The average number of daily pig movements was 682, with Thursdays being
2.44 times higher than the average, related to preparation for the
higher demand over the weekends and the higher activity of markets (Fig.
3A). In Fig. 3B, we plot the frequency of movements by week.
Furthermore, over the years, the mean number of weekly movements grew
from 3,599 in 2017 to 5,973 in 2019, which is supported by an increasing
trend over time (S=144, p<0.01 Mann-Kendall test) and the
detection of a change point (p=<0.001) on week 73
corresponding to May 2018 (K on Fig. 3B), related to the adoption of
stricter vaccination and movement policy. Cultural and political
influence affected the network, identified by weekly reductions from the
average of movements; -53.8% due to the celebration of Carnival holiday
(a in Fig 3B), 14% due to a extended national holiday (b in Fig 3B) and
73% due to road blockades during a national strike led by indigenous
groups (c in Fig. 3B).
Figure 3. Representation of pig movements in different time
aggregations. (A) Box plots of the number of movements grouped by day of
the week. (B) Movements grouped by week and filled by days of the week;
Pettit’s change point (k) at week 72, and highest reductions in the
weekly movements marked with letters a (carnival holiday), b (extended
holiday) and c (national strike).