Mass. Gen. Laws ch. 272 § 80A
Whoever, not being a veterinarian duly registered under chapter one hundred and twelve, crops or cuts off the whole or any part of the ear of a dog shall be punished by a fine of not more than two hundred and fifty dollars. If a dog with an ear cropped or cut off in whole or in part and with the wound resulting therefrom unhealed is found confined upon the premises or in the charge or custody of any person other than such veterinarian, or a dog officer of a city or town duly appointed under section one hundred and fifty-one of chapter one hundred and forty, such fact shall be prima facie evidence of a violation of this section by the person in control of such premises or the person having such charge or custody.
Mass. Gen. Laws ch. 272, § 80A