What are the reasons for pig immunization failure?

(1) The immunization program is unreasonable. Only a scientific immunization program will produce good immunity; if the immunization program is unreasonable, the immunity will be correspondingly reduced. With the conventional rush immunization injections in spring and autumn, because of missed prevention and missed injections, some pigs that should have been immunized do not receive immunization, causing some pigs to become ill.

(2) The epidemic prevention system is not strict. Some epidemic prevention workers and @#@227@#@, fearing that piglets will have a reaction and die after vaccination, do not carry out immunization injections, resulting in a decline in the immunization coverage rate of the pig herd, which likewise causes pigs to become ill.

(3) Lack of proper feeding and management. The pigs are weak in constitution, malnourished or suffering from chronic diseases, which weakens the immune response ability; although the pigs are vaccinated, no effective immunity is produced.

(4) Pigs with latent infections, such as roundworms, lungworms and other diseases, will have relatively severe reactions after vaccination, and may even die.

(5) The vaccine is diluted excessively or the inoculation dose is insufficient, so the pigs cannot produce strong immunity.

(6) It is advisable to choose a single vaccine, and best not to use a bivalent or trivalent vaccine. In our survey of farms and farmers where pig diseases occurred, most used trivalent vaccines; because the dosages among the combined vaccines are inconsistent, they more or less affect each other's production of immunity, and the effect is poor.

(7) The disinfectant solution is too concentrated and seeps into the needle hole or the injection needle, reducing or nullifying the vaccine's effectiveness.

(8) The diluent is too alkaline, exceeding pH 7.0, reducing or nullifying the vaccine's effectiveness.

(9) For various vaccines that require low-temperature storage, the temperature must not be higher than 10°C. When there is no refrigeration equipment, they can be stored in a wide-mouth insulated bottle or insulated box with ice added, but the vaccine must be used up within 10 days from the date of transport.

(10) The diluted vaccine was not used up within 4 hours and continued to be used.