What can this be a sign of? He's not lame, no swelling or heat. It started with one hind leg, and now he's doing it on the other too. Hooves are flat on the ground. He can stand normally with the pastern at the correct angle, but most times he will just move them to vertical.
He just had an adjustment and acupuncture a month ago and he was very locked in his right hip. His right fetlock will sometimes almost knuckle over. It doesn't seem like a stifle issue and he doesn't feel lame or off when being ridden in straight lines or circles.
He's a 26 yr. old Arab and built a bit downhill. Maybe his back still bothers him and he's raising his hind end (instead of putting his front end on lower ground)? I'm not sure a vet will really find anything and if I'm going to waste my money I'd rather just have another adjustment (chiro is a vet that only does chiro/acu--Carol Edwards). Everyone tells me that he's old and if it's not bothering him don't worry, but it is unusual and he must be doing it for some reason. Any ideas? Oh, he's been barefoot for many years and trimmed by a KC LaPierre trimmer, if that means anything. And on Recovery EQ for an old hind suspensory injury that he seems to have fully recovered from (left hind high suspensory).
Possibly, suspensory desmitis. It's a failure to properly lay down collagen, and is common in certain breeds. I've got an older Irish/QH cross who's got it in front, but wear and tear is a factor also with him. Common behind in brood mares. I think they can diagnose with ultrasound and/or biopsy. I've found MSM in liberal doses holds the line with my guy! He has no apparent discomfort, is pasture sound and hacks out lightly w/t.
My recently deceased (35 y.o.) Morab did the same thing, but he was much older than your horse when it started so I just thought it was arthritis setting in. He never did appear really lame from it but moved very stiffly all over. He could still canter in at feeding times.
Wow, a few replies a year later! My horse has started Pentosan so his joints must be feeling better now but still he does the hind fetlock thing. Sometimes they're normal, sometimes not, and most times are normal after being ridden. I thought it was an upright form of DSLD, Longneck threadworms, you name it. Vet said she could inject tetracycline (like they do for contracted tendons in foals) so I asked how often she's done this with older horses--sounded as if she hadn't done it before and I don't want my horse to be a guinea pig.
She suggested the Pentosan in case it was due to joint discomfort so he's doing better in that regard. I've considered MSM just because it's good for so many things even though it's not recommended for Cushings horses; right now he's only getting the supplement Source. (Those Pentosan shots make his supplement list so much simpler!)
So, people have mentioned DSLD here, even though the horse's fetlocks are knuckling forward, not sinking. I've read that there can be an upright form of DSLD, but I'm frustrated because I've read about it from one source. Try as I may, I can't find more than one sentence and one photograph (both from the same source) alluding to an upright form of DSLD in horses. I started a thread asking about an upright form of DSLD - how common is it, what's the progression, etc.. - and posters referred me to that one sentence and that one photograph. Is there really an "upright presentation"? How does it progress? Do they become more and more upright and eventually knuckle forward at all times? Do they reach a certain point of "uprightness" and then drop? How can so many people think that a horse that knuckles forward in the hind fetlocks without lameness has DSLD/ESPA when no one seems to know anything about an upright presentation??
I was one of the posters who referred you to that one photo. I also belong to the Yahoo DSLD/ ESPA group and there seems to be very few members with upright horses. As I said before, there are a lot of other symptoms listed on that website and my horse shows no signs of them.
http://www.angelfire.com/bc/curlygait/diagnose.html My horse's fetlocks look worse than those of the chestnut horse's next to "or may be upright with no sign of dropped fetlocks" and, when they're looking bad, can look like the photo next to "fetlock knuckling over".
If our horses had DSLD/ESPA, I think we would have noticed some of the unusual symptoms that go along with it.
The good news is that the herbal protocol that is recommended does seem to help a lot of those horses.