The effect of porcine circovirus type 2 (PCV2) on the development of anti-classical swine fever virus (CSFV) neutralizing antibody in various treatment groups of pigs. The pigs of group 1 (PCV2-infected/LPC-vaccinated/CSFV-challenged) and group 2 (PCV2-infected/CSFV-challenged) were inoculated with PCV2 at 0 dpi. The pigs of group 1 and group 3 (LPC-vaccinated/CSFV-challenged) were vaccinated with 1 dose of Lapinized Philippines Coronel (LPC) vaccine at 12 dpi. The pigs of all four groups were inoculated with CSFV (ALD strain) at 27 dpi. Data are shown as mean ± SD.