There is a reason why the horse has been (and should be) viewed differently than other types of livestock. The horse was a gift to man that allowed him to conquer, settle, and civilize the world. This would not have happened by now if not for the horse and we would all be living in much more primitive times. Just because man has outgrown the horse doesn't mean we should dismiss the importance of this fine beast. This is easy to forget when we hop into our shiny new Ford pickup and head down to the lumber yard. It is for this reason that horse meat will never touch my lips and I will wholeheartedly criticize any who views horsemeat as a tasty meal.
We own 3 Quarter horses, all of them fine animals. My wife shows the youngest horse and the other 2 are retired from showing and are used for pleasure and trail riding. First, I would say that I agree w/ CowboyDoc 100% that there are mean nasty horses that no one should own. Also, we have had a couple of very talented horses that we did not want because they were not particularly nice (somewhat mean). We did not judge then to be dangerous and made the effort in time and money to find a decent home for them with an experienced person that was willing to put up with their attitudes because they were otherwise fine show horses. Also, any animal that is suffering and can not be remedied in a reasonable manner should be put down. However, it is my belief that a responsible horse owner owes every good horse a good home when that animal gets older. If that animal has worked hard all his life he deserves that retirement pasture for as long as he is happy and healthy. Not being able to ride a horse anymore because he is old and worn out is NOT a good reason to send him off.
The problem as I see it is that there are too many people out there that have horses that shouldn’t. This is why (I would guess) that there are so many unwanted horses out there. While I believe that competition thru showing elevates the quality of a breed there are some negative aspects. I see way too many show brats out there that don’t have their own farm and can (or choose) only afford to have 1 or 2 show horses in board. If that horse isn’t winning enough of those blue ribbons, off with them and in with a new one, even though it may be a perfectly good horse. I have seen such people send perfectly good horses to the auction for a quick sale because they have already found the next one. And if it’s a slow night at the auction the packer surely gets them. These are the people who should not be allowed to have horses. Everyone owes a good horse that they own a chance at a good life.
As for what to do when a horses time comes. I would always choose to have my horse put down by the vet. No one is going to eat the fine beast that I cared for and enjoyed all these years. I know my vet wouldn't charge me anything close to $600 hundred dollars to do this. If there are vets out there that do charge this much, shame on them. They are part of the problem. I bury my horses on the farm and I defy anyone to come onto my property and tell me I can't do this.