Individual identification for management purposes is done by ear notching, ear tagging, tattooing (usually of the ear but sometimes on the shoulder) or micro-chipping. The procedures are normally carried out without anaesthesia or analgesia, and involve handling stress and acute pain from tissue damage.
Ear notching involves cutting several notches around the tip of each ear using notching pliers (other methods of identification such as ear tagging are also used). Research has indicated that the combined process of tail docking and ear notching piglets elicits a stronger pain response than handling alone (63). During the process, piglets who were tail docked and ear notched vocalised at a significantly higher frequency than those who went through a similar handling procedure without the mutilations (63).
A more recent study demonstrates that piglets display pain-related behaviour such as being awake and inactive after being mutilated (64).