TABLE 4.
Univariate analysis of factors associated with STEC shedding in beef cattle belonging to five herds in Michigana
| Characteristic | No. (%) with characteristic | No. (%) with STEC | OR (95% CI) | P value |
|---|---|---|---|---|
| Maximum temp 1–5 days prior to sampling | ||||
| >28.9°C | 129 (34.1) | 53 (41.1) | 6.0 (2.79, 12.70) | <0.0001 |
| ≤28.9°C | 249 (65.9) | 27 (10.8) | Reference | |
| Treatment for respiratory disease | ||||
| Several antibiotics | 129 (34.1) | 53 (41.1) | 5.9 (2.79, 12.70) | <0.0001 |
| Only one antibiotic type | 249 (65.9) | 76 (59.0) | Reference | |
| Anthelmintic/monensin treatment | ||||
| Yes | 324 (85.7) | 51 (15.7) | 0.2 (0.04, 0.57) | 0.005 |
| No | 54 (14.3) | 29 (53.7) | Reference | |
| Pasture access/unique diet | ||||
| Yes | 54 (14.3) | 29 (53.7) | 6.6 (1.77, 24.31) | 0.005 |
| No | 324 (85.7) | 51 (15.7) | Reference | |
| Breed | ||||
| Holstein | 83 (22.0) | 13 (15.7) | 1.0 (0.26, 4.14) | 0.019 |
| Angus | 54 (14.3) | 29 (53.7) | 6.6 (1.69, 25.89) | |
| Crossbreed | 241 (63.8) | 38 (15.8) | Reference |
a
Herd was included as a random effect in the univariate analysis. Generalized linear mixed models were used to calculate the P values, odds ratios (OR), and 95% confidence intervals (CI). The number of animals with a given characteristic may differ depending on the variable examined. Pasture access, corn silage diet, high-forage diet (100%), and 0% total mixed ration all yielded the same association, as these characteristics were unique to one herd with the highest STEC prevalence.