Optimization And Application Analysis Of Avian Influenza Immunization Procedures In Laying Hens

Avian influenza is a highly contagious infectious disease caused by influenza A virus infecting poultry.It is characterized by respiratory symptoms,decreased egg laying rate,swelling of the head and face,leg bleeding and extensive bleeding of internal organs.Highly pathogenic avian influenza is classified as a Class A infectious disease by the World Organization for Animal Health,which is widely distributed,spreads quickly and has a mortality rate of up to 100%.The key to the prevention and control of avian influenza lies in the immunization of vaccines.Numerous factors,such as the interference of maternal antibodies,the formulation of immunization programs,and the storage conditions of vaccines,will affect the immunization effect of avian influenza vaccines.In this experiment,laying hens were used as the research object to optimize the immunization program,and the optimized immunization program was used as a pilot in Tieling County,and was popularized and applied in large-scale farms and free-range households,respectively,and the immunization effect was compared and analyzed.In this study,440 chicks were randomly selected from a laying hen farm,and the immunization effects of different vaccination methods,different first vaccination days and vaccine storage conditions were compared in groups,in order to screen the best immunization program and vaccine storage method.The optimized immunization program will be popularized and applied among farms and free-range farmers in Tieling County,and the immunization effect will be monitored.The test results are as follows:1.The immune effects of different immunization procedures and vaccines on avian influenza vaccine under different storage conditions:(1)Influence of intramuscular inoculation and subcutaneous inoculation on the immune effect: the antibody titers after inoculation in both ways increased,reached a peak at a certain time,and then decreased.(1)When first immunized at the age of 14 days: the antibody titers of intramuscular inoculation were higher than subcutaneous inoculation on the 7th day(P<0.01)and 14 th day(P<0.05)after immunization.(2)When immunized at the age of 21days: the antibody titers of intramuscular inoculation were higher than those of subcutaneous inoculation on the 7th day(P<0.05)and the 14 th day(P<0.01)after immunization.(3)When first immunized at the age of 28: the antibody titer of intramuscular inoculation was higher than that of subcutaneous inoculation on the 7th day after immunization(P<0.05).However,from the 21 st day after immunization,there was no significant difference between the two methods of vaccination with different first immunization days(P>0.05).(2)The influence of different first vaccination days on the immune effect: when vaccinated in the above two different ways,the antibody titers at the first vaccination at the14 th day were generally higher than those at the first vaccination at the 21 st day and the first vaccination at the 28 th day,the difference was significant(P<0.05).(3)The impact of vaccines on immune effects under different storage conditions: the antibody titers of fresh vaccines(that is,within 2 months of the production date)and vaccines stored at 4°C were both higher,and there was no significant difference between the two;the antibody titers of vaccines stored at room temperature was low,and the difference was extremely significant with the former two(P<0.01).2.Monitoring of avian influenza immunization effects in large-scale farms and free-range farmers in Tieling County :After the introduction of chicks in April,the inoculation was carried out according to the optimized procedure.The qualified rates of immune antibodies of large-scale farms and free-range farmers were 95.8% and 87.8%,respectively.After the introduction of chick vaccination in September,the qualified rates of immune antibodies of large-scale farms and free-range farmers were 95.4% and 80%,respectively.The immune effect of large-scale farms is better than that of free-range farmers.To sum up,in this experiment,the method of intramuscular inoculation,the first vaccination at 14 days of age,and the use of the vaccine stored at 4℃,the immune effect is better.The same vaccines and immunization procedures were applied to large-scale farms and free-range farmers,and the immunization effect of the former was better,indicating that in the process of avian influenza prevention and control,while doing a good job in immunization,it is necessary to strengthen feeding management and improve biosecurity system.