76 (2) 124-129

A practical approach to the elimination of swine dysentery (Brachyspira hyodysenteriae) from single-site, farrow-to-finish...

Swine dysentery is causing severe economic losses in affected herds. In the present study an elimination protocol without depopulation was developed and evaluated on three farrow-to-finish farms using fecal examination. The elimination protocol consisted of stringent rodent control, hygienic measures and an elimination treatment of the sows using tiamulin 10 mg/kg BW or valnemulin 4 mg/kg BW for 3 weeks, followed by a 3 week treatment at half the dose. On day 10 of antimicrobial supplementation, treatment was accompanied by washing of the sows and cleaning of the environment. Once treated and washed according to this protocol, the sows were considered clean. Thus the piglets born from these sows in a clean environment were considered clean and were kept separated from the rest of the piglets and fatteners. For the piglets and fatteners born before the elimination treatment, no elimination treatment was done. Only pigs showing clinical symptoms were treated, in combination with hygienic measures to prevent spreading. Fecal samples from sows and clean pigs were monitored monthly until one year after the start of the treatment program. In two herds, elimination of the disease was successful: no clinical signs were seen and fecal samples remained negative until the end of the testing period. In one herd, clinical symptoms reappeared in the fatteners. The findings of this study confirm the potential usefulness of the elimination protocol described in single-site, farrow-to finish herds. In addition, the results of the prolonged follow-up strongly indicate that the causal bacterium itself, Brachyspira hyodysenteriae, can be eliminated at the farm level when this elimination protocol is applied.

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