Observation On The Growth And Decline Regularity Of Swine Fever In Pigs In Shanghai And Comparison With Different Swine Fever Vaccines And Different Immune Modes

The swine fever is a common infectious disease in pig farms,and its harm has been recognized by industry experts and scholars.There is currently no effective drug for the treatment of swine fever,so the prevention is mainly due to biosafety management and vaccine immunization.There is no conclusive evidence about the best immunization program in swine fever.There are many kinds of vaccine immunization programs for swine fever.The main vaccine varieties are cell seedlings and tissue seedlings.There is no definite conclusion for the experts and scholars of different vaccine varieties.The aim of this study was to determine the effect of different swine fever vaccine and immune mode on the antibody of piglets by monitoring the growth and decline of swine fever swine fever piglets,and to determine the swine fever program which is most suitable for the pasture.Experiment 1:Observation on the Law of Antibody Growth and Decline of Swine Fever in a Pig Farm in Shanghai.The experiment was carried out in two farms in Shanghai,one for the expansion field and one for the pig farm.One week before birth,one day before and after the expected date of birth,three times the birth rate of three healthy sows,respectively,in the sow,the choice of its health Jianzi 5,that is,two pig farm selection of 8 test sows and 40 test piglets.Sows were collected in postpartum 0(piglets before breast feeding),7,14,21,28,35 days before the collection of vena cava,The piglets were collected from 0,7,14,21,28,35,42,56,70,84,98,112,126,140,154 days before the collection of vena cava blood,all blood centrifuged to prepare Serum,to be determined swine fever antibody.The results showed that:1)The serum samples of neonatal piglets fed without colostrum had no swine fever antibody,and the level of swine fever antibody reached the peak at about 1 week after feeding colostrum,and then began to decrease gradually.At 21 days of age,the blocking rate of piglet maternal antibody was 37.8%,the positive rate was 41%,and the maternal antibody was almost undetectable after 56 days of age.The antibody-blocking rate was 56.3%,the antibody-positive rate was 56.3%,the antibody-blocking rate was reduced to 30%at 35 days,the antibody positive rate was 22.4%,and the antibody-positive rate was 56.4%The average blocking rate was reduced to 2.7%,when the piglets at 56 days of age,the positive rate of 0,maternal antibodies almost completely disappeared.Therefore,the best pig-free swine fever pig freebies for the 21-day-old,near the 28-day extension of the field,this time the first release,both to prevent maternal antibody interference,but also to avoid the emergence of immune blank period.2)There was a correlation between the antibody content of swine fever and the maternal antibody content of piglets.At the same time,the speed of the piglets used to resist the consumption of the maternal antibody is also related to the content of the maternal antibody,the maternal antibody content is high,the faster the antibody decays in vivo.from 56 to 98 days of age,piglet maternal antibody is almost undetectable,the positive rate of 0,but to 112 days of age piglets in vivo antibody has increased,some piglets antibodies from negative to positive,but No clinical manifestations,indicating that pig swine fever was negative infection,indicating that there is the risk of infection on the pig farm.Experiment 2,Comparison of different swine fever vaccines and different immunization modes The piglets were selected from the same batch of sows as the experimental piglets,among which the sows were the same as 3 times.Four healthy pigs were selected in each sow and were randomly divided into four groups,That is,each group of 16 piglets.The first group of piglets using cell seedlings,28 days of the first to avoid,at 56 days of age for the elimination of classical swine fever vaccine,the dose of 1 head/times;head;group II piglets using spleen lemphon,28 days of the first Free,at 56 days of age for the elimination of swine fever vaccine,the dose of 1 head/times.The third group of piglets were treated with spleen lemopathy and only 1 day/day at 28 days of age.The first group of piglets were treated with spleen lemopathy and 28 days old.Age for the elimination of swine fever vaccine,the first free dose of 1 head/head,two free dose of 1.5 head/head.All the experimental piglets were collected from 28(first immunization),42,56,70,84,112,140,170 days of age,and the antibody was measured.The results showed that the blocking rate and positive rate of immune antibody in group ? were better than those in group ?;the blocking rate and positive rate of immune antibody in group ? were better than that in group ?;the immunization antibody blocking rate and positive The rate is slightly better than the second group.It can be seen that the cell vaccine is less effective than the swine fever spleen leaching,the spleen leaching immune effect is better,and the second dose increases,the antibody level is higher,the maintenance time is longer.In this study,the changes of swine fever antibody in experimental ranch piglets were investigated.Based on the results,the immune effects of different vaccines and different immune modes were compared,which provided the basis for establishing the best swine fever program.The immune program of the pasture field was obtained as the first choice for the first half of the 28th day of the spleen leech,and the first dose was 1.5 days.