Effective immediately, there will be a pause on incentives such as trainer start bonuses and purse pay-out allocations to every race finisher through last place. Purse pay-outs will now be limited to the top five finishers.
Churchill Downs also announced ineligibility standards for poor performance, meaning horses that are beaten by more than 12 lengths in five consecutive starts will be ineligible to race at the track until cleared by the equine medical director.
In addition, the number of starts per horse during a rolling eight-week period will be restricted to four.
The changes were announced two days after an emergency summit called by the Horseracing Integrity and Safety Authority (HISA) was held in Kentucky.
At the summit, the Churchill Downs, Kentucky Horse Racing Commission and HISA veterinary teams reviewed all veterinary information available in the hope of better understanding the events surrounding the recent fatalities.
HISA welcomed the efforts announced by Churchill Downs and is implementing additional measures, including post-entry screening of previous pre-race inspection findings of entered horses to identify ones that may be at greater risk of injury.
HISA also said an analysis of Churchill Downs' racing and training surfaces by a seasoned track superintendent is ongoing and conclusions will be shared once the review is complete.
"HISA continues to urgently seek additional answers to more clearly identify the causes of these recent fatalities as well as tangible interventions to prevent them in the future," HISA said in a statement.
"All options remain on the table, and HISA will continue to vigilantly monitor events at Churchill Downs moving forward."
Since the Churchill Downs stable reopened for training on March 30, there have been 12 equine fatalities at Churchill Downs, which the racetrack previously described as a "highly unusual statistic."
While this year's Kentucky Derby, which is the first leg of US thoroughbred racing's Triple Crown, went ahead as planned last month it was overshadowed by horse deaths at the track and multiple others were scratched from the race due to injury.
