Table 3.
True herd-level antibody prevalence estimates and 95% confidence intervals for BVDV (bovine viral diarrhea virus), BoHv-1 (bovine herpesvirus-1), L. Hardjo (Leptospira Hardjo), S. Dublin (Salmonella Dublin) BRSV (bovine respiratory syncytial virus), MAP (Mycobacterium avium subspecies paratuberculosis), N.caninum (Neospora caninum), and M.bovis (Mycoplasma bovis) based on results from bulk tank milk sampling on 120, 109, and 91 unvaccinated dairy farms in 2018, 2019, and 2020, respectively.
| 2018 | 2019 | 2020 | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Pathogen | Overall (%) | 95% CI (%) | SDF (%) | 95% CI (%) | CF (%) | 95% CI (%) | Overall (%) | 95% CI (%) | SDF (%) | 95% CI (%) | CF (%) | 95% CI (%) | Overall (%) | 95% CI (%) | SDF (%) | 95% CI (%) | CF (%) | 95% CI (%) |
| BVD | 57.2 | 40.7–65.9 | 55.5 | 0.86–1 | 58.6 | 0.6–0.92 | 85.7 | 74–94 | 89.7 | 0.8–1 | 81 | 0.68–0.98 | 72.9 | 58–85 | 79.2 | 0.63–0.97 | 66.7 | 0.5–0.88 |
| BoHv-1 | 46.8 | 26.3–69.7 | 73.2 | 0.32–0.99 | 36.19 | 0.16–0.63 | 49 | 25–75 | 73 | 0.32–0.99 | 39 | 0.17–0.67 | 19 | 1–56 | 0 | 0–0.72 | 24 | 0.06–0.6 |
| L. Hardjo | 34.3 | 12.5 −63 | 39 | 0.074–0.81 | 31.7 | 0.08–0.67 | 59 | 33–82 | 75 | 0.35–0.97 | 51 | 0.24–0.76 | 73 | 33–99 | 100 | 0.43–1 | 59 | 0.22–0.88 |
| S. Dublin | 32.3 | 12.21–68.1 | 52 | 0.17–1 | 14.6 | 0–0.63 | 56.9 | 30.2–90.1 | 46.7 | 0.16–0.95 | 65.4 | 0.29–1 | 10.9 | 0 | 0 | 0–0.61 | 21.5 | 0–0.8 |
| BRSV | 100 | 99.5–100 | 100 | NA | 100 | NA | 100 | 100 | 100 | NA | 100 | NA | 100 | 100 | 100 | NA | 100 | NA |
| M. bovis | 53 | 3.95–6.84 | 54 | NA | 52 | NA | 0.42 | 0 | 2 | NA | 0 | NA | 30 | 21–41 | 29 | NA | 31 | NA |
Overall: SDF and CF. SDF, source dairy farmers; dairy farmers sending replacement heifers off-site for rearing purposes; CF, control dairy farmers; dairy farmers rearing their own replacement heifers.