7 Pa. Code § 205.460
All horses that have been nerved shall be so designated on the USTA registration certificate, electronic eligibility and be registered with the Commission Veterinarian. It is the responsibility of the owner of the horse at the time the horse is nerved to see that this information is placed on the registration certificate and the electronic eligibility. No trainer or owner will be permitted to enter or start a horse that is high nerved. It shall be the responsibility of the owner or trainer, or both of a horse that has been low-nerved to post on the bulletin board in the racing office at each racetrack where the horse competes the fact that the horse has been low-nerved and it is the responsibility of each track member to provide a space in the racing office where the fact of nerving can be posted in accordance with this rule.
7 Pa. Code § 205.460