105 CMR, § 330.200
A rabies tag of size, shape and color recommended by the National Association of State Public Health Veterinarians and approved by the Department of Public Health shall be provided by the vaccinating veterinarian for each dog and cat vaccinated. Each such tag shall be inscribed with the words Rabies Vaccinated as well as the year, name of the veterinarian and identification number of the vaccinated dog or cat. The owner or keeper of a dog shall cause the rabies tag to be attached to the collar or harness of the dog and worn at all times in the same manner as the license tag. The owner or keeper of a cat shall either have the cat wear the tag or have the vaccination record readily available for inspection by appropriate city or town officials upon request.
105 CMR, § 330.200