Figure 2

Comparison of test-negative herds and herds changing from test-negative to test-positive in areas with high prevalenence (>0.10) and areas with low prevalence (<0.10). A: The distribution of GR-scores in the high prevalence areas where 84 herds of totally 790 herds changed from negative to positive. B: The distribution of GR-scores in the low prevalence areas where 33 herds of totally 639 herds changed form negative to positive.