UPDATE: This issue has been fixed from what I can see.
Some of you hunters may have noticed your Call Stabled Pet has a longer cooldown than the 5 minutes listed. How about 25 days!? It’s a bug and Blizzard is aware of it. In the meantime, they offer this fix:
1. Oueue for an Arena Skirmish. To do so, visit any major city and visit the Arena Battlemaster. You do not need to be part of an Arena Team in order to queue for a skirmish.
2. Once the match starts, join it and enter the arena. This will remove the cooldown and allow you to utilize your pets as normal. You do not need to stay until the end of the match and are welcome to leave at any time.
Wow. That’s a hell of a fix. Tried it and it works like a charm though. Hope this bug doesn’t crop up too much till they fix it.