St.2012, c.193: An Act Further Regulating Animal Control is effective October 31, 2012. This new law establishes the Homeless Animal Prevention and Care Fund with a voluntary check-off donation on income tax returns. Prohibits declaring a dog dangerous solely based on the breed of dog. Also regulates health certificates for dogs and cats brought into or sold in Mass, kennel licenses, nuisance and dangerous dogs, euthanasia, animal cruelty, protection for animals in domestic violence restraining orders and more.
You can find a nice summary on the TuftsNow blog post, What's in the New Massachusetts Animal-Control Law?, and more on this and many other laws at our Mass. Law About Animals.