Mo. Rev. Stat. § 196.840
No person, firm or corporation owning, or in charge of, any herd of cattle containing five head of cows or more, after January 1, 1922, shall sell, offer for sale, give away, or deliver any milk, cream, butter, or buttermilk from any of the cows of such herd, unless all the herd of cattle containing such five head of cows or more, owned by, or in possession of, such person, firm or corporation have been duly inspected and tested and found free from tuberculosis and other communicable diseases, as determined by a physical examination and the tuberculin test by an official, duly authorized by this state or by the federal government; provided, that said examination and tuberculin test shall incur no expense whatever to the owner of said herd.
§ 196.840, RSMo