Improved growth performance by type 2 porcine reproductive and respiratory syndrome virus (PRRSV)-based modified live vaccine in a herd with concurrent circulation of type 1 and type 2 PRRSV

Abstract

The objective of this study was to evaluate type 2 porcine reproductive and respiratory syndrome virus (PRRSV)-based modified live vaccine in a herd with concurrent circulation of type 1 and type 2 PRRSV. Type 2 PRRSV-based modified live vaccine improved average daily gain by 48.24 grams/pig/day (631.17 grams/pig/day in the vaccinated group vs 582.93 grams/pig/day in the unvaccinated group; P < 0.05). Pathological examination indicated that the vaccination effectively reduced microscopic lung lesions compared with the control animals. The protection of this vaccine against type 1 and type 2 PRRSV provides clinical control of co-infection with both genotypes under field conditions.