Doggies, I'm going to assume you're male... because, believe me,
I can tell the difference in the smell of blood from a menstrual cycle vs. a wound. To dogs I imagine the difference would be all the more noticeable--I can't imagine any mix-ups there.
Although Middie does seem to love the smell. *sigh* I had to empty the trashcans this morning into the big one. Old cat food and used pads I would imagine are very tempting.
Now that I have sufficiently grossed you all out, my job here is done.