Many horse owners, and pretty much all owners of horses of any value, purchase insurance packages including medical and death benefit.
Many companies offer it. It's a free market. See Google equine insurance.
What was most interesting to me about the topic is that all of the medical insurance is Major Medical (which I believe to be the only sensible medical insurance to buy, but increasingly scarce) and it is quite inexpensive. Why inexpensive? Because it doesn't cover birth control, poison ivy, or the sniffles.
Here's one good little post on the topic.
I suppose one reason it is inexpensive is because you shoot a horse with a broken leg, which is thus an inexpensive and relatively quick procedure. However, surgery for colic can cost over $10,000. and is not reliably successful.
The NHS is well-known for letting the elderly ill pass away without care (no bullets or lethal injections yet), and Obamacare will do the same, in time.
I wish I could buy some of that inexpensive equine insurance for myself (minus the bullets unless absolutely necessary). I don't mind going to a vet instead of an MD.
Furthermore, I'd prefer a bullet or a bolt to drawn-out pain, misery, and incapacitation.