Assessment of pulmonary lesions associated with Porcine Respiratory Disease Complex in Colombian swine herds using slaughterhouse lung scoring systems

Abstract

Porcine Respiratory Disease Complex (PRDC) causes substantial economic losses in swine production due to decreased efficiency and increased reliance on pharmaceuticals for disease control. Diagnosis of PRDC can be achieved by evaluating lung lesions at slaughterhouses, which enables assessment of herd health status and the formulation of targeted control strategies. In this study, the MADEC and SPES scoring systems were employed to characterize lung lesions associated with PRDC in pigs slaughtered in Colombia. A total of 16,223 red viscera (lungs, heart, and liver) from 15 commercially advanced farms were examined, utilizing the MADEC system for cranioventral consolidations and the SPES system for dorsocaudal pleuritis. Additionally, histopathological analyses and multiplex PCR tests were performed on randomly selected samples to identify microscopic lesions and respiratory pathogens. Approximately 70% of diaphragmatic lobes on both sides exhibited mild lesions (MADEC1), while severe lesions (MADEC3–4) were predominantly observed in the cardiac and accessory lobes. The prevalence of pleuritis was 17.7%, with SPES types 1 and 2 being most common. Glaserella parasuis was the only pathogen detected in the analyzed samples. Furthermore, concurrent use of up to five antimicrobial groups was documented across the farms. In conclusion, the observed respiratory lesions likely reflect the widespread circulation of PRDC agents, underscoring the need to enhance biosecurity, vaccination programs, and epidemiological surveillance in Colombian swine production. The adoption of standardized systems, such as MADEC and SPES, facilitates effective monitoring and control of respiratory diseases throughout the production chain.