ELIMINATION OF PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME (PRRS) WITH SERUMIZATION, NATURAL EXPOSURE AND VACCINATION ON SIX PIG FARMS IN SLOVENIA

Porcine reproductive and respiratory syndrome (PRRS) is currently the most important swine disease worldwide. A variety of strategies have been described for PRRS eradication. The study involved six one-site small pig farms where the reproductive problems were observed. The owners were acquainted with strict biosecurity and herd closure for at least 200 days. Serum samples were tested with IDEXX X3 PRRS ELISA for antibodies detection and with one step RT-PCR (Qiagen, Germany). Production results after serumization improved 3 months after on both farms. Herds were also without virus. On farm 1 new boar without quarantine and new gilts were introduced in to the breeding herd. Eleven months after serumization production results decreased and same strain of PRRS virus was present in herd. Breeding herd on farm 2 is 13 months without PRRS virus. Only in group of growers of 10
weeks PRRS virus persists but the subtype of it is new. After natural exposure on both farms number of seropositive pigs was decreased and fatteners were seronegative. Both farms were also without PRRS virus. After vaccination on farm 5 production results improved and also number of high seropositive animals decreased. Fourteen months after vaccination number of seropositive
pigs increased and production results decreased. Results from second vaccinated farm were similar. Natural exposure with implementation the strict biosecurity protocols and improvement of management are the key factors for successful eradication of PRRS. At the moment serumization and vaccination are the methods with limited success.