Where to begin?
First we need to distinguish between footfall pattern, degree of collection, and simple style of movement.
The correct canter is three footfalls and a moment of suspension.
This footfall pattern pertains whether your horse has high knees or low knees, big steps or small steps. So a good daisy cutter hunter is doing a 3 best canter with a long low sweep of leg. As is a super collected dressage horse, or a jumper.
However the 3 beat canter can be broken up in several ways all of which English riders would consider wrong.
First Western Pleasure riders will deliberately slow the canter to a 4 best gait and worse. If you don’t know what I’m talking about go Google Western Pleasure.
Second the horse might be lame. There was a COTH thread recently about a horse with a stifle injury doing a bunny hop canter where the two hind legs landed at once. Very interesting, go look that up.
Finally a horse might have a broken footfall pattern because he is gaited. Again if you don’t know what gaited horses look like, lots of videos. A gaited horse will have the ability to one or more four beat gaits on the continuum between diagonal trot and lateral pace. This might be a foxtrot, amble, running walk, rack etc.
Standarbreds either trot or pace and are trained not to canter. They can have trouble learning a correct canter and can tend to throw in a lateral step.
Again go Google if this is new info to you. It’s just all readily available common knowledge.
Gaited horses in general can have a tendency towards a lateral canter. They can also have a tendency toward a broken trot.
But nongaited horses can also have impure gaits if they have tight backs or are weak. There is a whole set if YouTube videos on racking qusrtehorses which is fascinating but also wrong in so many ways.
A good coach will see the impurity in footfall in a nongaited horse and call in a lateralized trot or canter, and have ideas about fixing it.
And no, I can’t see any functioning dressage horse producing a lateral canter. Or indeed a lateral trot. Dressage training exists to fix this.
I imagine somewhere someone has a standardbred with the most gorgeous floaty trot in the world and wants to do dressage and is struggling with a lateral canter. And either they will get that fixed or they will quit after struggling for a few years and go trail riding :).
In other words this is not something that you will see in the dressage ring. Or indeed the hunters.
Anyhow it sounds like you are mixing up the question of footfall pattern with the question of style of canter. Maybr your eye isn’t developed enough to see the footfall problem. If you can play videos of canter in slo mo that might help.
