When did they stop pitbull fights?

Answer 1

The law states:

Dogfighting is a felony in all 50 states, the District of Columbia, Guam, Puerto Rico and the Virgin Islands, and the interstate transportation of dogs for fighting purposes is prohibited by the federal Animal Welfare Act. All 50 states, the District of Columbia, Guam and the Virgin Islands prohibit the possession of dogs for fighting; and 48 states, the District of Columbia, Guam, Puerto Rico, and the Virgin Islands prohibit being a spectator at a dogfight.

These laws were enforce since the mid 1970s.