Table 6: Multivariable Cox proportional hazards model of weather related factors associated with the survival of M. bovis in the environment.

Risk factor Parameter estimate Standard error Hazard ratio (95% confidence interval) Temperature* 0.06 0.02 1.06 (1.02–1.10)

*Results of purposeful selection of covariate and modified stepwise modeling in Cox regression. Only temperature remains in the model.