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United States Department of Agriculture

Agricultural Research Service

Research Project: HANDLING AND TRANSPORT STRESS INTERACTIONS WITH PATHOGEN BIOLOGY IN SWINE AND CATTLE

Location: Livestock Behavior Research

Title: Split Marketing as a Risk Factor for Salmonella Enterica Infection in Swine

Authors
item Rostagno, Marcos
item Hurd, Scott -
item Mckean, James -

Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 13, 2009
Publication Date: September 8, 2009
Citation: Rostagno, M.H., Hurd, S.H., Mckean, J.D. 2009. Split Marketing as a Risk Factor for Salmonella Enterica Infection in Swine. Foodborne Pathogens and Disease. 6(7):865-869.

Interpretive Summary: On-farm reduction of Salmonella prevalence in pigs requires the identification of risk factors to direct interventions. This study was designed to determine if split marketing of finishing pigs constitutes a risk factor for Salmonella infections, by comparing Salmonella prevalence in the first group of pigs selected for slaughter (“First pull”) versus the prevalence in the last group of pigs selected for slaughter (“Close out”) from multiple commercial finishing lots. Nine paired samplings were conducted consisting in matched groups of pigs from individual barns as the “first pull” and the “close out” with a 4-week interval between groups. From each group, fecal and meat samples were collected, on-farm and at slaughter, respectively. Fecal samples were selectively enriched, and analyzed for the presence of Salmonella, whereas meat juice samples were analyzed for the presence of antibodies against Salmonella. In 7/9 (77.8%) of the studied barns, an increase in Salmonella prevalence was observed, based on both bacteriologic and serologic analysis. Overall, there was an increase of 9.2% in bacteriologic prevalence, and 31.3% in serologic prevalence from “first pull” to “close out” groups. This study demonstrates that a significant increase of Salmonella prevalence occurs between the first and the last group of pigs from a finishing lot shipped to slaughter, with “close out” groups of market pigs posing a higher risk for Salmonella contamination of pork products. Therefore, it is concluded that split marketing is a risk factor for Salmonella infections in finishing pigs.

Technical Abstract: On-farm reduction of Salmonella prevalence in pigs requires the identification of risk factors to direct interventions. This study was designed to determine if split marketing of finishing pigs constitutes a risk factor for Salmonella infections, by comparing Salmonella prevalence in the first group of pigs selected for slaughter (“First pull”) versus the prevalence in the last group of pigs selected for slaughter (“Close out”) from multiple commercial finishing lots. Nine paired samplings were conducted consisting in matched groups of pigs from individual barns as the “first pull” and the “close out” with a 4-week interval between groups. From each group, fecal and meat samples were collected, on-farm and at slaughter, respectively. Fecal samples were selectively enriched, and analyzed for the presence of Salmonella, whereas meat juice samples were analyzed for the presence of antibodies against Salmonella. In 7/9 (77.8%) of the studied barns, an increase in Salmonella prevalence was observed, based on both bacteriologic and serologic analysis. Overall, there was an increase of 9.2% (P<0.05) in bacteriologic prevalence, and 31.3% (P<0.05) in serologic prevalence from “first pull” to “close out” groups. This study demonstrates that a significant increase of Salmonella prevalence occurs between the first and the last group of pigs from a finishing lot shipped to slaughter, with “close out” groups of market pigs posing a higher risk for Salmonella contamination of pork products. Therefore, it is concluded that split marketing is a risk factor for Salmonella infections in finishing pigs.

Last Modified: 4/19/2014
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