I knew a guy who was getting ready to move to a different town; he had five dogs -- three large ones and two smaller ones. He decided that taking the smaller ones with him would be too much of a burden, so he had them put to sleep. They didn't really do anything -- they never bit anybody, were good pets as far as I knew; he just didn't want to deal with them any more, whether that was because of the time and money involved, or if moving them would have just required an "effort." They were just in the way and a burden on his lifestyle, so he had them killed.
It never fails that no matter who I tell that story to, pro-choice or not, everyone thinks he was wrong to kill those dogs. Kind of interesting that there are people out there who would go to bat for a dog, but they support a woman's right to have a baby scraped out of her and killed.
That's because you don't have to oppose his right to put his pets down to oppose his specific decision to do so. I don't think hardly any people would oppose owners' right to put down their pets.
Of course it's an entirely different situation, as the question with the fetus (at least for me) is whether or not it has conscious experience, which is not a question with dogs.