Vaccination against Streptococcus suis: Effect on nursery mortality
Montserrat Torremorell, Carlos Pijoan, Emilio Trigo
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Purpose: To evaluate the effect of selected vaccines and administration routes on mortality of nursery pigs due to Streptococcus suis.
Methods: A field trial was conducted on one group of nursery pigs (N=330). Pigs were randomly allocated to one of four groups that each received one of the following treatments at weaning: an experimental autogenous vaccine administered intramuscularly (IM) (n=90); a standard autogenous vaccine administered IM (n=90); a commercial bacterin, administered intraperitoneally (IP) (n=60); or no vaccine (n=90). Nursery mortality was monitored from the start of the trial (18 days of age) until the end of the nursery period (9 weeks of age).
Results: Nursery mortality before the start of the trial was approximately 17%. There were no significant differences among the four treatment groups; however, there was a trend toward decreased mortality among pigs that received the experimental autogenous vaccine. Overall nursery mortality at the end of the trial had decreased to 3.3%. Following the trial, an IP vaccination protocol with the commercial bacterin was initiated among all nursery pigs for 6 months. Total nursery mortality while this protocol was in place was 3.48% (SD=1.45) and the mortality rate for pigs that showed CNS signs at the time of death was 2.55% (SD=1.2). After this 6-month vaccination program, the owner of the herd switched to a sow vaccination strategy with the commercial bacterin. For the 6 months during which the sow vaccination protocol was monitored, total nursery mortality was 2.66% (SD=1.65), with mortality of pigs demonstrating terminal CNS signs at 2.0% (SD=1.61).
Implications: Vaccination does not totally control S. suis.
Keywords: Streptococcus suis, vaccine, mortality
Cite as: Torremorell M, Pijoan C, Trigo E. Vaccination against Streptococcus suis: Effect on nursery mortality. J Swine Health Prod 1997;5(4):139-143.
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