Md. Code, Agriculture § 3–1002

Except as otherwise provided in federal law or regulation, this subtitle does not apply to antimicrobial use in:

(1) Cattle on a farm operation that sells fewer than 200 cattle per year;

(2) Dairy cattle on a farm operation with a herd size of fewer than 300 dairy cattle;

(3) Swine on a farm operation that sells fewer than 200 swine per year; or

(4) Poultry on a farm operation that sells fewer than 60,000 birds per year.