Abstract
The nursing vocalization of domestic pigs(Landrace$\times$Yorkshire) was investigated with respect to common features. All vocalizations uttered during nursings in 5 sows at 5 days after farrowing were recorded and 305 grunts were processed in a spectrograph. The sow's repeated grunting during nursing can be regarded as a contact call and a signal of the mother to start and synchronize the suckling behavior of the piglets. Analysis in the time domain revealed the gross structure of the call, whereas in the frequency domain the fine structure of single grunts was investigated. Nursing interval, duration of nursing behavior, duration of grunt, grunt rate per 10 seconds, fundamental frequency, 1 formant, 2 formant, 3 formant, 4 formant and spectrum were investigated. The results showed that mean interval between the nursing following one another was 25, 4.6 min and duration of nursing behavior was 3.2 $\pm$ 0.7 min. Average duration of grunt was 203.9 $\pm$ 63.6 ms. The formant contours could be identified. The nursing behavior might be disturbed by the grunts of alien sow.
