| a cross-sectional study of bluetongue virus and mycoplasma bovis infections in dairy cattle: i. the association between a positive antibody response and production efficiency. | in a cross-sectional study of bluetongue virus (btv) and mycoplasma bovis (m. bovis) infections, a sample of 572 california dairy cows was tested for the presence of antibodies to answer the question: is it possible to identify and to assess quantitatively the associations between positive antibody test and production? serum samples collected from these cows during december 1986 were tested for the presence of antibodies to btv and m. bovis using the enzyme-linked immunosorbent assay (elisa). da ... | 1990 | 2178288 |