Effect of transportation and feed withdrawal on shedding of Salmonella Typhimurium among experimentally infected pigs

Objective-To determine whether stress associated with transportation or fee d withdrawal increased fecal shedding of Salmonella Typhimurium among pigs experimentally infected with the organism. Animals-86 healthy pigs. Procedure-Pigs were challenge exposed with Salmonella Typhimurium at 4 week s old and reared conventionally. When pigs reached market weight, they were assigned to groups and subjected to various combinations of transportation and feed withdrawal. Ileocecal contents were collected after slaughter and tested for Salmonella Typhimurium . Results-Salmonella Typhimurium was not detected in feces collected from pig s just prior to slaughter. When feed was withheld for 24 hours prior to sla ughter, the proportion of transported pigs with Salmonella Typhimurium in i leocecal contents at the time of slaughter was not significantly different from the proportion of nontransported pigs. However, when feed was not with held prior to slaughter, the proportion of transported pigs with Salmonella Typhimurium in ileocecal contents at the time of slaughter was significant ly higher than the proportion of nontransported pigs. Conclusions and Clinical Relevance-When carrier pigs remained on feed, tran sportation stress increased the proportion positive for Salmonella sp. On t he basis of results reported here, it is suggested that producers withhold feed from pigs for 24 hours prior to transportation to a slaughter plant.