Interference effect of foot-and-mouth disease maternal antibodies following foot-and-mouth disease vaccination and its related factors in Hanwoo beef calves.

Foot-and-mouth disease (FMD) vaccinations have been conducted in Korea for > 10 years. However, few studies have confirmed the optimal timing of FMD vaccination in newborn calves. In this study, we aimed to evaluate changes in antibodies before and after FMD vaccination and identify potential factors affecting FMD maternal-derived antibodies in newborn calves. Calves were vaccinated at 8 and 12 weeks of age. Blood samples were obtained from dams 6 weeks before the estimated due date and from calves at 8 (pre-vaccination), 12, and 16 weeks of age. Antibodies against the FMD virus (FMDV) structural proteins were detected using Priocheck FMDV type O antibody enzyme-linked immunosorbent assay. Among 82 calves, 54 (65.9 %) exhibited a decrease in FMD percentage inhibition (PI) at 16 weeks. The mean pre-vaccination FMD PI values of calves whose FMD PI decreased and increased after vaccination were 92.4 ± 9.4 and 72.4 ± 16.9, respectively (p < 0.05). Our results indicate that FMD vaccination at 8 weeks is early due to the high levels of maternal-derived FMD antibodies in the body of Hanwoo calves. The FMD PI of the dam (β = 0.636) exhibited the most significant impact on the FMD PI of 8-week-old calves, followed by calf birth weight (β = 0.200) (p < 0.05). Calves born to dams with high FMD PI and heavy birth weight exhibited high FMD PI at 8 weeks.