PRRSV-1 Stabilization: A Way to Reduce Antibiotic Usage

This study reports an investigation into 19 French farrow-to-finish farms that successfully implemented the porcine reproductive and respiratory syndrome virus type 1 (PRRSV-1) stabilization protocol between 2007 and 2019. One year before (P1) and one year after (P2) the introduction of this protocol, the antibiotic consumptions (expressed in mg/PCU and ALEA) were compared for each farm. The difference between P1 and P2 was also calculated in percentages. The transition from P1 to P2 revealed that the higher the consumption levels were in P1, the greater the antibiotic reduction in P2. These results emphasize how stability against PRRSV-1 seems to reduce antibiotic usage, particularly in farms with a high level of consumption.

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The purpose of this study was to describe vaccinal strain detection using qPCR on blood samples collected from due-to-wean piglets after a mass vaccination of their dams with amodified live vaccine in five positive stable herds with different management practices including external and internal biosecurity measures.

Data concerning PRRSV-1 vaccine virus strains dissemination within vaccinated sow herdsare scarce. However, it is a big concern for swine practitioners when designing the PRRSV diagnostics strategy in vaccinated farms. At the same time, the possibility of vaccine virus transmission from sows to their offspring is important to have in mind in order to limit the risk of recombination between different PPRSV-1 modified live virus vaccine (MLV1) when both sows and piglets have to be vaccinated. This study was conducted in five PRRSV-stable breeding herds. The selected farms presented different characteristics regarding production parameters and biosecurity management practices in order to be, as much as possible, representative of French swine production herds. In four different batches following a sow mass vaccination with a PRRSV-1 modified live virus vaccine (ReproCyc® PRRS EU, Boehringer Ingelheim, Ingelheim, Germany), we failed to detect the vaccine virus in due-to-wean piglets in all of the herds. This should mean that the dissemination of the vaccinal strain is a rare event, even just after a sow vaccination, at least for the vaccine tested in our study.