Piggeries Research Articles

Seroepidemiological Survey of Hepatitis E Virus in Intensive Pig Farming in Vojvodina Province, Serbia.

Hepatitis E virus (HEV) is the causative agent of acute hepatitis E infection in humans. Two epidemiological patterns of the disease exist-endemic and sporadic. Genotypes 1 (HEV-1) and 2 (HEV-2) are transmitted through contaminated water and are responsible for the outbreaks of many large-scale epidemics in developing countries of Asia and Africa. Genotypes 3 (HEV-3) and 4 (HEV-4) have zoonotic potential and cause sporadic cases and small outbreaks in high-income countries. The first case of HEV infection in swine was confirmed in 1997 and later detected in other animal species. The aim of this study was to investigate the seroprevalence of HEV infection in pig farms in Vojvodina province, Serbia. Three hundred blood samples were collected from five different categories of pigs from 3 different farms on the territory of the South Bačka district in Vojvodina (Serbia). The analyses were conducted by in-house ELISA, while the western blot method was used as a confirmatory test for doubtful results. The presence of HEV IgG was detected on all three examined farms. The established seroprevalence in Farm A was 37%, 31% in Farm B, and 54% in Farm C. The mean seroprevalence for all farms was 40.66%. A higher seroprevalence was found in fatteners compared to younger categories of pigs. We concluded that HEV is widespread on pig farms with intensive management. Further analyses should be conducted with the aim of implementing a surveillance program to prevent possible human infection.

Impact of Stocking Density on Welfare, Behavior, and Growth Performance of Large White Yorkshire Pigs under Indian Condition

Aim: This study aimed to evaluate the effects of varying stocking densities on the welfare, behaviour, and production performance of growing Large White Yorkshire pigs. Study Design: The research focused on assessing the influence of decreasing floor space allowance per pig on welfare indicators, including behavioural patterns, growth metrics, and feed efficiency. Seventy-four weaned pigs were randomly divided into four treatment groups with stocking densities ranging from 0.3 m²/pig to 0.21 m²/pig. Behavioural data were recorded using smartphone cameras and CCTV, while growth and feed metrics were systematically measured. Place and Duration of Study: The experiment was conducted from 2020 to 2023 at the Piggery Farm, Department of Livestock Production Management, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, India (Latitude: 30°54' North, Longitude: 75°48' East). Methodology: A corn-soybean meal-based diet was provided ad libitum, and body weight, feed intake, and behavioural observations were recorded weekly. Negative and positive social behaviours, exploratory activities, and lying duration were documented for each group. Statistical analyses were performed using ANOVA and Duncan's Multiple Range Test to compare treatment effects at a significance level of P ≤ 0.05. Results: Growth performance, including body weight and average daily gain (ADG), showed no significant differences between groups; however, a linear increase in body weight was observed over time. Feed intake and feed conversion ratio (FCR) differed significantly, with pigs at higher stocking densities consuming more feed and displaying higher FCR values. Behavioural analysis revealed increased negative behaviours such as aggression and tail biting in higher stocking density groups, while exploratory and positive social behaviours were more frequent in these groups. Lower stocking density groups displayed more lying behaviour, particularly towards the end of the study. Conclusion: Decreasing floor space allowance significantly impacted pig behaviour, increasing stress-related activities and negative social interactions without significantly affecting growth performance. These findings emphasize the importance of optimizing space allocation in intensive pig farming systems to balance welfare and productivity.

Mature compost enhanced the harmlessness level in co-composting swine manure and carcasses in large-scale silo reactors.

This study aimed to investigate the impact of incorporating mature compost on the harmlessness and maturity level of composting from swine manure and carcasses from industrialized pig farms in continuously running large-scale silo reactor systems. The potential human or animal bacterial pathogens and core bacterial community in composting were analyzed by high-throughput sequencing of 16S rRNA gene amplicons. The results showed that the addition of mature compost in the GD group significantly increased the temperature of all depths, the accumulated temperature of compost, and the germination index (75.43%) compared to that in the HN group without mature compost. High-throughput sequencing revealed that the dominated genera in GD were Ureibacillus, Lactobacillus, Corynebacterium, Staphylococcus, and Jeotgalicoccus, and the addition of mature compost could significantly increase the relative abundance of Ureibacillus (16.82%) that was associated with the biodegradation of organics. A total of 421 potential bacterial pathogens were detected, and the dominated genera of pathogens were Streptococcus, Staphylococcus, and Anaerococcus. The potential pathogen in the GD group with mature compost was reduced from 7.16 to 0.77%, which was significantly lower than that (2.97%) in the HN group. Together, these findings revealed that mature compost addition in large-scale reactor composting could accelerate the harmless and humification process, providing an effective and environmentally friendly scheme to deal with the main organic wastes in intensive pig farms.

'The veterinary profession must condemn intensive pig farming'.

Steven McCulloch argues that the global intensive pig farming industry does not meet the welfare needs of pigs and that the veterinary profession should and must withdraw all support.

Prevalence, antimicrobial resistance and genomic comparison of non-typhoidal salmonella isolated from pig farms with different levels of intensification in Yangon Region, Myanmar

In Myanmar, where backyard, semi-intensive, and intensive pig (Sus scrofa domesticus) farming coexist, there is limited understanding of the zoonotic risks and antimicrobial resistance (AMR) associated with these farming practices. This study was conducted to investigate the prevalence, AMR and genomic features of Salmonella in pig farms in the Yangon region and the impact of farm intensification to provide evidence to support risk-based future management approaches. Twenty-three farms with different production scales were sampled for two periods with three sampling-visit each. Antimicrobial susceptibility tests and whole-genome sequencing were performed on the isolates. The prevalence of Salmonella was 44.5% in samples collected from backyard farms, followed by intensive (39.5%) and semi-intensive farms (19.5%). The prevalence of multi-drug resistant isolates from intensive farms (45/84, 53.6%) was higher than those from backyard (32/171, 18.7%) and semi-intensive farms (25/161, 15.5%). Among 28 different serovars identified, S. Weltevreden (40; 14.5%), S. Kentucky (38; 13.8%), S. Stanley (35, 12.7%), S. Typhimurium (22; 8.0%) and S. Brancaster (20; 7.3%) were the most prevalent serovars and accounted for 56.3% of the genome sequenced strains. The diversity of Salmonella serovars was highest in semi-intensive and backyard farms (21 and 19 different serovars, respectively). The high prevalence of globally emerging S. Kentucky ST198 was detected on backyard farms. The invasive-infection linked typhoid-toxin gene (cdtB) was found in the backyard farm isolated S. Typhimurium, relatively enriched in virulence and AMR genes, presented an important target for future surveillance. While intensification, in terms of semi-intensive versus backyard production, maybe a mitigator for zoonotic risk through a lower prevalence of Salmonella, intensive production appears to enhance AMR-associated risks. Therefore, it remains crucial to closely monitor the AMR and virulence potential of this pathogen at all scales of production. The results underscored the complex relationship between intensification of animal production and the prevalence, diversity and AMR of Salmonella from pig farms in Myanmar.

Rearing pigs with play opportunities: the effects on disease resilience in pigs experimentally inoculated with PRRSV.

Positive emotions can reduce disease susceptibility during infectious challenges in humans, and emerging evidence suggests similar effects in farm animals. Because play behaviour may support a positive emotional state in pigs, this study investigates whether rearing pigs with regular intermittent play opportunities enhances disease resilience when challenged with porcine reproductive and respiratory syndrome virus (PRRSV). Litters were assigned to either play (PLY; n = 5 L) or control (CON; n = 4 L) treatments at birth. In PLY, play was promoted with extra space and enrichment items for three hours daily from five days of age (doa). At weaning (25 ± 2 doa; mean ± SD), 28 pigs (14/treatment) were selected for a disease challenge, based on weight, sex, and sow. The pigs were transported to a disease containment facility and at 43 ± 2 doa (day 0 post-inoculation, DPI) inoculated with PRRSV. Skin lesions, blood, rectal temperature, clinical signs, body weight, and behaviour were collected pre- and post-inoculation. Play opportunities for PLY continued every other day until euthanasia of all pigs at 65 ± 2 doa (22 DPI). PLY pigs exhibited fewer skin lesions following transport and throughout the infection compared to CON. Although the viral load did not differ between treatments, PLY pigs had a lower probability of experiencing moderate and severe respiratory distress, with a shorter duration. PLY also performed better throughout the infection, showing higher ADG and greater feed efficiency. The immune response differed as well. PLY pigs had fewer monocytes on 8 DPI than CON, with levels returning to baseline by 21 DPI, whereas CON levels exceeded baseline. Regardless of day of infection, lymphocyte counts tended to be lower in PLY than in CON, and white blood cells and neutrophils were also lower, but only in slow-growing pigs. PLY pigs continued to play during the infection, demonstrating less sickness behaviour and emphasizing the rewarding properties of play. Results suggest that PLY pigs were less affected by PRRSV and developed increased resilience to PRRSV compared to CON. This study demonstrates that rearing pigs in an environment supporting positive experiences through provision of play opportunities can enhance resilience against common modern production challenges, underscoring the value of positive welfare in intensive pig farming.

Variation in bacterial pathotype is consistent with the sit-and-wait hypothesis.

The sit-and-wait hypothesis predicts that bacteria can become more virulent when they survive and transmit outside of their hosts due to circumventing the costs of host mortality. While this hypothesis is largely supported theoretically and through comparative analysis, experimental validation is limited. Here we test this hypothesis in Streptococcus suis, an opportunistic zoonotic pig pathogen, where a pathogenic ecotype proliferated during the change to intensive pig farming that amplifies opportunities for fomite transmission. We show in an in vitro environmental survival experiment that pathogenic ecotypes survive for longer than commensal ecotypes, despite similar rates of decline. The presence of a polysaccharide capsule has no consistent effect on survival. Our findings suggest that extended survival in the food chain may augment the zoonotic capability of S. suis. Moreover, eliminating the long-term environmental survival of bacteria could be a strategy that will both enhance infection control and curtail the evolution of virulence.

Instance segmentation of pigs in infrared images based on INPC model

Conventional segmentation methods based on visible images in intensive pig farming face various challenges. Examples include color differences between pig breeds, background interference and lighting conditions. To overcome these issues, we designed the infrared pig cascade segmentation (INPC) model for the first time on infrared images. The model uses a cascade structure. Each stage utilizes higher resolution feature maps to better preserve fine details. It also solves the problem of poor segmentation of small objects due to low resolution of infrared images. At the same time, the model’s cross-guidance strategy enhances the interaction between bounding box regression and mask prediction. This reduces errors caused by interference like feces and urine. Additionally, a progressive mask branch refines mask prediction, improving segmentation in scenarios like imaging haze or pig adhesion. To facilitate model training and evaluation, we built the first large-scale standardized infrared pig dataset. Experimental results demonstrate that INPC outperforms mainstream segmentation models in terms of average precision (AP), except for AP0.5. Specifically, INPC achieves AP0.5, AP0.75, AP0.5:0.95, AP0.5:0.95s, and AP0.5:0.95l of 97.9%, 97.1%, 88.2%, 71.5%, and 90.1% respectively. Inference for a single image on a GPU takes only 0.197 s. Some datasets are available at https://github.com/HUBUwg96/INPC.

Survey of mosquito species in intensive pig farms in Hunan province, China.

Mosquitoes (Diptera: Culicidae) are one of the most studied groups of arthropods worldwide due to their high transmission capacity for pathogens, including viruses and parasites. During June to October 2022, the prevalence of mosquito species in 12 intensive pig farms from 12 representative administrative regions in Hunan province of China was investigated using traps with ultraviolet light. All collected mosquitoes were counted and identified to species according to morphological and molecular methods. A total of 4,443 mosquito specimens were collected in the pig farms, and they represented one family, four genera and nine species. Culex pipiens pipiens (24%) was the most common mosquito species, followed by Armigeres subalbatus (23.4%) and Culex tritaeniorhynchus (20.6%). Phylogenetic analyses based on mitochondrial cox1 sequences revealed all mosquito species from present study grouping into distinct monophyletic groups corresponding to nine known mosquito species with strongly supported. The results of the present investigation have implications for the ongoing control of mosquito infestation in pig farms in Hunan province, China. This is the first report of mosquito populations in intensive pig farms in Hunan province, China.

Establishment of real-time viral pathogen detection method-surface-enhanced Raman scattering system for porcine circovirus type II

The transition towards large-scale intensive pig farming methods has resulted in an increase in cases of complex, mixed infections, and secondary infections. Porcine circovirus (PCV), the causative agent of PCV disease (PCVD), is a small nonenveloped DNA virus containing a single-stranded circular genome. Previously, PCV was even considered nonpathogenic to pigs. However, a novel strain of PCV, designated PCV-2, has been associated with various disease syndromes in pigs over the last 5 years. PCV-2 primarily induces post-weaning multisystemic wasting syndrome, characterized by clinical signs such as debility, dyspnea, palpable lymphadenopathy, diarrhea, and pallor or icterus. PCV-2 is now recognized as an important emerging pathogen. Early diagnosis and disease prevention have become crucial for effective pig farm management. However, clinical diagnosis may be complicated by antibiotic treatment and atypical disease symptoms. To ensure accurate pathology diagnosis, it is essential to integrate robust laboratory diagnostics with traditional methods. Surface-enhanced Raman Scattering (SERS) spectroscopy has emerged as a potentially powerful technique for whole-organism fingerprinting, enabling rapid identification of bacteria. Biosensors utilizing SERS offer promising capabilities for sensitive and quick detection of bacterial pathogens, thereby reducing diagnosis time. In this study, our aim was to characterize and evaluate a SERS-based diagnostic system for detecting and identifying PCV-2 present in pooled swine sera and feces. We compared the spectra of PCV-2 recovered from the specimens to those of pure PCV-2 to determine the PCV-2 molecular fingerprint. Our results demonstrated successful detection, identification, and classification of PCV-2 in swine sera and feces using SERS. SERS provided reproducible molecular spectroscopic signatures suitable for analytical applications. This approach presents a new and potent tool for real-time surveillance of animal viral pathogens in clinical settings.

Antimicrobial Use in Pig Farms in the Midwestern Region of Minas Gerais, Brazil.

The use of antimicrobials in swine production is an issue that concerns the whole world due to their impact on animal and public health. This study aimed to verify the antimicrobial use in 29 commercial full-cycle farms in the midwestern region of the state of Minas Gerais, since this region is a hub of intensive pig farming in Brazil, as well as the possible correlations between the use of antimicrobials, biosecurity, and productivity. A total of 28 different drugs used for preventive purposes were described. On average, the herds used seven drugs, exposing the piglets for 116 days and totaling 434.17 mg of antimicrobials per kilogram of pig produced. Just eight active ingredients made up 77.5% of the total number of drugs used on the studied herds. Significant differences were found between the variables, biosecurity score and number of sows, antimicrobial amount and number of drugs, number of drugs and number of sows, and between productivity and biosecurity scores. The use of antimicrobials was considered excessive in the swine farms in the state of Minas Gerais compared to what was reported in Brazil and in other countries. Educational measures and better control should be proposed to reduce the preventive use of antimicrobials.

Feasibility of Near-Infrared Spectroscopy in the Classification of Pig Lung Lesions.

Respiratory diseases significantly affect intensive pig farming, causing production losses and increased antimicrobial use. Accurate classification of lung lesions is crucial for effective diagnostics and disease management. The integration of non-destructive and rapid techniques would be beneficial to enhance overall efficiency in addressing these challenges. This study investigates the potential of near-infrared (NIR) spectroscopy in classifying pig lung tissues. The NIR spectra (908-1676 nm) of 101 lungs from weaned pigs were analyzed using a portable instrument and subjected to multivariate analysis. Two distinct discriminant models were developed to differentiate normal (N), congested (C), and pathological (P) lung tissues, as well as catarrhal bronchopneumonia (CBP), fibrinous pleuropneumonia (FPP), and interstitial pneumonia (IP) patterns. Overall, the model tailored for discriminating among pathological lesions demonstrated superior classification performances. Major challenges arose in categorizing C lungs, which exhibited a misclassification rate of 30% with N and P tissues, and FPP samples, with 30% incorrectly recognized as CBP samples. Conversely, IP and CBP lungs were all identified with accuracy, precision, and sensitivity higher than 90%. In conclusion, this study provides a promising proof of concept for using NIR spectroscopy to recognize and categorize pig lungs with different pathological lesions, offering prospects for efficient diagnostic strategies.

Real-time surveillance of zoonotic and pig pathogens using surface-enhanced Raman scattering system

The shift towards large-scale intensive pig farming methods has led to an increase in cases of complex, mixed infections, and secondary infections. Early diagnosis and disease prevention have become crucial for effective pig farm management. However, clinical diagnosis may be complicated by antibiotic treatment and atypical disease symptoms. To ensure accurate pathology diagnosis, it is essential to integrate robust laboratory diagnostics with traditional methods. Surface-enhanced Raman scattering (SERS) spectroscopy has emerged as a potentially powerful technique for whole-organism fingerprinting, enabling rapid identification of bacteria. Biosensors utilizing SERS offer promising capabilities for sensitive and quick detection of bacterial pathogens, thus reducing diagnosis time. In this study, we aimed to characterize and evaluate a SERS-based diagnostic system for detecting and identifying bacteria in specific pathogen free (SPF) mice, focusing on two bacterial zoonoses and swine bacteria present in pooled swine sera, feces, and meat. We compared the spectra of bacteria recovered from the specimens to those of pure cultured bacteria and conducted principal component analysis to determine the bacterial molecular fingerprint. Our results demonstrated successful detection, identification, and classification of these bacteria in mice specimens (sera and feces) and swine specimens (sera, feces, and meat) using SERS. SERS provided reproducible molecular spectroscopic signatures suitable for analytical applications. This approach presents a new and potent tool for real-time surveillance of animal bacterial pathogens in clinical settings.

Characterization of harmful gases and bioaerosols of pig farms: a review of the existing literature

From the ecological and economic point of view, intensive pig farming is drawing more and more attention due to the appearance of harmful substances, which significantly increases the risks of air, water and soil pollution. In addition, the optimal criteria for the content of harmful gases, dust and microorganisms in the environment of pig farms are currently not clearly defined. In order to better understand the interaction of harmful emissions and aerosols, the article reviews data from the literature on their main components, concentrations, and interactions. The results showed that the main pollutants in pig farming are harmful gases (ammonia (NH3), carbon dioxide (CO2), methane (CH4), nitrogen oxide (N2O), hydrogen sulfide (H2S), which are released from manure. The presence of even small concentrations of harmful gases in farm air can cause respiratory and cardiovascular system disorders not only in animals, but also in humans. Along with harmful gases, it is important to control the emission of solid particles and dust from livestock premises, which can form aerosols. Microbial aerosols in pig houses contain bacteria, fungi, viruses, which mainly come from the animals themselves, manure or service personnel. The bioaerosol includes the Firmicutes and Bacteroidetes bacterial divisions and their derivatives. In addition, the content of potentially dangerous bacteria in the bioaerosol can reach up to 40 %. A major concern causes the presence of a large number of antibiotic-resistant microorganisms in the air of these farms (including MRSA). The existing strategies and methods to combat these problems are still imperfect and need to be refined. Currently, the interaction of harmful gases, dust, solid particles and microorganisms is not taken into account, which can increase the toxic effect of each other on the animal's body. Therefore, there is a need for a better understanding of these interactions in order to improve the strategy for improving the microclimate conditions by correcting the microbiota, finding and developing biological preparations that contain natural bacteria capable of neutralizing odors and disinfecting livestock premises.

Serological survey on Hepatitis E virus in Namibian dogs, cats, horses, and donkeys.

The present study investigated the seropositivity rate of Hepatitis E virus (HEV) in domestic and working animals in Namibia, which included dogs, cats, horses, and donkeys. HEV poses a growing threat as a significant cause of human hepatitis globally and has several genotypes of varying zoonotic potential. As epidemiological data on the seroprevalence of HEV in Namibia is scarce, a serosurvey was conducted on archived serum samples of 374 dogs, 238 cats, 98 horses, and 60 donkeys collected between 2018 and 2022 from different regions, to assess the potential of these animals as sources of HEV infection. The findings revealed that 10.43% (n = 39/374) canine and 5.88% (n = 14/238) feline samples tested positive for HEV antibodies, whereas no seropositivity was detected in horses and donkeys. The study further examined the risk factors associated with HEV seropositivity, including animal sex, age, and geographical region, and noted a higher prevalence in dogs living in areas with intensive pig farming. Although there is no direct evidence indicating that these animals served as major reservoirs for HEV transmission to humans, the study underscores the importance of preventive measures to minimize contact exposure with pets considering the potential zoonotic risk, especially for susceptible risk groups. Further research is needed to explore the zoonotic potential of domestic animals and the epidemiological links between animal and human HEV transmissions in Namibia.

ARGENTINA: ENTRE O RECONHECIMENTO DOS DIREITOS DOS ANIMAIS E A INTENSIFICAÇÃO DA PECUÁRIA

Abstract The intensification of animal farming is a growing trend worldwide that poses serious environmental and animal rights challenges. In Argentina, it gained public attention for the first time after the government agreed with China to install intensive pig farms in the country in 2020. Although the environmental danger raised the most important concerns among the public, the opposition also came from animal rights advocates. This paper will offer a theoretical analysis of intensive pig farming from animal ethics and animal welfare perspectives. The analysis will include how some of the most recent advances in Argentinean case law, recognizing legal personhood for some animals, could influence the path to animal farm intensification and its regulation. The work is divided into four sections. In the first, a brief discussion of the contributions of animal ethics will be presented. The second section will describe the main concepts involved in animal welfare science. In the third section, the article will describe the life and death of pigs on intensive farms. Finally, the last section will survey Argentinean animal rights case law and animal law, highlighting the contrast between the contradictory trends: animal legal personhood recognition versus animal farming intensification.

Identified candidate genes for pig mental health: Insights from intensive farming systems

Abstract Understanding the genetic basis of porcine mental health (PMH)-related traits in intensive pig farming systems may promote genetic improvement animal welfare enhancement. However, investigations on this topic have been limited to a retrospective focus, and phenotypes have been difficult to elucidate due to an unknown genetic basis. Intensively farmed pigs, such as those of the Duroc, Landrace, and Yorkshire breeds, have undergone prolonged selection pressure in intensive farming systems. This has potentially subjected genes related to mental health in these pigs to positive selection. To identify genes undergoing positive selection under intensive farming conditions, we employed multiple selection signature detection approaches. Specifically, we integrated disease gene annotations from three human gene–disease association databases (Disease, DisGeNET, and MalaCards) to pinpoint genes potentially associated with pig mental health, revealing a total of 254 candidate genes related to PMH. In-depth functional analyses revealed that candidate PMH genes were significantly overrepresented in signaling-related pathways (e.g., the dopaminergic synapse, neuroactive ligand‒receptor interaction, and calcium signaling pathways) or Gene Ontology terms (e.g., dendritic tree and synapse). These candidate PMH genes were expressed at high levels in the porcine brain regions such as the hippocampus, amygdala, and hypothalamus, and the cell type in which they were significantly enriched was neurons in the hippocampus. Moreover, they potentially affect pork meat quality traits. Our findings make a significant contribution to elucidating the genetic basis of PMH, facilitating genetic improvements for the welfare of pigs and establishing pigs as valuable animal models for gaining insights into human psychiatric disorders.

Influenza risks arising from mixed intensive pig and poultry farms, with a spotlight on the United Kingdom

Diseases passed to humans from animals (zoonoses) constitute 75% of emerging infectious diseases. Farmed animals are considered a high zoonotic risk, especially poultry and pigs as evidenced by recent outbreaks of avian and swine influenza. This review sought to collate recent knowledge of the disease risks from keeping pigs and chickens intensively and in close proximity to each other. Recent knowledge on influenza viruses compounds the public health concerns; no longer are concerns about “mixing vessel” hosts limited to pigs, but several other animal species too at a high level of probability—most notably chickens and humans. More generally, scientific literature establishing positive associations between intensive animal farming, human population growth, reduced biodiversity, and increased zoonoses risks is abundant. This includes the publication of relevant systematic reviews. The collected scientific evidence on this issue is clear: there is exceptionally strong evidence for a link between low animal welfare levels and high zoonotic risks, exacerbated by animal crowding, low genetic diversity, compromised hygiene, and high animal stress levels which compromise immune systems. Based on this evidence, further industrialized animal farms—especially poultry and pig farms or a mix thereof, and particularly in areas that already have a high concentration of farmed animals—should not generally be permitted to proceed. Instead, efforts should concentrate on supporting arable agriculture (or transitions toward this) and de-intensifying remaining animal farms, in alignment with One Health/One Welfare approaches within which animal health and welfare are integral parts of any farming operation. Among numerous other factors, this would involve reducing stocking densities down to 11 kg/m2 (around five chickens/m2) for meat chickens, and down to one pig/1.5 m2 for pigs (assuming a 100 kg pig).

Performance and economic comparison of three annual air-conditioning systems in sow houses

Huge amounts of energy is usually consumed by intensive pig farms and the supply systems based on renewable energy and heat recovery contributes to reducing the reliance of fossil fuels. In order to determine the performance advantages and economic feasibility of a new spray cooling system with photovoltaic/thermal and heat recovery, it is compared with the two traditional air-conditioning systems in sow houses. Firstly, the models are established for three systems and the reliability is verified for their core component models. The results show that the maximum error is less than 12.9 % for the models. Meanwhile, the performance parameters and CO2 emissions are compared for three systems under different indoor load rates. The results show that compared with other two systems, the new system has significant performance advantages and social benefits. Specifically, the annual exergy efficiency and energy efficiency ratio of new system are at most 28.36 % and 28.45 % higher than those of other two systems, respectively. However, its annual energy consumption and CO2 emissions are at most 82.32 % and 87.90 % lower than those of other two systems, respectively. Finally, an economic study is performed for three systems. The results show that the initial investment of new system is at most 230.67 % higher than that of other two systems, while its annual operating and maintenance costs are at most 81.60 % lower than those of other two systems. Especially, compared with other two systems, the relative investment payback period of new system is at most 4 years. In summary, this research can provide guidance for the practical application of multiple energy coupling supply systems in intensive pig farms so as to improve their energy utilization efficiency and economic benefits.

Circularity and livestock diversity: Pathways to sustainability in intensive pig farming regions

CONTEXTIntensive pig farming is challenged by high environmental impacts and dependence on outsourced inputs. Circular feeding strategies to improve nutrient cycling and livestock diversity have emerged as pathways to improve the sustainability. OBJECTIVEThis study explored the potential of increasing feed circularity and introducing sheep to improve the sustainability of a typical pig fattening region in the semiarid zone of Spain. METHODSThree alternative circular scenarios were designed to relocate pig feed production while reintroducing sheep production. These scenarios were then compared to a business-as-usual (BAU) scenario. The feeding strategies scenarios differed in crude protein (CP) and in-feed amino acid (AA) supplementation for pigs (CircHigh, high CP with low AA; CircLow, low CP with high AA; CircNoAA, low CP without AA) and included grazing sheep to use crop residues, alfalfa and temporary vetch-oat pastures on fallow land. Yearly feed requirements for pigs were planned, and were met with cereal grains, oilseeds, legumes, rice bran and chopped alfalfa hay. Sheep carrying capacity was estimated from available forage sources. Indicators in five sustainability dimensions were considered: economic performance, landscape mosaic, livestock diversity, nitrogen (N) cycling, and feed-food competition. RESULTS AND CONCLUSIONSOutsourced (BAU) pig feeding without sheep had low scores for indicators in all five dimensions. The feeding strategy for pigs strongly influenced the land area required to produce feed as well as N cycling. Only the CircLow scenario could feed the current pig stocks in the region with the arable land available. The CircHigh strategy combined with grazing sheep scored highest for most of the dimensions, except for feed-food competition indicators. The CircLow strategy had good scores for most of the dimensions, except for N cycling indicators, whose scores decreased due to the lower N content of slurry. The CircNoAA strategy increased the use of rice bran as a food coproduct and decreased N surplus, but also impaired the economic performance (land productivity and feeding costs). Although the CircLow strategy required less land area to grow legumes, it resulted in a slightly higher crop diversity and a higher sheep carrying capacity when sowing temporary pastures. SIGNIFICANCEN cycling and overall sustainability of regions with intensive livestock production was improved through feed circularity, that included reducing CP with high in-feed AA, and livestock diversity, by reintroducing sheep as complementary livestock that can graze crop residues and temporary pastures. These results may help to inform future rural policies to help upscale more sustainable practices in intensive pig farming regions.