Ezra_Pandora is having a bit of a problem with her mare loping to the left. Horses having problems traveling one direction or the other is a very common problem. While it is relatively easy for a horse to travel either direction when they are loose, problems very often arise once they are under saddle.
We often assume that all horses are ambidextrous. When loose, we see them travel any direction they please with little trouble, barring injury or severe misalignment. In reality, about 80% of the saddle horses out there are actually left-handed. Why? Because that is the side that we handle them on the most. We catch and halter and lead and saddle and bridle and mount, all from the left side.
So in Ezra's case, it is a bit strange that her mare gets overwhelmed loping to the left. The first thought in most everyone's mind is a chiropractic adjustment. Ezra said she has had one done previously and that it had helped a bit. Another one wouldn't hurt, but the mare will never stay correct if she isn't also conditioned to carry herself properly. So while Ezra is waiting for the ever elusive chiro to show up, there are things she can be working on to build her mare's lateral strength.
If it were me in Ezra's place this is what I would do...
1) Turn the mare loose into a large area. If she wants to buck and play at first, I would just watch her. What are you watching for? I always watch which direction they go. If they are standing there and take off bucking and playing, do they always seem to go one direction? Do they pick up both leads easily? Do they seem to avoid turning or running in one direction or the other? A chiropractor once told me that a horse that is out in the hips will still buck and play-they just protect the misalignment by avoiding picking up one lead or the other and spend more time going one direction or the other. He said that horses that are out in their necks are not as likely to buck and play. I doubt there is any scientific evidence to his statements, just his observations.
2) When the high is off your pony, you can start moving them around the arena. It isn't about controlling their gait, but watching for the transitions. If you chouse her to the right, how does she move out? Does she transition easily into the lope? Pick up the correct lead? Can she maintain it for more than a few strides? Now move her to the left. Does she act the same or are there differences? If she picks up the left lead easily and can maintain control in that direction relatively easily, it may not be so much about a chiropractic adjustment as it is about a training issue. If she does not want to pick up the left lead or picks it up and either charges off or drops it and picks up the right lead to keep moving forward, she still may or may not actually need a chiropractor, but an adjustment wouldn't hurt.
3) Now, if I have the opportunity, I will take the horse to a round pen. This is a much better place to ask for controlled transitions. Again, I will send the horse the good direction first. What I really want to see is how he picks up his lead. I pay very little attention to anything but how the horse is moving. How does he move his head when asked to transition into a lope? Does it seem like a natural lift to help the transition or are they jerky or holding their head and neck cocked? How easily does he pick up his lead? Does he just lift and lope off or does he struggle? Once I have seen a couple of transitions up and down that direction, I reverse them and send them the other way. Again I ask for a few transitions, but this time let them lope a bit. Can they pick up the lead easily? Can they maintain a lope? Do you see any of the symptoms that happen when you are riding?
All of this work and observing should make it pretty easy to see if your horse is having trouble for physical reasons or if it is mostly a training issue. If your horse is lazy, you are going to have to get after them with a rope or buggy whip. Lazy horses are harder to read than hot horses. Because you have to get after them to keep them moving. They have a tendency to get pissy and it's hard to decide if that pissyness is from being lazy or from pain. The only thing I can tell you, is to just get after them and make them move out. If it truly is pain, you will start to see actual signs-dragging toes, short strides, a bobbing head or one carried as if they were bracing or a hip that might look higher or lower than the other one. Try to ignore the pinned ears and the crabby looks and look for true signs of discomfort.
If a round pen is not available, you can substitute using a longe line. Still the main goal is to see if you can see any physical reason why the horse wouldn't want to travel in a certain direction or gets panicky when they do.
Okay...all that time spent observing how your horse moves and hopefully you have been able to notice any problems your horse may have moving under his own power. If after all that and you say you can't see anything that might be causing the issue under saddle, then the chances are the problem isn't going to be fixed by a chiropractor. The only other physical problem that might cause a horse to have more difficulty moving one direction than another is a dental issue.
Next comes the riding part...to avoid turning this into a book, I'll get to that tomorrow.