Abstract
Respiratory diseases, such as pleurisy and pneumonia, cause significant health and economic losses in pig production. This study evaluated 867 finishing pigs from a farm with a history of respiratory issues, using macroscopic lesion scoring (SPES and CVPC), histopathological analysis, qPCR diagnostics, and economic modeling. Severe pleurisy (scores 3 and 4) was observed in 42.1% of carcasses and was strongly correlated with higher bacterial loads of Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, and Pasteurella multocida. Severe lesions reduced the average daily gain (ADG) and carcass weight, leading to increased production costs and lower profitability. Economic analysis revealed that pigs with higher pleurisy scores incurred an additional cost per kg (USD 1.29 vs. USD 1.32 for milder cases), reduced total revenue by 1.36%, and decreased return on investment (ROI) from 5.33% to 3.90%. These findings emphasize the critical impact of respiratory diseases on profitability and the necessity of robust health management strategies, including vaccination and enhanced biosecurity, to minimize economic losses in swine farming.