Table II.
Potential risk factors for Shiga toxin-encoding bacteria fecal shedding cattle in univariable logistic regression models
| Model | Variable | Levels | Number positive | Number of cattle | % positive | OR | P-value |
|---|---|---|---|---|---|---|---|
| All cattle | Farm type/size | Small organic | 30 | 458 | 6.6 | 4.5 | 0.04 |
| Small conventional | 23 | 579 | 4.0 | 2.7 | |||
| Large conventional | 18 | 1171 | 1.5 | 1.0 | |||
| Cattle group | Preweaned calf | 21 | 385 | 5.5 | 2.1 | 0.17 | |
| Adult cattle | 50 | 1823 | 2.7 | 1.0 | |||
| Season | Fall | 23 | 307 | 7.5 | 3.4 | 0.38 | |
| Spring | 26 | 969 | 2.7 | 1.1 | |||
| Summer | 22 | 932 | 2.4 | 1.0 | |||
| Status of diarrhea | Yes | 2 | 57 | 3.5 | 1.1 | 0.93 | |
| No | 69 | 2151 | 3.2 | 1.0 | |||
| All calves | Calf age | < 29 d old | 6 | 168 | 3.6 | 0.5 | 0.13 |
| 29–56 d old | 15 | 217 | 6.9 | 1.0 | |||
| Farm type/size | Small organic | 4 | 48 | 8.3 | 2.0 | 0.70 | |
| Small conventional | 6 | 84 | 7.1 | 1.7 | |||
| Large conventional | 11 | 253 | 4.4 | 1.0 | |||
| All cows | Number of parity | ≤ 3rd | 33 | 1413 | 0.9 | 0.5 | 0.20 |
| 4th or more | 16 | 379 | 4.2 | 1.0 | |||
| Stage of lactation | 0–30 d | 11 | 256 | 4.3 | 1.5 | 0.49 | |
| 31–120 d | 10 | 403 | 2.5 | 0.9 | |||
| 121–240 d | 10 | 509 | 2.0 | 0.7 | |||
| ≥ 241 d | 16 | 548 | 2.9 | 1.0 | |||
| Farm type/size | Small organic | 26 | 410 | 6.3 | 8.8 | 0.01 | |
| Small conventional | 17 | 495 | 3.4 | 4.6 | |||
| Large conventional | 7 | 918 | 0.8 | 1.0 |
OR — odds ratio.
Variables with P < 0.20 were eligible for inclusion in the multivariable model.
P-value originated from F statistics (Type 3 GEE analysis).