Molly's "handedness"

I needed to update this entry, as I have learned a lot more on this issue.

There are some discrepancies on the terminology and also on the effect handedness has on the horse's hooves.

Most horses prefer one side over the other. They bend easier to one side, they have an easier time to pick up the canter on the correct lead. Many horses also have an obvious asymmetry in their front hooves. One hoof is often bigger and has a more shallow dorsal wall angle while the other is often more upright. The bigger, more shallow front hoof is considered the "dominant" hoof. If this hoof is on the left side, the horse is said to be "left-side dominant" and if it is the right side, the horse is said to be "right-side dominant". Often times, a left side dominant horse will have its mane laying on the right side of the neck, it will sleep more often on the right side of its body and when grazing, it will place the dominant left hoof more often forward of the non-dominant front hoof. Because of this handedness (also called "side dominance") the dominant side usually has better developed muscles in the shoulder area.

Every single one of the observations listed in the paragraph above indicates that Molly is a left side dominant horse. Inspection of the picture below shows that Mollys FR hoof is more upright. When Molly stands on concrete, the difference is not actually this big, but since in the picture she stands on sand she can adjust her heel height herself and this is then how she comes up with such differently steep hooves.

It is also quite easy to see that Molly's pastern bone is much bigger on the left foot. I measured the circumference and it is about 1 cm bigger on the left than on the right. This is a strong indication that the left foot is her dominant one, meaning it receives more load and thus, during growth of the foal the bones lay down more material.

So far we were only concerened with the front feet. So what about the hinds?

There is one more observation with respect to a horse's handedness and this is the fact that the legs (both front and hind) on one side of the horse track more towards the outside of the body while the legs on the other side of the body track more towards the horse's midline. The dominant front tracks more towards the outside of the body, so this would suggest that the hind that tracks towards the outside is also the dominant one. I.e. a left side dominant horse has a dominant front AND hind left hoof.

However, there is some discussion about which hind leg is the dominant one.

David Farmillo writes:
"This same difference is also applicable to the hinds and will be diagonally opposite to the fronts."

Ute Miethe, on the other hand, observes that the dominant hind is on the same side as the dominant front and finds that left sided horses prefer the right-side canter, where they can use the dominant left hind leg for canter departures.

A swiss farrier (Eric Perreaux) wrote an article on asymmetric feet. I found it a couple of years ago on the web but it since has disappeared (but I still have the pdf). In this article, the farrier had kept records on 400 horses and draws interesting conclusions, that suggest that the handedness of the horse should maybe not be divided in "dominant" and "non-dominant", but instead in "weight-bearing" and "propulsive".

This farrier observed the following:

1) the diagonal hind to the bigger front is also bigger, and represents the "weight-bearing" hind, whereas the other hind is also smaller (like its diagonal front) and represents the "propulsive" hind. The weight-bearing hind is placed more towards the midline and the propulsive hind more towards the outside of the body.
2) the "bearing hind" exhibits a toe that points towards the outside, while the "propulsive" hind has a toe that points towards the inside.


So how does all this apply to Molly?

I must say that Molly, who from her front feet and every single other indication is a left sided horse, canters much nicer on the left lead, which is inconsistent with Ute Miethe's observations, that a left sided horse should prefer the right lead canter. Molly hates the right lead canter! I should point out that the same observation was made by Molly's  trainer, when Molly was 2.5 years of age and is documented on the video. Thus, this is not only my impression or something I may be doing wrong while riding her.

Also, as the picture shows clearly, the hind foot that is diagonal to Molly's big front left DOES point outwards, as observed by that Swiss farrier to be the case. Also, both of her right feet are placed more towards the midline and this also speaks for her right hind to be the one that does the weight-bearing amd thus explains why she canters better to the left. Also, the fact that she sleeps laying on her right side suggests that most of her body weight is on the right side when she is getting up again and therefore she needs a stronger right hind to get that weight off the ground.


In conclusion, as far as I understand that topic now (and my understanding may change ANY time) Molly is a left-sided horse, with a diagonal axis of weight-bearing front left and right hind.