Today, America's wild horses are still being rounded up and sent to slaughter.
Train-loads of horses arrived at slaughter plants as the Ken-L-Ration company bled the west dry of horses in its quest for even greater profits.
The town of Rockford, Illinois, witnessed what writer CuChullaine O'Reilly described as the most astonishing series of equestrian-related crimes perpetrated in early 20th-century America.
The company canned just under 150,000 pounds of horse meat in 1923. By 1933, it was putting nearly 30 million pounds of horse meat into cans each year.
In the 10 years from 1923, the company produced nearly 58 million cans of dog food.
When local horses dried up, the company turned to the wild horses of the western rangelands. When they, too, became scarce the company set up its own 1.6 million acre farm across Wyoming and Montana, where it farmed horses for their meat.
O'Reilly's account of the rise and fall of the Ken-L-Ration company includes the story of Frank Litts, a miner determined to stop the slaughter by targeting the company's prized Rockford plant - and he had the dynamite to do it.