Mo. Rev. Stat. § 273.400: Definitions.

As used in sections 273.400 to 273.405, the following words mean:

(1) "Adopter" , a person who is legally competent to enter into a contract and who is adopting or buying a dog or cat from a releasing agency;

(2) "Adult animal" , any dog or cat that has reached the age of one hundred eighty days or six months or more;

(3) "Releasing agency" , an animal pound, shelter, humane organization, or animal control agency, whether public or private, but not including an individual who occasionally renders humane assistance or shelter in his* home to a dog or cat;

(4) "Sterilization" , the surgical removal of the reproductive organs of a dog or cat in order to render the animal unable to reproduce, or the use of an approved serum which will permanently render the animal unable to reproduce.