The response of sows to novel visual, olfactory, auditory and tactile stimuli

Abstract

The responses of sows to 20 stimuli from five sensory categories were evaluated with the aim of selecting one stimulus from each category as a test of general environmental responsiveness. The visual stimuli evaluated were a novel rod, a hanging ball, a moving chime and an umbrella. The olfactory stimuli were eucalyptus oil, perfume, ammonia and glacial acetic acid. The auditory stimuli were the sound of a cap gun, a buzzer, playback of a piglet squeal and playback of a sow grunt. The tactile stimuli were a rub, a prod, a slap on the neck, a clip placed on the ear and water tipped on the back. The complex stimuli evaluated were response to a human, food and novel-coloured food. The effect of the stimuli was analysed by comparing changes in behaviour and posture of sows in 15-s scans for 5 min, before and after stimulus presentation. Sows showed little response to the visual stimuli; the umbrella and rod elicited more exploratory responses than the chime or ball. Sows ignored ammonia and glacial acetic acid, but responded to eucalyptus oil and perfume by raising their heads and rubbing their sides and backs on the side of the stall. Sows showed variable responses to the auditory stimuli; the buzzer elicited more movement away from the stimulus. Lying sows responded to the tactile stimuli by standing more rapidly in response to the water and a slap than to a rub or a prod. All sows responded to the clip by attempting to shake it off. Sows showed no fear responses towards the human and 12 out of 15 sows made frequent contacts. Sows showed a neophobic response to blue-coloured food and only three out of 15 sows attempted to eat it. The stimuli selected for further study of general environmental responsiveness were the novel rod, eucalyptus oil, playback of the sow grunt, the clip and exposure to a human.