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United States Department of Agriculture

Agricultural Research Service

Title: Effect of Mixing and Transportation Stress Parameters on the Recrudescence of Salmonella in Swine

Authors
item Stabel, Thomas
item LAY, JR., DONALD
item Toscano, Michael
item Scott, Karen
item Vote, Brian

Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 12, 2002
Publication Date: November 12, 2002
Citation: STABEL, T.J., LAY, JR., D.C., TOSCANO, M.J., SCOTT, K.A., VOTE,B. EFFECT OF MIXING AND TRANSPORTATION STRESS PARAMETERS ON THE RECRUDESCENCE OF SALMONELLA IN SWINE. CONFERENCE OF RESEARCH WORKERS IN ANIMAL DISEASES. 2002. ABSTRACT P. 49P.

Technical Abstract: Largely anecdotal reports have implicated the stress associated with marketing swine as an important cause of Salmonella shedding at time of slaughter; however, recent correlative data have provided mixed results as to the effect of such stress. Our goal was to experimentally induce recrudescence of Salmonella in pigs by mimicking stress parameters associated with the marketing of swine. Salmonella-free pigs were inoculated intranasally with 1 x 10**6 Salmonella choleraesuis/pig 3 weeks prior to feed withdrawal, mixing, and transport. Fecal samples were collected and cultured for S. choleraesuis at various time points post inoculation: 8 h, 24 h, 48 h, 7 d, 14 d, 21 d (pre-stress), 21 d (post mixing/transport), 21 d (post mixing/transport/mixing), 22 d (1d post stress), and 23 d (2 d post stress). Ileocecal lymph node samples were collected 23 d post inoculation (2 d post stress), and cultured for S. choleraesuis. Results indicate that carrier pigs taken off feed the evening prior to transport, mixed together for 2 h, herded to a waiting trailer, transported for 2 h, mixed together again for a second 2h period, and then put back on feed did not shed S. choleraesuis in the feces until 24 h after the end of transportation or 22 h after resumption of feed. In addition, lymph nodes cultured for Salmonella at time of necropsy indicated that some pigs were lymph node positive even though they never shed Salmonella in the feces before or after stress. Other pigs remained Salmonella culture negative (fecal and lymph node) for the duration of the study. The role of feed intake, or lack thereof, on the time-line of Salmonella recrudescence is currently under investigation. These results indicate a serious increased risk of Salmonella fecal shedding if shipped pigs are not processed in a timely fashion after arrival at their destination.

Last Modified: 8/19/2014
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