In the
case the sow stood or walked, activity was registered
continuously as all occurrences into 3 categories: nestbuilding
behavior (the sow roots with the snout on the
fl oor, carries straw, or paws with front leg against the fl oor),
head in trough (head in trough or touching the trough with
the snout), and other type of activity (behavior different
from nest building and head in trough).