning to the end of the finisher stage on a subset of commercial swine farms in Ontario, Canada, and to examine the association between nursery diet and antibody responses.ResultsOverall, older pigs were more likely to test seropositive for PRRSV and less likely to test seropositive for M. hyopneumoniae (p < 0.001). Pigs were more likely to test seropositive for IAV at weaning and the end of the grower and finisher stages compared to the end of nursery (p < 0.001). Pigs that were seropositive for IAV were more likely to test seropositive for both PRRSV and M. hyopneumoniae (p < 0.001). Two, 9, and 4 groups that had more than 20% of pigs seropositive to PRRSV, IAV, and M. hyopneumoniae, respectively, from the end of nursery to the end of finisher were classified as seropositive. Pigs fed a plant-based (low complexity) diet during nursery were more likely to be seropositive for PRRSV (p < 0.001) but there were no significant differences in seropositivity to IAV or M. hyopneumoniae due to nursery diet complexity.ConclusionsThis study provides information regarding changes in serum antibody in pigs across different stages of production and highlights periods of vulnerability. Additionally, these findings may encourage further research into the effects of nursery diet complexity on disease susceptibility and immune response.

The Social Profile, Constraints, and Its Impact on Swine Herd Size in Tra Vinh Province, Vietnam

The objective of this study was to describe social profile, constraints of swine farmers, and its impact on swine herd size in Tra Vinh Province. This study was conducted in Tra Vinh Province, one of the provinces in Mekong delta, Vietnam. A total of 120 swine farmers selected from small swine farms to commercial swine farms were surveyed with information gathered on 11,466 swine. All of the swine farmers in this study were purposively chosen and interviewed with the questionnaires for data collection. All swine farmers have kept at least 1 swine per farm or had experience at least 1 year for raising and trading swine. The results showed that the majority of farmers were males (57.5%), with the age range of 20-40 years old (47.5%), having more than 10 years of experience (52.5%), having 1-3 members in the family (87.1%), 85% of farmers focused on farm, farmers having livestock farming plus cropping accounted for 55.8%, and farmers having medium farm size with an average of 95-96 heads/farm. In addition, there were 4 constraints that farmers confirmed, i.e., capital (31.6%), disease outbreak (75%), low bargaining power (40%), and the fluctuation of feed price (59.16%). Moreover, experience (p&lt;0.01), education (p&lt;0.01), disease outbreak (p&lt;0.05), and the fluctuation of feed price (p&lt;0.05) had a strong influence on swine herd. It could be concluded that farmers having higher experience and education kept a larger number of swine than others. In contrary, when disease outbreak and the fluctuation of feed price emerge, farmers tended to control their swine herd size.

296 Awardee Talk: The Genetics of Sow Longevity

Abstract Sow longevity is a key productivity indicator trait that has real economic and welfare importance for commercial swine farms globally. The average parity at culling is 3.8 parities. Reports indicate that it takes 3 to 4 parities before a sow “pays for herself.” Research groups around the world have reported heritabilities estimates for sow longevity traits ranging from 0.05 to 0.35. Estimate differences result from the animal population under evaluation, the trait being evaluated, and the methodology employed to obtain the genetic parameter estimate. Because sow longevity is measured at the end of the sow’s productive life, indicator traits like age at first farrowing, leg conformation, and other traits are utilized in gilt selection programs. The genetic correlations between sow longevity and lifetime production traits range have been reported to range from 0.64 to 0.94, suggesting that selection will improve sow longevity. Genetic markers have been identified that affect both sow longevity and other indicator traits. Selection to improved sow longevity still requires phenotypes. Future technologies, e.g. CT scans, digital images, and automated disease detection, will provide additional phenotypes. Continued hardware, software, and molecular developments will improve selection accuracy for sow longevity traits and related traits. Research is needed to evaluate the impact that non-additive genetic effects have on sow longevity and other fitness-related traits. Sow longevity seems to be an ideal trait to employ genomic selection in order to make more rapid trait improvements because it is measured late in life, it is sex-limited, and the trait is not directly measured on nucleus animals. In conclusion, sow longevity and related traits have sufficient heritability and variation to improve through traditional and genomic enhanced selection methods. Selection programs employing effective genomic selection programs will be more effective in improving sow longevity trait and related traits and ultimately economical return.

Molecular epidemiology and glycomics of swine influenza viruses circulating in commercial swine farms in the southeastern and midwest United States

Tracking the genetic diversity and spread of swine influenza viruses (SIVs) in commercial swine farms is central for control and to reduce the potential emergence of SIV reassortants. We analyzed the diversity of SIVs in nasal washes or oral fluids from commercial swine farms in North Carolina using influenza M qRT-PCR and hemagglutinin (HA) and neuraminidase (NA) subtyping. We found a predominance of H1 HAs and N2 NAs in the samples examined. The majority of the H1 HAs could be further classified into gamma and delta subclusters. We also identified HAs of the H1 alpha cluster, and those of human novel pandemic origin. Glycan binding profiles from a representative subset of these viruses revealed broad α2,6 sialylated glycan recognition, though some strains exhibited the ability to bind to α2,3 sialic acid. These data show that SIV surveillance can aid our understanding of viral transmission dynamics and help uncover the diversity at the human-swine interface.

First molecular detection and complete sequence analysis of porcine circovirus type 3 (PCV3) in Peninsular Malaysia.

Porcine circovirus type 3 (PCV3) is a newly emerging virus in the swine industry, first reported recently in 2016. PCV3 assembles into a 2000 bp circular genome; slightly larger than PCV1 (1758–1760 bp), PCV2 (1766–1769 bp) and PCV4 (1770 bp). Apart from being associated with porcine dermatitis and nephropathy syndrome (PDNS), PCV3 has been isolated from pigs with clinical signs of reproductive failures, myocarditis, porcine respiratory disease complex (PRDC) and neurologic disease. Given that PCV3 is increasingly reported in countries including Thailand and U.S. with whom Malaysia shares trade and geographical relationship; and that PCV3 is associated with several clinical presentations that affect productivity, there is a need to study the presence and molecular characteristics of PCV3 in Malaysian swine farms. Twenty-four commercial swine farms, three abattoirs and retail shops in Peninsular Malaysia were sampled using convenience sampling method. A total of 281 samples from 141 pigs, including 49 lung archive samples were tested for PCV3 by conventional PCR. Twenty-eight lung samples from wild boar population in Peninsular Malaysia were also included. Nucleotide sequences were analyzed for maximum likelihood phylogeny relationship and pairwise distances. Results revealed that PCV3 is present in Peninsular Malaysia at a molecular prevalence of 17.02%, with inguinal lymph nodes and lungs showing the highest molecular detection rates of 81.82% and 71.43% respectively. Despite wide reports of PCV3 in healthy animals and wild boars, no positive samples were detected in clinically healthy finishers and wild boar population of this study. PCV3 strain A1 and A2 were present in Malaysia, and Malaysian PCV3 strains were found to be phylogenetically related to Spanish, U.S. and Mexico strains.

Antimicrobials Used in Backyard and Commercial Poultry and Swine Farms in the Philippines: A Qualitative Pilot Study.

Chicken and pork are the most frequently consumed meat products in the Philippines. Swine and poultry are reared in either commercial farms (CMf) or backyard farms (BYf); the latter production system is relatively common and essential to food security in low- and middle-income countries (LMICs) such as the Philippines. Similar to resource-limited LMICs, antimicrobial use (AMU) surveillance has not yet been established; thus, AMU in food animals is a knowledge gap in understanding the emergence of antimicrobial resistance (AMR) in zoonotic foodborne bacteria in the country. This qualitative AMU pilot study aims to describe the antimicrobial active ingredients (AAIs) used and associated AMU practices (e.g., source of AAIs and informed AMU decisions) by poultry and swine CMf and BYf in the Philippines. Ninety-three farms across four regions in the Philippines voluntarily provided AMU information as part of a larger biosecurity and good practices study. The percentage of farms using AAI over the total number of farms was the metric used to describe AMU. In total, there were 30 AAIs used (CMf: n =27 and BYf: n = 13); per farm, the number of AAIs used ranged from 1 to 7. The spectrum of AAIs was more diverse in swine (n = 24) compared to poultry (n = 18). Enrofloxacin was the most frequently reported AAI in poultry (33%) and swine (36%) farms. Respiratory diseases were the most frequently reported reason for AMU in both species. Between production systems, significant differences were observed in the percentage of farms using amoxicillin (27% CMf vs. 3% BYf), colistin (17% CMf vs. 3% BYf), and oxytetracycline (12% CMf vs. 39% BYf). In terms of AMU practices, of important concern was the over-the-counter access of AAIs at retail outlets and the limited veterinary oversight in BYf. Our data indicated that antimicrobials critically important for human medicine are frequently used in poultry and swine farms in the Philippines. This study can inform the development of guidelines for curbing AMR through prudent AMU and serves as a reference point for AMU surveillance capacity development in the Philippines.

The Prevalence, Genetic Characterization, and Evolutionary Analysis of Porcine Pegivirus in Guangdong, China.

Porcine pegivirus (PPgV) is a member of the Pegivirus genus in the Flaviviridae family. PPgV is an emerging virus that has been discovered in swine herds in Germany, the United States, China, Poland, Italy, and the United Kingdom, indicating a wide geographical distribution. In this retrospective study, 339 pig serum samples were collected from 20 different commercial swine farms located in nine cities in Guangdong Province, China, from 2016 to 2018, to investigate the prevalence and genetic diversity of PPgV in this geographical region. PPgV was detected in 55% (11/20) of the farms using nested reverse transcription PCR, with 6.2% (21/339) of pigs testing positive for PPgV. The yearly PPgV-positive rate increased from 2.6% to 7.5% between 2016 and 2018. Sequencing of PPgV-positive samples identified two complete polyprotein genes and seven partial NS5B genes from different farms. Comparative analysis of the polyprotein genes revealed that PPgV sequences obtained in this study showed 87.4%-97.2% similarity at the nucleotide level and 96.5%-99.4% similarity at the amino acid level with the reference sequences. Sequence alignment and phylogenetic analysis of the complete polyprotein gene and partial NS5B and NS3 genes demonstrated a high genetic similarity with the samples from the USA. The finding of the wide distribution of PPgV in swine herds in Guangdong Province will contribute to the understanding of the epidemiological characteristics and genetic evolution of PPgV in China.

Practical aspects of PRRSV RNA detection in processing fluids collected in commercial swine farms

Processing fluid samples are easily collected under field conditions and provide the means to test more piglets more frequently in a practical way, thereby improving PRRSV surveillance. However, a deeper understanding of the diagnostic characteristics of this newly described sample type is still required. Therefore, the objective of this field-based study was to determine the relationship between viremic piglets and the detection of PRRSV RNA in processing fluid samples. In two PRRSV-positive breeding herds, processing fluids (n = 77) and individual piglet serum samples (n = 834) were collected from 77 litters in three sampling events and tested for PRRSV RNA. Among the 77 litters in the study, 55 litters (71.4%) contained no viremic piglets and processing fluids tested negative for PRRSV RNA. Among the 22 (28.6%) litters with ≥1 viremic piglets, 10 litters contained a single viremic piglet and 5 of the 10 processing fluids from this group tested positive for PRRSV RNA. Based on a fitted mixed effects logistic regression model, the probability of detecting PRRSV RNA in processing fluids was highly dependent on the number of viremic piglets contributing to the sample. When the within-litter prevalence was ≥39%, the probability of detecting PRRSV RNA in processing fluids was ≥95%. By extension, the results suggest that pooling processing fluids from several litters increases the probability of PRRSV RNA detection because of the greater likelihood of including multiple litters each with ≥1 viremic piglets. In contemporary breeding herds that use processing fluid samples for PRRSV surveillance, the diagnostic costs associated with testing 100% of the processing-age piglet population can be estimated at €0.077 ($0.086 USD) per pig weaned. In contrast, to achieve an equivalent testing coverage with the use of individual piglet serum samples, the diagnostic costs associated would be €4.48 ($5.00 USD) per pig weaned. Processing fluid represents a practical, reliable and efficient method to surveil breeding herds for PRRSV because it allows for continuous surveillance at a low cost.

Association between oropharyngeal microbiome and weight gain in piglets during pre and post weaning life.

Birth weight and subsequent weight gain is of critical importance in the survival and performance of piglets on a commercial swine farm setting. Oropharyngeal microbiome could influence immunity, and feeding behavior thus impacting health and weight gain. We used 16S rRNA gene sequencing to profile the composition and predicted metabolic functionality of the oropharyngeal microbiota in 8 piglets (4 with a birthweight ≤ 1.0 kg and 4 with a birthweight ≥ 1.7 kg) at 11, 26, and 63 days of age. We found 9 genera that were significantly associated with average daily gain (ADG) at 11 days (false discovery rate, FDR < 0.05) and 26 days of age (FDR < 0.1), respectively. The microbial functional profile revealed several pathways associated with ADG (FDR < 0.05). Among these, pathways related to degradation of catechols showed a positive association with ADG at 11, 26, and 63 days of age, implying a potential to breakdown the host-derived catecholamines. We also noted that pathways related to the biodegradation of nucleosides and nucleotides increased with ADG during the pre-weaning phase, while those involved in their biosynthesis decreased. Our findings provide insights into the oropharyngeal microbial memberships and metabolic pathways that are involved in a piglet’s weight gain. Thus, providing a basis for the development of strategies aimed at improving weight gain in pigs.

Full-genome sequences of porcine circovirus 3 (PCV3) and high prevalence in mummified fetuses from commercial farms in Brazil

The clinical implications of recently discovered porcine circovirus 3 (PCV3) infections are still unknown. The potential role of this emerging virus in reproductive loss in swine has been described. Herein, we report a high prevalence of PCV3 in mummified fetuses from sows maintained in modern farms in Rio Grande do Sul, Santa Catarina, Paraná, Goiás, and Mato Grosso do Sul states, Brazil. For this analysis, 276 mummified fetuses from 11 commercial swine farms were included. The presence of PCV3 DNA was confirmed using PCR, and the complete sequence of five different viral strains was obtained. Sequences of PCV3 genomes available on GenBank were then used for phylogenetic tree construction. Of the 276 mummified fetuses examined, 270 (nearly 97%) were positive for PCV3. In 93.1% of the fetuses, co-infections with at least one of the following agents were identified: porcine parvovirus (PPV), porcine circovirus 2 (PCV2) and Leptospira spp. Twelve fetuses were positive for PCV3 alone. The amino acid sequence of the capsid gene for the five viral strains shared 98–100% homology among them. Analysis of the DNA sequence indicates that the viruses identified in this study belong to the PCV3a1 subgroup. In summary, PCV3 DNA was detected in mummified fetuses at a surprisingly high rate. The role of PCV3 in porcine circovirus-associated disease (PCVAD) is still uncertain. However, considering that PCV3 has been detected in a variety of conditions, even in healthy animals, the present results confirm the need to investigate PCV3 as a causative agent of fetal mummification in swine.

Assessment of reproductive and growth performance of pigs on commercial swine farms in southern Kyushu, Japan.

The objective of the present study was to assess the productivity of pigs to investigate the time-dependent change in productivity and compare productivity according to breeding company group and porcine reproductive and respiratory syndrome (PRRS) status on commercial swine farms in southern Kyushu, Japan. Data used in the present study were 245 annual productivity records from 2014 to 2018 obtained from 72 farms. Average sow inventory was 481.2 sows. Mean numbers of pigs weaned per sow per year and market pigs sold per sow per year were 23.7 and 21.6, respectively. Pigs born alive per litter increased from 11.1 to 11.9 pigs from 2014 to 2018 (p<.05). Farms using domestic breeding companies had similar numbers in 2016 to those using international breeding companies, but fewer pigs in 2014, 2015, 2017, and 2018 (p<.05). Farms with an unknown or unstable PRRS status had fewer pigs born alive per litter and pigs weaned per sow per year than those with stable or negative PRRS statuses (11.2±0.06 vs. 11.8±0.08 pigs and 22.6±0.38 vs. 25.0±0.22 pigs, respectively; p<.05). These results can be used to establish feasible targets and standards of performance to identify problem areas and improve production.

Prevalence and antibiotic resistance of Campylobacter coli and Campylobacter jejuni in Greek swine farms

Campylobacter species are one of four key global causes of human diarrheal diseases, according to W.H.O. It is considered to be the most common bacterial cause of human gastroenteritis in the world. The objective of this study was to estimate the prevalence of Campylobacter coli (C. coli) and Campylobacter jejuni (C. jejuni) in Greek commercial swine farms, and describe the antimicrobial resistance of the isolated strains. A total of 1,000 rectal swabs (50 per farm) were collected from twenty swine farms in Greece. Ten rectal samples had been randomly collected from each of five age-groups (suckling piglets, nursery pigs, grower pigs, finisher pigs, sows). Isolation of Campylobacter spp. was performed using the ISO 10272-1:2017. A PCR method, based on the amplification of mapAC.jejuni and ceuEC.coli specific genes, was used for identification of the isolated strains. All isolates were tested for their susceptibility against gentamycin, erythromycin, ciprofloxacin, tetracycline and meropenem; EUCAST guidelines were used for the interpretation. The results showed that 16 out of the 20 farms (80%) and 491 (49%) of the samples were positive for Campylobacter spp. Prevalence of C.coli was 38% (95% CI 35.1-41.1) and of C.jejuni 10.9% (95% CI 9,1-13.0). Sows were 1.4 times more likely to be colonized by Campylobacter spp than sucking piglets (p<0.05) while nursery and grower pigs were 2.14 and 2 times more likely to be colonized than sows p<0.001). However, colonization was not associated with farm size. High rates of resistance were recorded for tetracycline (67,3%), while 18,1%, 7,3% and 3.9% of the isolates were resistant in ciprofloxacin, erythromycin and gentamycin respectively. Thirty-two of the isolates (6,52%) were classified as multidrug resistant; resistance to meropenem was not found. Our findings indicate high prevalence of C.coli and C.jejuni in Greek pig farms with high resistant rates to tetracycline and ciprofloxacin; this constitutes a potential reservoir for resistance genes spread to the community.

Piglet production by non-surgical transfer of vitrified embryos, transported to commercial swine farms and warmed on site.

We investigated the feasibility of piglet production by non‐surgical embryo transfer (Ns‐ET) of vitrified porcine blastocysts and expanded blastocysts transported to commercial farms and warmed on site (V/T/W embryos). Ns‐ET was performed by depositing 11–20 vitrified and warmed embryos at a proximal site within the uterus via a catheter. In Experiment 1, the effect of donor–recipient estrous cycle asynchrony on the efficiency of Ns‐ET of vitrified and ordinary warmed embryos was investigated at the experimental facility. With a 1‐day delay recipients relative to that of donor, the farrowing rate was 50.0% and the survival rate to term was 21.1%. In Experiment 2, Ns‐ET using recipients with a 1‐day delay and vitrified embryos after one‐step warming and dilution was evaluated at the experimental facility. Although the resulting farrowing rate was 42.9%, the survival rate was 6.4%. In Experiment 3, Ns‐ET was conducted using V/T/W embryos at four commercial farms, where piglets derived from them were produced. When artificial insemination was conducted prior to Ns‐ET, the farrowing and survival rates obtained using V/T/W embryos were 75.0%, and 21.3%, respectively. These results show that Ns‐ET of V/T/W embryos using this protocol would be feasible for piglet production at farms.

Evaluation of Short-Term Exposure Levels on Ammonia and Hydrogen Sulfide During Manure-Handling Processes at Livestock Farms

BackgroundAmmonia and hydrogen sulfide are harmful gases generated during aerobic/anaerobic bacterial decomposition of livestock manure. We evaluated ammonia and hydrogen sulfide concentrations generated from workplaces at livestock farms and determined environmental factors influencing the gas concentrations.MethodsFive commercial swine farms and five poultry farms were selected for monitoring. Real-time monitors were used to measure the ammonia and hydrogen sulfide concentrations and environmental conditions during the manure-handling processes. Monitoring was conducted in the manure storage facility and composting facility. Information on the farm conditions was also collected through interview and walk-through survey.ResultsThe ammonia concentrations were significantly higher at the swine composting facilities (9.5–43.2 ppm) than at other manure-handling facilities at the swine and poultry farms, and high concentrations of hydrogen sulfide were identified during the manure agitation and mixing process at the swine manure storage facilities (6.9–19.5 ppm). At the poultry manure-handling facilities, the ammonia concentration was higher during the manure-handling processes (2.6–57.9 ppm), and very low hydrogen sulfide concentrations (0–3.4 ppm) were detected. The air temperature and relative humidity, volume of the facility, duration of manure storage, and the number of animals influenced the gas concentrations.ConclusionA high level of hazardous gases was generated during manure handling, and some levels increased up to risk levels that can threaten workers' health and safety. Some of the farm operational factors were also found to influence the gas levels. By controlling and improving these factors, it would be possible to protect workers' safety and health from occupational risks.