Evaluation And Pathogen Analysis Of Bovine Viral Diarrhea In Large-Scale Cattle Farms

Bovine viral diarrhea is one of the important pathogens that are produced by the bovine viral diarrheal disease virus(BVDV).40 days of infection to 120 days of gestation cows,even after the end of pregnancy can produce calves,but this time the calves have the virus "immune tolerance" phenomenon,and will be transformed into new groups Infection(persistent infection of cattle,PI),gestational cows can continue to infect calves(PI)through this way is an important source of infection in the population.Since PI cattle often develop viremia and continue to emit the virus to the environment,its identification and elimination of PI from the herd is an important part of the procedure for the control and eradication of BVDV.In this study,BVDV antibody was used to detect BVDV infection in pasture cattle,and the epidemiological status of BVD in Heilongjiang Province was analyzed by combining the results of milk samples.Through the antibody detection results,the target purified cattle field was selected and a reasonable purification procedure was established.BVDV antigen detection was carried out for the whole cattle.Test results for positive cattle,2-3 weeks after its re-sampling test(in order to discharge a transient infection interference)if the re-sampling antigen detection is also positive,it is recommended that the cattle out.And then take a long time to monitor antibody antibody to see if there is a large level of antibody fluctuations to determine whether there is the presence of PI cattle in order to timely screening of the antigen to ensure the effectiveness of eradication.Completed the initial screening of the target purified cattle farm PI cattle.The virus was isolated and the virus was observed by electron microscopy,physical and chemical properties and some related biological characteristics.The one-step growth curve of the isolated strain was drawn and the type of virus was determined by phylogenetic tree.