1. Early wild virus infection or virulent strain infection: Generally speaking, chickens will not be effective immediately after immunization, chickens need a certain period of time to produce immunity after vaccination, and this period is just a potential dangerous period, once there is wild virus invasion or the body has not produced antibodies before the infection of virulent, it will lead to the occurrence of disease, resulting in immune failure.
2. Maternal antibody: Farmers should pay attention to the immunization procedure is based on the level of maternal antibody when formulating the immunization procedure. If the level of maternal antibody is relatively high, vaccination will neutralize the reaction between the vaccine and the antibody, which not only consumes maternal antibody, but also loses the number of vaccines, and can not stimulate the body to produce enough antibodies, so that the immune effect will be reduced, and even lead to immune failure. Therefore, maternal antibody should be tested before immunization, and then immunized when maternal antibody level drops to the critical value.
3. Human factors: There are many factors, such as inappropriate transportation or incorrect preservation of vaccines purchased by farmers, which can make the quality of vaccines deteriorate or even invalidate. Another point is that the way, method and dosage of vaccination are incorrect when farmers are immunized. Without strict disinfection, the above factors can lead to the failure of immunization.
4. Environmental factors: The environment in the chicken house will also affect the success or failure of immunization, such as temperature, humidity, density, ventilation, environmental hygiene and disinfection in the chicken house. Poor environment can cause different degrees of stress reaction in animals and affect the immune effect.
5. Body health and immunosuppressive diseases: If the chickens are subhealthy or sick during immunization, immunization failure will occur easily. Diseases such as infectious bursal disease and avian influenza will lead to immunization failure of other vaccines. The body's own ability to respond to vaccines is also reduced.
6. Drug abuse: Farmers should pay attention to the fact that it is not possible to disinfect chicken houses and flocks within a few days before and after vaccination, otherwise disinfection before and after vaccination can kill inactivated vaccines and affect the immune effect. There is also the fact that if farmers give chickens too much medicine and too long course of treatment, it can also affect the immune response ability of the body.
Simple design layer chicken equipment will be better choice in chicken raising field.