Determination of the best vaccination age of calves in the presence of maternal antibodies to foot and mouth disease under natural conditions

The first vaccination against foot and mouth disease (FMD) has long been carried out when the calves reach 4 months of age in Turkey. But, it is believed that this strategy creates a gap in herd immunity because almost fifteen percent of the cattle population consists of animals younger than 4 months old. Fifty-four calves aged 9 to 114 days were used in this study. The calves were divided into 5 groups. All of the animals were bled on day 0. Oil adjuvant FMD vaccine, containing the O1/Manisa, A22/Iraq and Asia-1/Shamir strains, was administered twice to Groups I-IV with a one-month interval between administrations. Group V was not vaccinated to monitor maternal antibody titer changes. The maternal antibody levels decreased in all strains in Group-V in a manner dependent on time. Antibody titers against strains O and Asia-1 increased after the first vaccination in Groups III and IV but decreased in Groups I and II. However, in all groups, the mean antibody levels continued or started to increase after booster vaccination. It was concluded that in endemic countries, calves that are born to vaccinated dams and that receive colostrum during the first hours of life should be vaccinated at 2 to 2.5 months of age, and a booster vaccination should be implemented for better protection.