Table 7.
Final multivariable logistic regression model describing the association between risk factors and detection of Histophilus somni by PCR on pooled broncho-alveolar lavage samples from epidemic respiratory disease in calves1
| Independent variable | Category | n | % positive | b | SE | OR | 95% CI | P-value |
|---|---|---|---|---|---|---|---|---|
| Intercept | −1.1 | 0.3 | <0.001 | |||||
| Bedding type | Straw | 103 | 35.0 | Referent | ||||
| Sawdust | 10 | 70.0 | 1.6 | 0.8 | 5.2 | 1.2–23.0 | 0.03 | |
| Vaccination against Mannheimia haemolytica | No | 61 | 29.5 | Referent | ||||
| Yes | 52 | 48.1 | 0.9 | 0.4 | 2.6 | 1.1–5.8 | 0.02 |
1
b = regression coefficient; OR = odds ratio.