Assessment of the cost effectiveness of compulsory testing of introduced animals and bulk tank milk testing for bovine viral diarrhea in Japan

ISODA, Norikazu; ASANO, Akihiro; ICHIJO, Michiru; OHNO, Hiroshi; SATO, Kazuhiko; OKAMOTO, Hirokazu; NAKAO, Shigeru; KATO, Hajime; SAITO, Kazuma; ITO, Naoki; USUI, Akira; TAKAYAMA, Hiroaki; SAKODA, Yoshihiro

The ecology of BVD is influenced by feeding style, animal hygiene awareness, and local policy; hence, there is no single effective control intervention that is commonly used worldwide. Scandinavian countries had successfully eradicated BVD approximately 10 years after initiating detection programs for antibodies against BVDVs present in bulk tank milk (BTM) or serum samples and have maintained their BVD-free status ever since [16, 28, 31, 33, 36] . A virus detection system using the ear notch approach has been implemented to detect PI animals in Switzerland [2, 30] . Germany has adopted antigen detection, also mainly using ear notch samples, as well as mass vaccination as an optional biosecurity measure, although optional vaccination has not been widely implemented due to a certain BVDV vaccine causing infection because of bovine neonatal pancytopenia [3, 9] . Importation of infected cattle or pregnant PI dams carrying the fetus is considered to be the main route of BVD introduction into BVD-free countries [25] . BTM is widely used in screening tests for BVDV infection in dairy cattle. Vaccination is adopted to a BVD control measure in Japan; hence, detection of BVDV antigens rather than antibodies against BVDV in BTM has been developed and is commonly implemented domestically [20, 21] .