Problem with Mack, my dad's horse. 11yo Paint gelding, good trail horse, gentle, always been reactive and deals with stressful situations by rearing, but always manageable in the past. A humane twitch usually works wonders, and he freezes and lets you do whatever unpleasant thing (clipping, vaccination, etc.).
Last week the grazing muzzles went on, 'cause the whole herd is fat. And around that same time, Mack started freaking out. (Now, his nose is raw and sore from the muzzle, but it was not when the behavior change started, though I'm still wondering about the obvious time correlation....).
He snorts far more often than he should, both with and without the muzzle. He seems distressed, and stands off by himself, sometimes not grazing. Under saddle, he has started bad, violent head-tossing. I thought his loose tie-down might be the problem, but nope. I took off his normal snaffle bit and put a Little S hack on him, and that worked for one ride, and then he was right back to the head-flipping, something he hasn't done for years.
And you all of a sudden can't touch his face. He's always been a little on the headshy side, but never this violent. The vet came out to check him today, and he wouldn't let her get near him without rearing and striking--he's bad, but he's never THIS bad. I finally got some Dormosedan gel under his tongue, but it had no effect. Then I managed to get a shot of IM Xylazine in him, and again, that barely took the edge off, and he was still running backwards every time the vet approached. She had to give him two additional doses of IV Dormosedan, to the point where he was covered in hives and barely able to stay on his feet, before she could examine him.
She found nothing in his ears. His eyes seem normal. Same for his sinus. No nasal discharge, swelling, or foul odor. She did a thorough oral exam and again, nothing. In short, no physical cause for the sudden behavior shift.
I still want to place the blame on the muzzle, but I'm not sure that's it. I'm going to treat this like a training issue now, since he's regressed back to where he was when we bought him five years ago. If there isn't a physical problem, I'm pretty confident I can fix him again. But what if there is and we're overlooking it? Any thoughts? While neurological problems are a possibility, he has no other symptoms...