The influence of porcine reproductive and respiratory syndrome (PRRS) on reproductive performance in pig production farms in Styria (Austria)

The influence of porcine reproductive and respiratory syndrome (PARS) on reproductive performance in pig production farms in Styria (Austria) Introduction The porcine reproductive and respiratory syndrome (PARS) is one of the most important diseases of swine. The economic impact caused by PARS is estimated to be 560 Mio. US Dollars per year in the United States. However, the results are not comparable to the situation in Austria because of the different sizes and structures of herds. The purpose of this study was to evaluate the present PARS prevalence and the influence of a chronic infection on the reproductive performance of Styrian pig breeding farms. Additionally, the effects of management features on reproductive performance were analysed. Material and methods Altogether, 130 suitable farms were chosen randomly and assigned to one of the following groups: group A = PRRSV-antibody (Ab)-negative, group B = PRRSV-Ab-positive, and group C = PRRS-MLV-vaccinated. To increase comparability, 65 of these farms were separated due to specific criteria (groups A(1), B(1) and C(1)). Results and conclusion Between groups A(1) and B(1) no significant differences concerning reproductive performance could be found, but there was a trend towards higher preweaning mortality in group B(1). Less piglets were born alive in the vaccinated group when compared to group A(1) and also more returns to estrus were evident. Furthermore, management had a significant impact on reproductive performance. In conclusion, the influence of a chronic PRRSV infection on reproductive performance seems to be minor under the Styrian conditions. However, the negative effect of vaccination should be discussed critically and vaccination schedules should be adapted to local conditions.