Himmler, C; Graage, R; Palzer, A; Frebig, K; Eggen, A; Knoeppel, HP; Ritzmann, M; Hennig-Pauka, I; Ladinig, A
Comparison of reproductive parameters in sows vaccinated intradermally or intramuscularly with a modified live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine, in consideration of parity and season.
Introduction: There are different routes of application for vaccines against PRRSV in swine; the most common ones are intramuscular vaccination or intradermal vaccination using a needle-free device. The aim of this study was to compare reproductive parameters in sows after intradermal or intramuscular vaccination with Porcilis (R) PRRS (MSD Animal Health, Boxmeer, The Netherlands), a European, modified live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine. Materials and Methods: Data for this study were obtained on a breeding herd managing 2000 sows. All sows were vaccinated against PRRSV. For the purposes of the trial the sows were divided into two groups, in which the IDAL Group (N=945) was vaccinated intradermally with Porcilis (R) PRRS (MSD Animal Health, Boxmeer, The Netherlands) using the IDAL (R)-Injector and the i.m. Group (N=670) was vaccinated intramuscularly with the same vaccine but using syringe and needle. Reproduction parameters (piglets born alive, stillborn or mummified piglets, and piglets died before weaning) were analysed from August 2010 up to and including May 2011. The impact of this bias factors (parities, season) on piglets born alive was compared with the effect of vaccination method. A multi-factor analysis of variance corrected by Scheffe was used to check if vaccination method, season or parity had a significant influence on the number of piglets born alive. Results: The study showed no significant differences of the reproductive parameters between both groups. To detect the impact of parities and season, the number of piglets born alive was taken as main parameter Significant differences were observed between sows in their third to sixth parity compared to sows in their first and second parity (p<0.001) and sows with more than seven parities (p<0.001). The highest number of life born piglets was at parities three to six in both groups, 13.46 (IDAL) and 13.30 (i.m.), respectively. The season of farrowing compared with route of application had a significant impact on the number of piglets born alive (p=0.002). In summer, the mean number of piglets born alive was higher in both groups (N=13.17) than in spring (N=12.37) and autumn/winter (N=12.5). The comparison between the vaccination method and the number of parities and season showed that both the number of parities and the season, had a significant impact (p<0.001) on the number of piglets born alive. In contrast, the route of administration had no significant impact to the number of piglets born alive. Conclusion and Discussion: The study showed no significant differences between both vaccination methods. Based on the results of this study, the use of the IDAL (R)-Injector for intradermal vaccination against PRRSV can be recommended as a suitable alternative method to conventional intramuscular technique of vaccination.