Rate of loyalty gain is based on the XP you would be getting from killing mobs.  Make sure you and your pet are killing mobs that are at least green (will loyal faster with yellow, etc).  I captured one of these ravagers this weekend, and had it loyaled up in about 4 hours (ground talbuk/clefthoof) in Nagrand.  Also be sure to feed it often (even if his face isn't less than happy yet).  Max happiness while loyalty grinding is also key in expediting the rate of loyalty gain.