My own horse is not great about needles. Unfortunately, I bred him and have been his owner since birth. He’s just always been like that. He is also difficult about mane pulling and is VERY sensitive on stuff “touching” him. Like one time his dressage braid came unbuttoned and the braid was lightly scratching his neck. He threw himself at the walls trying to rub it out. I had to walk him and undo the braid as we walked. Or he overreacts to flies on his body. I think the skin/needle/mane pulling issues are all related.
Anyways, after watching one vet try to muscle him into submission I said screw it: let’s just twitch him every time. He gets cookies, we slip the twitch on, we wait until his eyes sort of glaze over with endorphins, stick him, undo the twitch, more cookies. He is actually MUCH better and I can give him IM shots on my own as a non-issue. However, knowing how he has been in the past I will never let my vets give him a shot without a twitch. I do not want them at risk and it’s my duty to make sure they are safe around my horse. It’s a non-event and twitching him is not a dramatic thing for him.
But again, it has gotten better!