|  |  |  | Serum | |
---|---|---|---|---|---|
 | Sampling |  |  | Positive | Negative |
Herd 1 (n = 50) | 1 | Oral fluid | Positive | 39 | 4 |
 |  |  | Negative | 1 | 6 |
Herd 2 (n = 65) | 1 | Oral fluid | Positive | 43 | 22 |
 |  |  | Negative | 0 | 0 |
 | 2 | Oral fluid | Positive | 65 | 0 |
 |  |  | Negative | 0 | 0 |
 | 3 | Oral fluid | Positive | 64 | 1 |
 |  |  | Negative | 0 | 0 |
 | 4 | Oral fluid | Positive | 65 | 0 |
 |  |  | Negative | 0 | 0 |
Total | Â | Â | Â | 277 | 33 |