VOCAL INDIVIDUALITY DURING SUCKLING IN THE INTENSIVELY HOUSED DOMESTIC PIG

Nursing vocalizations, signalling lactation, were recorded for ten Lar ge White X Landrace sows, parity 1-8 held in the minimal disease pigge ry at The University of Queensland, Veterinary Science Farm (Australia ), The aim was to characterize the individual nursing sounds using Can ary 1.2 Software to produce a spectrogram from a recording, to discern auditory features of the nursing grunts that could form the basis of the piglets' ability to discriminate among sows, Sows were significant ly different (P < 0.001) from one another for both slow and rapid grun ts for five variables MaxF (maximum frequency), MinF (minimum frequenc y), MainF (the section of the spectrogram with greatest power in dB), Length (duration of the call in s) and Gap (duration of interval betwe en successive grunts), A sixth variable, Volume (maximum volume), was less reliable. Individual sows also showed significant difference in t hree variables (MaxF, MainF, Volume) measured early (up to 14 days pos t parturition) and late (more than 14 days post phase for both slow an d rapid grunts. It was also found that there were distinct changes ove r time (P < 0.0001) in the six variables, MaxF, MainF, Volume, MinF (m inimum frequency of grunt), Length in seconds (duration of grunt) and Gap in seconds (duration of interval between successive grunts) for th e slow vocalizations, when all sows were combined. Also, changes in ra pid grunts over time for the combined sows were significantly differen t in MaxF, MainF and Volume(P < 0.0001). There was strong evidence (us ing Discriminant Function Analyses) that the variables measured do ena ble sows to be distinguished on the basis of their vocalizations.