Star Horse by Jane Smiley

Gee Whiz is a striking horse, and only part of that is because of his size. He is tall, but also graceful. He keeps his eye on things, not as if he's suspicious, but as if he's curious.

Abby is curious, too, about just how little of the world she has seen compared to those around her. Her brother receives a draft notice to Vietnam, her best friends return from their boarding school, and the wise, lovable Brother Abner opens her eyes with tales of his many years spent traveling. Then, her beloved horses Jack and True Blue are both offered opportunities to broaden their horizons away from the ranch.

Will she let them go, with hopes that she might one day do the same?

A perfect books for horse lovers approx aged 8-12