Maryland Code, Business Regulation § 11-538

(1) the breeder of the horse has maintained a place of abode in Maryland for more than 9 months immediately before registration;

(2) the breeder of the horse keeps breeding stock continually in Maryland;

(3) the horse was conceived in Maryland during the previous season;

(4) the horse's dam was sent to Maryland to foal and after foaling was covered only by a Maryland stallion during the season of the horse's birth; or

(5) if the horse's dam dies, is permanently retired, or is certified by a veterinarian as unable to be bred, the horse resided in the State for at least 6 months after the horse was foaled.