I'm not sure, about this...I think that she might have done quite a bit though....because, don't quote me...but she did hurt her back, while doing this movie...that lead to her later back problems...and put her on prescription drugs....which she kind of abused....
so....
susan
She is clearly riding in many of the scenes. I especially like the scene where she leaps on Miss Ada bareback and wheels her out of the yard with only a halter.
If you look at the rider in the red jumper in the middle of the movie when they are training the Pie to jump various types of fences, it is not Elizabeth Taylor. Look closely at the face and the thickness of the rider's body. Monty Roberts claimed that he did some of the stunt riding in this movie, but I don't know in which scenes.
The scenes of the actual race riding are not of Elizabeth Taylor, but she is riding the horse in the part when the horse is galloping "alongside" the train (looks like rear projection). She was a good rider, but I don't think the studio execs let her do the more obviously dangerous jumps.