Implicit in your question is the rather difficult-to-define notion of love. If you are willing to accept it as a rather universal ******** of emotions experienced by many, if not all, mammals then you are in luck. Your dog's medial forebrain bundle does probably rocket neural impulses and release dopamine upon the sight of you, the feeder, the walker, the shit-collector. For a more satisfying answer I'd suggest looking into studies of seeing eye dogs and especially whether they have acted in ways humans would judge 'altruistic.'