Fecal shedding of Salmonella by pigs housed in buildings with open-flushgutters

Results: In two herds (herds A and B), which received pigs and feed from the same sources, prevalence of positive fecal samples varied widely (60% and 4% respectively). In herd A (60% positive), gutters were flushed intermittently and the prevalence of pigs found to be shedding Salmonella was higher in downstream pens with respect to the flow of effluent. In herd B (4% positive), prevalence of fecal shedding was low, although gutters were flushed continuously with effluent recycled from single stage lagoon. In the other four herds, prevalence varied widely (4% to 59%) and no association between fecal shedding and pen location with respect to effluent flow was evident. In two herds, differences in serotype distribution between sides of barns suggested pen-to-pen transmission to be important. Clustering of positive pigs in some pens was also apparent.