I'm sure it's great for horses, but it's also used to safely & successfully treat a snake for intestinal worms that they may have contracted from their prey items. Yes, really!
Obviously the small dosage must be suitable for the size of the snake, and it's given orally either by tube-feeding it, or for a milder effect, by hiding it in their dead prey. I used to rescue rattlesnakes, and one time I noticed that my "houseguest" was digesting his food WAY too fast! Like in a day, day & a half...thanks to all the worms he was harboring! No wonder he was so thin! Since the only safe way to help him was by dosing his food, it took about 3 meals with Panacur to fix him up...lucky snake to come to my house! I keep only harmless snakes now, but I still admire them all!