Pretty much any shit from any animal can be used as fertilizer so long as it has decomposed enough. Some poops take longer than others to break down into usable material but it all ends up the same in the end. Take, for example, a compost bin. You're not going to toss orange peels and onion rinds in your soil mix. You throw the organic material into a bin and let it break down into a rich usable compost. Off the shelf manure is decomposed to a degree, but if they shoveled fresh cow patties into bags it wouldn't be nearly the same thing. So, yea, you could use dog poop if you give it enough time to break down. I'm not really sure how much time that is, but don't waste it. Just go buy some shit from the garden center already packaged and ready to use.