I'm a dog owner and I do clean up after my dog, simple because I can do the maths. There's a large area of common land near me, if you consider the number of dogs in the area and the fact that they should get walked twice a day, then consider how lomg a dog egg takes to naturally decompose, it gets a bit scarey. Especially when you consider that although there's a large area, the majority keep to the paths.
The number of people how leave dog eggs on the ally ways that lead to the land is a reall p155 take.
As for dog poo vs cow vs sheep vs horse, poo for vegatarian animals, while not pleasant, is a lot less offensive