Sex-linked dwarfism and response to two Newcastle disease vaccines.

In a series of battery trials, normal-sized (AG) broiler type and sex-linked dwarf chicks (D2) were vaccinated with a double dose of Roakin or LaSota strain Newcastle Disease (ND) vaccine, or were challenged with the Gilbert-Boney ND virus. The AG chicks developed higher hemagglutination inhibition titers but suffered more mortality than the D2 chicks following administration of Roakin strain vaccine. Similar percentages of mortality occurred in AG x AG, AG x D2 and D2 x D2 male chicks challenged with the Gilbert-Boney ND virus. Results indicate that the dwarf strain and the AG x D2 cross strain chicks are no more susceptible to ND than the AG strain.