Are Horses Still Sent to the Glue Factory?

Last updated: November 3, 2026

By: Miles HenryFact Checked

Spend enough time around horses, and you’ll hear somebody say an old horse is headed for the glue factory. It’s one of those barn sayings everybody knows, but most people aren’t sure whether it was ever true. So is glue made from horses, then or now?

Here’s how horses got into the glue business, what the records do and don’t show about how much glue one horse produced, and whether horses are still used to make glue today.

How Horses Ended Up in Glue

Animal glue is made by boiling down collagen, the protein in skin, bone, tendons, and other connective tissue. People have made it for thousands of years, and it was the main woodworking glue until synthetic glues came along in the 20th century. Horses were one source, but so were cattle, pigs, sheep, deer, rabbits, and fish. A 1913 trade manual, The Glue Book, lists glue stock from “cattle, sheep, deer, horses, and other animals.”

Horses ended up in glue because of what happened to them when their working lives were over. In cities that ran on horsepower, they went to the knacker. In 1893, William John Gordon wrote in The Horse-World of London that about 26,000 horses a year went through London’s knackers. A knacker was the man who bought and broke down dead and worn-out horses, and Gordon wrote that the skin and hoofs went to “the glue-makers and blue-makers,” while the bones, meat, and fat went to other trades.

So glue was one product among many, and horse glue wasn’t anything special. Slate notes that pigs and cattle were the more common sources, and horse glue wasn’t any stronger than glue from other animals.

How Much Glue Can You Get From One Horse?

This is one of the most common questions about horse glue, and I couldn’t verify a reliable figure tied to a historical record or a glue maker’s data. You’ll see numbers floating around online, but a figure in pounds needs to say which parts were processed and whether it measured dry glue or glue mixed with water.

Glue came from collagen-rich parts like the hide, bones, and connective tissue, not the whole horse, so a horse’s body weight won’t tell you much. The yield depended on the size and condition of the horse, which parts went to the glue works, and how the stock was cooked. Hooves get mentioned a lot in the glue factory story, and Gordon’s account lists them among the materials sold to glue-makers. But they’re mostly keratin rather than collagen, and in his account of visiting Milligan & Higgins, woodworking writer Bob Flexner notes the factory didn’t use hooves or horns.

Is Glue Made From Horses Today?

Not the glue you’re likely to buy. Most of what’s on the shelf is synthetic, made from polymers like polyvinyl acetate (PVA), epoxy, cyanoacrylate (super glue), and polyurethane.

Elmer’s is a good example. That bull on the bottle still fools a lot of people, and it comes from Borden, the dairy company behind Elsie the Cow. Borden’s early glue was even made from casein, a milk protein. Elmer’s Glue-All today is a synthetic PVA adhesive, not traditional animal hide glue.

Animal glue is still made, just on a much smaller scale. Hide glue is used in violin and guitar making, piano repair, pipe organs, and antique furniture restoration, because hide glue joints are reversible with moisture and can be repaired and reglued. The raw material for hide glue is mostly cattle skins from tanneries, according to furniture conservator Norbert Gutowski. In a 2016 Popular Woodworking piece, Bob Flexner described visiting Milligan & Higgins in Johnstown, New York, in the 1990s, where the hide glue was made from cowhide trimmings from a tannery. Rabbit-skin glue and fish glue are made for artists and specialty work, too. Gelatin, a close cousin of hide glue, mostly comes from pork skins, pork and cattle bones, and cattle hides, not horses.

Do Horses Still Go to Glue Factories?

The U.S. hasn’t had a horse slaughter plant since 2007, when court rulings upholding state bans closed the last plants in Texas and Illinois, according to a Congressional Research Service report. That didn’t end slaughter for American horses. The Animal Welfare Institute counts 25,128 U.S. horses exported to Mexico and Canada for slaughter in 2025. Those figures concern the horse-meat trade, and they don’t show that those horses were used to make glue.

Hide Glue vs. Modern Glue

Here’s how the old-style animal glue stacks up against the synthetic glue most people use now:

Why the Glue Factory Saying Stuck

The saying stuck around long after the practice faded because it was true for a long time, and because it’s a vivid way to say something has outlived its usefulness. The idea also appears in George Orwell’s Animal Farm, where Boxer, the hard-working cart horse, is hauled away in a van marked “Horse Slaughterer and Glue Boiler.”

Around the barn, it’s mostly a joke now. But it hits home for people who love horses, because it’s a reminder that horses were once treated as equipment, used up and sold for parts.

So the glue factory was real, but it’s largely history. The glue in your toolbox is almost certainly synthetic, and modern hide glue is generally made from cattle rather than horses.

Miles Henry

About Miles Henry

Racehorse Owner & Author | 30+ Years in Thoroughbred Racing

Miles Henry (legal name: William Bradley) is a professional horseman based in Folsom, Louisiana. He holds Louisiana Racing License #67012 and has spent over three decades managing Thoroughbreds at premier tracks including Fair Grounds, Delta Downs, and Evangeline Downs.
Expertise & Hands-On Experience: Beyond the track, Miles has decades of experience in specialized equine care, covering everything from hoof health and nutrition to training protocols for Quarter Horses, Friesians, and Paints. Every guide on Horse Racing Sense is rooted in this “boots-on-the-ground” perspective.
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