- 2 minutes, 2 seconds
- Expertise article
- Pauline Berton, Valérie Normand1, Franck Bouchet1, Josselin Metais1, Gwenaël Boulbria, Eric Lewandowski, Ingrid Messager, Nathalie Robert, Arnaud Lebret
INTRODUCTION
PRRSV stabilization proved to be efficient thanks to mass vaccination of the animals combined to strict biosecurity measures1. In farrow-to-finish farms, where pig and human flows are sometimes difficult to respect, eradication of the virus in fattening units is a challenge. This clinical case highlights the benefits of reinforcing the vaccination protocol to control PRRSV circulation from weaning to slaughter.
MATERIAL AND METHODS
This field study was implemented in 2015 in a farrow-tofinish 240-sow herd, weaning 21 day-piglets every 2 weeks and located in Brittany (France). Gilts were purchased from a PRRSV-negative farm at 110 kg and were quarantined during 8 weeks before entering the herd. Sows were vaccinated with a killed virus (KV) vaccine against PRRSV. The farmer faced reproductive disorders (low fertility rate, abortions), and high loss rate on growers and finishers. Circulation of a PRRSV European strain was confirmed in May 2015. Analyses and results are presented in the table below. 
A PRRSV stabilization protocol was then established. In June 2015, the herd was closed for 8 weeks, and all the animals were mass-vaccinated (94881 vaccine strain: REPROCYC®PRRS EU in sows, INGELVAC PRRSFLEX®EU in 21-day pigs and older) twice 4 weeks apart. As the farmer’s objective was to produce his own gilts, eradication was aimed on fattenerunits: thereafter 20 batches of piglets were vaccinated at weaning and 4 weeks later to strengthen the protocol with INGELVAC PRRSFLEX®EU. Strict biosecurity measures were implemented, including unidirectional pig and human flow, exclusive use of artificial insemination (purchased doses), enhanced hygiene measures of cleaning and disinfection of pens and corridors. The stabilization protocol ended when the last batch of piglets was vaccinated, in April 2016. Mass vaccination was maintained on sows every 4 months.
RESULTS
Following Batista et al protocol2, monitoring started in May 2016. It aimed to assess the absence of transmission of the virus from the sows to their piglets, and the absence of PRRSV in growers and finishers. Sampling and results are presented in the table below. The herd was declared stable. As no PRRSV circulation and exposition could have been diagnosed, eradication was concluded in growers. In addition, 10 due-to-slaughter pigs were tested PRRSV-negative 4 months after the termination of the monitoring phase.
CONCLUSION
Results of the monitoring showed the absence of transmission of PRRSV from sows to their piglets, and the absence of PRRSV circulation within the sow herd. The absence of contamination of growing pigs on the 2 successive batches confirmed the eradication of PRRSV in fattener-units.