What is the ruling on cropping dogs' ears and docking their tails for cosmetic purposes?

Cutting the ears of livestock is not permissible. This is indicated by the careful inspection of the eye and ear, and the prohibition of sacrificing an animal that is blind in one eye (عوراء), or whose ears are cut from the front (مقابلة) or from the back (مدابرة), or whose ear is split (خرقاء), or whose ear is torn lengthwise (شرقاء). If cutting the ear of a domesticated animal (bahimah) is prohibited despite its purity and benefits, then the prohibition is even more applicable to dogs, due to their impurity and the prohibition against keeping them, except for a dog for herding or hunting. This is also because angels do not enter a house that contains a dog or a picture.