On a working ranch everything has a purpose.
If it ceases to fulfill it's purpose, you get rid of it.
You might not eat it, but it will be gone.
You can't stay in business with a bunch of pets.
If I ever get another dog I'm not going to name it.
Just "dog", like John Wayne called his.
It was only a movie with dialog written by some screenwriter from New York City and who had never been on a horse in his life.
I have worked on cattle ranches, and good horses, that have worked well are retired, not sold to the killers. They are rarely, if ever, sold by a well run outfit. That fact, in itself, should tell you something. The old horse teaches the next generation to ride and is usually shot by its owner at the end of its days and the carcass buried on the ranch or in the mountains.