Zebras are far more aggressive and unpredictable than horses.
-Zebras bite hard and latch on, and their powerful kicks can break a lion's jaw or kill a person. Zebras, unlike horses, will not accept a dominant leader. Zebras do not share the same nature that easily bends to human training.
Zebras like to have a leader to follow.
Zebras are generally larger than horses and built for carrying heavy loads.