Long time lurker first time poster here looking for some ideas.
I have an odd case with my current horse and while I’m working very closely with my vet, I wanted to see if anyone had any creative ideas or out there anecdotes that might be worth pursuing.
I bought my 8yo TB in September last year. I went to see him and rode him myself. I also did a basic PPE with some radiographs (front feet & hocks) which he passed with flying colors.
The only concern was that this horse was VERY underweight, so as soon as I purchased him I dewormed him, did his teeth, and started to feed him more groceries. My vet watched his progress closely and he very quickly gained weight and better body condition. I was riding him lightly during this time (WTC) working on him using his body correctly and traveling forward and straight. I was also doing some stretches and core strengthening exercises with him from the ground as he was very stiff all over and kind of oddly muscled (pencil neck, REALLY defined glutes).
Body condition, stiffness, and overall symmetry improved. My vet was out every 4 weeks to reassess him, do chiro work, and was VERY happy with his weight gain and overall progress.
The one thing that started getting worse was his breathing and head shaking. When I tried him he did not head shake, cough, or blow at all. His previous owners swear he didn’t do this at all with them and they have plenty of videos of him going normally. After 1-2 weeks with me, I noticed he would cough/blow 2-5 times once we stepped into trot. Then it became more like 10 times. Then he would do some mild head flipping before he finished clearing. This is September - October and I personally have horrible fall allergies, so we opted to wait and see if this resolved itself.
November rolls around and it’s getting worse, so my vet had me try him on antihistamines (slowly ramping up the dosage). The first week he was coughing in his stall (new) but after that was only coughing/blowing under saddle, and the head shaking was getting progressively worse with less coughing/blowing, even as we upped the dosage.
During this time I am also doing other little trials with him - I had him on magnesium & Smartbreathe for 8 weeks with no change. I was adjusting his tack - different bits, different material bits, having the bit sit higher/lower in his mouth, Tight noseband, loose noseband. Anatomical bridle, normal bridle. Nose net. NOTHING made him improve (not even the nose net), but two things made him worse: he went NUTS when I tried to ride him in a (not too tight) flash noseband, which is interesting because when I tried him he was in a flash noseband and totally fine. He also panicked in a hackamore - walking backwards til I dismounted.
January rolls around and he’s unrideable. He starts flipping his head around as soon as I get on him. In trot, he’s shaking his head so violently he’s actually tripping up front. So I stop riding him and start trying to lunge him in both a bridle and halter. As soon as he picks up the trot the head shaking and flipping happens on the lunge too. If I turn him loose in my indoor, he will run around but will eventually start head flipping and coughing/snorting. It’s been two weeks since I’ve done anything with him for these reasons.
I had my vet out earlier this week and while he’s a bit stumped he’s taking it seriously. When I lunged my horse for the vet he decided to go straight up in the air, strike out, and tangle himself in the lunge line. A very extreme response to being asked to trot on a circle for 30 seconds.
The vet looked him over, checked in his mouth, and we x-rayed his head with no answers - all teeth look healthy, no fractures, no mucus build-up. I’m now waiting on (basic) bloodwork and will be scoping his throat sometime next week. If that yields nothing my vet suggested a dynamic scope to see what’s happening inside during work.
Any ideas or thoughts on where else to look?
For my horse’s basic setup if helpful - I’m in the northeast USA and he’s stalled overnight, turned out with a buddy in a good sized flat field with run in from sunrise to sunset. He has hay and water 24/7 and gets grain (TCS) 2x a day. Eats and drinks completely normally, pees and poops completely normally. Bright eyed and playful with his turnout buddy. Does not act sour in any way save for the head shaking - no girthiness or evasiveness tacking up/mounting. Not even tail swishing. He is a bit mouthy but beyond that he’s a really solid citizen to handle. The rear on the lunge line was completely out of character for him.