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In fact, the research on swine fever vaccine in China has been relatively mature, the quality of swine fever vaccine is guaranteed, and the immune failure is not all due to the vaccine problem.
Defects in the immunization program are the main cause of immune failure. At present, the immunization procedures for piglets in large-scale pig farms are diverse and very confusing. Mainly in the absence of guidance to the sub-pig immune time, frequency, dosage, etc., to develop immunization program arbitrary large, resulting in highly undesirable immune effects; increasing immunization dose (two copies - 5 copies); in addition, the use of Three immunizations, four immunizations, and the immunization dose is increased to more than 10 servings.
At present, the industry is more controversial about pre-pregnancy immunity, which is theoretically feasible. Because most of the maternal antibodies in pigs cannot enter the fetus through the placenta, there are very few maternal antibodies in the newborn pigs, which is insufficient to interfere with the contact of the attenuated vaccine with immune cells. Pre-pregnancy immunization can make the attenuated vaccine have sufficient proliferation time in the body without being neutralized by the maternal antibody in the blood, so that the piglet can obtain active immunity as soon as possible, and the attenuated strain of the piglet has no residual virulence to the suckling pig. Safety. However, it is difficult to implement in practice, and it takes a lot of labor. For example, the sow delivery process may be prolonged or the sow will give birth at night, the piglet has sucked the colostrum after birth, and the vaccine is diluted for too long, which will lead to Immunization failed.
Maternal antibodies have protective effects on newborn pigs, but they also affect the immune effect of the pigs, that is, the duality of maternal antibodies. Therefore, whether a good immune effect can be associated with maternal antibody titers when using high quality vaccines for piglets. When the maternal antibody titer is high, immunization is carried out, and the vaccine virus is neutralized by the maternal antibody without protection. Therefore, the titer of the maternal antibody should be considered before the immunization is carried out, and attention should also be paid to the uniformity of the maternal antibody. The specific method is to measure the maternal antibody titer before immunization, adjust the uniformity of the maternal antibody, ensure that the antibody level of the empty sow piglet is not less than 1:64, and the antibody level of the sow piglet is not less than 1: 32. Sows and drug-bearing sows that are still low in antibody levels after repeated vaccination should be completely eliminated.
In addition, daily feeding management, nutritional health, drug abuse, etc. will affect the immune effect.
In fact, there is no immutable method for how to formulate a scientific immunization program. It is best to arrange the immunization time according to the results of the pig antibody test. The first exemption time of the swine swine fever vaccine should be based on the growth and decline of the maternal antibody. To arrange. Before the first exemption, the blood test antibody level of the pigs was divided into weeks, and the growth curve of the maternal antibody of the pig was drawn. When the maternal antibody was lowered to a lower level, the injection of the swine fever vaccine could minimize the effect of the maternal antibody on the vaccine. It will not form an immune space.
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