Abstract

Objective: To determine the prevalence of Mycoplasma hyopneumoniae at weaning in litters originated from vaccinated and non-vaccinated sows. Materials and methods: A weekly production group of sows from an 800-sow commercial herd was randomly divided into two treatment groups. One group received a commercial vaccine (Respisure; Pfizer, New York) 5 and 3 weeks prior to farrowing, and the other group was unvaccinated (controls). Blood samples were collected from each sow prior to vaccination and at farrowing. Additionally, blood samples were collected at weaning and 2 weeks post weaning from four piglets from each sow. Samples were tested for antibodies to Mycoplasma hyopneumoniae by Tween-20 ELISA. Nasal swabs collected at farrowing from each sow and at weaning from each piglet were tested for M hyopneumoniae by nested polymerase chain reaction (N-PCR). The herd was not vaccinated for M hyopneumoniae before the study began, and no antibiotics effective against M hyopneumoniae were used during the study. Two replicates were performed using sows and litters in 2 consecutive weeks of production. Results: Over 80% of the vaccinated sows seroconverted and their antibodies were transferred to the piglets via colostrum. Prevalence of M hyopneumoniae in nasal swabs from sows did not differ among groups. Prevalence in piglets was lower in litters from vaccinated sows, but was significantly lower only in the first replicate. Implications: Vaccination of sows against M hyopneumoniae reduced prevalence of N-PCR-positive piglets at weaning, and could be used to control M hyopneumoniae in modern swine production systems.