Since 2018, the Republic of Korea (ROK) has been vaccinating all susceptible livestock with one out of three approved vaccines which serotype O and A antigens according to the prime and boost vaccination schedule. We were carrying out continuously monitoring the vaccination status and immunity level through serological surveillance and if the standard antibody positive rate is below, a heavy fine will be imposed. In this regard, in this study, serological surveillance was performed using serum collected in 2021, and the collected data were analyzed immunity level.