ANTIBODY-RESPONSE IN DANISH-JERSEY-HEIFERS TO FOOT-AND-MOUTH-DISEASE VACCINE

Danish Jersey heifers (pregnant) imported from Denmark were vaccinated with foot-and-mouth-disease (FMD) polyvalent (0, A22,C, Asia-I) vacci ne. A booster dose was given on day 21. Primary and secondary antibody responses were assessed by micro-serum neutralization test (microSNT) . The animals did not have detectable level of antibody prior to vacci nation supporting the fact that these animals were imported from FMD-f ree country and that they were neither exposed to infective virus nor to immunizing antigen. There was onset of antibody response on day 7 p ost-vaccination (PV), and the titres on day 21 PV were 1.58+/-0.4, 1.5 5+/-.03, 1.55+/-.03, 1.54+/-03 against types 0, A22, C and Asia-I viru ses. The percentage of animals exhibiting protective titre (greater th an or equal to 1.5) on day 21 PV stood as 84, 88, 92 and 92 against ty pes 0, A22, C and Asia-I respectively. After the booster dose the titr e attained maximum levels, viz. 1.84+/-0.09, 1.81+/-0.08, 1.84+/-0.09, 1.81+/-0.08 against types 0, A22, C and Asia-I, respectively, within a week. At the end of quarantine period, viz. day 40 PV or day 19 post booster vaccination, the percentages of animals with protective titre (greater than or equal to 1.5)were 96, 98, 98 and 98 against types 0, A22, C and Asia-I respectively.