Animals
Heifers used in this study were from the same farm and had
four previous FMD vaccinations, corresponding to FMD campaigns
of November 2011, March 2012, November 2012 and March 2013.
Thirty-two animals were selected from a herd of 120 heifers
according to the levels of antibodies against FMDV (O1/Campos
strain) measured by ELISA (LPBE, see below) a week before vaccination.
Animal handling, vaccination and serum sampling procedures
were previously approved by INTA’s Animal Welfare
Commission (protocol approval No. 025/2011).