Fig. 1

Correlation matrix showing Pearson’s rank correlation coefficients among ten farm characteristics. Cells with an X indicate a non-significant correlation. AMR prevalence was calculated as the proportion of plates on which resistant isolates were recovered (number of positive plates/8), and Salmonella prevalence was calculated as the proportion of stages positive for Salmonella (number of stages positive/4). AMR: antimicrobial resistance prevalence; External biosec.: external biosecurity score; Internal biosec.: internal biosecurity score; Piglet mort.: piglet mortality; Pigs sow year: number of pigs produced per sow per year; PRRS: porcine reproductive and respiratory syndrome status (positive or negative); W + F mort.: weaner + finisher mortality; ZnOAb: use of zinc oxide and medicated feed (yes or no)