Canker?!

Here is Australia it is cheap and easy to keep horses living outside in yards and/or paddocks 24/7. Most of the country has relatively mild winters (only small pockets of the country actually get snow) and a few good waterproof rugs is generally all you need for winter.

So, I have not been exposed to the delights and pitfalls of the stabled horse. There is a lot about managing the stabled horse that I have no clue about or have never heard of. One of those things is Equine Canker.

I was googling for some pictures of frogs for an upcoming post and came across this canker business. I thought canker was just an old English word for cancer. And apparently that is sort of what it is - hoof cancer. The pictures I saw were grotesque. I'll post a few at the end of this post.

Here is a link to an Aussie PDF info page about canker:
http://www.barehoofcare.com/fact%20sheets/equine_canker.pdf

The short of it is that canker is an eventual result of infected feetsies standing around in excrement for too long. It is an over growth of hoof tissues and apparently smells pretty disgusting due to the overactive cells getting infected with all sorts of vile and disgusting microbes. Yummo.

It is treatable but is degenerative and needs to be sorted out pretty early apparently.

I have never even heard of this. So there you go.

Notes on the Pedal Bone - *warning cadaver pictures*

(Please be aware that there will be some pretty gross pictures of hoof disections in this post - please try to check them out though, the knowledge gained is invaluable!)

 

An x-ray of a normal hoof. 'A' indicates P3. (B is the navicular bone, c is P2 or the short pastern bone, and D is P1 or the long pastern bone).

A cross section of a cadaver leg.

 

This is an awesome digital image of P3 in relation to the lateral cartilages (light blue) and tendons.

Pedal Bone, Coffin Bone, P3, Distal Phalanx - this bone goes by a few different names. I like to refer to it as P3 as it is quicker to type and say!

P3 is the primary bone in the horse's hoof. To me, it looks like a little miniature version of a hoof - the outer hoof should match the bone on the inside. A bigger, flatter-soled P3 will show a flatter soled larger hoof. A very concave P3 bone will show as a hoof with magnificent concavity. There are soft tissues and blood vessels attached to P3 including the soft laminae that attach the bone to the hoof capsule.

Hoof with capsule removed showing the solar corium (the blood filled pad separating the sole and lower surface of P3), the soft laminae and the coronary corium from where the hoof horn grows.

Look at the solar surface! The sole and frog corium (which is just a fancy name for soft tissues if you ask me) looks like a play-doh cast of the hoof! This shows why it is important to have sufficient sole depth.

I did some googling and there are some VERY interesting pictures of P3 bones out there!

Various P3 bones of front feet from the top. The one top left has significant damage probably from an abscess or infection of some kind.

Same bones as the picture above but viewed as if holding the hoof in your hand to be picked. Note the different soles and how they differ in concavity.

As viewed from the side.

Here is P3 in the hoof capsule

And again on a shod hoof. Here it shows really well the concept that the collateral grooves (the valleys beside the frog) are a good indicator of sole depth - the shallower they are, the less sole you have.

You will hear about P3 being talked about in relation to rotation and balance, particularly with cases of laminitis.

Anterior to posterior balance refers to the angle of P3 in relation to the ground surface. The accepted norm is 3-5 degrees rotation when viewed from the side. This is to allow some movement of P3 and the structures in the back half of the foot to 'sink' when the hoof is loaded and expands (that is why it is important to trim in quarter scoops to follow the live sole plane).

The red lines show the amount of rotation - imagine this hoof being loaded when taking a step - the angle made by the two red lines would close when loaded to absorb impact.

Laminitis is as we all know when the laminitic structures loose their connection for a plethora of reasons and P3 can and often does rotate.

Here you can see the tip of P3 making the sole bulge just in front of the frog. Your brain should be screaming a warning at you if you ever pick up a hoof and see this! This is why a laminitic horse uses the infamous 'laminitis' stance - where a horse throws his hooves out in front of him and loads his heels to take the pressure off  P3 and the excruciatingly painful laminae)

An x-ray of a laminitic foot. See how P3 has rotated, the hoof wall has ripped away from the front surface of P3? See how the foot would bulge?

The best way to see without an x-ray machine if the horse has an ideal or acceptable amount of rotation is to draw a line straight through the pastern and hoof - the angle of the hoof capsule should closely match that of the pastern.

Here is Gracie back in March this year - you can see the angle of the pastern vs the hoof is broken forward - the tip of P3 is is rotated slightly forward and down, which is evident in the flare on this hoof (most of which I removed).

Here is Allie in April. The angle is broken slightly backwards - her P3 would be more ground parallel than Gracie's. Both are functioning, sound feet.

What else would you add to this P3 post? :)

Fulcrum - what does this mean?

I want to write a post about the hoof's fulcrum - a term I have struggled with and still don't quite get even after my most recent hoof workshop. I want to put it into layman's terms to cement it in my mind. Hopefully I 'get it'

Google defines 'fulcrum' as:

ful·crumNoun/ˈfo͝olkrəm/

1. The point on which a lever rests or is supported.

 

So my little brain translates that as the middle of the see-saw - the point of which the see saw levers around.

How on earth does this apply to the horse's limb? (Other than when a horse steps on a big rock!).

"Fulcrum represents the relationship of the ground weight bearing foot surface with the weight bearing axis of the limb" - The Barefoot Blacksmith advanced trimming workshop booklet.


The lower limb needs to be able to absorb impact - the pastern flexes to absorb force (along with a host of other shock absorbing features in the leg). This can look quite scary - have you ever taken photos of your horse at the gallop?
 

Here you can see the down force through the pastern, absorbing the impact of the stride.

There needs to be the facility to absorb impact. However, the leg still needs to minimise the lever effect of the hoof being in front of the rest of the limb.

Red = weight bearing axis of the limb. Pink = weight bearing foot surface. Blue = pastern angle.

The weight bearing foot surface (pink) needs to be as close to the weight bearing axis of the limb (red) as possible - preferably underneath it. Above is Allie with a fairly fresh trim (maybe a week old). You can see that the red line bisects her heels, but that the weight bearing foot surface (pink) doesn't quite come close enough. Below is a photo of Allie when she is way over due for a trim (maybe at 5 or 6 weeks?). You can see that the pink line has moved forwards to the point where it is coming nowhere near the red line. The weight bearing foot surface has grown forwards so much that it has taken her out of balance.

 

 

 

Here is the full photo of the above - see how being out of balance just gives her lower fore limb a weak look? See how the pastern/hoof angle is broken forward, and how the lever forces are working against her?

Compare to this photo with a fairly fresh trim. The lower limb in front looks far more stable.

So where is the 'fulcrum'? How do I find it? What can I do with that information once I do find it?

The fulcrum can be found normally by drawing a line across the sole of the hoof at the widest point.

Easy peasy, if you have hooves that are near perfect.

Red = fulcrum. Pink lines show the edges of the weight bearing foot surface. Blue line shows that the fulcrum should be in the centre of the hoof, bisecting it in two. Half of the foot in front, half behind. Voila!

Then there are the special feet.

WTF is the fulcrum?

The widest part of this horse's foot seems to be just forward of the centre of the hoof, closer to the apex of the frog - but that can't be right as I know this horse's toe is way too long. Other landmarks are where the bars end there is often a little crack like line on either side of the frog. This can point to the fulcrum. In Archie's foot above (the special one) I can see where the fulcrum should be - the bottom red line. Where I think the fulcrum probably is, is closer to the middle red line. The top red line is another 'widest' point on this foot. This is where it gets confusing.

In a deformed foot finding the fulcrum can help you envision where the foot is meant to be. When you know where you want it to go, you can trim to encourage it.

Pink = weight bearing foot surface. Red = fulcrum. Orange is where the toe should be, relative to the fulcrum.

Ok, I think I need to digest this for a while. And I need to stop drawing lines on photos. This is getting ridiculous.

Advanced Trimming Clinic 26.08.11

I am EXHAUSTED! I took both my mares to the Barefoot Blacksmith advanced clinic today and I think I slept about 3 minutes last night as I was so nervous about hauling my skatty mares over an hour away in peak hour traffic but I shouldn't have worried, they were perfect.

For now, I'm just going to post some notes I took on my iPhone. I might write some more later once I recover from this god awful headache.


Hoof advanced notes

High level performance horses - shod vs bare - safety for rider vs what is best for hoof.

Hoof balance = biomechanical neutrality - PEDAL BONE. Normal rotation 3-5 degrees. Needs to be some rotation to allow for vertical loading. Quarter scoop for high impact. Absolute ground parallel is NOT SOUND. no where to give in back part of the foot. Hinds slightly steeper than fronts - powerhouse. For correct movement. Very important for soundness.
Sole is the landmark for pedal bone. No bone in back part of foot, totally plastic, open to deformity. Hard ground and soft ground heel length different. Capsule angle matches Pastern angle.

FULCRUM - relaShionship between the foots centre of gravityand the limbs centre of gravity. Limb gravity behind foots gravity (lines). Half foot infront of centre of gravity. 

MEDIAL LATERAL BALANCE
Horses don't have straight legs. Symmetrical is not sound. Movement brings legs closertot the midline. HORSES LAND LATERAL (outside) SIDE OF HOOF FIRST SLIGHTLY. this is normal. Medial side is steeper, takes most of the forces on landing. Guiding landmark is the sole plane for front of foot, but frog is best anatomical guide to balance the back of the foot. Hind feet when resting lateral side of hoof on ground is loaded and medial mostly unloaded. Balance according to frog. 

GRAZING STANCE
Front legs all over the place. Horses are meant to be browsing off low shrubs, NOT the ground. Have to spread their feet wider to reach grass. Habitual grazing patterns need to be taken into account.

The best balanced feet are on the horse that moves the most!

The direction of the frog is where the pedal bone points.

1.5 cm sole thickness minimal for hack size horse. 

Bullnose = top much toe on!! Negative pedal bone angle leads to bull nosing.

Club foot - be carefull with how you take away heel - instead concentrate on bringing back breakover - the toe. Match the dorsal wall (front of the foot) to the pedal bone. Laser tips on a club foot works well to help soundness. Grazing stance unloads the club foot and tightens up the flexor tendon. Tight flexor tendon = pulling on the back of the pedal bone which leads to club foot.

Keep the toe backed up on the hinds.

PIGEON TOES
lands opposite - medial side first I.e. Lateral side takes the brunt of the force. Leads to ring bone and side bone. Medial side is built to take more force but not the lateral side. 

Dealing with lat/med balance. Concentrate on the lateral side keeping it short on fronts. Opposite on the hinds.

Toe first landings lead eventually to navicular. :(



That's it! TTFN!

Archie 6.08.11

Archie's previous trim.

Third Archie trim - he was one week overdue because I had a bad injury to my finger two days before he was due where the pad of my left ring finger was ripped off by a broken broom handle. Stupid injury. It has only prevented me from doing the things I love (i.e. trim and ride) but I still have to go to work and pack the dish washer.

So, Archie (and Remy and Bertha) were late. Harumph.

Archie was suffering from thrush again poor thing. Apparently he has not been sore this time though. He went out on a trail ride sans boots and was fine. I would still recommend booting up for every ride though at this stage.

Near fore

This was the last hoof I trimmed - I was pooped, and I know you are not supposed to sit on a crate to trim and that it is very dangerous, but I just wasn't strong enough. He was a total raging beast about being trimmed too.

rawr

See what happens when you don't trim for three weeks? You loose it.


ANYWAY

 Moving on... as always, pre trim on left, post on right, click to enlarge.

Thrushy crumbly yucky sole. HEAPS of flappy frog on all four, harbouring thrush. Central sulcus widening. Black hole from old abcess getting smaller. Should be gone next trim.

Big bevel, quarter scoop, bring breakover at toe back, heels lowered but not by much due to weak frogs.

Sorry about the angle difference. Heels no lower than the frog (i.e. frogs in passive contact with ground when hoof weigh bearing). Central sulcus still deep, but opening.

Heel comparison to set up trim. They look weaker sadly.

Near hind

Weird massive bars popped up, but flicked out very easily. The question is, did they pop put just due to thrush or did the foot really not need them anymore? They will grow back if they were needed. Removed crappy thrushy flaky sole and frog, then bevel all around.

Didn't take the heels down too much. Needs more sole depth.

Mainly heel and wall height removed from this angle.

Comparison to set up trim - a very different foot! The outside (left in the pic) bar is larger in both pics. Maybe to give support due to his many issue from his injury?

It is midnight now, I shall update with the other two feet's pictures soon. :)

Remy - 3.07.11

Remy is a 5 year old 17.2hh (!!) arab warmblood. Unknown shoeing history prior to 12 months ago but I think he would have been shod. He has been barefoot trimmed for the past 12 months except for a couple of weeks with shoes on the front while he was for sale.

The new owners (who also own Bertha) are hoping to do dressage with him but at the moment they are putting weight on him and just taking it easy.

Off fore (click to enlarge, as always before on the left)

Flare, long toe.

Bit of thrush in the frog, not too bad. Heels a bit contracted (deep central sulcus).

Dry cracked frogs, owners will need to keep on top of thrush prevention with all the wet weather we have been having.

These feet were long. They will come good very quickly with regular trimming.

Near Fore (we shall call him.... "The Clubby One")

This is the clubby foot. It's not the worst I have seen. High heels, still a little flare to grow out.

Deep central sulcus with some old thrush, long looking foot, which is interesting in a clubby foot.

Heels slightly contracted.

I should have done more of a quarter scoop on this one. From this view, looks like there is plenty of room to take the heels down, but compare to the heel and solar shots - I took them down as far as I could at this trim (i.e. no lower than the frog, and/or no lower than a credit card's thickness above live sole).

He has lovely thick walls! As thick or even slightly thicker than Allie's and Gracie's walls. And my girls have the thickest walls I have ever seen!

Archie 18.06.11 - Set Up Trim

Archie is an 11 year old grey quarter horse. He has been shod most of his life however he has been out of shoes for about 12 months. He had an injury about 12 months ago to his off hind leg, taking out the two tendons at the front. It is a big, nasty, ugly mess of a wound, and his owner has spent a lot (I'm thinking thousands?) into getting him better. He is battling proud flesh, and the injury affects his movement. He walks like he has float boots on that leg (goose-stepping) until he has loosened up. Vet has told the owner to keep him in light work, and once warmed up, he is happily cantering around the trails. She is a weekend rider.

Archie has very contracted heels, deep deep central sulcus on both fronts. He was referred to me after another client of mine helped Archie's owner a few weekends ago when Archie was showing up extremely footsore. Extreme thrush infection was the problem. My client helped Archie's owner with a variety of thrush treatments, and by the time I came to trim him it was all but gone.

To get to the next step with his feet, Archie needs at a maximum 4 weekly trims (previously at 8 weekly intervals or more!) and to keep the thrush in check.

Left front, after trim. Very contracted heels, very very deep central sulcus. Black hole is the site of an old abscess blow out - abscess was about three months ago! He has been hanging onto all the sole he can... When I scraped away at the hole there was a little black thrushy lymph like fluid that came out.

Left front heels post trim. Again, contracted heels, deep central sulcus.

Left front post trim. A little tiny bit of concavity, but needs more.

Left hind, pre trim. No where near as contracted as the fronts, just need thrush prevention. No concavity, but ok sole thickness.

Left hind, pre trim.

Left hind, pre trim.