Field efficacy of a novel porcine reproductive and respiratory syndrome modified‐live virus vaccine with an emphasis on growth performance

Abstract Background This field evaluation was designed to evaluate the efficacy of a new porcine reproductive and respiratory syndrome virus‐2 (PRRSV‐2) modified live virus vaccine at three independent pig farms. Methods Three farms were selected for this study based on their respiratory disease status caused by PRRSV‐2 infection in post‐weaning and growing pigs. Each farm housed a total of 40, 18‐day‐old pigs that were randomly allocated to one of two treatment groups. Pigs were administered a 1.0 mL dose of the bivalent vaccine intramuscularly at 21 days of age in accordance with the manufacturer's recommendations, whereas unvaccinated pigs were administered a single dose of phosphate buffered saline at the same age. Results Vaccinated groups were measured and calculated significantly (p