OK, as Bill Maher would start, New Rules:
All animals, particularly home companions, should be referred to as "him," "her," "who" and "whom," rather than "it" and "that." For people who truly love their animals, this should not be a difficulty, as they already regard them as thinking, feeling individuals - much of the time, anyway. However, many people who do love their pets, to a degree, still think of them as vastly mentally and emotionally inferior to humans, and those who do not care for animals at all generally see them as little more than objects. Let's face it, as soon as we find out what gender even a fetus is, most of us define it as "she" or "who", and the animals in our lives have at least as much cognizance as a zygote (unless you are of the opinion that only humans have spirits or thought processes and animals are purely mechanical/instinctive, which theory I may address further later).
If we are to promote fair and humane treatment of animals, changing peoples' perspectives just a little by making this simple switch could do a lot towards making them perceive all creatures as just a little bit more "human", and thus worthy of consideration. Even the act of having to pause a moment and consider what gender an animal might be in order to say "he" or "she" switches one's train of thought towards differentiating them from others of their kind, as well as towards seeing them as living beings rather than objects.
A small thing, perhaps, but try it. Let's see what happens.