Efficacy of lyophilized turkey herpesvirus vaccine against Marek's disease in broilers

Field trials involving approximately 1,250,000 chickens vaccinated with cell-free turkey herpesvirus (HVT) vaccine and 635,000 chickens vaccinated with cell-associated HVT vaccine howed both vaccines equally effective in reducing condemnations (attributable to Marek's disease) at the poultry processing plant. Vaccinated chickens were progeny of hens vaccinated at 1 day of age with cell-associated HVT vaccine. The maternal antibody did not interfere with the ability of either the cell-free or cell-associated HVT vaccine to provide protection for chickens against challenge from the virulent Marek's disease virus.