Buck Buchanan 
Denni-Jo and Pinto [PDF ebook] 

A seven-year-old ranch girl (she’s almost eight!) wakes up to a beautiful day for an adventure, and gets permission from her mom to ride her pony Pinto solo across the ranch to visit her grandparents. She has exciting experiences along the way, including a rattlesnake scare and a runaway bunny, and she saves a calf stuck in a mud hole using her training in roping on horseback. She successfully leads the calf and its momma cow to her grandparents’ corral.