Fig. 2

ROC curves demonstrating the performance of BM Ab and YS Check Tests as predictors of the presence of a PI animal(s) where delays occurred between the initial herd screen and the WHT. The ROC curves were generated from the seventeen dairy farms in Fig. 1 with full initial herd screens and WHT results. YS = Youngstock check testing and BM Ab = Bulk milk antibody testing. Farm 2 is considered negative for BM Ab analysis and positive for YS analysis. AUC = Area under curve. Coordinates of the curves are given in Table 2