Fig. 1

Map of the pig farm and surrounding area (Dovadola municipality, Forlì province), 44.114325°, 11.906907° (downloaded from Google Earth Pro); the black arrows show the north. a The investigated pig farm; the red triangle shows the outside fenced area, where sows had access from 40 up to 100 days after fertilization with the boar for the control of estrus in sows; scale bare 50 m. b The investigated pig farm (in the red circle) with the surrounding environment showing a wooded area on the left, cultivated fields in the central picture and badlands with minimal vegetation on the right; scale bar 250 m. c Map of Italy showing Forlì Province, Emilia Romagna region, Northern Italy