I've owned horses for years. I've met "kill buyers", bought from auctions, regularly visit the low end (meat) auction in my area, and do rehab work for neglected horses. I have seen much of this firsthand, and I'm in the trenches working to give at least some of these horses a second chance. The myth that horses going to slaughter are all old, sick, unsound, and useless is FALSE. The vast majority are neither old nor useless.
The argument for banning commercial slaughter in the US is not about what a dead carcass is used for. It's not against people eating meat. And it has nothing to do with a farmer putting a horse out of his misery.
Commercial horse slaughter in the United State is an entire process: from the time the horse leaves his last good him, to auction, to broker, to kill buyer, transport up to 1500+ miles, to feed lot for fattening up, to transport again, and then to the "kill room" inside the slaughterhouse. It can take literally months for a horse to go from point A to his final destination.
The trouble is that during those months the horses get absolutely no veterinary care whosoever. I encourage anyone who doubts this to check; it's hard to believe, but it's true. No pain management, no medicine, no protecting elderly horses from harassment by others in the same pen. Local law enforcement won't get involved once the horses are sold for "meat", so they refer the complaints to the USDA. The problem is that the USDA is not an animal welfare agency. The USDA's purpose is to protect the price of meat and to ensure only quality, safe meat leaves the plant headed for human consumption. In short, nobody can touch the kill buyers, feed lots, or packing plants.
Let's say you have a mare that is foundering. Instead of having her put down locally, you sell her because you were led to believe slaughter is a place horses who need to be put down should go. So you drop her off at a meat sale, where she stands around for a few hours and a broker gets her. She's loaded on a big trailer and hauled off to the broker's lot a few counties away. In a few days he gets around to sorting all his buys, and he realizes her stance isn't quite right. He doesn't call a vet. She stands there untreated. Laminitis/founder often will be a progressive, painful disease if the source of the laminitis isn't found. It results in a great deal of pain, and the horse stands in a bit of a parked-out stance.
The broker would know he couldn't try to sell the foundering mare as a riding horse, so he'd put her aside. When that pen gets full enough, he'd send a big shipment to a kill buyer. In the meantime, as laminitis progresses it gets harder for her to walk around without pain. Aggressive herd mates pick on her. She can't get near the hay piles. Finally a week goes by and there are enough in the pen to fill a truck.
A horse who doesn't load into a meat truck is "motivated" any way they have to. Since there are no animal cruelty laws against "meat" horses, these guys do what they need to in order to get her to step on. She doesn't budge even with a whip, so she may be hit by a 2x4. She finally shuffles on, and the remaining horses are loaded.
The distance from the local dealer's lot to a kill buyer may be 300-500 miles. A common route would be to drop off a horse at a place like New Holland auction in Lancaster county, the brokers are in neighboring counties, and one of the region's big kill buyers is in central New York state. So that's about 4-5 hours for a weak, suffering horse to try to keep their balance in an overheated, crowded trailer with others pushing and shoving against her.
She's unloaded reluctantly into a "kill pen", a special pen just for horses the big buyer has written off as "meat". She may be feeling unwell at this point. She might've gotten Strangles or rhino from all the other horses around, and with the stress of the trip, she's likely to get sick. When large amounts of discharge come from her nostrils and her temperature is over 103 nobody notices. She just stands there and waits. Could it get any worse?
Finally she'd reloaded into a tractor-trailer sized truck heading right for the final stop: the slaughterhouse lot. These are regulated by the USDA, but remember the USDA is not an animal protection agency. They exist to help farmers and protect meat price & quality.
From central New York to the nearest horse slaughterhouse (Illinois) would be a good 1,000 mile drive. That's right: all horses must be shipped cross-country to either Texas or Illinois if they're sold for use as meat. 1,000 miles is a 3-4 day drive if you keep moving. Horses are not unloaded, nor does anyone look in the trailer to care for them. In the summer that's 90+ degree days of constant moving in a trailer crowded hip to hip with warm equine bodies. Maybe by the time she arrives the worse of her nasal discharge has stopped. She's still exhausted, her foundering feet hurt her, and she may arrive "downed" in the trailer.
The USDA does not allow the meat companies to use "downed" horses for human consumption. It's in the killbuyer's best interest to get the horses unloaded as soon as possible, so there is no evidence of any "downers". They've been caught using things like electric cattle prods on horses. Keep them up and moving, and move them into corrals to graded. Then the killbuyer is paid by the pound, and the men rush back to their hometown lot to refill the truck for the next load.
Slaughter plants do not run "the line" every day, so she's left to stand again, waiting. It's been weeks now, and she hasn't gotten anything for the extreme pain her feet are in. She stands parked out, in the characteristic laminitic stance. Several days go by. She stands in the same spot because walking hurts too much now. Finally it's Monday morning and the slaughter plant comes to life. She's made to get in line in the chute leading to the kill room, again using motivational tools like a scrap of lumber. She shuffles into the kill room.
The final moments are when the captive-bolt gun, a mechanical cylinder of metal designed for cattle not horses, is held up to her head. In theory the fast release crushed the skull and destroys the brain stem. In reality, it's only being held up to her skull by someone's hand. If she flinches at just the wrong moment, they miss, puncturing her head but not rendering her unconscious. A second hit is sometimes needed (hard to believe it, but you can verify this yourself). Their aim is to get her down and "render her unconscious" when they hoist her up by a back leg to be bled out. The reality is if her heart is still beating, her brain is still getting oxygen. Who's to say she's not aware of these last gruesome moments?
One of the leading equine vet associations, the AVMA, actually feels the captive bolt is not an acceptable, humane way to destroy a horse (reference: their own web site). They state that chemical euthanasia (what your vet does) is preferable. If that is absolutely not possible, a skilled use of a firearm is their second choice.
And it's not until the horse is dead that the slaughterhouses scan for microchips. If your horse was stolen, even if you alert them, odds are they won't know until it's too late. They must scan to remove them so they don't taint the meat. There is no law, however, that requires they check for stolen horses before killing them. If these were cars, the auto salvage yard who tears apart care without regard to them being stolen is now a "chop shop" and in possession of stolen property. A horse slaughterhouse is not held responsible, and the most a horse owner can hope to do is prosecute the person who took the horse in the first place.
Interesting stats:
In California in 1998 they banned horse slaughter for human consumption. The rate of neglect or abandonment did not go up. The rate of theft went down significantly.
All three slaughterhouses are owned by foreign corporations creating a product Americans find distasteful.. The slaughter plants themselves are so unpleasant to be around, they harm the neighborhoods nearby. In Texas there have been repeated lawsuits to get one of the plants to close, but the wealthy corporate lawyers just keep filing appears. Texans don't want the plants, Americans don't want to eat horsemeat, and in every general public poll, the average American is against this system.
In short, the system is inhumane at every step of the way. It encourages neglect and theft. It doesn't benefit Americans. Owners can still put the horse down locally, and can still do what their wish with the carcass. We're just saying we've had enough to this whole long, unpleasant commercial killing process.