It's probably appropriate to use the word inhumane when referring to the improper treatment of animals, but I was just curious if there was another term in the English language that refers to the improper way to treat an animal.

Generally speaking, inhumane simply means lacking qualities of sympathy, pity, warmth, compassion, or the like; cruel; brutal, but it can also mean not suited for human beings. But I think that the ethical standards for treating a human are slightly different than the standards for treating any other animal, so it would be appropriate to have its own word. Does such a word exist?