I have a 6 year old Warmblood X Arab on full loan, who was left in the field until he was 4 and broken in when he was 5. He's been in light work since he was broken in, 20 mins of schooling, a few times a week and 10 minute hacking every now and again. Since I have had him, which has been about one month now, we have discovered he has a back issue. When he first came, there was no problem, schooling beautifully. I then had a lesson of around half an hour, and he started threatning to rear up. He is one of the sweetest horses, and it was not like him to act in this way. We gave him a few days off after this, and have since then been long reining him for around 20-30 mins nearly every day, and occasionally trying to ride him, but no luck, as he now completely refuses to move forward and still threatens to rear. He was quite sore touch and looked very much so in discomfort, and tried to bite you when you touched his withers or the area were the back of the saddle sits. We have purchased a new saddle which has made no difference, he's been on bute, which did relieve the pain slightly but we feel this wasn't a very productive way of keeping him rideable, a physio has also been out to see him, and said he was sore, but nothing major and to carry on long reining. We have, but there is still no change, we are running out of options and I fear we may have to give him back. I have become very attatched to him and he has so much potential in dressage or show jumping, I really don't want to part with him.
Is there anything else I can try that may be affective? Thank you.