Assessment and management of protected pig units

The risk of arial contamination of selection farms, in areas where animal density is high, can be a problem. The protection of farms by filtering air as well as bio-security measures are proposed. Different systems of air filtration are currently being studied in the facilities of Veterinary Research Institutes, for example, at AFSSA Ploufragan (France). A small pig unit was built at the agriculture development farm of Guernevez in Brittany. The air-filtered unit was set-up at the heart of a conventional pig farm in order to look at the efficacy of the system. Three trials were subsequently carried out.In the first trial 36 SPF pigs were transferred from Ploufragan and raised in 2 totally separate rooms within the new unit at Guernevez. One of the 2 rooms was equipped with an air filtration disposal system (level of filtration EU9). For both rooms, high bio-security measures were used, which included shower for the workers. Pig health and performance were followed in detail. A severe outbreak of swine influenza (A/H1N1) occurred in the adjacent fattening buildings of the conventional unit. The SPF pigs kept in the two experimental rooms were also infected as seen by a mild form of the disease with clear seroconversion. In the second trial the air-filtration system was improved (level of filtration EU12).It is not possible to draw a conclusion because there was no viral outbreak in the conventional farm. The SPF pigs were not infected. In the third trial the pigs tested were not SPF, but early-weaned piglets (7 d) from the conventional herd.They were housed in the air-filtration rooms (EU12). Whereas seroconversions against PRRS, PRCV and PPV occurred in the pigs raised in the conventional herd, no trace of such infections occurred in the air-filtered bio-secured room.