Table 3.
Estimated odds ratios with 95% CI and coefficients with standard errors, along with p-values based on a logistic regression model on factors associated with herd level BCoV-status as measured by antibodies in bulk tank milk in 1194 dairy herds in two counties on the west-coast of Norway.
| Variable | OR | 95% CI | Coefficient | Std. Error | p-value |
|---|---|---|---|---|---|
| Herd size | 1.05 | (1.03–1.07) | 0.052 | 0.009 | <0.01 |
| Herd disease incidence* | 1.003 | (1.001–1.005) | 0.003 | 0.001 | <0.01 |
| x-coordinate (longitude) | 0.78 | (0.63–0.95) | −0.25 | 0.11 | 0.017 |
| y-coordinate (latitude) | 3.54 | (2.53–4.95) | 1.26 | 0.17 | <0.01 |
| Log of mean distance to 5 nearest herds, in km | 0.46 | (0.37–0.56) | −0.78 | −0.78 | <0.01 |
| In degree**, category 1 | 1, reference | ||||
| In degree, category 2 | 1.73 | (1.28–2.34) | 0.53 | 0.15 | <0.01 |
| In degree, category 3 | 5.97 | (2.94–12.10) | 1.80 | 0.36 | <0.01 |
| Constant | – | −77.02 | 10.12 | <0.01 |
*
Herd disease incidence per 100 cow-years (year 2012).
**
The number of a herd’s direct ingoing contacts through animal purchase from unique herds over a period for almost five years. Category 1 includes herds with in-degree 0–1, category 2 for in-degree 2–9 and category 3 for in-degree more than 9.