Effect of Ingelvac® PRRS MLV on semen quality after boar vaccination

Vaccination is one of the effective methods to control boar from PRRSV infection in China. But, many people are hesitant to vaccinate boars because they worried vaccination could affect boar semen quality. The aim of this study was to evaluate the effect of a PRRS modified live vaccine (Ingelvac® PRRS MLV) on boar semen quality to provide a reference basis for PRRS boar vaccination.

The trial was carried out in a 2100-sow farrow-to-finish production system in China. It was a PRRSV-positive stable farm. Sows were massively vaccinated with Ingelvac® PRRS MLV three times per year and piglets were one shot at 14 days of age. boars were without vaccination. 13 adult boars with average weight 250~300 kg and 15 to 22 months of age were randomly divided into experimental group and control group; each group had 7 boars and 6 boars respectively. Each boar was in a single pen at the same closed and isolated house. House cleaning, disinfection and vaccination of other vaccines were implemented the same and according to the farm’s procedures. Seven boars in experimental group were vaccinated with Ingelvac® PRRS MLV at the same day. Semen collection was in accordance with the normal production schedule of the farm which was about one collection per week. Semen index of every boar (sperm quantity, sperm density, sperm motility and malformation rate) were recorded and compared before and after vaccination within one month.

The statistical analysis of the recorded semen data of 7 experimental boars before and after PRRS vaccination, revealed no significant differences in semen collection capacity (P =0.8746), Sperm density (P =0.1347), sperm vitality (P =0.8744), while there was significant difference (P =0.0468) in sperm malformation rate, and the sperm deformity rate of boars before vaccination was higher than that of boars after vaccination. In addition, in the period of time after vaccination, there was no significant difference in 4 semen quality indexes between control and test groups. The P values of sperm quantity, sperm density, sperm motility and malformation rate were 0.093, 0.6597, 0.7966 and 0.5066.

This experiment showed vaccination of Ingelvac® PRRS MLV would not affect boar semen quality. An interesting finding was Ingelvac® PRRS MLV could provide some certain improvement in sperm malformation rate of experimental boars. Four weeks before the trial total 13 boars were collected blood sample to do PRRSV infection test, the only positive one was randomly assigned into the control group. We were not sure whether this was factor that affected the result, and we need to get more date to confirm this conclusion.

Disclosure of Interest: None Declared.