I recently bought a mare that came to me with the caution “she is REALLY bad about shots”. I warned my vet of this–and explained that I don’t actually know what “really bad” means in this case–and he has been working with her (and me) on it.
The first time we exposed her to a needle (for a blood draw), he put a chain on her upper gum and had me tug on it gently and repeatedly while he stuck her. This wasn’t popping the chain or pulling. I was using my thumb to sort of massage the chain at the corner of her mouth. He called it “talking to her” with the chain and she didn’t even flinch when he inserted the needle. This was out in a run-in shed.
For her spring shots, they sedated her (for dentistry) first, using the same method as above, but it did not go as well. She jerked her head and swung her body when she got stuck. Nothing horrible, but not something that I’d want to deal with every time as a vet. This was in a stall.
For her boosters, the vet had me bring her into the ring, put on the lip chain, and then he walked her away from me and the tech. He kept some gentle pressure on the chain and the shots were perfect. She didn’t even flinch. We decided that perhaps being confined was part of the issue, so the plan is to keep doing shots in the arena as we can.
Her previous owner talked about twitching her and having battles. I really think the calm method my vet is using is going to break her of the needle phobia within a year.
Something else to consider is your own injection giving technique if you are the one giving the Adequan. I had a gelding that was getting Dex shots for a while and I noticed that when I gave them, he flinched, but when the vet or the BO did, it was fine. I concluded that I was doing something wrong. 