Susceptibility of three phenotypes of village chickens to Newcastle disease in Adamawa State.

* bo The susceptibility of three phenotypes of Village chickens to Newcastle Disease Virus (NDV) (Hertz 33/56) was investigated at Modibbo Adama University poultry farm, Yola. Forty five (45) village chickens, made up of fifteen (15) each of Frizzle, Naked neck and Smooth feathered types were infected with NDV (Hertz 33/56) through intraocular and intranasal routes and subsequently bled on day 0, 3, 7, 14 and 28 post infection. A morbidity rate of 100% and mortality rates of 58.3%, 41.7% and 75% for frizzle, naked neck and smooth feathered types was observed respectively. The mean antibody titre of all the phenotypes before the infection was zero and naked neck started developing protective antibodies on day 7 post infection (PI). All the phenotypes, with the exception of the naked necks in the intraocular group, exhibited highest Geometric mean titre (GMT) of NDV HI antibodies on day 28 PI through both routes. The GMT in the control group remained low throughout the experiment. It could therefore be concluded that, the naked neck group and their crosses were the most resistant phenotype, followed by frizzle feathered and their crosses and the smooth feathered and their crosses were the least resistant and poor sero-converts to NDV infection. It is therefore recommended that naked neck group and it crosses should be adapted into the rearing programmes.