Comparison of Newcastle disease vaccines by serology using serum, tears and feather pulp samples.

Seroconversion of 3 lentogenic commercial Newcastle disease (ND) vaccines and experimental V4 vaccines was compared based on the haemagglutination inhibition (HI) test against ND. It was found that for primary vaccination all the vaccines produced similar response but for vaccinations V4 and LaSota were better than RDVF. Eight-five samples each of serum, tears and feather pulp were collected from respective birds and antibody assessment was done against ND by HI test. The geometric mean HI titres (GMT) of serum samples were highest followed by tears and feather pulp samples before vaccination and 3 weeks after vaccination by oculonasal route and the difference was statistically significant (p < 0.01). Three weeks after booster vaccination by oculonasal route, however, the GMT of serum samples were highest followed by feather pulp and tear samples. The ease of collection of feather pulp samples and their role in ND serology is discussed.