Wiktionary
mustanging
n. (context US English) The hunting of mustangs (wild horses) either for military use or for slaughter as pet food
Usage examples of "mustanging".
Seems he'd left the horse-trading for mustanging, and then drifted west and found himself a ranch in the wildest kind of country.
We did the mustanging ourselves, or rather, Judith and her father and his brother did.