His horse stumbled on the loose rock and he went down.
The horse stumbled beneath him and he almost fell from the saddle.
The whip's horse had stumbled, and the whip was out of the running.
Then one tall rider's horse put a foot wrong and stumbled.
We filed through the pass in a long line, our tired horses stumbling.
A horse screamed and stumbled, dragging the others down with it.
As the black rider turned to go, his horse stumbled over Gomez's body.
When his horse stumbled, other horses fell, and there was a general massacre.
He was leaning back to say this when the horse caught its foot in a hole and stumbled.
A horse could stumble over a root, break a leg on a stone.