new addition to horse boot rack

Father Christmas brought a pair of Renegade boots for Molly!

This complements my 2 pairs of Equine Fusions, first and second generation. The EFs, I think, are the best turnout boots, but I wanted something with a better break-over for riding. 

saddle fit journey

Just as my "journey to better hooves" has taught me incredibly much about horses, so has my "journey to better saddle fit". The saddle fit journey started with my gelding Gus, who came to me in June of 2009, with some "baggage", especially when it came to riding him. The story is too long and complicated to tell, suffice it to say that the problems he had could be traced down to improper saddle fit.

It took me more than one year to really understand what the problem was and probably one more year to solve it. I bought and sold 3 saddles, none seemed to be working for Gus. I just knew that he was uncomfortable under saddle. These were the observations:

1) when I rode Gus it was hard to keep im from not rooting his nose down to the ground.
2) Gus often tried to lay down with the saddle on
3) worst, Gus often bucked with the saddle on, with and without rider

Because of these problem, I never really rode Gus very much. The few times I did ride him and he actually worked hard enough to sweat I saw the following sweat pattern:

One can see a dry area just behind the shoulder blade. This dry area indicates too much pressure from the saddle in this place. Too much pressure stops the sweat glands to secret sweat. This was the same with the 3 different saddles I bought and sold again.

I inspected Gus' back and did notice a "swelling" in the muscles right there, exactly where the dry spots were, but I could not find a saddle that would alleviate the problem. So I basically stopped riding Gus altogether. After all, I got him as a companion horse and Molly was my main riding horse. And I did not have the time to ride two horses anyway.

Then, on one of the many occasions when I searched for information on saddle fit, I found this website:

http://www.equineinspired.info/the-baroque-horse.html

This article introduced me to the "Thoracic Trapezius" muscle. This muscle was exactly where I always saw that "swelling" on Gus back and where his dry spots were when I rode him. Many "Baroque" horses have this enlarged trapezius muscle and Gus, being a cross between "American Cream and White" (a very rare draft horse breed) and a QH, has those too!

Then, another coincidence came my way. I became a Clinton Anderson "follower". I bought the Fundamentals and taught them to both horses. But maybe more importantly with respect to saddle fit, Clinton designed his PRS pad (pressure release pad) that has a cut-out in the area where Gus has his enlarged trapezius muscles. It turns out a lot of Quarter horses do have that issue too.

I bough the PRS pad and it solved the pressure issue immediately on Gus. However, the pad is very thick with 1 inch, and the cut-out isn't exactly where Gus' muscle enlargements are. Every horse is built differently. After a whole lot more research I found Tom at Skito pads, who made me my own custom PRS pad, 3/4 inch memory foam insert that fits in a cover made out of wool (bottom) and canvas (top). My Skito pad is the best pad I have ever owned!

In addition, I ordered Gus a custom made saddle, that accommodates Gus' back best possible. Allegany Mountain Saddlery made it possible. They sent me Steele tree fit forms that I could place on Gus' back and inspect for fit.

Steele had just come out with a new tree, a cross between a draft horse (wide in the front) and Arab (a lot of "rock" to the tree) tree, that Stacy, the owner of Allegany Mountain saddles, said she has had great success with on horses like Gus. She included the whole tree for me to try as there was no fit form available yet. This is the "HW" tree in the front of the picture. Sure enough, this was by far the best fitting tree for Gus, only the bars were a bit too long.

Stacy ordered the HW tree for me at Steele with even shorter bars, especially for Gus, and built the whole saddle to my exact specifications.


This is what came out of this endevour:

And this is now a happy horse :-)!

It is kind of ironic: I have two horses, one has a really difficult topline (Gus) and one has a really difficult front leg anatomy (Molly). Molly's front leg anatomy has left her with damage in her lateral cartillages and Gus topline issues have left him with severe behavioral issues when it comes to riding. In neither case is it the horse's fault! Horses were not born to live in fenced in properties and carry people around on their backs. It is our responsibility to provide them with the best care we can give and not leave them damaged along the way.

Both my guys confronted me with enormous challenges, but after all they only left me stronger and a better horse person. On the go I became a hoof expert and saddle fitting expert and now I am even becoming a problem horse trainer. Gus still needs to overcome his fear of the saddle, to trust that it will never hurt him again. It may take another 2 years for this trust to develop. What else do I need to get an expert on in this vast country of "unlimited opportunities". Due to the size of the United States of America people have to become their own experts, due to lack of experts to rely on close-by. The internet makes it all possible.

first major frost

Today finally winter arrived. Let's see for how long. It was -8 C in the morning and the water puddle at the lower part of the paddock has frozen. Very interesting for Gus :-)!

Since the ground is very very hard and has huge holes in from all the rain before I was a bit afraid how the horses would handle it. But since I am the kind of person "better safe than sorry" I decided I equip both my horses with their Equine Fusions today, Molly even with thin felt pads in. I just thought I give their hooves a bit more time to adjust, especially given all the rain the hooves were really soft. On the frozen ground, the EFs are really perfect. Since the sole is flexible the horses still can feel everything, they just have that little layer of extra protection. With their boots on, both horses did very well on this frozen terrain, so that by the afternoon I removed Gus' boots and he manoeverd the terrain still like a champ. My impression is he prefers the hard ground over the soft muddy one. Molly walks a little bit like a stork, lifts her legs up high as if she is not sure where she should place it when it comes down. It looks quite funny.  But she is not lame or sore at all, just careful. 

one should always take a camera to the barn

My Gus is really a "wild horse" at heart! We had a lot of rain last night and this morning the lower part of the paddock was under water, about 5 inches deep. For Molly this means she is not even coming close to that large water body. With big eyes she stared at the big lake. But Gus is totally the opposite. He marched right in the center of the water and started digging. The water/sand mixture splashed up high and the more it splashed the more violently he dug the ground to make the water splash higher. He really gave himself a mud-bath. In the end he decided he may as well lay down in that lake of mud and water. It is cold and very windy today, really horrible weather here in NW Indiana, so Gus did not take that bath because he was hot. He just so much enjoys playing with the water. And maybe it reminded him of his youth, where he would spent the hot summer days in Southern Texas in exactly that sort of pond.

In any case, I really regretted not having my camera with me. I have never seen any horse doing what Gus just did, apart from Mustangs in the film "Cloud".

Update, a few hours later Gus has dried up (and shaken off the sand) and decided to sleep with his front hooves in the puddle. Not sure if this is the greatest thing, but he won't stay there for long I hope...

This is the good thing about a Palomino horse: one really can't see if it is dirty or clean :-)!

another Rockley farm horse example

that is very important to look at:

http://rockleyfarm.blogspot.de/2011/04/symmetry-twisted-legs-and-strengthening.html

This is the same horse self-trimming itself, before (left) and after (right). I find amazing how the leg has straightened up with the hoof being allowed to wear as it likes, a short lateral toe and a slight medial flare.

Rockley farm rehab horse shows same pattern as Molly's FR

I was very excited this morning to read Rockley farm's most recent blog post:

http://rockleyfarm.blogspot.com/2012/12/balance-is-more-about-leg-than-hoof.html

For those who do not know Rockley farm, it is a rehab facility in the UK, that instead of trimming horses into some certain balance a human thinks is right, submits them to various terrains and controlled exercises and allow the horses to self trim their hooves. This is only possible with large amount of land, that I, as most horse owners, do not have access to. So I need to trim my horse in addition to allowing them to wear their hooves.

This horse's front right hoof shows the same conformation as Molly's. I would be willing to bet his medial side of P1 is longer too. The way this horses has self trimmed itself is consistent with how I have determined Molly's FR balance: the coronary band is not straight, but raised slightly towards medial. And this horse too has a short lateral toe. Overall the hoof capsule is much shorter than it used to be. All these features are identical to Molly's FR, as I am trimming it now. Of course I am only systematically trimming her like this for a short amount of time and problems usually only show up later, but seeing this horse makes me confident that my understanding of Molly's FR is correct and I should keep going as I am.

Thanks Rockley farm for posting the progress of your horses so diligently!

2 years

I took pictures today, for a different reason and so I also took one of Molly's FR. It is making so much progress it is hard to believe, given how long I have wanted this progress to happen. The picture is not great, but I could not help to post this comparison: today I saw for the very first time in 2 years Molly's complete sole to show normal, healthy consistency, instead of "inflammation" sole. I really did not think this sole would ever recover, I certainly did not think it would take two whole years and then suddenly be normal, but with the proper balance, it did recover 100%. What an amazing capacity for healing these hooves have.

long lateral toe

I have reconstructed the (likely) sequence of events that have resulted in Molly's front right hoof problems. To recap: Molly had, from at least of the age of 3 years on, the tendency to hit the ground with her lateral toe on her front right hoof. This prevented her to land heel first and caused her to develop side bone in her FR and frequent abscesses.

I now know why this happened, at least I think so. It is pretty trivial and can be simply explained by sloppy work by farriers and trimmers, who never really bother to look how the horse walks. If someone would have looked carefully they would have recognized that Molly's lateral toe had become long and was hitting the ground before the heels had a chance to land first.

The picture below shows what happens when Molly places her foot on the hoof stand: the leg is crocked, it has a strong tendency to lean inwards. As explained in a recent post this tendency is caused by the fact that the medial side of her P1 is longer that the lateral side (see this entry). Molly can absolutely not extend the leg for it to become straight on the hoof stand, something that Gus has absolutely no problems with. Also, her FL is straight on the hoof stand. But not her FR.

The consequence of that leg anatomy is that the lateral toe area is pretty much out of the trimmers sighting when the hoof is up on the hoof stand. The picture does not show it all that well, but I can tell everyone who doubts what I am saying: the lateral toe is invisible from the trimmers perspective when the trimmer looks down from the top at the hoof on the hoof stand.  The trimmer would need to lean down far enough to the height of the hoof to really inspect the growth lines on the lateral toe in order to see them. This was not done, not by my trimmers and most likely not by the hoof care professionals who trimmed Molly before I owned her. This has resulted in the toe never really being trimmed properly along the growth lines and simply becoming long.

This picture is from today, and Mollys foot is now, finally, after 2 years, balanced

The picture below shows Molly's hoof in January 2011, when I released my last trimmer from her duty because I no longer wanted to accept the frequent abscesses. In the left picture I have indicated the growth line of Molly's hoof 2 weeks after she had been trimmed last by my professional trimmer. It is obvious that the lateral toe wall was pushed up, indicating a lot of excess hoof wall in this area. This was exactly the area where Molly hit the ground. Also, on the sole, one can see a black hole in the lateral toe. This was a chronic bruise, that was the reason for the frequent abscesses. Moreover, the whole hoof had taken on a weird triangular shape (I now know due to the side bone that developed due to that excess wall pulling on the lateral cartillages in unnatural ways).

Now the problem was that I myself was a total beginner when I started trimming. When I looked at  the hoof from the front it looked quite balanced. I always noticed the bulge in the coronary band on the lateral side, but I was told to address it via quarter relief, which I tried. Quarter relief proofed unproductive placing even more pressure on the lateral toe. So the hairline did not come down. What Molly needed was lateral toe relief, actually placing more weight on quarters and heels instead of on the toe.

I realized that relatively early on but I ran in problems: as the sole around that area was constantly inflamed (hard and plastic like, due to the constant hitting of the ground), I almost always, when I tried to lower the wall through the sole, hit blood or wound serum. So I was hesitant but still kept going slowly removing sole and toe wall in the lateral toe. Since watching Gene Ovnicek's videos, I knew at least how I could find the life sole in the quarters. He also has quite good explanations on how one can project that life sole plane forward from the quarters in the toe. So at least since I knew about Gene's method, which was not until very recently, I was pretty confident that the bruises/serum pockets that I had seen in the toe were not actually live corium.

In May 20012, Molly had another abscess (the only one since I started trimming in January 2011) in exactly that lateral toe. It erupted at the coronary band. It grew down until 2 weeks ago, when it had grown down enough that the lateral toe wall underneath broke off (see picture below, orange line indicates where toe wall broke off).

I think that this breaking off of the lateral toe wall gave the hoof the final push towards healing. Molly is now able to get her toe out of the way when she lands and all bruises are gone from that area. The sole is still a bit unusual in its consistency in the lateral toe area, but this is hardly surprising given in was inflamed for probably 6 years running.

Just in the last 2 weeks since this toe wall has broken off, Molly made enormous progress, her hairline is dropping and the foot is getting rounder and rounder. My goal is to revert the side bone! We will see if this is going to be possible. The next x-ray will show.

Gus "swapping study"

I wanted to upload some pictures of Gus' hooves for a while now.

Gus was born and raised in Texas and for most of his first 4 years of his life lived on large pastures on ranches with horses, cattle, ponds and streams. He grew up a lot like a wild horse. He never wore shoes in his life. He also never had any injuries to speak of. I know this as he was owned by my sister, who bought him when he was a 2 cell embryo :-)! So between my sister and me, we know every day of Gus' life.

When he came to me in June of 2009, NW Indiana, temperate climate, I had no idea that I could have done my own personal "brumby swap" study, observing how Gus hooves would respond to the sudden change in environment, from dry, hard and rocky ground 24/7 on search for food, to soft, wet and sandy with hay available 100% of the time (plus limited grazing). Unfortunately, I knew not much about hooves back then. Gus was incorporated in Molly's trimming schedule, which was every 8-10 weeks trimming by a professional farrier. Unfortunately, I have only very few pictures of Gus feet when he first arrived. And these pictures were not dedicated hoof pictures. They just happened to show the hooves in some meaningful way.

August 2009

August 2009

I think what is pretty obvious from these pictures is that within 8 weeks Gus hugely overgrew his walls and bars above sole level. Also nice to see on the picture above is that even the sandy environment allows for some wear, in Gus' case, he wears the lateral toe and wall more than the medial. This is caused by his conformation and the fact that he rolls over his lateral side. This is 100% normal. Nowadays, since I understood that natural asymmetry of the hoof I am integrating this feature in my trim, so that Gus does not have to wait for 3-4 weeks until he would be able to wear this hoof in this way. I am now maintaining (to a certain degree!!) this natural asymmetry.

found Molly's training video

Yesterday, I suddenly remembered that I had kept Molly's training video. I had not watched it in a while as it was in a PC format and I have a Mac. But I decided I needed to see it because I wanted to find out if she already then showed signs of hitting the ground with her lateral toe on her FR. I found a conversion program and actually managed to upload it on youtube:

It was taken on Nov. 26, 2006 and Molly was 2 years and 8 months old. As far as I know this has been her second month of riding at the trainers. I did not yet own Molly, she was still owned by her breeder.

First and foremost, I fell right back in love again with Molly! She is such a sweet horse. Was and still is. A pleasure horse with a pleasure mind. And I would have bought her on the spot again!

I saw several interesting things on the video.

1. While I cannot see the hooves clearly it is rather obvious that Molly makes small sand clouds (indicating the toe hitting the ground) when landing with her FR much more than when landing with her FL. 
2. When Molly backs up, she has a much easier time placing her FR back than her FL.
3. At some point in the video I hear the trainer saying "much better on this side". This is when he canters on the left lead. This is true for me too, she canters much nicer left hand than right hand! On the right lead, she "dives" in the corners. 
4. As this video was taken PRIOR to her injury to the right hind leg (Molly got stuck in a fence om May 07, 2007, also still at her breeder's) I can finally rule out that this old injury (where she until today has a scar on the leg) had anything to do with her landing patterns. 

I think it is now really clear that Molly's leg and hoof conformation developed out of her habit of her placing the FR back and her FL forward when grazing. Until today this is how she grazes preferentially, the FL is forward the FR backwards nearly always.

I recently came across an interesting article: "The embryology of the right front club foot", written by Amy Hayek, DVM, MA, CVA, CVC. It can be found here.

The first sentence reads: "The tendency to have a clubbed foot on the right, or to not extend the right front when grazing can be linked to embryological development of the G.I. tract and post partum sensory input from the environment that encodes for a gait pattern causing shortness of stride and compensation in the right front limb."

You will need to read the article to fully understand the connections. I cannot repeat this here. I wonder if this is why Molly has such a predisposition to place her FR back. I doubt, however, it is the only reason, as Molly always had plenty of grazing (or ad lib hay in slowfeeders), and at least for the past 2 years did not eat any concentrated feeds but only a ration balancing vitamin/mineral supplement, pre and pro biotics. 

plane of assessment

I found this article, written by Dr. Deb Bennett, PhD, in EQUUS issue 420, September 2012. I came across this author before, when researching hind leg conformation. Dr. Bennett has written a book on conformation.

Some time ago on this blog I have written about my difficulties deciding whether my horses are toed-in or toed-out. It depended on what angle I looked at the feet. Now, after reading this article, I realize that I am not the only one with this problem, only not many people seem to notice that it indeed IS a problem.

In order to properly assess the forelimb conformation one needs to position oneself in the plane of assessment which bisects the horse's knee.

None of the pictures that circulate in books and in the internet make this point, they always look from the front on the horse's leg.

I am going to have to look at my horses legs in a new light now.

Przewalski horse

The Przewalski horse (Equus caballus przewalskii) is the closest relative to the modern horse (Equus caballus caballus). In contrast to Mustangs, which are feral domestic horses (Equus caballus caballus), the Przewalski horse is the only true "wild" horse that is alive today, although severely endangered to go extinct. Only 2000 Przewalski horses are alive today. The natural habitat of Przewalski horses are the steppes of much of Eurasia.

People often assumed that the Przewalksi horse is closely related to the domestic horse, having split from each other around the time of domestication of the modern horse, around 6,000-10,000 years ago. However, as my colleague at Penn State discovered, based on sequencing the complete mitochondrial DNA of 4 Przewalski horses, the split between the 2 subspecies of horses occurred much earlier, ~150,000 years ago.

I recently browsed the internet to find some pictures of Przewalski horses' hooves. In my opinion, it is always good to look at some structure with respect of the evolution of that structure, as the horse just like we humans, are a product of millions of years of evolution by natural selection. Below are some pictures that I think stem from horses that really live in the wild and also in some native steppe habitat, in which this subspecies of horse evolved, and not an Animal Park, such as San Diego Animal Park, or Tierpark Hellabrunn in Munich.

I think what is pretty obvious is that these hooves look less than "ideal" for our understanding. There are horses with extremely chipped hoof walls, high heels, and some with extremely long toes. Yet, they seem to be doing just fine. What these horses do not seem to have so badly is underrun heels. Underrun heels, as far as I understand it, is the main cause of navicular syndrome. How these horses maintain a good heel angle despite a long toe is the question. Maybe the toe just does not stay that long for a long time.

One point of consideration is that these horses nowadays (and in contrast to much of their evolutionary history), do not face any pressures from predation anymore. The Sabre Tooth tiger has been hunted to extinction by humans. It most likely was the major predator of large herbivores such as the horses in the steppes. It went extinct 11,000 years ago, as modern humans settled the continents out of Africa. The threads that the Przewalski horse faces nowadays is habitat loss.

So the question is how their hooves would be if natural selection would actually operate on those horses as it has done for millions of years before today.

extremely steep hairline angle

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"geometric" vs. "result-oriented"

This paper describes the two methods that I used to balance Molly's front right hoof:

***********************************************************************************
http://www.ncbi.nlm.nih.gov/pubmed/1874681

J Am Vet Med Assoc. 1991 Jun 1;198(11):1980-9.

Factors involved in the balancing of equine hooves. 

Balch O, White K, Butler D.

Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, College of Veterinary Medicine, Washington State University, Pullman 99164.

***********************************************************************************

The two methods are: the "t-square (geometric)" method and the "result-oriented" method.

The 2 pictures below are taken from that paper. The case shown is very similar to Molly's case, "base-narrow and toed-out". And this horse too lands on his lateral quarter/toe just like Molly does.

This sentence was especially encouraging:

"Use of Moyer and Anderson's result oriented technique is often more successful in treating lameness than the geometric procedure."

If it treats lameness better, it must be better for Molly, who thankfully never was lame.

balancing Molly's front right hoof

This topic is the reason for this whole effort with the blog.


I wanted to give an as comprehensive overview of what I have observed so that I can get additional suggestions with respect to Molly's FR balance.

As I have shown, the leg is crooked. This crookedness has been my major struggle with knowing how to balance exactly.

hindleg conformation

I have no pictures of my horses hindlegs but I have looked at them often and found that just like the forelegs are slightly valgus, so are the hind legs. In the case of hind legs one often speaks of cow-hocked.  Here again, the "textbook" knowledge indicates that straight legs are ideal. However, I found this picture on the web:

This is an excerpt from a book:

It states: "Most breeders would add cow hocks to the list, but this is incorrect. Horses are differentiated from other mammals precisely on the basis of the fact that horse hock bones (and stifle joint structure) force them to stand with their hocks pointing inward. In other words, a horse that is not cow-hocked is not horselike.; in fact, a horse with "straight" hocks as seen from the rear (figure 32b) is likely to move with wobbly, pathology-generating hocks. There are degrees of cow hock: if extreme enough to cause interference (figure 32c), the fault is a serious one, but hocks that face in are not a fault per se."

I am reasonably convinced, my horses hind legs conformation is absolutely fine, normal and healthy. They look just like picture 32A above, maybe even a bit straighter than this example.

landing patterns

I made this slide to show how Molly is walking. As a consequence of the leg conformation, she has the tendency to impact the ground with her lateral side first. It is particularly obvious on her FR, the one foot that has the offset P1 (long pastern bone), where Molly most of the time hits the ground with her lateral toe first. The FL lands flatter, but also lateral side first.

forleg conformation

I have tried to compare the front and hind leg conformation of my horses to the "textbook" examples.

The conformation that is considered ideal is straight legs, defined as:

"Ideally, when viewing the forelegs from the front, a straight line from the point of the shoulder should bisect the entire column of bone all the way to the toe, with equal portions of the bone on either side of the bisecting line."

 From: http://www.extension.org/pages/10255/relating-form-to-function:-horses-frontlegs-front-view

Both my horses definitely do NOT have straight legs like those above! Their front legs seem to be slightly knock-kneed (also called valgus).

Gus front leg conformation

Molly front leg conformation

Several pieces of evidence suggest that a slight valgus leg conformation is actually normal, if not beneficial.

1) This website states that a slight valgus conformation is normal.
2) This study based on injuries of racing Thoroughbreds states: "An increase in the carpal angle as viewed from the front (carpal valgus) may serve as a protective mechanism, as the odds for a carpal fracture and carpal effusion decreased with an increase in the carpal angle."



When I pick Gus' legs up and bring them forward and look down the cannon bone from the knee, the legs down from the knees are completely straight.  The same is true for Molly's left front. Molly's right front, her problem foot with the side bone, however is different: the cannon bone, and the short pastern are "offset". This can be best seen on the x ray.

 See this picture for terminology of bones:

Molly's offset long pastern bone is most likely something that has developed as a foal, due to bad hoofcare and/or injury of some sort. Today, at 8 years of age, this is nothing I can change. Molly's hoof has obviously suffered from this leg conformation, as she developed side bones in this hoof but not in her other front hoof. I am reasonably sure that she had this side bone already as a 3.5 year old, as I remember specifically asking the vet about that bulge that she had in her coronary when I bought Molly. The vet at that time said it was nothing to be concerned about. I guess he is correct, Molly has arranged herself with the situation, she has never been lame, but her FR is a long term liability and I want to do everything in my power to at least provide it with the best balanced trim given her leg conformation. So far, everything looks quite good, the joint spaces are relatively regular and to the degree that this rather bad x-ray can tell, there is no sign of calcifications (arthritis). Not yet! My goal is to keep it this way.

Natural asymmetry and hoof wear

The most important skill of a trimmer is to observe the horse during movement and interpret the pattern of hoof wear.

Early on, before I knew anything about the natural asymmetry, I observed that both my horses showed more wear on their lateral sides. The white line always seemed more separated on the lateral than the medial side.

This is pretty easy to explain now, as the lateral side receives more pressure during movement it also receives more wear, especially at the toe, as the hoof rolls over that lateral toe more than the medial when leaving the ground.


In the beginning I misinterpreted the fact that the white line separation was wider and deeper laterally and lowered the lateral wall. This was a mistake, that I luckily caught in time, before the hoof looked like these:

The hooves in the picture above also shoes a wider lateral side than medial, but this has nothing to do with "natural asymmetry" as now the lateral walls drift away and the coronary band is no longer straight but curves down medial-laterally. This asymmetries has to be distinguished from the natural asymmetry. 


In summary, the principles of natural asymmetry of the hoof and the patterns of locomotion as detailed in the previous entries of this blog requires hoof care practitioners to balance the surplus of wear on the lateral side by adjusting the medial side if necessary.

Natural asymmetry and locomotion

The hoof has to fulfill two important functions. It needs to carry the weight of the horse, and it needs to balance the horse during locomotion, when at some points in time, the horses' weight is carried by a single hoof.

The illustrations below are referenced from this very informative website.

The static load is distributes equally on both front legs:

The dynamic load however can be concentrated on either one of the two front legs:

In order to balance the weight of the front half of the horse on a single hoof, the horse loads the lateral side 10-20% more:

I have found, that the horse performs this "balancing act" by moving the leg slightly towards the mid-line.

My horse Gus provides a good example for this. He has rather straight legs (very slightly base narrow) and I have not seen any horse with more healthy and regular hooves than his, yet he places his front feet in such a way that they load the lateral side more, by placing them towards the midline. This specific way of walking is more pronounced in soft ground, most likely as there is more need for balancing the weight on soft ground. But it also can be seen on harder ground.  On a level surface, like a tarmac road, Gus lands heel first or flat and this placement of the legs towards the midline is not very obvious, but to some degree it can be seen even on a hard flat surface.

It is interesting to note that the same conclusion has been drawn by the author of this website:
http://otherideas.typepad.com/christine_sander_hufbalan/

The article is in German, but the first picture shows this specific way of advancing the legs towards the midline.

Taken together these observations suggest (as has been done here) that the lateral side of the horse's hoof is wider and flatter because it is the "balancing side" of the hoof, and the medial side is primarily involved for the static load bearing of the leg.

It may also be worth noting that as the weight of the horse increases, so is the need to balance the horse's weight during locomotion, when temporarily only one leg carries the weight. The heavier the horse, the more balancing on the lateral hoof side is required.

Natural asymmtery - fossil horse bones

The ancestor of all mammals (and thus the horse) had five digits on each limb involved in locomotion. The horse, while still having remnants of all 5 digits, has reduced 4 of them and only uses one for locomotion: the middle digit (III), equivalent to the human middle finger. The reduction of the weight bearing digits was gradual during horse evolution, as can be seen here:

As an evolutionary biologist, I find it interesting to look at the evolution of the bones, changes that occurred represent mainly adaptations of the horse lineage to its environment, and also developmental constraints.

I was very excited to see this study. The authors report a well-preserved skeleton of a 4.6 million-y-old three-toed horse (Hipparion zandaense) from the Zanda Basin, southwestern Tibet.

Hipparion zandanese must have looked like this:

 In the supplemental material of the PNAS paper, they show actual pictures of fossilized (4.6 Million years old) bones.

Based on what I know about the horse's hoof, I think the Figure legend must be a mistake, this is not the right front foot, but the left, based on the shape of the coffin bone. The coffin bone of this 4.6 Million year old ancestor of the modern horse shows a clear asymmetry,  that is also characteristic of the modern horse, including MINE! Most likely the steeper and slightly smaller medial side is adaptive for the horse, exactly why I have not yet figured out, but will try and find answers. The answer will lay in the biomechanics of the hoof.

trimming toe sole

This entry on the Easycare blog is important for me. As my horses develop that excess sole in the toe, especially on their hinds. I have been doing exactly as this person describes, rasp flat over that excess sole, until the collateral grooves at the tip of the frog come down to about 9 mm.

Sidebone

Molly has sidebone on her FR, it is pretty obvious to see on her X ray and also from directly looking at her hoof. Today, someone posted in a hoof forum a picture of a dissected foot showing side bone. Molly's are not as advanced but still, it is quite amazing to actually see them being elevated beyond the capsule. I can definitely feel them on Molly's FR. Also, her hoof has a similar triangular shape, just like this one.

I have ordered this balm and will apply it to her coronary band, according to this short movie:

I am not particularly hopeful that this is going to make a huge difference but on the other hand, if bone can demineralize as in osteoporosis, why should cartilage not demineralize too, once the hoof is properly trimmed and correct hoof mechanics restored. I see Molly itching herself often just underneath those ossifications.


Molly's sidebone can be seen here. It is more pronounced on the lateral side. But she does have it on both sides of her hoof. Her front left does not have any signs of side bone. Her front left is such a healthy hoof, it is a real joy to look at it!