This does not answer your question but -

I used to raise fat hogs on a small scale - maximum 60 head divided into four pens ranging in size from 40 lbs up to 220 lbs. Concrete pen floors. Each pen had a post standing by itself away from the pen fences. The hog catcher that I had was simply a 1/2" pipe about 3' long with a small diameter cable attached at one end and the length of cable running through the pipe, forming a loop at one end. Homemade. The loop was slipped over the pig's snout and tightened. The pig went into rapid reverse and I would steer him toward the post with him going on one side and me on the other side of the post. One of my legs over his back had him trapped. It was rare for a pig to run forward, but if he did it was easy to circle him around to the post. Without the post it would be an exercise in frustration. This catch method was not used on every hog in the pen. An occasional abscess that needed lanced, or a wound that needed treatment. I was young then. I wouldn't be man enough to do it at my present age.

Years ago our little town had Saturday livestock sales. Livestock cars were waiting on the railroad siding, and winning bidders would load the purchased animals on the rail cars for shipment to the slaughterhouses in and near St. Louis. It was not uncommon to see a farmer heading for town early on a Saturday morning, switch in hand, walking behind a fat sow with a rope tied to one hind leg. The switch made her go and he steered her with the rope.