An Integrated Analysis of Abattoir Lung Lesion Scores and Antimicrobial Use in Italian Heavy Pig Finishing Farms.

Simple Summary: Abattoir lung lesion scoring is a common practice to assess the impact of respiratory diseases in pig production, but whether the information obtained could be used to optimize antimicrobial stewardship programs has rarely been investigated. In this study, lung and pleural scores collected at slaughter from Italian heavy pigs were compared with on-farm antimicrobial use during the six months prior to slaughtering. Lung scores were positively associated with the past use of antimicrobials considered critical for human medicine, suggesting that batches with worse scores may have been unsuccessfully treated with first-choice antimicrobials. This result emphasizes the role of abattoirs as strategic observatories for pig respiratory diseases, which may also be helpful for antimicrobial stewardship. The information obtained could provide useful feedback aiding the identification of gaps in biosecurity or inadequate vaccination plans, thus helping to reduce on-farm antimicrobial use. Respiratory diseases significantly affect intensive pig finishing farms, causing production losses and increased antimicrobial use (AMU). Lesion scoring at slaughter has been recognized as a beneficial practice to evaluate herd management. The integrated analysis of abattoir lesion scores and AMU data could improve decision-making by providing feedback to veterinarians and farmers on the effectiveness of antimicrobial treatments, thus rationalizing their use. This study compared lung and pleural lesion scores collected at Italian pig slaughterhouses with on-farm AMU, estimated through a treatment index per 100 days (TI100). Overall, 24,752 pig carcasses, belonging to 236 batches from 113 finishing farms, were inspected. Bronchopneumonia and chronic pleuritis were detected in 55% and 48% of the examined pigs, respectively. Antimicrobials were administered in 97% of the farms during the six months prior to slaughter (median TI100 = 5.2), notwithstanding compliance with the mandatory withdrawal period. EMA category B (critical) antimicrobials were administered in 15.2% of cases (median TI100 = 0.06). The lung score was not associated with the total AMU, but significant, positive associations were found with the past use of critical antimicrobials (p = 0.041) and macrolides (p = 0.044). This result highlights the potential of abattoir lung lesion monitoring to rationalize antimicrobial stewardship efforts, contributing to AMU reduction. [ABSTRACT FROM AUTHOR]