Porcine Aggression: Measurement and Effects of Crowding and Fasting

Abstract

Three experiments were conducted utilizing 120 growing-finishing pigs to correlate measures of aggressive behavior and to determine the effect of restricted space allowance, fasting and straw bedding on porcine agonistic behavior. Number and duration of bites correlated well (r = .79; r = .77; P<.01) with total aggression, which was measured as the sum of the number of attacks, replacements at the feeder and threats. Pigs that were fasted for 24 hr engaged in more biting activity (P<.05) than pigs fed ad libitum. Duration of biting activity (seconds per 10-min observation period) among four unfamiliar growing pigs that were mixed and fed ad libitum was 74 compared to 103, 114, 80 and 86 for pigs fasted for 12, 24, 36 and 48 hr, respectively. Straw bedding did not reduce (P>.10) biting behavior among growing pigs that were fed ad libitum but tended to reduce (P<.10) agonistic behavior among fasted pigs. Neither a reduction in pen size from .7 m² pig⁻¹ to .4 m² pig⁻¹ nor addition of straw bedding at the time of mixing altered (P>.10) biting behavior among finishing pigs fed ad libitum. These data demonstrate that inanition exacerbates aggressive biting behavior when unfamiliar pigs are mixed, with the most biting occurring about 24 hr after withdrawal of feed. Results of two studies with growing and finishing swine fed ad libitum do not support the general recommendation of adding straw bedding when pigs are mixed to reduce aggressive behavior. Copyright © 1980. American Society of Animal Science . Copyright 1980 by American Society of Animal Science.