A cross-sectional study of risk factors associated with pulmonary lesions in pigs at slaughter.

A cross-sectional study was conducted to identify herd-level factors that may influence the prevalence and severity of macroscopically visible pulmonary lesions in pigs at slaughter. Data were collected following abattoir inspection of 50 randomly-selected batches of 6335 pigs and by interviewing the producers. Macroscopic lung lesions were identified and scored semi-quantitatively in ≥ 80 pigs/herd and the prevalence of pleuritis and pneumonia was 20.76% and 23.85%, respectively. Following multivariable analysis, the seroprevalence of Actinobacillus pleuropneumoniae (P < 0.001) and Mycoplasma hyopneumoniae (P = 0.018) and the number of pigs/nursery pen (P = 0.023) were positively associated, whereas average weaning age was negatively associated (P = 0.001) with the pleuritis score. Risk factors associated with a higher prevalence of pneumonia were the presence of pleuritis (P = 0.001) and the frequent purchasing of pigs (P = 0.020). The findings of this study indicate that the prevalence of pleuritis and pneumonia remains high in Belgium and management factors are central to disease control.