Intratypic heterologous vaccination of calves can induce an antibody response in presence of maternal antibodies against foot-and-mouth disease virus

Background - Maternal antibodies can interfere with foot-and-mouth disease vaccination. In this study we determined whether intratypic heterologous vaccination could help to improve herd immunity. Results - In unvaccinated calves, a half-life of maternal antibodies of 21 days was determined. At two weeks of age, calves without maternal antibodies showed a good antibody response against both vaccines used in the trial, while in calves with maternal antibodies no antibody response to homologous vaccination (A Turkey 14/98) but a limited antibody response to intratypic heterologous vaccination (A22 Iraq) was observed. Conclusion - Two weeks old calves without maternal antibodies respond well to vaccination, but when emergency vaccination is carried out in a region that uses prophylactic vaccination, using an intratypic heterologous vaccine strain may improve the immunity in calves with maternal antibodies