Table 1.
Parameter estimates (standard error—SE, odds ratio—OR and the OR 95% confidence interval—CI) of the proportional odds mixed model for changes on the fecal culture results across time for Mycobacterium avium subsp. paratuberculosis in dairy cows in Minnesota, USA.
| Parameter | Levels | Estimate | SE | OR | CI | P value |
|---|---|---|---|---|---|---|
| Intercept* | 0 | −6.44 | 0.54 | <0.01 | ||
| 1 | −2.43 | 0.34 | <0.01 | |||
| 2 | Reference | — | — | — | — | |
| Months, n | 1 | 0.13 | 0.02 | 1.14 | 1.10, 1.18 | <0.01 |
| Temperature, C° | −18° | 0.79 | 0.31 | 2.20 | 0.82, 5.99 | 0.08 |
| −70° | Reference | — | — | — | — | |
| Initial bacterial load** | 1 | 4.38 | 0.56 | 79.80 | 13.4, 478.02 | <0.01 |
| 2 | 2.47 | 0.53 | 11.82 | 2.21, 62.97 | 0.02 | |
| 3 | 1.65 | 0.46 | 5.18 | 1.19, 22.85 | 0.04 | |
| 4 | Reference | — | — | — | — |
*0: negative, 1: mean of 0.25–50 colonies/tube (CPT)), and 2: mean of >50 CPT.
**1: mean of 0.25–9 colonies/tube (CPT)), 2: mean of 10–49 CPT, 3: heavy (mean of 50–100 CPT), and 4: >100 CPT.