Association between the level of antibodies in bulk tank milk and bovine respiratory syncytial virus exposure in the herd

Klem, T. B.; Tollersrud, T.; Østerås, O.; Stokstad, M.

Bovine respiratory syncytial virus (BRSV) is a pneumovirus of the paramyxoviridae family (Valarcher and Taylor 2007) . The infection is prevalent worldwide (Elvander 1996 , Paton and others 1998 , Uttenthal and others 2000 , Klem and others 2013 , and BRSV is considered one of the major pathogens of the bovine respiratory disease complex (Griffin 1997 , Snowder and others 2006 , Brodersen 2010 . To diagnose the infection, different strategies can be chosen according to the given situation and the purpose. For larger epidemiological studies, antibody analyses are used (Hägglund and others 2006 , Beaudeau and others 2010 , Ohlson and others 2010 , Klem and others 2013 . Infected animals seroconvert and IgG can be measured in serum and milk long after the virus is no longer present. Studies on the longevity of antibodies against BRSV are scarce, but Elvander (1996) found that such antibodies could be detected in the serum of adult cattle for at least two years postinfection.