Mo. Rev. Stat. § 67.140: Ownership of domestic animals, no laws or regulations to prohibit.

No political subdivision of the state nor any local government, city or county, or any agency, authority, board, commission, department or officer thereof, shall enact any ordinance or promulgate or issue any regulation, rule, policy, guideline or proclamation describing the relationship between persons and domestic animals as other than persons may or can own domestic animals.