Fig. 3

Predicted Probability Curves indicating the probability of a study herd containing a PI animal with the stated BM Ab and YS Check Test results. Data points demonstrating PI presence are ‘jittered’ around 0 or 1 on the y axis to show the number of farms that contribute to the curve at each point, a BM Ab OD Ratio and the probability of identifying a herd containing a PI animal with delays between performing the BM test and the WHT; b Number of YS positive out of the ten tested and the probability of identifying a herd containing a PI animal with delays between performing the Check Test and the WHT; c BM Ab OD Ratio and the probability of identifying a herd containing a PI animal with no delay between performing the BM test and the WHT; d Number of YS positive out of the ten tested and the probability of identifying a herd containing a PI animal with no delays between performing the Check Test and the WHT. Farm 2 is considered negative for BM Ab analysis and positive for YS Check Test analysis