Upon seeing this question, I immediately when to your gallery to see what seemed like would be the best to study - Your equines look very good. I didn't see many felines or canines, so it was hard  to decide between them. I essentially saw more felines. If you draw them more frequently, maybe practice Canine? Or perhaps it's reverse, that you should practice feline because you draw them? Up to you,  but personally, I put my vote into 'canines (wolves, jackals, dogs).'