(Long) Aggressive Gelding - Best Long Term Solution?
I have a 4 year old paint cross gelding. I have owned him since May of 2012. He was mouthy when I first got him, which I took to be typical young horse behavior. I begun ground work and light riding with him, and worked on reprimanding the mouthiness and teaching respect on the ground. His mouthiness persisted, however, although he was calm and fairly agreable under saddle. For the entire month of December and January, I was riding him daily for short periods of time either in the indoor or outside, but his behavior deteriorated. He would try to run me over when I would get him in the indoor, and generally act up whenever I asked him to stop or back on the ground (throwing his head, trying to bolt). About 4 weeks ago, I asked him to stop and back by the mounting block, and he lashed out, aggressively, to bite my face. Luckily I was wearing a helmet, so he got that instead. I then proceeded to make him think I was crazy and going to kill him (deep angry voice, flailing my arms, chasing him off) and lunged him very hard for at least 20 or 30 minutes straight. He was very respectful when that session was done, and seemed to get the message completely. I was pretty shaken up by the experience, and was away on vacation for the week after that incident. A friend of mine, who is more experienced with young horses, rode him while I was gone, and he did the exact same thing to her again at the mounting block. He also reared and struck out at the barn managers head when being led in a few days ago.
Since he tried so aggressively to bite at the mounting block specifically, I thought maybe he may be in some sort of pain when he is mounted. I have scheduled a lameness exam for him for next week to see if maybe he is in pain. But, it seems to me that his behavior has been progressively getting worse the more training and riding he's had. I have been reluctant to work with him in the last few weeks as I am just emotionally drained from trying to deal with his aggression.
I do not have the money to put him into a professional full time training program, and honestly am not sure it is worth it to spend hundreds on this upcoming vet exam. I am considering having him put down humanely, as I would not let him go through the local auction to a slaughter house or someone who might starve/abuse or neglect him. I would not feel right trying to sell him cheaply or give him away when he is so dangerous to handle.
I would love some positive feedback from anyone who might have a suggestion. I know the concept of putting a horse down is awful in itself, and it is a last resort for me, but I want to do what is best for him in the long run. I do not want to risk myself, or others, getting hurt.
I'm not sure if this is the right section for this topic, if not I apologize.
Thank you for reading and for any help you can give!