ELIMINATION OF SALMONELLA-TYPHIMURIUM INFECTION BY THE STRATEGIC MOVEMENT OF PIGS

Three field investigations were tarried out to assess the feasibility of raising salmonella-free finishers from pigs born in infected herds, by moving the pigs to clean and disinfected facilities before their e xpected exposure to the bacteria from the environment. Three herds wit h persistently high levels of subclinical infection with S typhimurium in the finishing pigs were used, They practised all-in all-out manage ment in the nurseries and in the grower units, A total of 844 pigs wer e moved, either at weaning, from the nursery, or from the grower unit to newly built or rigorously cleaned and disinfected finishing units w ith no known history of salmonella infection, No detectable infection was observed at slaughter either serologically or bacteriologically by random testing of the pigs which had been moved, whereas a proportion of the pigs raised at the same time in the continuous systems on the farms were found to be infected.