58 Pa. Code § 163.102
A horse may not be allowed to start unless a Jockey Club registration certificate is on file in the office of the horse identifier and the horse has been lip tattooed. If an error or omission on the foal certificate of a horse entered to race which precludes tattooing pending correction or completion of the certificate, the horse may be permitted to run without a tattoo for no longer than a single 30-day grace period. Before the horse is allowed to run during the 30-day grace period, the error or omission shall be noted on a photostatic copy of the certificate and attested to by the stewards and the horse identifier and a complete and attested copy of the certificate shall be retained at the track and filed with the Commission field office where the horse is running, and the correction of the certificate by the Jockey Club has been applied for before or at least at the time of the race, and the horse is identified to the complete satisfaction of the stewards. Only a single grace period is allowed for a horse entered for racing in this Commonwealth.
58 Pa. Code § 163.102
This section cited in 58 Pa. Code § 165.216 (relating to illegal entries).