Sero-Conversion Status of Different Breeds of Chickens Vaccinated With Newcastle Disease I2 Vaccine Type around Hawassa, Ethiopia

Abstract

Chickens are vaccinated with live attenuated and inactivated vaccines in order to control Newcastle disease (ND). The vaccine can be administered by eye drop, aerosol or drinking water. Humoral antibodies usually appear within 6 to 10 days after vaccination in the serum and also locally in the upper respiratory tract and in the intestine. The efficacy of vaccinations can be estimated best with challenge experiments but they are expensive and time consuming. For the current study, a cross sectional study was conducted to determine the sero-conversion status of ND I-2 vaccine type provided to chicken reared in intensive, semi-intensive and extensive farms in Sidama region, Ethiopia. Of the total 401 samples collected from 29 various flock sizes 363(90.5%) were protective at individual bird level; whereas at flock level 86.2% (25/29) were met above 80% protection. Of 29 flocks 12 (42.4%) flocks were found 100% protective from the disease. The CV% varied between 21.2% and 122.3 percent among the flocks. The uniformity of average antibody titer for Bovans breed (CV%: 56.7) was comparatively better followed by Sasso (CV%: 69.2), Local breed (CV%: 73.1) and mixed breeds (CV%: 83). The overall average minimum, maximum and mean antibody titer for this study was 1179.8, 13840.1 and 5945, respectively. However, the minimum and maximum antibody titer for this study was 37.4 for Sasso breed with the age of 8 months and 20465.8 for mixed type of breed with the age of 12 months respectively. Significant antibody titer variation was observed among Breeds (p=0.018) and Ages (p=0.001) of the birds in this study. In general, the vaccination scheme for the current study revealed ND I-2 vaccine type was effective in protecting the chickens from the disease in respective of the age of birds at vaccination although the pattern of uniformity for antibody production is variably interrupted among the flocks.