Are there more than 300 horse breeds?

Well, I haven't counted them all but i think there are over 300 horse breeds, as there are many rare and unknown breeds which are not included on the Horse Breeds page on Wikipedia, although this is still a good list. I found a website which is new, so, unfortunately incomplete. However, they have listed many horse breeds. Check out the website if you are interested: http://equi-mania.wikidot.com Hope I've helped you answer your question!