In order to prevent the spread of bovine viral diarrhea virus (BVDV) in public pastures, since 2013 all heifers in the Tottori Prefecture have been tested for BVDV using reverse transcription polymerase chain reaction (RT-PCR) before they are pastured. However, because RT-PCR is time consuming and labor intensive, a new commercial ELISA based on the detection of the Erns antigen was evaluated as an alternative method. Twentytwo sera of persistently infected (PI) cows and two paired sera of transiently infected (TI) cows were tested to evaluate sensitivity. All sera of PI cows were positive, and paired sera from the TI cow were negative. Field samples of 646 sera, including one PI cow, were tested for BVDV antigen using ELISA. Only one sample from the PI cow tested positive. However, it displayed a negative result when the PI serum was mixed with a high BVDV antibody-positive serum. Therefore, although performing ELISA on PI calves in the presence of persistent maternal antibodies requires attention, it is a useful screening test for detecting BVDV because of its high sensitivity and ease of use. ─ Key words : antibody-positive serum, antigen detection ELISA, bovine viral diarrhea virus (BVDV), reverse transcription polymerase chain reaction (RT-PCR).
