 In June 2019, Gillibrand and Arizona senator Martha McSally cosponsored the Horse Racing Integrity Act, a bill that would form a national standard for drug restrictions, testing, and enforcement at venues for horse racing that presently operated under both varied and conflicting regulations of their respective states and establish the U.S. Horseracing Anti-Doping and Medication Control Authority to enforce drug bans and rules.The bill was introduced in the aftermath of a spike in racehorse deaths at various tracks that had stirred controversy from animal rights groups.In March 2019, Gillibrand, along with senator Marco Rubio and Representatives Steve Cohen and Mark DeSaulnier, introduced the Stop Underrides Act.