After a field infection or after vaccination, sows pass on antibodies against PRRS to the piglets via colostrum, which protects the piglets for several weeks. However, this maternal immunity differs strongly per piglet and depends, among other things, on the amount of colostrum ingested and how many hours after the birth of the first piglet, the piglets have drunk the colostrum. The protection of a flock will therefore vary during the nursing period. There is therefore a chance that a small proportion of the piglets may be infected with a PRRS field virus.
Fighting maternal immunity
The French institute Anses (1,2) has conducted research with two vaccines used in the Netherlands that can already be used in young piglets. In piglets that had drunk little colostrum, early vaccination gave good protection. However, this was not the case with piglets that had drunk good colostrum. These vaccines fail to compete with the maternal immunity, which means that these piglets do not build up good immunity against PRRS after vaccination.
In contrast, a PRRS vaccine from Boehringer Ingelheim, which can be administered from 17 days of age, appears to be effective in the presence of many colostrum antibodies. (3,4) and can therefore be safely used with young piglets.
The right vaccination moment: as late as possible and as early as necessary
During the first weeks of a piglet’s life, the immune system starts to function better and better. With that knowledge you would rather not want to vaccinate shortly after birth. On the other hand, you may want to vaccinate a few weeks before infection to give the immune system time to build up protection. The best vaccination moment takes both into account, whereby it is not recommended to vaccinate shortly around weaning because stress has a negative influence on the build-up of immunity.
Search for the best vaccination moment for each company
The best time to vaccinate is usually from week two to three in the farrowing pen and from two weeks after weaning. If PRRS problems only arise in the fattening pigs, it is not even necessary to vaccinate at the sow farm. At the request of a fattening pig farmer, vaccination can possibly take place no later than two weeks before delivery or after laying in the fattening pig barn.
Want to know what the right vaccination moment is for your piglets? Together with your vet, we are happy to offer you our support.
Conclusion:
vaccinate as early as necessary, but as late as possible!
TIP: with 1 injection your pigs are protected against PRRS and Circo
Protecting pigs at the right vaccination time against PRRS and at the same time also against Circo is possible and very simple. A PRRS vaccine is available that can be dissolved in a Circo vaccine and then administered in one vaccination and therefore in one action. This is twice the advantage: you save labor and the pig gets one less shot.
references:
1. P. Renson, C. Fablet, M. Andraud et al., Maternally-derived neutralizing antibodies reduce vaccine efficacy against porcine reproductive and respiratory syndrome virus infection, Vaccine, https://doi.org/10.1016/j.vaccine.2019.06.045
2. Mahé e.a. Interference of maternally derived antibodies with Suvaxyn PRRS MLV vaccination is dependent of the antibody level, ESPHM 2020+1
3. Balka et al. Porcine Health Management (2016) 2:24 DOI 10.1186/s40813-016-0037-y
4. Kraft et al. (2019) Evaluation of PRRSv specific, maternally derived and induced immune response in Ingelvac PRRSFLEX EU vaccinated piglets in the presence of maternally transferred immunity. PLoS ONE 14 (10): e0223060