Unsurprisingly, the kernel parameters were not significantly different if allowed to be different before and after 31 st March, neither did this model prove to be the best fit. Overall, while the variations in mean deviance (Figure 2b ) seen between model variants were much smaller than for the models conditioned on the first infection (Figure 2a ), the interaction model allowing for time varying cattle infectivity gave the most adequate fit (measured by both mean deviance and DIC, see Table 2 ).