Efficient BVD control on large industrial dairy farms infected with different subtypes of Pestivirus A strains

Bovine viral diarrhea (BVD) is a major economically significant disease condition of cattle, occurring worldwide and caused by Pestivirus A, B, and rarely D viruses. Infection by the virus has a peculiar epidemiology that involves immunotolerant, persistently infected (PI) calves, which spread the virus lifelong in high amounts, and therefore finding and eliminating them is the cornerstone of most eradication programs, aided by provision of sufficient immune status for the dams to prevent the emergence of PI offspring. We demonstrate the efficient control of the prevailing Pestivirus A subtypes 1b, 1d, and 1f, in various Hungarian industrial dairy farms, by following the principles of bovine viral diarrhea virus (BVDV) eradication, such as screening the herds for the presence of and removal of PI animals, proper vaccination, and monitoring the BVDV status of the herds by laboratory testing. The tested partial Npro coding sequences indicated the presence of herd specific strains in each farm. The results confirmed that vaccination is a powerful tool for eradication of BVDV even if the live vaccine strain is heterologous compared to the field strains circulating on the affected farms.