Porcine perception of auditory stimuli

• Main Author: Talling, Janet C.
• Published: University of Edinburgh 1996
• Subjects: 636.089
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.662709

Animals are adapted to live in fluctuating environments. Some stimuli to which they are exposed will be ignored, some will be avoided and others will be approached. Stimuli perceived as a threat or associated with a painful stimulation will tend to be avoided. Therefore to understand more fully how an animal copes with a particular situation, e.g. transportation, its perception of all stimuli needs to be determined. The aim of the study reported in this thesis was to determine how auditory stimuli, to which pigs are exposed during production, are perceived by individual pigs. A field study was carried out to characterise the sounds to which pigs are exposed during production and studies were made of pig responses to sound under experimental conditions. The sound pressure level in artificially ventilated fattening units was quite loud (70 to 80 dB(Lin)), but relatively constant. In contrast, naturally ventilated units were quieter (60 to 70 dB(Lin)), but more variable. Sound pressure levels during transport were more than 88 dB(Lin) and highly variable. Similar levels were measured in articulated transporters and small livestock trailers. Sound pressure levels measured in abattoir lairages varied from 77 dB(Lin) to 89 dB(Lin). Equivalent sound pressure levels (Leq 20 min) of 97 dB(Lin) were measured in the stun pen of one abattoir that used electric stunning. Pigs' perception of mechanical sounds between 85 and 100 dB(Lin) was assessed. The onset of sound activity and visual searching. Stronger responses were measured for louder sounds. Over a constant exposure period of 15 to 20 minutes the responses observed decreased towards basal levels.