After this weekend's Kentucky Derby, a horse by the name of Eight Belles had to be put after she collapsed on Saturday.

Now the People for Ethical Treatment of Animals (PETA) is calling for a change in how race horses are treated.

In a letter to the Kentucky Horse Racing Authority (KHRA), PETA president Ingrid Newkirk urged regulations that were described as a "bare minimum for horse safety:"

-Thoroughbreds under the age of 3 should not be permitted to race.

-Synthetic surfaces or turf — which result in fewer injuries — should be mandated at all race courses.

-Whipping should be banned.

PETA representatives plan to protest at the Kentucky Horse Racing Authority's Lexington, Ky., headquarters on Tuesday.