Postweaning Multisystemic Wasting Syndrome (PMWS) is a set of clinical signs that is often associated with Porcine Circovirus type 2 (PCV-2) infection.  Typically affecting pigs that are 5-8 weeks of age, PMWS results in wasting, diarrhea, jaundice, and increased respiratory rate.  Most of the affected pigs will either die from the disease or require euthanasia.

A recent Swiss study looked at the role of vaccinating sows during gestation on the subsequent performance and health parameters of the pigs born to those sows.  In the study, investigators vaccinated 113 sows before breeding (4 and 2 weeks prior), along with giving a booster dose of vaccine at week 12 of pregnancy (approximately 4 weeks before farrowing).  A commercially-available, inactivated PCV-2 vaccine was used.  Other sows in the same cohort were given “sham” vaccines. 

Compared to pigs born to the “sham” vaccinated sows, pigs born to vaccinated sows showed significantly higher levels of antibodies against PCV-2 in their bloodstream.  While none of the pigs in either group developed clinical signs of PMWS, four pigs from unvaccinated sows were observed to seroconvert, or develop an antibody response to PCV-2, indicating that they had become subclinically infected. 

Perhaps the most interesting and important finding of the study was that piglets from vaccinated sows experienced significantly higher weight gains than pigs from unvaccinated sows: 33 grams per day in one herd and 20 grams per day in the other.  This resulted in a reduction of 6.7 and 5.5 days to slaughter in each herd, respectively. 

The performance effects in pigs directly vaccinated with PCV-2 vaccine have been previously documented, but this study sheds new light on the health effects of pigs born to sows who have been given PCV-2 vaccine.  Full details of the study can be found in the article, “Vaccination of Dams Increases Antibody Titer and Improves Growth Parameters in Finisher Pigs Subclinically Infected with Porcine Circovirus Type 2”.