WCBS reports (video link) that the investigation does appear to be related to Bruno's close, strictly-horse-based relationship with Jared Abbruzzese.
They also note the particularly unfortunate timing for the state's soon-to-be highest-ranking Republican. With Spitzer riding a wave of reform in and Hevesi riding a wave of scandal out, Bruno may find himself particularly vulnerable.
Hank Sheinkopf: "Senator Bruno seemed to be away from the problem, now he’s right in the middle of it. The calls for reform will only increase, and there’ll be more attacks on the Albany politicians."
Meanwhile, it's up to us to find a proper name for the emerging scandal. Saddlegate? The Horse Pork Affair? Albany Cowboys? I got nothin'.