PERSISTENCE OF MATERNALLY DERIVED ANTIBODIES IN CALVES TO VACCINATION AGAINST FOOT AND MOUTH DISEASE

This study aimed to know the level of maternally derived antibody (MDA) titer in calves born to cows vaccinated with inactivated trivalent (type O, A and Asia 1) Foot and Mouth disease vaccine. Three groups of calves (10 calves in each group) of different age were randomly selected from two organized farms from Savar Upazilla of Bangladesh where the dams are routinely vaccinated with trivalent FMD vaccines. Blood samples were collected from these selected calves in six occasions five weeks apart and sera (n=180) were tested for antibody titer against FMDV by using liquid phase blocking ELISA (LPB-ELISA) test. The test is based upon specific blocking of the FMDV antigen in liquid phase by antibodies in the test serum sample. Protective level (PI value >50) of maternal antibody against FMDV was found in serum of calves up to the age of 22-23 wks (above five months) and decreased below protective level (PI value <50) at 27-28 weeks (above 6 months) of age. Irrespective of vaccine types, male calves had slightly higher level of MDA than that of female calves and PI values were comparatively higher against serotype O than the other two serotypes (A and Asia 1). Calves born to vaccinated dams could be vaccinated for first time after five months of their birth to lower the incidence of foot and mouth disease.