Field evaluation of the efficacy, compatibility and serologic profiling of a combined vaccine against porcine reproductive and respiratory syndrome and Haemophilus parasuis in nursery pigs.

The aim of the study was to compare the efficacy and compatibility of a separate or combined vaccination against the porcine reproductive and respiratory syndrome (PRRS) and Haemophilus (H.) parasuis. The study was conducted in a 1200 head nursery farm. A total of 360 piglets at an age of 26 days were randomized into three groups. Group A was vaccinated separately against H. parasuis (Porcilis(®)Glässer) and PRRS (Porcilis(®)PRRS), group B was vaccinated with a combined vaccine of both vaccines and group C remained unvaccinated as control group. The compatibility was evaluated by measurement of the body temperature and a palpation score of the injection site 0, 4, 24 and 72 h after vaccination. During the nursery and the fattening period the average daily weight gain (ADWG), the number of runts and the mortality was evaluated. Additionally blood samples were taken every 2 weeks during the nursery period to perform an OppA-ELISA and a PCR for PRRS virus. No significant difference could be seen regarding the body temperature between group A and group C. Piglets which were vaccinated with the combined vaccine showed a significantly higher body temperature 4 and 72 h post vaccination than piglets from group A. The palpation score was significantly higher in group A 4 and 24h post vaccination compared to the control group, whereas no significant difference was observed between group A and B. No significant differences between groups were seen in the ADWG during the nursery period. The mortality rate during the nursery period was significantly higher in group C than in group A. The ADWG during fattening was significantly higher in the vaccinated groups than in group C. A PRRS genotype1 field virus was detected at the end of the nursery period. No significant differences were observed in the number of OppA-ELISA positive animals, but vaccinated pigs seemed to react earlier. All pigs of the vaccinated groups that were positive in the OppA-ELISA did not develop Glässer's disease and remained in the study until slaughter. The combined administration had no negative influence on efficacy but showed a slightly worse compatibility than the separate administration of both vaccines. The results of the present study indicate that vaccination against Glässer's disease using Porcilis(®)Glässer might influence the results of the OppA-ELISA.