Clefthooves (pl. also "clefthoof") are large, hairy kodo-like beasts native to Nagrand and Alternate Draenor. They can be found in southern Nagrand. They are skinnable for Thick Clefthoof Leather and drop Clefthoof Meat when killed.
Clefthoof are large herbivores native to the plains of Nagrand. They seem to have adapted to complete exposure, their wooly coats and thick skin protecting them from the elements, and living only in open areas. They have evolved with large, powerful horns and bony neck plating, both of which can be assumed to function mainly in dueling between males over mates due to the absence of a predatory species in Nagrand able to take down the clefthoof. Their great size is most likely the only deterrent the clefthoof needs against natural predators.
Although stated by a strategy guide, it would seem impossible for kodos and clefthoof to be related to each other (except through a titan connection). During the original Horde incursions into Azeroth, any such animal accidentally finding its way through the Dark Portal would have found itself in the Eastern Kingdoms where no currently-living animals resemble the kodos or clefthoof. Although both are plains animals, the kodo is native to the plains of Kalimdor, where it was domesticated by the tauren, long before the Dark Portal ever linked Draenor and Azeroth. That said, it should be noted that there are many other races native to Azeroth that are also native to Draenor, including skunks, tallstriders, scorpions, ancients and even worgs and wolves, among other things.
Another possible reason for their similarities is parallel evolution, where in different environments with similar conditions, animals tend to take the same body shapes.