It's an inept analogy. A baby is a parasite, feeding off the mother's body as it develops. A dog is not. A baby cannot survive apart from the mother's body prior to the 24th week of development (the cut-off point for a legal abortion). A dog can. Babies are not dogs, and so do not equate to dogs legally, morally, or logically.
That is something I would expect from a pro-abortion advocate. "It's not a baby, it's a parasite".
Well, that child that you so kindly refer to as "parasite" didn't hide in the bushes outside of some innocent, virgins window, wait until she was asleep and then climb inside her. In almost all cases of pregnancy, women consent to sex ... which is consenting to the absolute possibility of pregnancy.