Effective Vaccination Schedule for Controlling Infectious Bronchitis in Broiler Farms of North-West of Iran

Infectious Bronchitis (IB) is one of the important causes of economic losses in poultry industry of the world and it appears in forms of respiratory disease and nephritis. It causes a decrease in egg production and quality. S۱ gene consequence study by Iranian researchers indicated ۷ genotypes including massachusetts, ۷۹۳/B, IS۷۲۰, variant ۲, QX, IR-۱ and IR-۲ that all appear in poultry farms of Iran. Poultry vaccination schedule is performed for prevention and control of the disease and it aims to stop or decrease the occurrence of clinical cases in farm level. Vaccination schedule should never replace management and biosecurity procedures. A good vaccination schedule along with good management and biosecurity procedures should play a role inprevention and control of the disease. For judging the efficacy of thevaccination schedule, we can consider mortality and some factors related to flock performance like Feed Conversion Ratio and number of downgrading birds.Laboratory tests of serum including antibody response of vaccinated birds should be accessed which can be used as a good criterion in evaluating efficacy of vaccination schedule. Findings of researchers show that vaccination schedule is very effective in the control of Infectious Bronchitis.In retrospective surveys in several years about massachusetts genotype specially H۱۲۰ for control of Infectious Bronchitis, in spite of using the vaccine, high prevalence of the disease in broilers was observed.After emerge of ۴/۹۱ vaccine and using that in combination with H۱۲۰, we could observe a meaningful control of the disease in North-West of Iran. In this survey, broiler farms that used only H۱۲۰ vaccine, had a higher prevalence of Infectious Bronchitis compared to broiler farms that used the combination of H۱۲۰ and ۴/۹۱. Also vaccination method was an important factor too. In this survey, in high risk regions, applying eye drop in one day old chicks showed a better protection compared to spraying in one day old chicks.Results of this survey indicate that eye-drop vaccination with combination of H۱۲۰ + ۴/۹۱ on day one and repeating the vaccination with ۴/۹۱ on day ۱۴ is the most effective vaccination schedule for controlling Infectious Bronchitis in broiler farms of high risk areas of north-west of Iran.

کلیدواژه ها:

Infectious Bronchitis ، Broiler ، Vaccination ، IRAN.