Why did you get the Classical Swine Fever Vaccine or get it?

Why did you get Classical Swine Fever Vaccine or get Classical Swine Fever? it caused huge losses to pig production.

The phenomenon of swine fever sows carrying virus can not be ignored.

The virus-carrying phenomenon of sows is quite common in China, and the percentage of pregnant sows with virus is as high as 43%. Persistent infection of classical swine fever is caused by vertical and horizontal transmission in infected sows. Piglets congenitally infected with classical swine fever developed acquired immune tolerance and became persistent infected pigs with no antibody after repeated injection of the vaccine. If this kind of pig is mistaken for backup breeding, a new herd of infected pigs will be formed, which will lead to the formation of a vicious circle of classical swine fever transmission.

The quality and usage of the vaccine itself are worthy of attention.

The quality of the vaccine itself directly affects the immune effect of the vaccine. A large number of clinical data have confirmed that tissue vaccine (such as spleen lymphoid vaccine) is better than cell vaccine, and classical swine fever single vaccine is better than classical swine fever combined vaccine.

Most vaccines must be preserved and transported at low temperatures. For example, classical swine fever vaccine should be preserved and transported under the condition of-15 ℃, and repeated freezing and thawing is strictly prohibited. However, grass-roots distributors mostly use freezer 0 ℃ storage, repeated freeze-thaw phenomenon is also very common. In this way, the quality and potency of the vaccine will be greatly reduced.

There are also problems with the method of use. The diluted vaccine cannot be used up within 2 hours, and the vaccine is ineffective; disinfect needles with iodine tincture or other disinfectant to artificially kill the attenuated vaccine; injection with large needles leads to vaccine leakage; flying injections lead to insufficient immune doses and missed injections; fight with a needle to the end, epidemic prevention becomes spread with virus.

The immune dose of classical swine fever is worthy of further study.

Although the attenuated classical swine fever virus vaccine currently used in China is still safe and effective in preventing the current epidemic of classical swine fever virus, in the past, the evaluation of the immune effect of the vaccine and the establishment of immune standards were usually based on the prevention of clinical infection. however, the antibody level of some pigs often can not reach the level of preventing subclinical infection, so the vaccine should be able to prevent subclinical infection.

The subclinical infection state is mainly caused by long-term infection of sows, persistent infection of classical swine fever virus and transmission of the virus to piglets, and the virulence of the virus belongs to low and medium level. Although it does not show obvious clinical symptoms, it has become a major killer of pig farms because it carries the virus, disperses the virus and spreads the virus all its life.

The factors affecting the antibody level after immunization with classical swine fever vaccine are the maternal antibody level and the antibody level of pigs before immunization. Properly increasing the immune dose can neutralize the maternal antibody and the antibody of the pig population before immunization, reduce its effect on the vaccine, and help to improve the antibody level. When the dose is insufficient, the replication and carrying of the virulent virus in the body can not be prevented after attacking the virus.

The recommended immune dose in the national swine fever immunization program is 1 dose, which is 150RID (rabbit response dose), which is much lower than the international standard. It is obvious that the application of this dose in areas with unstable incidence of classical swine fever is not enough to cut off subclinical infection of classical swine fever. It is necessary to increase the immune dose in pig production, especially in areas where classical swine fever exists. Although the attenuated vaccine of classical swine fever used in this farm was qualified according to the rules in the laboratory, the subclinical infection of hog cholera field virus could not be effectively controlled by 1-3 doses per time. After the outbreak of the epidemic, the immunization dose of 5-10 doses proved to be good.

The prevalence of immunosuppression is the main reason for the poor immune effect of classical swine fever vaccine.

Immunosuppression is caused by three main reasons: first, nutrition, second, medicine, and third, disease.

Nutritional factors, that is, whether nutrition is comprehensive, especially fat-soluble vitamins, proteins and trace elements. The problem of feed mildew is prominent. Various mycotoxins in moldy feed can cause hepatocyte degeneration and necrosis, lymph node bleeding and edema, serious damage to the immune organs and immunosuppression.

Drug factors, improper use of immunosuppressive drugs, such as Dimi, Bupleurum, sulfonamides, etc.

Disease factors, such as blue ear disease, circovirus disease, classical swine fever, streptococci and so on, cause stunted growth, slow down or stagnation of pig growth, directly invade pig immune organs and immune cells, and cause inhibition of cellular and humoral immunity. There is a phenomenon that classical swine fever is still released after being vaccinated against classical swine fever. The infection rate of PRRSV and PCV-2 is very high in pig herds in China, and the double infection rate is more than 50%. The respiratory diseases in pig farms are quite serious, secondary infections are common, and reproductive disorders can be exposed at any time. These two immunosuppressive diseases are also the most fundamental reasons why swine diseases are becoming more and more common, epidemic diseases are becoming more and more complex and pigs are more and more difficult to raise in China in recent years.

The low immunity of pigs is the main reason for the poor effect of the vaccine. give up the abuse of drugs, vaccines, disinfectants and hormones, use it correctly and rationally, adopt immune health care technology in the whole group, and create a good immune group to cooperate with the corresponding vaccine for epidemic prevention. will produce high-quality immune effect, so as to achieve a good disease prevention effect.