Mass. Gen. Laws ch. 129 § 41
All persons who transport bovine animals upon any public way in connection with the purchase or sale thereof, shall have in their possession a bill of sale or memorandum signed by the owner or vendor of such animals, containing the address of such owner or vendor, the date of purchase or sale, the number of animals, breed, ear tag number or other means of identification of each animal.
Any person transporting bovine animals shall on demand exhibit such bill of sale or memorandum to any officer qualified to serve criminal process.
No person shall accept any bovine animal over six months of age which has been transported over any such way unless accompanied by such bill of sale or memorandum. The person accepting such animals shall endorse the bill of sale or memorandum in such manner as will signify his acceptance of each animal.
This section shall not apply to such licensees under section thirty-nine as are exempted from the provisions hereof by the director, by rules or regulations made under the authority of said section thirty-nine.
Mass. Gen. Laws ch. 129, § 41