Behavior Comparison During Chronic Heat Stress in Large White and Creole Pigs Using Image-Analysis

Behavior is a good indicator of animal welfare, especially in challenging environments. However, few studies have investigated how pig behavior changes during heat stress. The current study is a proof-of-concept using Convolutional Neural Network (CNN) models to monitor pig behavior in order to investigate the differences in behavioral response to heat stress of two contrasted breeds: Large White (LW), selected for high performance, and Creole (CR), adapted to tropical conditions. A total of 6 slaughter pigs (3 CR and 3 LW; 22 weeks of age) were monitored from 8:30 to 17:30 during 54 days. Two CNN architectures were used to detect the animal (Yolo v2) and to estimate animal's posture (GoogleNet). Pig postures estimated by the neural network showed that pigs spent more time lying on their side when temperature increased. When comparing the two breeds, as temperature increases, CR pigs spent more time lying on their side than LW pigs, suggesting that they use this posture to increase thermoregulation and dissipate heat more efficiently. This study demonstrates that neural network models are an efficient tool to monitor animal behavior in an automated way, which could be particularly relevant to characterize breed adaptation to challenging environments.

Investigations on the occurrence of a muscular disorder in Austrian slaughter pigs

Background In slaughterhouse, veterinarians responsible for meat inspection are often confronted with abnormalities in carcasses, not only in pigs but in all livestock species. In 2017, a veterinarian responsible for meat inspection in a slaughterhouse in Styria, Austria, observed gluteal muscles infiltrated by fat and muscle tissue obviously being replaced by fat in two different slaughter pigs. These muscles were sent for further diagnostics to the University Clinic for Swine. Results The two muscle samples were investigated histopathologically and diagnosed with fatty muscular dystrophy. The results of routine histopathology were confirmed by dystrophin-specific immunohistochemistry. Sex of the two affected animals was determined retrospectively using a PCR-based protocol and resulted in one male and one female pig. A survey to determine the prevalence of fatty muscular disorders of pork revealed that this phenomenon gets frequently observed in Styria, but also occurs in Upper Austria and Lower Austria. Mostly gluteal and lumbal muscles were affected and approximately 20–40% of the affected muscles were replaced by fat. Conclusions Fatty muscular dystrophy or muscular steatosis, as it was sometimes called in early literature, seems not to be an uncommon and rare event and is known to have several different causes. As it was detected in both sexes, our observations are different to the described case in Japan, where only one male individual was affected. To avoid further increase of such cases (fatty muscular dystrophy), it would be useful to clarify the cause. First, whether the cause is environmental or genetic, and in case it is genetic it would be key to disentangle the underlying genomic architecture. Having causal variants described—one could think about integrating this information (depending on the mode of inheritance and the number of loci involved) in the breeding program of pigs. Furthermore, the proportion of non-Austrian pig genetics used for commercial pig production in Austria should be reviewed in order to be able to make reliable statements about the spread of the disease not only in Austrian pig breeds, but also in pig breeds worldwide.

Correlations Between Lung Pneumonic Lesions and Serologic Status to Key Respiratory Pathogens in Slaughtered Pigs in Northern Uganda

Background: A cross-sectional study was conducted in three selected slaughter slabs in Lira district Uganda in 2019 to (i) determine prevalence and severity of pneumonia and (ii) establish associations between lung pneumonic lesions and serologic status to key respiratory pathogens in slaughter pigs. Blood samples were collected from pigs at antemortem from which sera were prepared. Using enzyme-linked immunosorbent (ELISA) assays, sera were screened for antibodies against Mycoplasma hyopneumoniae (M. hyo), Actinobacillus pleuropneumoniae (App), porcine reproductive and respiratory syndrome virus (PRRSv) and porcine circovirus type 2 (PCV2). At post-mortem, lungs were scored for possible pneumonic lesions and the type of pneumonia as previously described. Pneumonia types were grossly characterized as catarrhal purulent bronchopneumonia (CPBP), pleuropneumonia (PLP) and pleuritis as previously described. Metastrongylus spp infection was determined by examining lungs for gross presence or absence of helminths as previously described. T-tests were used to compute prevalence of pneumonia. Chi-square tests were used to compare the percentage of lungs positive or negative to CPBP, PLP and pleuritis. Ordinal logistic regression model was used to evaluate the odds of multiple pneumonia forms, with serostatus for different pathogens and Metastrongylus spp. infection as predictors. Results: One hundred and sixty seven (n=167) lungs were examined for pneumonic lesions. The prevalences of CPBP, PLP and pleuritis were 29.9% (95% CI 22.9-36.9), 74.2% (95% CI 67.5-80.9) and 17.3% (95% CI 22.4-36.3), respectively. The odds of multiple pneumonia forms increased in pigs with multiple pathogens and concurrent Metastrongylus spp. infestation (ORs 2.6, p=0.01 and 2.5, p=0.003, respectively), reaffirming synergistic effects of coinfections in the induction of lesions. Conclusions: This study revealed a high prevalence and severity of pneumonic lesions in slaughter pigs. It provides baseline information, undeniable evidence on the magnitude of pneumonia and justifies future studies on its potential economic impacts in Ugandan pigs.

Investigations on the occurrence of fatty muscular dystrophy in Austrian slaughter pigs

Background In slaughterhouses, veterinarians responsible for meat inspection are often confronted with abnormalities in carcasses, not only in pigs but in all livestock species. Regularly occurring pathological abnormalities such as abscesses, milk spots or muscular necrosis in case of vitamin E/selenium deficiency usually are undoubtful and need no further investigations for a diagnosis. Contrarily, sometimes rare and unexpected observations are reported. In 2017, a veterinarian responsible for meat inspection in a slaughterhouse in Styria, Austria, observed gluteal muscles infiltrated by fat and muscle tissue obviously being replaced by fat in two different slaughter pigs. These muscles were sent for further diagnostics to the University Clinic for Swine. In 2013, Japanese researchers reported of a disease similar to Becker Muscular Dystrophy of humans in slaughter pigs, which can be assumed also in our case. Results The two muscle samples were investigated histopathologically and diagnosed with fatty muscular dystrophy. The results of routine histopathology were confirmed by dystrophin-specific immunohistochemistry. Sex of the two affected animals was determined retrospectively using a PCR-based protocol and resulted in one male and one female pig. A survey to determine the prevalence of fatty muscular dystrophy of pork revealed that this phenomenon gets frequently observed in Styria, but also occurs in Upper Austria and Lower Austria. Mostly gluteal and lumbal muscles were affected and approximately 20% – 40% of the affected muscles were replaced by fat. Conclusions Fatty muscular dystrophy or muscular steatosis, as it was sometimes called in early literature, seems not to be an uncommon and rare event. As it was detected in both sexes, our observations are different to the described case in Japan, where only one male individual was affected. To avoid further increase of such cases (fatty muscular dystrophy), it would be useful to clarify the cause. First, whether the cause is environmental or genetic, and in case it is genetic it would be key to disentangle the underlying genomic architecture. Having causal variants described – one could think about integrating this information (depending on the mode of inheritance and the number of loci involved) in the breeding program of pigs. Furthermore, the proportion of non-Austrian pig genetics used for commercial pig production in Austria should be reviewed in order to be able to make reliable statements about the spread of the disease not only in Austrian pig breeds, but also in pig breeds worldwide.

Necropolitical Governance and State-Corporate Harms: COVID-19 and the U.S. Pork Packing Industry

The coronavirus pandemic has magnified the interdependence of the state and corporations in the pork packing industry. In 2020, when over 67,000 meatpacking and processing workers were infected with the virus, the state allowed and encouraged this industry to coerce a racialized workforce to risk their health and lives to slaughter pigs. While it would seem reasonable to call for more regulation to protect labor in this industry, we find by analyzing the state’s actions in 2020 that its interests are too far aligned with corporations’ interests to expect one to police the other. Our analysis underlines the state as a symbiotic partner of corporations, and places workers’ illnesses and deaths in a necropolitical framework that demands attention to the state’s tacit approval of inhumane working conditions, use of law to keep packing plants open, and attempts to limit the liability of corporations for any deaths or illnesses they have caused.

Slaughter pigs as carrier of Listeria monocytogenes in Germany

Listeria (L.) monocytogenes as the cause of human listeriosis is widespread in the environment and a hazard considering food safety. Almost all animal species as well as humans can be asymptomatic carriers of this bacterium. In pigs, the tonsils are identified as the organ with the highest detection rate compared to other sample matrices. We sampled 430 pigs in total in two slaughterhouses in Northwest and East Germany, two structurally different and important regions in pig production, to re-examine pigs as a possible source of Listeria-contamination of pork products. We detected a low prevalence of L. monocytogenes in tonsil samples of 1.6% (7/430) on single animal level and of 11.6% (5/43) on herd level with no significant difference between the two German regions. Apart from L. monocytogenes, the usually non-pathogenic L. innocua had a prevalence of 1.2% (5/430) on single animal level. From 200 pigs from Northwest Germany, intestinal content samples were analysed in addition to tonsil samples from the same animals, but no positive sample was found for L. monocytogenes (0.0%, 0/200), while four pigs were positive for L. innocua (2.0%, 4/200). Although the prevalence of L. monocytogenes in tonsils is low, the risk of cross-contaminating meat with the pathogen is still given.

Infection dynamics and persistence of hepatitis E virus on pig farms – a review

Background Hepatitis E virus (HEV) genotype 3 and 4 is a zoonosis that causes hepatitis in humans. Humans can become infected by consumption of pork or contact with pigs. Pigs are the main reservoir of the virus worldwide and the virus is present on most pig farms. Main body Though HEV is present on most farms, the proportion of infected pigs at slaughter and thus the level of exposure to consumers differs between farms and countries. Understanding the cause of that difference is necessary to install effective measures to lower HEV in pigs at slaughter. Here, HEV studies are reviewed that include infection dynamics of HEV in pigs and on farms, risk factors for HEV farm prevalence, and that describe mechanisms and sources that could generate persistence on farms. Most pigs become infected after maternal immunity has waned, at the end of the nursing or beginning of the fattening phase. Risk factors increasing the likelihood of a high farm prevalence or proportion of actively infected slaughter pigs comprise of factors such as farm demographics, internal and external biosecurity and immunomodulating coinfections. On-farm persistence of HEV is plausible, because of a high transmission rate and a constant influx of susceptible pigs. Environmental sources of HEV that enhance persistence are contaminated manure storages, water and fomites. Conclusion As HEV is persistently present on most pig farms, current risk mitigation should focus on lowering transmission within farms, especially between farm compartments. Yet, one should be aware of the paradox of increasing the proportion of actively infected pigs at slaughter by reducing transmission insufficiently. Vaccination of pigs may aid HEV control in the future.