The Research Of General Control Measures Of Porcine Reproductive And Respiratory Syndrome For Large Scalea Pig Farms

The porcine reproductive and respiratory syndrome (PRRS) is one of the causative diseases which has risen humorous economic losse on swine industry. Its pathogeny is the porcine reproductive and respiratory virus (PRRSV). The disease is characterized by reproductive troubles such as abortions farrowing or weak piglets, preweaning piglets pneumonia mortality and mortality in sows. Since it was first reported in 1987 in the United States, PRRS has been one of the most economically important diseases of the global pig industry.The epidemiological investigation of PRRS of 12 large scale pig farms in Henan provice was carried out by using the ELISA kits of IDEXX. The results show that, to the swine which were not immunized, the average positive rates were 56.4%, the positive rates of sows and piglets were 78.5% and 39.3%, respectively. To the swine which were immunized using PRRS vaccine, the average positive rates were 87.0%, the positive rates of sows and piglets were 91.3% and 83.5%, respectively. The results of RT-PCR show that there are 7 large scale pig farms were positive in PRRSV antigen test. The positive rates and the average positive rates were 58% and 12.6%, respectively. These results show that the swine's infection with PRRSV wild strain in large scale pig farms is still relatively serious. As a result, great attention should be paid to the findings.Indirect enzyme-linked immunosorbent assay (indirect-ELISA) was set up by this experimentation . The work can develop to detect anti-PRRSV antibody. The indirect ELISA has optimum work conditions as follows: The concentration of coating antigen was 8.257μg/mL and the coating fluid was CBS(PH9.6,0.05M). The time of coating was 1 hour at 37℃and then stored at 4℃;The blocking materia was 1% gelatine; The labeled goat-anti-mouse enzyme ought to be diluted to 1:2000.On this basis, we established general control measures of PRRS for large scale pig farms by referenced to the successful experience of foreign. A series of measures against PRRS had been taken such as establishing reasonable immunization procedure, updating feeding and management technologies, enchancing the system of sanitation and epidemic prevention, improving abilities in differential diagnosis to prevent mixed infection by other pathogens and nursing infected pigs etc. After these measures was put into practice, sows average live litter size increased from 6.84 to 9.20, mainly adding 2.36 live litter size averagely, the loss rate of dead fetus and abortion has decreased from 26.8% to 4.51%, and piglets death rate has declined from 25.6% to 8.5%. The results show that the study used mainly to immunization with disinfection and immunologic surveillance, virus elimination abortion sows, develop a healthy swine-integrated control techniques to meet the actual production in China, and could effectively prevent and control the occurrence of PRRS in large scale pig farms.