Comparative analysis of the productivity and iImmunogenicity of an attenuated classical swine fever vaccine (LOM) and an attenuated live marker classical swine fever vaccine (Flc-LOM-BE^rns) from laboratory to pig farm

Herein, we compared the productivity of pigs inoculated with one of two classical swine fever (CSF) vaccines (low virulent of Miyagi (LOM) or Flc-LOM-BE^rns) plus the swine erysipelothrix rhusiopathiae (SE) vaccine. The feed intake and weight increase of the pigs inoculated with Flc-LOM-BE^rns + SE were normal. However, the feed intake of the pigs inoculated with LOM + SE dropped sharply from four days post-vaccination (dpv). In addition, the slaughter date was an average of eight days later than that of the pigs inoculated with Flc-LOM-BE^rns + SE. All pigs inoculated with the Flc-LOM-BE^rns + SE vaccine were completely differentiated at 14 days against CSF E^rns antibody and at approximately 45 days against the bovine viral diarrhea virus (BVDV) E^rns antibody; the titers were maintained until slaughter. Leucopenia occurred temporarily in the LOM + SE group, but not in the Flc-LOM-BE^rns + SE group. Expression of tumor necrosis factor (TNF)-α and IFN-γ was significantly (p < 0.05) higher in the LOM + SE group than in the mock (no vaccine) group. When conducting the same experiment on a breeding farm, the results were similar to those of the laboratory experiments. In conclusion, the biggest advantage of replacing the CSF LOM vaccine with the Flc-LOM-BE^rns vaccine is improved productivity.