Table 2.

Vocalization variables gathered during the REMOVAL of piglets from a sow

Variable	Description
Properties*
Number, #	Total number of calls performed by a single sow
Duration, s	Amount of time that a call was performed
Interval, s	Time between the beginning of each call
Variables†
Frequency, Hz	Highest frequency produced above 30 dB averaged across entire call
Amplitude, dB	Loudness at the peak frequency averaged across entire call
Bandwidth, Hz	Difference between the maximum frequency (referred to here as “Frequency”) and minimum frequency averaged across the call

The REMOVAL period was recorded during a 5-min duration starting when the first piglet was removed from the farrowing crate by an unknown handler until the first piglet was returned to the farrowing crate.

*Completed on all recorded calls, regardless of background noise level.

^†Mean of call variables were performed only on calls recorded without disrupting background noise (other sows, piglets, or metallic noise from crates) and were analyzed taking an average for each call.