I hope no one minds a thread venturing into the political realm, but If anyone is so inclined...
HR 113, the Safeguard American Food Exports Act of 2017, was introduced in the House of Representatives earlier this year. (It has bipartisan support and has been referred to committee.) It would deem equine parts unsafe for human consumption and would ban the sale and/or transport of equines destined for the slaughterhouses in Mexico or Canada.
If so inspired, you can write your Representative and encourage them to support the bill and to consider becoming a co-sponsor if they aren't already.