Table 17.

ABMs of group stress in cow–calf contact systems

ABM	Comments
Headbutts, displacements and kicks from cow	Definition: A calf receives a head butt or is displaced from a cow (i.e. any interaction involving physical contact where the cow is butting, hitting, thrusting, striking or pushing the calf with forehead, horns or horn base with a forceful movement and the calf is either staying at its position (=head butt) or giving up its position (=displacement); modified from WQ® 2009) or is kicked by a cow (i.e. the cow lifts its leg, moves it quickly in the direction of the calf and finally strikes the calf with the leg); interactions without physical contact, i.e. threats or kicking movements without striking the calf, are not counted. The number of head butts, displacements and kicks (=aggressions) per calf per hour is calculated (Waiblinger et al., 2020). Sensitivity: High. Specificity: High.
Injurious events	Definition: Calf is either falling (see Table 3 for falling definition) or bumping into equipment such as a cubicle partition when withdrawing from an aggression from a cow or is being pushed or pressed into the equipment by the cow. Sensitivity: Low. Group stress does not always result in injurious events. Specificity: High.
Displacements by calves	Definition: A calf is displaced by another calf (for the definition of displacement, see above). Sensitivity: High. Specificity: High.