However, it's important to note:
* Sustained speed: While they can reach that speed, they can't maintain it for long distances.
* Individual variation: The actual speed a Mustang can achieve depends on factors like age, training, and individual fitness.
* Environmental factors: Terrain, weather, and load can all affect a horse's speed.
So, while a Mustang *can* reach 45 mph, it's not their typical cruising speed.