Table 2.
Risk factors associated with E. coli isolates in calves by univariable and multivariable logistic regression.
| Risk factors | Category | No. tested | Sample positive (%) | Univariable | Multivariable | ||
|---|---|---|---|---|---|---|---|
| COR(CI) | P | AOR(CI) | P | ||||
| Age (weeks) | 1–2 | 44 | 33 (29.5) | 6.66 (2.35–18.89) | 0.001 | 4.029 (1.22–13.27) | 0.022 |
| 3–8 | 39 | 16 (14.3) | 1.55 (0.56–4.26) | 0.399 | 0.968 (0.28–3.31) | 0.954 | |
| 9–16 | 29 | 9 (8.0) | 1.00 | 1.00 | |||
| Sex | Female | 89 | 49 (43.8) | 1.91 (0.75–4.86) | 0.177 | 2.55 (0.79–82.13) | 0.116 |
| Male | 23 | 9 (8.0) | 1.00 | 1.00 | |||
| Breed | Cross | 94 | 48 (42.9) | 0.64 (0.23–1.78) | 0.390 | – | – |
| Local | 18 | 10 (8.9) | 100 | – | |||
| FCFT | > 6 h | 20 | 16 (14.3) | 3.41 (1.15–10.19) | 0.027 | 3.73 (1.01–13.76) | 0.048 |
| < 6 h | 92 | 42 (37.5) | 1.00 | 1.00 | |||
| CF | The same barn | 66 | 37 (33.0) | 1.51 (0.72–3.24) | 0.279 | – | – |
| Separated pen | 46 | 21 (18.8) | 1.00 | – | |||
| AMGPT | 1–1.5 L | 49 | 37 (33.1) | 4.63 (1.74–12.30) | 0.002 | 5.38 (1.66–17.45) | 0.005 |
| 1.5–2.5 L | 33 | 9 (8.0) | 0.56 (0.19–1.62) | 0.287 | 0.73 (0.20–2.84) | 0.631 | |
| Unknown | 30 | 12 (10.7) | 1.00 | 1.00 | |||
| Navel treatment | No | 54 | 35 (31.3) | 2.80 (1.30–6.04) | 0.008 | 1.93 (0.75–4.94) | 0.173 |
| Yes | 58 | 23 (20.5) | 1.00 | 1.00 | |||
COR crude odd ratio, AOR adjusted odd ratio, CF calving facility, AMGPT amount of milk given per time, CI confidence interva, P probability, 1.00 rreference group.