Field Experience of Antibody Testing against Mycoplasma bovis in Adult Cows in Commercial Danish Dairy Cattle Herds

Abstract

<i>Mycoplasma bovis</i> in cattle is difficult to diagnose. Recently, the ID screen^® mycoplasma bovis indirect ELISA (ID screen) was commercially released by IDVet. The objectives of this study were to: (1) gain and share experience of using the ID screen in adult dairy cows under field conditions; (2) determine the correlation between antibody levels in milk and serum and (3) compare the ID screen results with those of the Bio K 302 (BioX 302) ELISA from BioX Diagnostics. Paired serum and milk samples were collected from 270 cows from 12 Danish dairy herds with three categories of <i>M. bovis</i> disease history. The ID screen tested nearly all cows positive in all, but the three non-infected herds, while the BioX 302 tested very few cows positive. The ID screen is therefore a much more sensitive test than the BioX 302. However, cows in five exposed herds without signs of ongoing infection and two herds with no history of <i>M. bovis</i> infection also tested ID screen positive. Therefore, the performance and interpretation of the test must be investigated under field conditions in best practice test evaluation setups. A concordance correlation coefficient of 0.66 (95% CI: 0.59-0.72) between the ID screen serum and milk results indicates that milk samples can replace serum samples for the ID screen diagnosis of <i>M. bovis</i> in adult cows.