Many Americans probably have no idea that over 100,000 U.S. horses are sent to other countries each year just to be slaughtered.

And last year, many of the over 30,000 U.S. horses trucked to Canadian slaughterhouses suffered inhumane conditions as they were sold at auction and transported, a new report found.

Auction horse with broken front legA horse with a broken front leg in a holding pen at auctionAnimals' Angels

Ever since the last horse slaughterhouses here in the U.S. closed in 2007, unwanted horses have been transported long distances to meet their sad end.

Much of the horse meat is exported to the European Union (EU) for consumption. But in 2015, the EU banned the import of horse meat from Mexico because sick horses, or horses with dangerous drugs in their systems, were being slaughtered and it was almost impossible to trace whether the meat would be safe for consumption by people. Now, advocates are pushing for a full-fledged ban, citing what the latest investigation of horses sent to slaughter in Canada has revealed.

Crowded pens where unwanted horses are kept before being sent to slaughterAnimals' Angels

Maryland-based advocacy group Animals' Angels (AA) has spent the last two years investigating the horse slaughter pipeline to Canada. The group found blind, sick, emaciated and disabled horses with sores and infections packed into trucks, which drove them for up to 20 hours to their final destinations. Some were discovered dead on arrival.

Slaughter-bound horses being loaded onto truckHorses bound for slaughter being loaded onto transport truckAnimals' Angels

Through firsthand observation of livestock auctions and transport trucks, as well as information obtained from the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (USDA-APHIS), AA concluded that inhumane and illegal treatment of horses bound for slaughter in Canada is rampant.

Emaciated horse being sold for slaughterAn emaciated horse being sold for slaughterAnimals' Angels

At the U.S. auctions where horses are sold to "kill buyers," people who buy horses at low prices to send them to Canada for slaughter, investigators found that the horses were cruelly handled and packed into dirty pens.

After horses were purchased, investigators found that almost every single kill buyer "demonstrated a complete lack of concern for the well-being and the welfare" of horses in their care. "Horses are routinely kept in overcrowded, filthy conditions without shelter. Access to necessary veterinary care ... is virtually nonexistent and wounded or ill horses are often left to die alone."

Horse with eye infection at auctionUnwanted horse with severe eye infection being sold at auctionAnimals' Angels

AA, along with a coalition of European animal welfare groups, supplied its findings to the EU Commission in hopes that it would issue a full ban on horse meat imports from Canada.

"In the field, we continue to witness the inherent cruelty of the horse slaughter trade," a release from AA stated. "The complete indifference to the suffering of the animals is shocking."

Horse biting another in crowded penStressed horses in crowded pens sometimes turn on each otherAnimals' Angels

But there are several ways people can help these horses, especially now. In January, the Safeguard American Food Exports (SAFE) Act (H.R. 113), a bill aiming to stop horse slaughter, was introduced to Congress.

"We encourage everyone to contact their representatives and urge them to support the SAFE Act," Sonja Meadows, director of AA, told The Dodo. "We believe that raising awareness is the key to promoting the long-term, positive changes our horses need."

Valerie Pringle, equine protection specialist with The Humane Society of the United States (HSUS), added that people can have a real impact in protecting America's horses by supporting legislation that seeks to protect horses against the horse meat industry, and by making the right decisions when getting a horse.

Unwanted horses and foals without shelterUnwanted horses and foals without shelter in frigid temperaturesAnimals' Angels

"The overpopulation of American horses needs to be addressed by the horse industry; [it] should focus on eliminating overbreeding and expanding and supporting adoption and horse rescues," Pringle told The Dodo. "Horse owners who can no longer keep their horse have many other options, and the HSUS has resources to help them find a humane option."

She added that people interested in owning a horse "should adopt from a reputable horse rescue, whose horses deserve a second chance." Pringle's own horse, Braveheart, was saved when Pringle adopted him from an auction house. "I could not be happier with him!" she said.

Braveheart was bound for auction when Valerie Pringle saved his life by adopting himValerie Pringle

To help pass the SAFE Act, you can contact your representatives and tell them to support the bill. You can also urge the EU to stop horse meat imports. To help Animals' Angels continue these important investigations, you can make a donation.