Table 1.

Behaviours and definition used in this study. Categories used for analysis are provided¹.

Category1	Behaviour	Description	Type
Standing idle		The focal calf is standing while not performing, or receiving any of the behaviours described below. It may, or may not, be moving its head while looking around, or it may be standing vigilant (i.e. with head raised and ears erect)	State
Contact environment		The focal calf’s muzzle is in close contact with any part of the environment, e.g. floor, barriers, trough. This includes, when observable, any chewing, licking or biting of the environment	State
Invisible		It is unclear what the focal calf is doing because the calf is not entirely visible	State
Other		Any state behaviour not described above (e.g. coughing, rubbing etc.). This behaviour fills the gaps between the other state behaviours and may run in parallel with other ‘event’ behaviours	State
Play*	Individual locomotory play	Jump, gallop, buck, buck-kick, fast turns, sometimes accompanied by headshake. Performed alone, i.e. no other calf in the pen or visible adjacent pens performs any of these elements	Event
Play + social (given2)	Parallel locomotory play	Jump, gallop, buck, buck-kick, fast turns, sometimes accompanied by headshake. The focal calf’s play is simultaneous with the play behaviour of other calves in the pen or adjacent pens (visible on the video)	Event
Play + social (given)	Frontal pushing	The focal calf is placed front to front to another calf in the pen while the two are mutually butting their heads against the head or neck of the other without this behaviour resulting in withdrawal	State
Play + social (given)	Mounting	The focal calf lifts both forelegs and then rests forelegs and sternum on the back, side or head of another calf	Event
Social (given)	Contact other calf	The focal calf’s muzzle is in contact with any part of the head or body of another calf in the pen or a calf from an adjoining pen	State
Social (given, negative)	Body pushing	The focal calf is pushing its head with force on any body part, except the head or neck, of another calf	State
Social (given, negative)	Disturbs lying calf	The focal calf is stepping on, hitting or otherwise causing other calves to stand up due to its activity	Event
Social (given, negative)	Displaces other calf	The focal calf body-pushes, or rests its head on the back of another calf and this causes the other calf to move (all four legs move) away (from trough, water, or position)	Event
Social (received)	Is contacted by other calf	A calf (from the same or another pen) has its muzzle in close contact with any part of the body or head of the focal calf. When the other calf walks away and then returns contacting the focal calf, this interrupts the behaviour and the behaviour is scored again	Event
Social (received, negative)	Disrupted lying	The focal calf is being stepped on, hit or otherwise made to stand up due to the activity of another calf	Event
Social (received, negative)	Is displaced	The focal calf moves (all four legs move) away (from trough, water, or position) due to the behaviour of another calf (e.g. head butting of the body, or rests its head on back of the focal calf)	Event
Social (received, negative)	Is being mounted	The focal calf is being jumped onto. The other calf lifts both forelegs and then rests its forelegs and sternum on the back, side or head of the focal calf	Event

*Jensen et al.⁵⁷.

¹State (durations) and event (counts) social behaviours were grouped into separate categories, which means that the following (categories of) behaviours were ultimately analysed: standing idle (duration), contact environment (duration), play (count), social interactions (duration), social interaction (count), social interaction given (count), social interaction received (count), negative social interaction (count).

²The terms given and received indicate whether the calf was the actor in the behaviour or was receiving the behaviour from another calf, respectively.