FIELD-STUDY FOR REDUCTION OF SPREAD OF AUJESZKYS-DISEASE VIRUS IN FINISHING PIGS WITH DIFFERENT VACCINATION REGIMES

In a comparative field trial in feeder-finishing pigs on 8 farms with a history of Aujeszky's disease (AD) the incidence and spread of Aujes zky's disease virus (ADV) and serological effects of vaccination were investigated. Nobi(R)-Porvac Aujeszky live (strain Begonia) was used e ither dissolved in the aqueous adjuvant Diluvac Forte (DF) or in Uniso rve (watery solvent) to vaccinate whole feeder-finishing units one or two times. Incidence of ADV measured by gI ELISA within infected finis hing units was significantly reduced by the use of the adjuvant solven t DF. Furthermore the use of the adjuvant DF improved the efficiency o f the vaccination as was shown by significantly higher virus-neutralis ing (VN) titres at slaughter time. The number of samples without detec table VN antibodies at the end of the finishing period was significant ly lower in the finishing units vaccinated once with DF. The latter ef fect, though not statistically significant, was also seen after double vaccination in combination with the adjuvant. The investigation of VN antibody titres at the moment of the first vaccination (around 10 wee ks of age) suggests that on problem farms the spread of infection can start earlier than that time.