Gee Marjorie, I hate to deflate your bubble but the law was that it was illegal to slaughter horses in Oklahoma for commercial use since there were no USDA inspectors for horse slaughter. Since it wasn’t USDA inspected you couldn’t peddle ol’ Dobbin to the corner grocery store or even to the local dog food factory ruining the old joke “if I wanted to get on a horse I’d stand on a can of Alpo.”
On the other hand if Dobbin has outlived his usefulness and been replaced by an ATV, the owner can do his own slaughter, butchering, and eating. Of course your needle method wouldn’t work, after all who wants to eat something you just poisoned? Additionally your needle method costs about $60 as opposed to a $.57 bullet.
As to worrying about an overseas child eating horse, in the 1970’s horse meat stores were all over California due to the government buying out the dairy cattle to keep up the price of dairy products and wiping out the largest source of beef on the west coast. Of course the problem was that horse makes lousy burgers because the patties break up and fall through the grill unless you add additional fat to it or shredded cheese works, too.
While old horses may end up as whinny burger, the sick ones will end up in the carcass dump. If USDA is inspecting things horse will be handled like beef.