I think we should eat horses...we don't need them like we used too in the old days before cars etc...they are only used these days to make money ie racing etc, and sports. Other than that they are useless animals...they are not a food supply for any other animals so they wouldn't be missed in that sense.
Oooooh dogs I never thought of that. We probably already do. You get more meat off a horse anyway, but there are more dogs in the world so its much of a muchness.
Doesn't matter to me anyways...I am a vegetarian