Equivalent for "inhumane" in regard to animals

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?

Cruel is possibly the most often used adjective for this context, though from my experience cruelty (as a noun) is more common. (E.g. SPCA stands for the Society for the Prevention of Cruelty to Animals.) The Wikipedia article is called Cruelty to animals and says that it is also called animal abuse or animal neglect.

Though there is no such word used exclusively for animals, we are not much the worse for the lack, since context will dictate the meaning of any word we choose when describing cruelty to animals. For instance, if someone spoke of "inhumane treatment of animals", we would not think he meant "not suited for human beings"; we would understand that he was referring to cruelty to animals. This shows that many synonyms of cruel/inhumane can be used and understood properly.

It's worth noting that even if the word inhumane is not commonly used to describe cruelty to animals, humane appears to be most often used as its antonym, as in the Humane League, Humane Society, or humane treatment.

Inhumane can be used for how the person is acting towards the object, whether the object is human or something else.