Tuesday, 7 May 2013

What happens when hoof wall "wears away"...

Surely the commonest - and most misunderstood - reason given for horses "needing" shoes is the perceived "protection" that shoes provide. One of the flaws in last week's H&H article was a vet's assertion that "working on roads can wear away the hoof wall" which, according to the author, leads to pain and means that only horses who work on soft surfaces can cope unshod.
The Worshipful Company of Farriers also cites this in support of shoes. When working an unshod horse, according to its website, "you can have problems with grip, excessive wear and damage to the hoof capsule." There is apparently a risk that unshod hooves "may wear a lot quicker than the hoof wall growth can replace itself, thus making potentially sore feet with lack of performance".

Despite the slightly bizarre grammar, the point is clear: both the vet and the WCF have assumed that horses depend on their hoof wall to support the limb and that therefore once a horse has worn away its hoof wall the hooves become sore.  
If you shoe horses, this is a perfectly logical assumption because - after all - a shoe sits round the rim of the hoof. It not only effectively prevents any wear to the hoof wall but ensures that the horse is loading most of its weight onto the hoof wall; in a shoe the sole and frog have very limited load-bearing.

If you are used to a foot loading like this (what Bowker calls "peripheral loading") then you will assume that even out of a shoe it should load the same way - round the edge of the hoof onto the hoof wall.
And, if you simply take a shoe off, then many horses will indeed load this way for a short time and if they are kept on soft surfaces. The horse above was peripherally loading out of shoes and walking on its long hoof wall (there was at least an inch of hoof wall proud of the sole - the sole shot of the same hoof is below). 
Once the level of wear exceeds the level of growth or the horse works on hard surfaces, the hoof wall length will reduce till the horse is no longer walking on a rim but (we hope!) landing heel first and engaging frog, heels and sole.

This is the same foot a short time later, after turn-out on our tracks but no trimming. 
In a really hard-working barefoot horse (like the self-trimming example below) the hoof wall will be almost completely worn away at ground level and there certainly won't be a rim of hoof wall for the horse to load. The frog, heels and sole will be the main areas of loading, not the periphery. 
These - two of my favourite photos - provide a really clear illustration of how differently shod and bare feet load on the same surface. 
The shod hooves load only the periphery and there is no contact with frog or sole...
The bare hoof loads frog and sole and though the hoof wall makes contact with the ground its not bearing the majority of the load.  For me, its clear that the bare hoof is functioning better - but why do I think this?

Not just because - in a healthy hoof - a "lack" of hoof wall won't impair soundness but more importantly because hoof wall isn't designed to support the whole weight of the horse. 
Think about it - hard hoof wall evolved as a protective shell. Anatomically, its a toenail - as this illustration makes clear...
...and horses have hoof wall for the same reason that we have toenails - to protect internal structures from damage. But we don't walk on our toenails and neither do hoofed animals - its the soles of the feet (even though they are apparently softer!) which are designed for that. 
Walking like this - for us or our horses - allows for proprioception, shock absorption and balancing in a way which would be impossible if we were on hard, unyielding nails or hoof wall.

In fact any walker will tell you that if you go hiking with toenails which are too long, so that they come into contact with the end of your boot as you walk downhill, it quickly becomes painful because toenails (like hoof wall) aren't designed to take significant load.

Loading the soles (and in horses' case the frogs too) also means that the surface which is in contact with the ground (the epidermal layer) is capable of growing and thickening in response to stimulus. Another quality that hoof wall doesn't have but which allows the hooves on horses working barefoot to grow faster in response to increased work on abrasive surfaces like roads.

So the next time someone tells you that horses need shoes so their hoof wall doesn't wear away, ask them whether they walk on their toenails or their soles...

22 comments:

Julie Highton-spencer said...

Very well explained I hope a few riders with shod horses read this article .

Nic Barker said...

Thanks Julie :-)

Gill said...

Very interesting.
Recently I asked (of carriage driving trainer in shod type yard)'Do you think my pony will be able to stay barefoot when he gets properly driving?'
Answer: No, you might get away with it for a while'
5 weeks later trainer as we pound down the road in trot:'His feet are standing up really well. Who does your trim?' 'My farrier' 'Oh thats OK then (not a podiatrist!), they are really well balanced to be able to do this'
We will see! They look great.

Andrea said...

The mention of the human toenail in boots thing made me laugh - I run/walk in the Vibram 5-finger shoes, and let me tell you what, if your toenails are even a hair too long in those, forget about it... I was just working in them yesterday and thinking about this same thing!

Kate said...

Very nice post - thanks!

I have a question, if you have a moment. I have three barefoot horses, all are worked regularly and are turned out in pastures that have a lot of very abrasive surfaces - rocks, sand, gravel. Two of the horses basically self-trim and need only very minor touch ups. The third, who has fabulous feet and is a rock-cruncher, grows an enormous amount of hoof wall - his hoof walls are also very thick and hard - and although he chips off pieces, the hoof wall doesn't wear away much and he does need quite a bit of trimming - he chips instead of wearing. I assume this is just natural variation.

Nic Barker said...

Thanks all :-) Kate, it may just be genetic variation - its something I've seen occasionally in draught types.

Generally though - with the horses I see here, who are all different shapes and sizes - its uncommon for a horse not to reach an equilibrium where work and wear balance each other.

As you said, even the horse who grows a lot of hoof wall will chip it off - perhaps he is just hankering to do more mileage :-)

Katherine Coles said...

Great article! I have just recently taken my horses shoes off as he never felt sound after shoeing. Its great to see the photos in this article as this is why my boy is going through at the moment, loosing excess wall around old nail holes. He does become footy at times but I am trying to leave him alone for a bit and let nature do its thing, he has only been barefoot about 3 weeks. I purchased some boots for riding but after seeing this am wondering if in fact I should be walking him out now to help with the self trimming process?

rod said...

Hi, I have a horse that had some issues with his hooves and I've put him in the day time on a rough track and abrasive sand. His heels are nice and low, flare has almost grown out but he has worn the sole by the toe so much that the white line is not visibel anymore, I guess I'm looking at the white line under his sole? What to do now? Put him back on softer ground to grow his sole back?

V. Viola said...

I'm on my horse 5th barefoot trim after years with shoes. At first he was on "pins and needles" and developed stress rings. The most recent trim, he has really began to regain a heal/toe stride. His once "clubby" hoof has expanded about an inch in the frog. It has taken time but I can really see the overall health of the hoof has changed so much.

julie said...

There is a young rising 4 year old mare on our farm, not yet
under saddle. She's never been shod. However, she is
now....why? During the winter as
her owner started
ground work and hand walking her on roads and the gravel
paths around our farm. All of this was hand walking,
no rider, no saddle, no more than three times per
week. Just showing
this young mare the lay of the land. This mare
came to this farm over a year ago after growing to
this age in a mixed herd on pasture land. After
approximately four weeks of very lightly increasing
the ground work schedule and walks around the farm
the mare gradually was wearing down so much wall that
it was decided she needed something to help her
soreness. She was gimping lame from foot soreness
and tenderness. There hasn't been any abcess,
only the wearing down of the wall and the lameness.
How can you explain this considering the
entry to your blog above?

Peter and dolly said...

My horse had shoes when I got him...I took them off and let him go barefoot and he was way too "ouchy" on any harder surfaces. He then got a traumatic injury to his coffin bone, and the only thing keeping him sound are special shoeing. Wish he could be barefoot, but he needs heel support and a clean break over.

Nic Barker said...

Rod, I'm not sure what you are describing - the white line is not a surface marker, its the junction of the laminae so isn't something which "wears away".

Julie and Peter - you need to start reading about how nutrition affects hooves :-) Horses can go from sound to sore in a matter of hours, particularly at this time of year. The commonest culprits are high levels of sugar in grass and/or mineral imbalances in forage.

"Heel support" IME is best achieved with a strong digital cushion and frog and believe it or not horses are pretty good at setting their own breakover ;-)

C-ingspots said...

Very well said and easy to understand, even for us anatomically uneducated hoof people. Personally speaking anyway! I'd be interested in seeing more posts like this so that we, who own and ride horses can better understand foot function. I love learning about this stuff! My mare is navicular and has aluminum wedge-heeled shoes and shorter, bobbed toes. She remains unsound. If we pulled her shoes and put in some pea gravel in frequently traveled to areas, do you think it would help her grow heel and strengthen sole and help with her lameness issues? I'd really like to be able to return her to some hacking/trail riding. She's a wonderful horse to ride. I'd appreciate any help or advice you'd be willing to offer. Thank you!

Azrayel and Avalanchian said...

This is somewhat unrelated to the subject of your article but I was wondering if you could give an opinion anyway.

My mare has sidebone in one of her front feet (couldn't tell you which off the top of my head) and as a result, we have been advised not to take her barefoot as we have been told she will not get the support she needs and the problem could get worse. She is very rarely lame and doesn't seem to have pain or inflammation. She is bare on her back feet and my gelding has been barefoot for several years now.

I am not convinced that going barefoot would make her situation worse. I am trying to convince my farrier and vet to support trying her barefoot, but they're not keen on the idea.

My gelding has all but recovered from navicular as a result of going barefoot. He went from chronically lame to completely sound within a few weeks. I really want to try my mare, having seen the huge improvement in my gelding.

What do you think?

Belbe said...

completely agree! but there is a catch. If the horse lives in completely diferente footing than the one he'll work on, and if that work is sporadic (like hacking at weekends), the problema will not be excessive Wall wear but excessive SOLE wear! we get that with our horses a lot, specially in the winter because paddocks are mud pools and trails are dry lava gravel.
However, that still is no excuse for shoeing as technology is already sufficiently advanced to Grant you a functioning hoof boot for such emergencies.

Nic Barker said...

Consistency of work is important, Belbe, but its really no different than working your horse within his fitness level.

You wouldn't expect a horse who just hangs out in a field all week to suddenly go and do a 3 hour ride and feet are no different.

Soles can adapt to wear - that's the point of my article - as the epidermis responds to stimulus by increasing cell production. You just need to think of foot fitness in the same way as body fitness :-)

C-ingspots - if you search through the blog for a horse called Dillon you will see lots of pictures of rehab from wedged shoes.

AandA - Charlie B and Abbey are both rehabs from ringbone and doing well - you can also search for them. Ringbone seems to be a result of medio-lateral imbalance and going barefoot IF done properly can result in a much more balanced foot and therefore a sounder horse.

clydesdalekid said...

Hi, I work my carriage horses on road all day long barefoot!
I have a small carriage company in Tucson, and I bring my two clydesdales from my house (they have a dry lot) to downtown 5 days a week to pull a carriage and give history tours. I do my trimming myself and keep the hooves free of chipping by keeping them "mustang rolled".
I have not come across one single person who'se jaw doesn't drop when I mention my horses hare barefoot.

They look at me like I am from the moon. And if they are farriers they will snicker "well that won't last long".

The road is a great material to wear hooves, its basically a giant nail file, and I get better traction barefoot than I ever did working horses shot with bolts or borium in other places.

My horse hooves are so healthy I would throw a fit if anyone tried to nail something into it! Thats how I explain it to others.

However, I have seen other people working carriage horses here that have run out of hoof. Its very sad. their horses live in 20x10 corrals that are strait manure, and they think that because the manure is dried out, it is ok.

Between the people who think barefoot is crazy and the people who are keeping barefoot horses because it is cheaper, I feel like I am surrounded by idiots!

Nic Barker said...

Your last sentence made me smile Clydesdalekid because I often feel the same way :-)

Its quite true that work is great for healthy feet but as you point out, healthy feet in a domestic environment are the result of good management, good nutrition and lots of hard work by the owner.

Your carriage horses sound like they are a credit to you!

John Greaves said...

This sounded so interesting I would like to find more info on barefoot , my horses problem is if she throws a shoe, she goes moderately lame there's nothing wrong with her i can only assume because all her life she's been shod she has sensitive sole or frog or both lol. How would I overcome this problem id want to know before I removed her shoes.

Nic Barker said...

Sole sensitivity is usually dietary, John (metabolic issues can also play a part). A horse on a really good diet will come out of shoes with no problems so what you need to do is address her nutritional needs first and get that spot on before taking shoes off.

Most horses need 6-8 weeks on a really good diet so plan any shoe removal to be after this. There is lots on nutrition in this blog - you want low starch and sugar and a very good mineral balancer, such as Progressive Earth or Equinatural.

Harry Johnson said...

Great article!

Constantly learning pensioner said...

I have a 12 year old Section D ex broodmare that has never been shod and I am determined to keep her that way despite her being footy on hard surfaces when the ground is soft (she's better in summer when the ground is dryer). I have had her for nearly four years and last year, through listening to a so called expert and possibly the lack of nutrition for most of her life whilst she was in foal and nursing her feet were appalling. She got grit in the white line on both her fore feet and a split on her near hind that my farrier has been dealing with by cutting a cleft reappeared, I only realised what was happening by the lack of correct growth and decline in condition of her 2/3 year old son. After reading a book by a well known and respected nutritionist I put back into their diet what I had been advised to take out, added small quantities of herbs and products for gut health and put them on Progressive Earth Pro Hoof Platinum. I had not expected much obvious improvement for several months but in four weeks I could see a difference in my mare's coat which did not fade as it had in previous years but remained a lovely dappled mahogony bay and her son's black coat which for the two previous summers had a red tinge has remained black as have his mane and tail. By eight weeks I was surprised to see an obvious improvement in my mare's feet, now, four months in, there is a very obvious mark where the old growth meets the new, the grit in her white lines is no longer there, the cleft in her near hind has worn away on its own and (touch wood) there is no sign of the split returning, even the slight flare that has always been present on the inside of her near fore is gone, she is now walking much more energy and balance and has even started to exercise herself with a lot of help from her very cheeky son :) Never again will I listen to anyone that think they know about equine nutrition, I will ask the people that have the evidence to prove that they do!