Behavioural responses of domestic pigs and cattle to humans and novel stimuli

Two experiments were conducted on pigs and beef cattle to study whether or not regular exposure to either humans or novel objects resulted in stimulus-specific or generalised behavioural responses. Groups of pigs and cattle were allocated to one of three treatments: regular brief exposure to either (1) an experimenter handling the animals in a positive manner (Human treatment) or (2) three novel objects (Novel Object treatment) and (3) minimal contact with humans and novel objects (Minimal treatment). After 4 weeks of treatment, the behavioural responses of the animals to humans and novel objects were studied. Pigs in the Human treatment were quicker (P < 0.01) to physically interact with the experimenter in the Human Approach Tests than pigs in the other two treatments, Pigs in the Human treatment were also quicker (P < 0.05) to closely approach the experimenter than pigs in the Novel Object treatment. Cattle in the Human treatment spent more time (P < 0.05) close to the experimenter in the Human Approach Tests than cattle in the other two treatments. Furthermore, cattle in the Human treatment were also quicker(P < 0.01) to closely approach the experimenter than cattle in the Minimal treatment, Pigs in the Human treatment were quicker (P < 0.01) to approach within 0.5 m of the novel stimulus in the Novel Object Approach Tests than pigs in the Minimal treatment and there was a tendency for pigs in the Novel Object treatment to approach the novel stimulus more rapidly (P < 0.07) than pigs in the Minimal treatment. The approach behaviour of cattle to the novel object in the Novel Object Approach Tests was similar for the three treatments. The results of these experiments provide evidence that changes in the behavioural response of animals undergoing regular positive handling by humans is stimulus specific to humans. Furthermore, there was some evidence that the behavioural response of pigs, but not cattle, to the novel stimulus was affected by previous exposure to that stimulus and other novel stimuli.