These dried calves hooves are really popular with our Basenji puppy. They last for ages and unlike rawhide don't turn into a grotty bit of soggy white gunk. One hoof will easily last a couple of weeks concerted chewing before it gets too small to become a choking risk. The only down side is the incredible whiff they give off if you get too close.
Update 2/3/15, now our puppy is fully grown , they do last considerably less time, typically about a day of concerted chewing. Still good value though.