Table 6.
Final multivariable logistic regression model describing the association between risk factors and detection of Mannhaemia haemolytica by PCR on pooled broncho-alveolar lavage samples from epidemic respiratory disease in calves (2016–2018, Belgium)1
| Independent variable | Category | n | % positive | b | SE | OR | 95% CI | P-value |
|---|---|---|---|---|---|---|---|---|
| Intercept | −2.6 | 1.0 | 0.07 | |||||
| Number of animals per pen in outbreak group | Individual | 13 | 23.1 | Referent | 0.03 | |||
| <5 per group | 22 | 18.2 | 0.02 | 1.0 | 0.98 | 0.13–7.3 | 0.98 | |
| 5–10 per group | 43 | 58.1 | 2.1 | 0.9 | 8.0 | 1.4–46.9 | 0.02 | |
| >10 per group | 30 | 46.7 | 1.5 | 0.9 | 4.5 | 0.7–27.4 | 0.10 | |
| BCV | Negative | 67 | 32.8 | Referent | ||||
| Positive | 44 | 54.5 | 1.4 | 0.5 | 3.8 | 1.5–9.8 | <0.01 | |
| Bedding type | Straw | 106 | 37.7 | Referent | ||||
| Sawdust | 8 | 87.5 | 2.9 | 1.2 | 18.3 | 1.8–191.6 | 0.02 |
1
BCV = bovine coronavirus; b = regression coefficient; OR = odds ratio.