A health monitoring project in contract nursery/finishing barns has demonstrated the effectiveness of implementing a simple biosecurity protocol in reducing porcine reproductive respiratory syndrome (PRRS) transmission.

Approximately 567,000 PRRS-negative pigs were placed at 42 finisher sites (total of 121 barns) during the course of the project. The barns were all located in Sioux County, Iowa, which has a pig density of 1,132 per square mile, or approximately 1.6 times the pig density of Perth County, Ontario. PRRSV is endemic in the area.

Approximately 40 per cent of the barns used, at a minimum, a Danish entrance (clothing change and hand washing) and the pigs in those barns were significantly less likely to become PRRS infected during the project than those that had no entrance biosecurity protocols.

In addition, in those barns with a Danish entrance, average daily gain and feed conversion ratio were significantly better and the opportunity cost per pig was almost US$2.00 less.

In this study, the previous PRRSV status of the barn had no impact on the PRRSV status of subsequent groups of pigs, demonstrating the effectiveness of cleaning and disinfecting in killing the virus.

Season did have an impact: there were significantly more PRRSV breaks in January-March than at other times of the year. This is not surprising since previous research has demonstrated that the virus is stable in freezing conditions.

As a result of these findings, the entire production system has implemented mandatory Danish entries in all barns as a means of reducing the risk of PRRSV infection.

This summary is based on a presentation by Dr Steve Dritz at Big Bug Day VI on 3 December 2008.

March 2009

Further Reading

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Find out more information on porcine reproductive respiratory syndrome (PRRS) by clicking here.