Md. Code, Agriculture § 3–403

All swine imported into the State for breeding purposes or show purposes shall be accompanied by a health certificate issued by a graduate veterinarian stating that they are free from every infectious or contagious disease, and that no infectious or contagious disease has existed for at least 30 days prior to shipment on the premises from where the swine are shipped. The Secretary shall approve all certificates. This section does not apply to swine imported for immediate slaughter.