Monitoring And Analysis Of Immune Antibody Against CSFV In Different Scale Pig Farms In Suihua City

Classical swine fever(CSF)is an acute,febrile and highly contagious infectious disease caused by Classical swine fever virus(CSFV),a member of the Pestivirus genus in the Flaviviridae family.Due to its widespread,high infection rate,high mortality and extremely serious harm to pigs,CSF is one of the most important swine infectious diseases for prevention and control in the pig farming nations of the world.Since immunization is the main measure to prevent and control CSF,testing the antibody level of immunized pigs,timely grasping the immunization status of pigs,determining the optimal immune time,reducing the interference of maternal antibodies,shortening the immune blank period of pigs,and establishing a scientific immunization program play a crucial role in the prevention and control of CSF.Some pig farms of a certain size in China have suffered serious economic losses due to low qualified rate of CSF antibody or immunization failure.The purpose of this study is to comprehensively and systematically monitor the antibody levels of pigs immunized with CSF vaccine from different scale pig farms in Suihua city,to understand the level of immune antibodies,to evaluate the scientificity of the current CSF vaccine immune procedures used by pig farms,and to provide technical support and scientific experimental basis for the government to guide pig farms to formulate the prevention and control strategies against CSF and specific plans suitable for local pig farms.In this study,pigs immunized with CSF vaccine from 184 of different scale pig farms in Beilin district of Suihua city,Wangkui county,Zhaodong City and Hailun City were used as the study objects.From January 2018 to December 2018,1150,1039 and 875 sera of pigs immunized with CSF vaccine from large,medium and small farms were collected,and the level of CSF antibodies were measured by blocking ELISA kits to analyze and explore the pass rate of CSF antibodies under different breeding scales,different seasons,different monthly ages,different counties(districts),and different immunization procedures,respectively.The analysis and test results showed that(1)The qualified rates of CSF antibodies in different scale pig farms were different,which was 82.7% in large scale pig farms,78.3% in medium size pig farms and 76.3% in small size pig farms,respectively,showing the trend that the smaller the size,the lower the pass rate of CSF vaccine immunization.(2)The qualified rates of CSF antibodies in immunized pigs in different quarters were different,the qualified rate in the second and fourth quarters(78.9%～86.3%,80.5%～86.4%)were higher than that in the first and third quarters(71.8%～79.9%,74.1%～78.6%).The smaller the pig farm,the lower the qualified rate.(3)The qualified rates of CSF antibodies in immunized pigs of different monthly ages was different,with the lowest qualified rate(69.0%～75.5%)for 2-to 5-month-old pigs and the highest qualified rate(81.4%～88.4%)for pigs over 12 months of age.The smaller the pig farm,the lower the qualified rate of antibodies.(4)The qualified rates of CSF antibody(95.5%,80.0% and 82.8%)in immunized pigs from large,medium and small pig farms in Hailun city were higher than that of similar pig farms in other areas.(5)The qualified rates of antibodies of CSF antibodies in immunized pigs with different immunization procedures were different,the qualified rates of antibodies were 88.0% and 95.2% for routine immunization and zero-time immunization,respectively,and the effect of zero-time immunization was better than routine immunization.Immunization trials with different immunization programs conducted on the same pig farm also demonstrated the superiority of zero-time immunization over routine immunization.Through testing and analysis,the CSF antibody levels of pigs immunized with CSF vaccine from large and medium pig farms in Suihua are qualified;The qualified rates of CSF antibody antibody in pigs immunized with CSF vaccine from small pig farms are low,there is a risk of the occurrence of CSF,and further strengthening of feeding management and immunization prevention and control work is needed;The qualified rates of CSF antibody induced by zero-time immunization procedure with CSF vaccine is significantly higher than routine immunization,therefor,the zero-time immunization procedure with CSF vaccine should be used in the pig farms with a greater risk of CSF occurrence.