ELECTRONIC SENSING OF NONDESTRUCTIVE CHEWING BY GROWING PIGS

Non-destructive chewing (i.e., the normally harmless chewing performed by pigs on their pen-mates and surroundings) is considered to be the behavioral pre-cursor of tail-biting outbreaks. A simple method for mo nitoring this behavior was developed, based on a chewing sensor consis ting of a canvas-covered tube and sealed air chamber. Compression of t he tube by chewing causes an increase in air pressure that is detected by a pressure transducer and logged by a computer. Video recordings o f pig behavior showed that activation of the sensor was caused almost exclusively by chewing and rarely by other activities. Hourly chewing counts by the sensor were closely correlated (r = 0.83) with oral beha vior as detected by video recording of six groups of six pigs over 72 h. Chewing counts showed large differences between groups and between individual pigs. The behavior showed daily peaks at mid-day and late a fternoon, corresponding to the animals' diurnal pattern of general act ivity but not corresponding to fee&ng behavior.