Origins Some of America's wild horses carry genes from horses that belonged to early Spanish explorers. The settlers that followed conquistador Juan de Oñate y Salazar in 1598 had with them had 1,000 stallions and more than 375 mares and colts. Expeditions and homesteads failed and horses got loose and spread north into Texas, New Mexico and onto the Great Plains where tribes of Indians became adept horsemen. Over the centuries horses from Europe added to the mix as colonists brought their native breeds to America to work farms and provide transportation. Horses got loose from wagon trains, or ran off when their soldiers were killed. Many were stolen.
As the west began to settle, ranchers often considered themselves the owners of the horses that ran wild on land they used. It was a common practice to turn domestic horses loose to breed with the wild herds and produce strong off spring.
Uses Wild horses have been captured for many uses during the time they've roamed the American west. Thousands of wild horses were shipped to Europe to pull guns and carry soldiers during World War I. And in 1922 Ken-L-Ration was introduced as the new complete diet for dogs. The largest ingredient in the product was horse meat. When the company no longer found enough old horses to process, they turned to the wild horse herds. In the book Wild Horse Annie & the Last of the Mustangs (pg.53) the author tells us 50 million pounds of canned dog food were produced during 1933-34. An estimated thirty-thousand to thirty-five thousand wild horses were killed to feed dogs.
Grazing When the Taylor Grazing Act as passed in 1934, ranchers wanted the grass for cattle. Wild horses were cruelly rounded up with trucks and airplanes and literally dragged to slaughter. Groups that weren't captured were fenced away from water and food with thousands of miles of barbed wire. Other herds were run off cliffs or shot from airplanes. Captured animals were brutally treated.
Congress Helps Velma Johnson, aka Wild Horse Annie, spent much of her adult life trying to get legislation passed that would protect the wild horses.
In 1971 Congress passed the Wild and Free-roaming horses and burros act in which they declared "...wild free-roaming horses and burros are living symbols of the historic and pioneer spirit of the West; that they contribute to the diversity of life forms within the Nation and enrich the lives of the American people;..." Here is a link to the act https://www.govinfo.gov/content/pkg/STATUTE-85/pdf/STATUTE-85-Pg649.pdf
Numbers of Horses Today the Bureau of Land Management oversees 26.9 million acres of land used by wild horses. There are about 25,300 horses and burros on that land. Horses are continuously rounded up and sent to confinement because BLM says there are too many wild horses. The round-ups are grueling and cruel, and once captured the horses are not well treated. There are approximately 50,000 captured wild horses and burros in government holding pastures, and many people believe the BLM is trying to overwhelm the system so the horses can be slaughtered.
If you want to learn more For a horse lover, the wild horses are an emotionally charged issue. If you'd like to learn more, I recommend Laura Leigh's website, Wild Horse Education, https://wildhorseeducation.org