Auditory stimuli are used by pigs as a means of communication in all social activities (Gonyou, 2001). Pigs exposed to 90 dB prolonged or intermittent noise increased time lying down and decreased social interactions (Otten et al., 2004). According to Talling et al. (1996) pigs show an aversion to sudden loud noise during tested in an open-field. This response was stronger for a frequency of 8 kHz than for 500 Hz and for an intensity of 97 dB than for 85 dB, although habituation occurred relatively quickly (Kittawornrat and Zimmerman, 2011). Repeated exposure of pigs to noise levels of 90 dB has negative implications on their welfare (Kanitz et al., 2005).