Title: Torremorell M. 1995;4:139-143. Vaccination against S suis
Headings: Vaccination against
Streptococcus suis
:
Effect on nursery mortality

Field study
Vaccination against Streptococcus suis:
Effect on nursery mortality
Montserrat Torremorell, DVM; Carlos Pijoan, DVM, PhD; Emilio Trigo, DVM, PhD
Summary
Material and methods
Herd history and clinical evaluation
Field vaccine trial
Statistical analysis
Posttrial vaccination protocols
Results
Discussion
Implications
References

Content: Posttrial vaccination protocols
Following this controlled trial, the producer adopted a new vaccination protocol that was designed to boost the immune response and protect pigs with different levels of maternal immunity. Starting in late November 1995, piglets were vaccinated with the commercial bacterin IP at 5 days of age, revaccinated IP at weaning (15 days of age), and revaccinated again 10 days later IM. This program was followed in the herd for 6 months. A TGEV outbreak in March 1996 convinced the producer to begin attempts to determine the causes of nursery pig mortality. Thus, after March 1996, the herd records differentiated between total mortality data of pigs and mortality that could be directly attributed to S. suis ( i.e., pigs that exhibited obvious CNS distress, ataxia, tremors, and paddling). In May 1996, the producer decided to adopt a sow vaccination protocol, which was less expensive, less time consuming, and easier to implement. Sows were vaccinated IM with the commercial bacterin at approximately days 77 and 98 of gestation. Piglets were followed during the nursery stage, and mortality rates were used to evaluate the effectiveness of this protocol. This protocol was still in use at the time of this report. Results
Pigs that received the experimental autogenous vaccine tended to have lower morbidity/mortality ( P <.1) than pigs in the other groups  ( Figure 2 ).