Cattle-to-cattle and sheep-to-sheep transmission is higher (by 19% and 54% respectively) for the model with non-random mixing, whereas the sheep-to-cattle and cattle-to-sheep transmissions dropped by 41% and 37 % respectively. Conditioned on 23 rd February, 7 model variants have been considered (Table 2 and Figure 2b) . We examined the baseline and interaction models (no change in parameters over time), allowing cattle infectivity to vary on 31 st March and both cattle and sheep infectivity to vary by the same factor after 31 st March (with and without heterogeneity in mixing) and allowing both kernel parameters to vary on 31 st March.