Sens. Bob Menendez (D-NJ), Lindsey Graham (R-SC)., Sheldon Whitehouse, (D-RI), and Susan Collins, (R-Maine), introduced the bill

Tens of thousands of American horses are shipped each year to Canada and Mexico to be slaughtered for human consumption. This being a practice that 80% of American voters oppose. 

Horses in the US are not raised for food and receive a wide range of medications that are prohibited for use in meat products. 

How is there a problem of horses and burros being butchered for human consumption? 

It persists because “kill-buyers” can legally purchase horses at auctions or from unsuspecting owners to then ship them to slaughterhouses abroad.