With regards to weaners in PRRSv positive and stable herds. Is it possible to wean piglets PRRSv-free when they came from vaccinated (with inactivated vaccine) sows? If it`s possible, what would be the best age to wean? On farm we have possibility to wean 2,5 week old piglets. And second question: Is it possible (and how) to stabilize PRRSv to get opportunity to change vaccine form live one to inactivated.
Yes, it is possible if you wean that early but you have (i) to close the herd and (ii) test the weaned piglets for PRRSV.
And regarding the second question, the change to inactivated vaccines might be of interest and successful in farms where clinical signs (e.g. abortion) are not really attributed to PRRSV rather than to other pathogens.
The live vaccine is able to elicit a good immune response but is in comparison to the inactivated vaccine also associated with a more pronounced stress to the immune system which might in some clinical settings with a load of co-infections not always be helpful.
In farms with clinical problems not directly caused by PRRSV the inactivated PRRSV vaccine might be worth to use.
Leipzig University – Germany