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Serological survey of antibodies against Toxoplasma gondii and Neospora caninum in pigs from various regions of Poland
Evaluation of the utility of testicular-only processing fluid for porcine reproductive and respiratory syndrome virus diagnostics and the effect of sample pooling on the test results
Abstract Introduction The testicular-only processing fluid (TOPF) obtained from piglet testicles after castration could be an alternative sample for porcine reproductive and respiratory syndrome (PRRS) laboratory diagnosis. If this matrix were proved useful, testing it would spare piglets the stress of blood drawing and eliminate some labour required to take blood samples. The aim of the study was to evaluate the utility of TOPF for this diagnostic purpose. Material and Methods Serum-and-TOPF pairs from male piglets and sera from female piglets were tested using commercial ELISA and real-time RT-PCR kits. For the pooling simulation, 10 μL aliquots of TOPF separated into low-, moderately and highly positive were mixed with appropriate volumes of negative TOPF samples. This simulated pools of 5, 10, 20, 40 and 80 samples containing 1 positive for serological analyses and pools of 10, 20, 40, 80, 160 and 320 samples containing 1 positive in molecular analyses. Results The percentages of anti-porcine reproductive and respiratory syndrome virus (PRRSV) antibodies were statistically significantly different (P-value < 0.05) between boar sera (69.55%) and TOPF (54.49%), as well as between gilt sera (74.52%) and TOPF. However, after adjusting the cut-off value, no significant differences were noted. The RNA of PRRSV was detected in 21.26% of male sera, 15.23% of TOPFs and 17.00% of female sera. Pooled sample testing revealed discrepancies in positive results associated with the pool size and original sample positivity strength. Conclusion TOPF samples can be a valuable matrix for laboratory PRRS diagnosis in piglets. However, it is important to be aware of the potential for false-negative results.
Detection of infectious agents in lungs of slaughtered pigs in association with cranioventral pulmonary consolidation
Abstract Introduction Respiratory diseases have a substantial impact on swine production worldwide. Understanding the relationship between gross lung lesions and the presence of infectious agents is crucial for developing effective disease control strategies that target both primary and secondary pathogens. Material and Methods A cross-sectional study was conducted on 22 pig farms in western Poland. Cranioventral pulmonary consolidation (CVPC) in slaughtered pigs was assessed, and 20 lung tissue samples were collected from each herd. The presence of common bacterial and viral respiratory pathogens was identified using PCR-based methods. Results The disorder was observed in 79.3% (95% confidence interval 75.3–82.8) of slaughtered pigs across all examined herds. The most frequently detected pathogens at both the herd and individual animal levels were Glaesserella parasuis, Mycoplasma hyopneumoniae and porcine circovirus 2. Co-infections involving two or more respiratory pathogens were prevalent, occurring in 100% of herds and 87.7% of individual pigs. Mean CVPC scores were significantly higher in pigs infected with Mycoplasma hyopneumoniae, Mycoplasma hyorhinis and porcine reproductive and respiratory syndrome virus 1. Conclusion These findings highlight the multifactorial nature of respiratory infections in pigs. Effective control measures should consider the high prevalence of co-infections and their impact on lung lesion severity to improve overall herd health and productivity.
Relationships between pig farm management and facilities and lung lesions' scores and between lung lesions scores and carcass characteristics
Abstract Background The objective of this study was to examine the inter-relationships between pig farm management and facilities (as assessed by questionnaire) and post-mortem lung lesion (lung score assesment), which are the result of respiratory infections. The relationships between carcass characteristics and post-mortem lung lesion scores were also investigated. Results Questionnaire responses were collected from 22 self-selecting pig farmers about their farm facilities/management and health condition of the respiratory system of pigs, including the occurrence of clinical respiratory signs, results of laboratory testing for respiratory pathogens, and the use of respiratory vaccines. When fatteners were sent to the abattoir, their carcasses (n = 1,976) were examined for evidence of respiratory disease by lung lesion (pleuritis pneumonia-like (PP-like) and enzootic pneumonia-like (EP-like) lesions) scoring and the Actinobacillus pleuropneumoniae Index (APPI) was calculated. Carcass characteristics were recorded and, retrospectively, the prevalence of cachectic pigs was calculated. Using these variables, the relationships between farm facilities/management and lung lesions scores and the relationships between the latter and carcass characteristics and cachexia were explored. The key findings relating farm facilities and management to lung lesions were: slatted floors were associated with significantly higher EP-like lesions scores than litter bedding in weaners, single-stage fattening in the same building was associated with significantly higher EP-like lesions scores than two-stage fattening, but herd size, stocking density, use of all-in/all-out (AIAO) rule, technological break duration and variation in daily temperature did not affect lung lesions scores. The key findings relating lung lesion scores to carcass characteristics were: a significant, negative correlation between EP-like scores and carcass weight but not with other carcass characteristics, a significant positive correlation between PP-like scores and carcass meat content and prevalence of cachectic carcasses and a significant positive correlation between lung APPI and prevalence of cachectic carcasses. Conclusions It can be concluded that both farm facilities and management affect lung lesions scores and that the latter affect carcass characteristics. Lung lesion scoring is an inexpensive technique suitable for rapid monitoring of large numbers of carcasses that can be performed after animal slaughter. It provides useful information to inform producers about possible deficits in farm facilities or management and is a predictor of economic loss due to poorer quality carcasses.