I'm not financially stable enough to own a horse. But I ride two. One of them is an Andalusian named Rowan who has suffered from EPM for quite a while. It wasn't caught early, and he's had lasting problems for several years. I'm not an expert on his condition, but the gist is that's an attack on the central nervous system that causes all kinds of lovely problems, most notably in Rowan's case, a loss of coordination and extremely unpredictable lameness/stiffness. He had to be worked so that his muscles wouldn't "lock up" and that's where I came in to things.
Recently, he spooked and fell backward so severely that he essentially landed on his butt. His owner was flung clean off (a rare thing, she's very skilled). I was asked to keep riding him, but he started to lock up, and a vet was called to take a look at him: his back was super sensitive and he could not be ridden. A second visit confirmed that his condition has progressed to the point that he can't really "feel" anything behind his shoulders, and he's unable to catch himself if he starts to fall. The vet out and said that it's not just that he can't be ridden anymore: he could quite literally topple over at any time, and is dangerous to handle in general.
With this, and the fact that Rowan is a proud horse who pines if he is not ridden and handled, his owner has made the decision to put him down while he is still in good spirits and before he begins to suffer (she imagines that the winter conditions in this area would lead to bad falls for him, and a frozen ground that would prevent an at-home burial).
It's very hard to put a sick horse down. It's harder to put down a horse whose illness you cannot truly see, and who seems happy, until he loses control of his own limbs.
I knew him for about a year and a half and I will really miss him. It hasn't sunk in that tonight was the last night I'd ever see him. Please pray or think kind thoughts for his owner, who loves him and has agonized over this decision for some time.
I am scratching post.