Bud Murphy is one of those elusive authors about whom I’ve been able to find out little. I have only been able to find one book written by the author under this name, the horse book Wild Stallion.
Finding the book: easy to find in the USA; it was not published in the UK.
Links and sources
Many thanks to Lisa Catz for the photograph and summary.
Bibliography - horse books only
Wild Stallion World Publishing Company, 1952, 172 pp, illus William Moyers
Everyone had heard of the big palomino stallion, but few had seen him, and no one had ever captured him. When a wealthy Easterner buys a ranch and hires a crew to catch the stallion at any cost, he becomes the laughing stock of the nearby ranchers. Foreman Red Saunders is one of the few who has met the stallion. Red and the stallion finally face off again in an exciting climax.