Efficiency of the I-2 Newcastle Disease Vaccine produced at the Ministry of Livestock, Development and Fisheries in Dar-es-Salaam
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In Tanzania the I-2 Vaccine is produced at the Ministry of Livestock, Development and Fisheries in Dar-es-Salaam. The horizontal transmission under laboratory conditions and the efficiency in the field is evaluated. The results suggest that more than 80% of the chickens in the contact group produce a sufficient antibody titer against ND, but apparently the titer level in the contact group decreases at a faster rate than that of vaccinated group, which has protective antibody titers for at least 4 months. In the field flocks were sampled at different times after vaccination. Some of them had protective antibody titers against NDV and other flocks were not protected, while vaccination was only between 1 and 3 months ago. Also one flock with a average titer of 8.67 was found, probably due to a field infection. It was found that more than 40% of the flocks in the field have titers below the protective level within 3 months after vaccination.