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THE INFLUENCE OF GROWTH PROMOTANT ANTIBIOTICS AND MANAGEMENT SYSTEM ON PRESENCE AND PREVALENCE OF SALMONELLA IN SWINE

J.N. Nielsen, J.A. Patterson, A. Sutton, A. Schinkel, B. Richert

Purdue University Department of Animal Sciences
West Lafayette, IN 47907

 

This study compared the incidence of shedding of Salmonella during the late finishing phase of production in littermate swine reared under different management conditions. The treatments compared were: 1) multi-site segregated early weaning (SEW) versus continuous flow (CF) rearing practices, 2) feed rations with or without the growth promotant antibiotics Carbadox in nursery rations and Bacitracin Methylene Disalicylate in grower/finisher rations. In addition, the effect of a 24 hour fasting period on subsequent fecal shedding of Salmonella by pigs in pens containing at least one Salmonella positive pig was evaluated.

Of the 288 pigs on study, a total of 9 pigs (3.2%) were fecal culture positive for Salmonella on one or more occasion. One Salmonella positive pig was identified in the CF facilities, 8 were identified in the SEW facilities. Seven of the nine Salmonella positive pigs received growth promotant antibiotics in their feed. Fasting alone did not cause shedding of Salmonella in 14 pigs subjected to one or more 24 hour fasts. Two pigs that were previously negative for Salmonella, when fasted, shipped and held commingled with a Salmonella positive pig for 12-18 hours prior to slaughter, had Salmonella isolated from cecal contents at slaughter.

The data collected in this study suggests that specific management practices prior to slaughter affect the number of Salmonella positive pigs at slaughter. Further research on Salmonella incidence rates in swine reared under high health management systems and interdiction methods to decrease the incidence is warranted.


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