Is it permissible to dock a dog's tail?

It is not permissible to cut off a dog's tail because it constitutes wanton mischief and tormenting an animal, and the Prophet, peace and blessings be upon him, forbade that. It is mentioned in the Fiqh Encyclopedia that cutting off an animal's tail is a crime, and Hanafī jurists stated that whoever cuts off a packhorse's tail shall be subject to ta'zīr (discretionary punishment). There are numerous hadiths urging kindness to animals and forbidding harming them, and the Prophet, peace and blessings be upon him, forbade "sabr al-ruh" (confining an animal to be killed). Therefore, it is not permissible to cut off a dog's tail.