Original Article

The use of tylvalosin (Aivlosin®) in the successful elimination of swine dysentery on a farrow-to-finish herd

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Abstract

Swine dysentery causes severe economic losses in swine industry. Eliminating the disease at farm level can become problematic when resistance of the causative agent, Brachyspira hyodysenteriae, against pleuromutilins is reported. In this study, the use of tylvalosin (Aivlosin®) in eliminating the disease in a single-site, farrow-to-finish herd was evaluated. In addition, productivity parameters and antimicrobial use were compared prior to and after implementing the elimination protocol. On a mixed farm of 200 sows and 1500 finishers with a history of chronic dysentery, the B. hyodysenteriae isolate was resistant to pleuromutilins but had a low minimum inhibitory concentration for tylvalosin (2 μg/ml). Combined with a strict program for rodent control and hygiene, sows were treated with tylvalosin at a dose of 4.25 mg/kg BW daily for four weeks. The sows were washed one week after the start of the treatment before entering a clean stable. Piglets born from sows that had received this treatment, were considered free from dysentery and were kept separated from infected, untreated animals on the farm. A monitoring program with monthly sampling of sows and fatteners was installed to evaluate the absence of B. hyodysenteriae on the farm. After treatment, the clinical symptoms in the treated sows disappeared and remained absent in the offspring born after the procedure. Fecal samples examined by PCR remained negative for the whole testing period (14 months after the end of the treatment) and no clinical outbreaks were reported afterwards. The feed conversion ratio improved by 12%, the mortality rate with 37% and the antimicrobial use decreased by 71.5%. We conclude that the elimination of swine dysentery on a single-site, farrow-to-finish herd is possible using tylvalosin (AivlosinR) combined with strict hygiene and rodent control. The improvements of the technical parameters in this study are not only the result of the elimination of B. hyodysenteriae, but also changes in management practices influenced these parameters.