Salmonella infection in a multiple-site swine production system in Brazil

A longitudinal study was conducted in a multiple-site swine production system. Individually identified piglets were sampled for Salmonella fecal excretion and serology. Furthermore, intestinal content, mesenteric lymph nodes and blood samples were taken from these animals at slaughter. In addition, feed samples were taken throughout the study period. Piglets were fecal-culture and serology negative until the nursery phase, but became Salmonella positive in the early finishing phase. On this sampling day, 28.6% of finishers were seropositive and 75% were shedding Salmonella in feces. At slaughter, the seroprevalence (76.9%) was higher than in the early finishing, but Salmonella was isolated from intestinal content or mesenteric lymph nodes in only 19.2% of the sampled pigs. Salmonella was isolated from three out of 26 feed samples, being all positive samples collected during the finishing period. In spite of being isolated from different system sites, 89.56% of all Salmonella strains belong to serovar Typhimurium