OK what do pigs have to do with us? Well, when their tail is amputated, everything! Here's an interesting European study from 2017 about nerve sensitivity at the amputation site:

Characterization of short- and long-term mechanical sensitisation following surgical tail amputation in pigs

Long-term hypersensitivity was also observed in tail-resected pigs at either two or four months following surgery. Tail amputation in pigs appears to evoke acute and sustained changes in peripheral mechanical sensitivity, which resemble features of neuropathic pain reported in humans and other species and provides new information on implications for the welfare of animals subjected to this type of injury.

This study followed current UK guidelines for health and welfare of the animal s in the study ("All animal procedures were performed in accordance with the International Association for the Study of Pain guidelines for the Use of Animals in Research")