Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/18/2006
Publication Date: 10/17/2006
Citation: Bahnson, P.B., Cray, P.J., Ladely, S.R., Mateus-Pinella, N.E. 2006. Herd-level risk factors for salmonella enterica subsp. enterica in U.S. market pigs. Veterinary Microbiology. 76(3-4):249-262. Interpretive Summary: of contaminated food. Infection with Salmonella can cause mild to severe gastroenteritis in humans while infection in food animals is often with clinical signs of disease. In order to control infection with Salmonella, it is important to identify factors in production that pose the biggest risk for acquiring Salmonella. We cultured feces from swine on-farm and feces and lymph nodes at the slaughter plant from 65 swine herds in the United States for bacteriologic culture to determine if pigs were infected with Salmonella. In addition, through use of written and oral surveys, we collected on-farm production characteristics to identify factors that were most likely to contribute to swine both becoming infected with, or shedding, Salmonella. The use of bowl or bowl/nipple drinkers was associated with higher shedding prevalence when compared to the use of only nipple drinkers. Further, use of dry feed only was associated with higher prevalence when compared with herds that provided feed and water mixed at the point of delivery. These data indicate that changes to nipple drinkers and/or mixing of feed and water on-farm may reduce the numbers of swine that become infected with Salmonella. This is important for scientists, commodity groups, government regulators, and animal industry personnel who study ways to reduce Salmonella as a means to reduce the incidence of human salmonellosis.
Technical Abstract: To identify risk factors for Salmonella shedding among slaughter weight pigs, 65 herds Midwest USA herds were studied. Samples were cultured using conventional means from farm (feces) and slaughter (distal colonic content, cecal content and ileocecal lymph node) derived samples. Approximately 15 pigs were studied per herd, for a total of 3,827 samples. Herd characteristics were described by a combination of interview and written survey. Salmonella culture positive prevalence was positively correlated among all samples collected. The use of bowl or bowl / nipple drinkers was associated with 0.267 higher shedding prevalence when compared to the use of only nipple drinkers. The provision of dry feed only was associated with 0.215 higher prevalence when compared with herds that provided feed and water mixed at the point of delivery. Interventions at these two points should be considered when designing growing pig facilities to reduce Salmonella shedding.