Join an Organization!
Support an organization against horse slaughter, and help them in their campaigns. Even organize a protest! Remember, it's all for the horses.
At the very least...
Okay. So you've seen this website. Why don't you go and submit a pledge against horse slaughter? Because there's one right here on this site. Let's see how many pledges we get. The number of pledges will be posted on the pledge page, which you are currently clicking on and filling out.