When is a horse placed behind another, or disqualified, for interference?

An interference objection (bumping, boring, crossing, jostling, intimidation or similar) is decided by an Objection Board under Rule 69.3 of the NHA Rules of Racing. It is only upheld if the board is satisfied that either:

1. A placed horse was interfered with by another placed horse (or its rider), and the horse interfered with would otherwise have finished ahead. The board then places the offending horse behind the horse it interfered with, or may disqualify it; or
2. Any horse's chances were jeopardised by interference from another horse, and the board considers the interference serious enough to warrant it. The board may then disqualify the offending horse.

For these rules a "placed horse" means any of the first five finishers as declared by the judge (Rule 69.4).

There is no appeal against an Objection Board's decision (Rule 67.6). Separately, the stewards can penalise the rider for careless, negligent or reckless riding even if the result stands.