| Summary: | 碩士 === 國立屏東科技大學 === 獸醫學系所 === 96 === The performance of a commercial chicken farm is based on several factors, in which the vaccine program plays a very important role. The major chicken diseases including Newcastle disease (ND), infectious bronchitis (IB), infectious bursal disease (IBD) and reovirus infectious disease (Reo) are especially needed to pay more attention in vaccine programs in Taiwan. The purpose of this study is to long term monitoring the sera titer of ND, IB, IBD and Reo in selected chicken farms using two serological methods, haemagglutinin inhibition test (HI) and enzyme-linked immunosobent assay (ELISA). The data obtained from above were analyzed by a commercial software, and ploted sera titer baseline graphs. Serum samples were collected from 10 chicken farms including broiler, native broiler, breeder, pullet and layer farms from Jan to Dec in 2005. The result reveals that breeder and layer farm had more serious field type virus contamination than other types of farms. The HI titer of ND was as high as up to 212 and CV value of 195%. It suggested that farms could not adopt strictly “all-in all-out” policy, and carried out bio-safety management incompletely. The sera data regarding IBD was analyzed by “Deventer formula” proposed by Dutch National Poultry Health Center. Based on it, the best date for IBD vaccine inoculation was selected, and following by challenged with high pathogenic IBDV at 2 weeks later. The efficacy of designed vaccine program was evaluated by gross and histopathological examines such as bursa and body ratio (BBR), bursa gross lesion (BGL) and bursa histopathological lesion (BHL). In addition, total RNA of bursas was isolated from both control and test group for RT-PCR amplification. The result showed that IBD vaccine strain applied alone could induce the bursa damage at range 1 to 2 of BGL and BHL. However, vaccinated chickens still have 1 to 4 lesion scores of BGL and BHL after challenged with field IBDV, and virus genome could be detected 5 to 7 days post challenge.
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