Antibodies are not the only criterion for determining immune effects

How should the immune response of the herd be assessed? Many farms evaluate antibody levels as an important reference for evaluating vaccine quality. However, many vaccine laboratories are currently unable to distinguish between vaccine antibodies and wild-type antibodies. At present, only the pseudorabies virus can distinguish between vaccine antibodies and wild-type antibodies. As a result, it can only be judged by production indicators. However, in a complex domestic farming environment, it is difficult to assess the impact of a single vaccine on pig production indicators.

"High antibody levels do not mean that the protection rate is good." At the expert (key customer) meeting held by Luoyang Plex Biotechnology Co., Ltd. (hereinafter referred to as Plex), Zhang Guihong, a professor at the Veterinary College of South China Agricultural University, believes that antibodies Levels can only be used as one of the indicators for evaluating vaccine effectiveness, but not the only one. Because the antibody levels of some vaccines are not positively related to the protection rate, such as the ring vaccine. She further explained that because the immune mechanism of the ring vaccine is more complicated, in addition to cellular immunity, it also involves humoral immunity. She believes that it is more appropriate to use the average daily gain to evaluate the degree of protection of the ring vaccine.

Dr. Zhang Lichang, general manager of Pleco's piglet business unit, also said that the current farmers have too much confidence in the level of antibodies after immunization, and to evaluate the protection rate of the vaccine against the herd. In fact, this is not correct. Taking hog cholera as an example, although the antibody level of hog cholera vaccine is positively correlated with the protection rate, the antibodies detected include both vaccine antibodies and antibodies produced by wild venom.

He has encountered a case: the level of antibodies to swine fever is high, but the pigs are still outbreaks on the field, and the farmers are puzzling. "It can stimulate the body to produce antibodies, in addition to the swine fever vaccine, as well as BVDV (bovine diarrhea virus), they often overlook the latter." He believes that production indicators are the most convincing evaluation criteria, but coexist in many diseases in China. The environment is difficult to assess the effectiveness of a single vaccine.

"The effect of the vaccine is still difficult to assess. What is more important is that many farms have a lot of confusion about how to use the vaccine and whether the vaccine is useful." Chen Yuliu, a professor and doctoral tutor at the College of Veterinary Medicine, South China Agricultural University, believes that immunity is affected. There are many factors in the effect, such as the health of the body, environmental control in the field, etc. Many feeds have antibiotics added, and antibiotics often have immunosuppressive effects, which often lead to poor immune effects.

Dr. Fan Fuhao from the Ministry of Agriculture's Pig Breeding Center stressed that pigs must be healthy in the immunization vaccine, otherwise it may cause serious illness and lead to death. According to his laboratory monitoring, the current problem of pig poisoning is very serious. The outbreak of the disease is often caused by immunosuppression. A certain virus or bacteria is just a fuse. “The quality of domestic feed ingredients is worrying. It is recommended that feed mills do a good job in the quality of raw materials.”

In this regard, Changjiang Food Co., Ltd. (hereinafter referred to as Changjiang Food) general manager Mai Yueyi has a deep understanding. "According to national standards, we can't buy corn." Mai Yueyi said that the factory imported a device from the United States last year to detect mycotoxins, and so far there is no batch of qualified corn. Fan Fuhao believes that pigs are raised and not treated. Feed is an important factor in determining the health of pigs. As long as the farms are well managed, the vaccine effect is better.

Zhang Lichang said that it is difficult for manufacturers to recommend a universal immunization program, because the breeding conditions and models in the north and south are different. Many manufacturers are constantly improving themselves, and constantly explore the most suitable immunization program in combination with the actual production.