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.

The virus is reported to spread effectively in a herd during outbreaks, resulting in high within-herd prevalence of antibody positive animals (Rossi and Kiesel 1974 , Stott and others 1980 , Verhoeff and van Nieuwstadt 1984 , Bidokhti and others 2009 . Antibodies in bulk tank milk (BTM), pooled milk samples from a selected number of cows or serum from several animals at a selected age have been used to classify a herd or given population (Paton and others 1998 , Uttenthal and others 2000 , Klem and others 2013 , Ohlson and others 2013 . Since animals are known to be seropositive for a long time, classification of herds based on serology in young animals (Klem and others 2013) , or pooled milk samples from primiparous cows (Ohlson and others 2013) , will give a more up-to-date picture than BTM testing. Recent studies show that testing of antibodies in BTM is a reliable tool for identification of BRSV-negative herds (Klem and others 2013, Ohlson and others 2013) .