Duncan McLaughlin



I am a profesional trimmer and horse masseur. I began natural hoof trimming in 2001, just when barefooting was just taking off here in Australia. I like to combine my barefoot trimming with my experiences as a rider and as a horse masseur (Cert IV Equine Myofunctional Therapy). I have trained and competed in a range of horse activities but perdominantly dressage and endurance riding (including Tevis, Shahzada and Quilty buckles). This broad perspective helps me integrate barefoot/booted hoofcare into my client's horse management, training and competition regimes.

I enjoy working with veterinarians and other horse health professional to create postive outcomes for horses experiencing serious hoof pathologies. I have successfully rehabbed unrideable foundered and 'navicular' horse back to riding soundness.

I have recently moved to the beautiful Sth Coast of NSW and am setting up a new clientelle. My workaday area ranges from Batemans Bay to Bega, with regular trips north to Nowra and to the Hawkesbury/Windsor region of Sydney.

0427283654
duncanmclaughlin@yahoo.com.au

Skill-Drills For Efficient Movement

In human endurance sports, winning performance is a result of both technique and fitness: in that order. Technique accounts for up to 60-70% of endurance performance, more so in swimming and cycling, less so in running, while fitness accounts for 30-40% of endurance performance, less so in swimming and cycling, more so in running. The importance of technique is most clearly demonstrated by studies on the very successful African marathoners who score around average, when compared to other elite marathoners, on all commonly measured fitness parameters (VO2max, lactate threshold, height to weight ratios, muscle fiber types and proportions, etc) - their exceptional speed comes from exceptional technique.

By contrast, successful performance in endurance horses is due primarily to fitness, for two reasons:
1. Endurance horses are nowhere near as fit as endurance humans. Winning horses are generally performing at around 30% VO2 max (compared to winning humans performing at around 70% VO2 max), so even small increases in fitness can create a major performance advantage; and
2. Practically no endurance riders work to improve their horse's technique.

And there is a third reason: aesthetics. As endurance riders, our concept of what constitutes a good moving horse is still largely derived from other equestrian disciplines. Aesthetics drawn from dressage, eventing and showjumping - where good technique involves increased articulation of the joints, a relatively slow tempo, and an emphasis on increased weight carrying by the hindquarters - are particularly pervasive. Movement like is this is entirely appropriate for these sports but incredibly inefficient in getting your horse down the trail over long distances: Our endurance horses should not move like dressage horses! That is not to say your endurance horse should not do regular arena work - he should. Dressage is unparalleled in creating strength, flexibility and balance in your horse. If your horse is conditioned enough to be run a competitive 100 mile endurance ride he should also be comfortably performing arena-work gymnastics (trot shoulder-in, trot and canter half-pass, flying change) with correct longitudinal flexion and some degree of collection, to build strength and suppleness. But he shouldn’t move down the trail like that.

So what is efficient movement like? In human endurance athletes efficiency is characterised by:
1. A relatively short stride;
2. A relatively fast tempo;
3. Minimal vertical displacement (movement is channelled forward, not up and down);
4. Reduced or no braking effect on foot strike; and
5. Utilisation of gravity rather than muscular effort where possible.

The same characteristics apply to efficient movement in horses - it is the type of movement horses evolved to make prior to selective breeding (think hackneys, warmbloods), long hoof capsules and fancy shoeing. In fact, we have a very good model of effecient equine movement in our wild/feral horses.

Watching the desert brumbies in this promotional video from the Australian Brumby Research Unit you can see horses demonstrating unparalleled efficiency of movement. These brumbies serve as a much better model for distance covering technique than do our traditional ideas of good moving horses.

But brumbies are not domestic horses - are they really an applicable model?


Here is The Fury working out for his Haggin Cup award at Tevis 2010. The Fury shows habitual economy of movement, even when razzed up by his handler and encouraged by a vocal crowd. I did a bodywork session on The Fury a few hours prior to this workout and his muscular condition was outstanding. He finished Tevis more muscularly able than most horses start it and could easily have gone out, run and won a 50 miler that morning. Efficient movement is easy on the body.

In this spirit of efficiency I want to introduce two skill-drills that will improve your horse's technique: the school trot and trotting downhill. Skill training involves feelings, movements and habits that may feel unusual or awkward at first, for both you and your horse. Initially, approach these skill-drills in short intervals. As technique improves, gradually increase their duration and difficulty. Once consolidated, you can incorporate your horse's improved technique in general conditioning rides as both of these skill-drills lead to an extremely efficient way to go down the trail. Indeed, the technique developed in these skill drills should eventually become habitual ways for your horse to move and you wont need to give them a second thought.

The School Trot
The school trot (for want of a better name) was introduced to me by Manuela McLean of the Australian Equine Behaviour Center. The AEBC is a successful training establishment in Australia that promulgates classical, ethical and evidence-based horse training. The AEBC have a well developed, systematic and increasingly sophisticated approach to training, oriented more toward traditional FEI disciplines and racehorses, based on correct response to the rider's aids. We cant go into all that here - do take time to look at their articles, books or DVDs.

The school trot consolidates a correct response to the rein aid. In my experience, having ridden many, many endurance horses, practically none understand the rein aid - many barely slow at all, and many more just pull harder. And almost every horse goes faster when the rein is softened.

Ask for the school trot while riding a normal trot with soft rein contact then  increase your rein aid sufficiently to have your horse slow his pace. When he slows, immediately return to the soft rein contact. He should continue at that slowed pace and not speed up as you soften the rein. After a period of time in the slow trot ask him to move forward from your leg aid  to a normal trot. Then repeat the rein aid for the school trot again. Then use the leg aid for a more normal trot. Etc. This is a basic stop and go exercise. Once consolidated it can have a dramatic and positive effect on those horses that pull or are otherwise difficult to the bridle when out on the trail.

The happy by-product of the school trot as a stop and go exercise is your horse quickly assumes a soft, longitudinally stretched frame, with a forward reaching poll and gently raised back. The movement is flat with little or no suspension and the joints maintain a very slightly flexed position through the entire stride sequence which minimises vertical (up/down) movement of his body as he travels forward. The lack of impulsion enables him to role through the stance phase of the stride quickly and easily with very little braking action. As these attributes becomes habitual in the slow trot your horse will be able to carry them forward in a stronger trot.


Here is a short video, in normal speed and slow motion, demonstrating the school trot. The exercise is still new to this horse, an off the track Arabian who shows some of the contact issues common to ex-gallopers. He also lacks the relaxation and balance to slow the trot significantly, but does so enough I think to demonstrate the concept. The school trot is primarily a neuromuscular skill - once the neural wiring is established and your horse can maintain good balance in the absence of momentum, the trot can become very slow and sustained for very long periods of time.

Practice the slow trot exercise a few times a week, starting with five to ten minutes and building to fifteen, even twenty, minutes. Initially, the majority of the work will be in a normal tempo with just a few strides, maybe half a circle, of school trot. Gradually increase the amount of time spent in the school trot and further decrease the energy until you can maintain a REALLY SLOW trot for several circles with no loss of balance, no change in stride length or tempo, and a consistent but slight flexion through all the leg joints. Once established, try building the qualities of the slow trot (relaxed, longitudinal flexion, minimal suspension) into the normal trot. Spend a few weeks working on this and then start incorporating periods of school trot while out on the trail during conditioning rides. Continue to focus on correct response to the stop and go aids and allow the relaxed back to be raised and a forward stretching neck (NEVER mechanically pull your horse's nose in with a rein aid to put him 'on the bit'), remembering that elevation and suspension (up and down movement) is wasted energy and does nothing to move your horse along the trail.
 

Established School Trot

In this photo, a less complicated horse is learning the school trot. Particularly note the relaxation through the body. Tension and activity is reduced so only those muscles that are absolutely required are used: all others are fuly relaxed making this horse appear draped from the rider's seat.

Trotting Downhill
Trotting downhill requires all the attributes of efficient technique we have been discussing. Developing the downhill trot in a skill-drill will further consolidate those attributes of movement common to overall efficiency. And because the ability to trot downhill provides you with a minimal-energy, gravity-assisted method to cover more distance in less time, once good technique is developed, you can include trotting downhill in your conditioning and competition strategy with obvious benefits.

 But first a couple of caveats:
1. Before beginning our trotting downhill skill-drill, ensure the school trot is well and truly consolidated and your horse has sufficient coordination and balance to move at a slow tempo with minimal suspension - what goes up must come down and, thanks to gravity, it comes down harder when moving downhill. A relaxed, slightly raised back is also needed as the lumbar region experiences increased flexion (lumbar tuck); and
2. This skill-drill is not appropriate for shod horses. Trotting downhill, requires a healthy foot with intact energy dissipation structures (refer to Is Concussion Really A Problem for details) and good health of the muscles and tendons involved in elastic recoil (where muscles and tendons store energy from impact and transfer it into propulsion - a system that does not fatigue and can perform indefinitely). A peripherally loaded hoof cannot dissipate energy correctly and trotting downhill, where mass is accentuated by gravity, further predisposes stressed tissues with increased risk of concussive injuries like ringbone, sidebone and road-founder. The digital descent of the coffin bone and poor anterior/posterior balance of shod horses also means they are rarely are able to benefit from elastic recoil as a propulsive force, leading to increased muscular stress.

The videos above should help convey the concept and the 'feel' of travelling downhill. On the left we see poor technique: a lot of muscular effort, a longer, slower stride, feet landing well in front of the center of balance with significant braking action on foot strike and concurrent shock and braking action. On the right we see good technique: lightness of foot, smaller faster strides, the body balanced over the foot on foot strike with minimal braking and shock. Watching these videos, imagine what this might feel like in your own body. Or, better still, go out and try it for yourself (but begin on a gentle, smooth, grassy slope until you get proficient!).

Start practicing your horse's school-trot on downhills. Begin on a gentle grade, with good footing, and for a short distances, concentrating on all the attributes you developed in the school trot. Focus on correct technique! As your horse becomes proficient, practice on steeper grades, more complex footing and/or longer distances. Once your horse gets the technique he will feel like he can trot like this forever. Eventually you will be able to build up to a faster trot while moving downhill and, with his correct form, gravity provides your horse with additional propulsion instead of additional impact stress. However, whenever the grade is steep or the footing suspect, stick to the slower tempo you developed in the school trot. Of course, with some minor changes in emphasis, everything that applies to the trot, also applies to the canter, but that is a whole other blog...



Here is the horse we saw in the school trot video above, using the attributes of the school trot to practice the trotting downhill skill-drill. Notice that the horse remains on a light contact without speeding up. He remains relaxed and attentive with good balance. His lightly flexed joints and short strides allow him to descend with minimal impact and concussive strain. Even when he takes a misstep onto a rock, his good balance and relaxed, slightly raised back allow him to continue down the hill without making a large corrective move. Horses that lack correctly trained rein aids and are up on the bridle lack this balance and are prone to tripping on rocks and slipping in muddy conditions, even when on the flat.

With a little practice these two simple skill-drills can have a tremendous impact on your horse's ability to perform efficiently, not only in the arena or on those downhills but by improving his technique to minimise energy expenditure while over the entire trail. Happy riding!


Fats: The Good, The Bad And The Ugly

Any discussion about your endurance horse’s diet must include discussion on fat : fat is so important in the energetics of sustained exercise. But before we begin, lets cover some terms:

Adipose fat is what we commonly think of as ‘fat’; fat storage depots around the body. Think ‘love handles’ and you get the idea.

Intramuscular Triglycerides (IMTGs) are specialised fats stored in-between muscle fibers and are an important source of fuel for sustained exercise.

Essential Fatty Acids (EFAs) are fats that must be supplied in the diet. These include your Omega3s and Omega6s. Simply put, Omega3s are involved in anti-inflammatory responses and Omega6s are involved in inflammatory responses but both are required by your horse’s body for many metabolic processes.

Volatile Fatty Acids (VFAs) result when microbes in the hindgut breakdown fiber. The VFAs are then absorbed by your horse’s digestive system for use. The most important VFAs are acetate, butyrate and propionate.
1. Acetate is easily converted to acetyl-CoA and used directly as an energy source by muscle for aerobic exercise. Excess is converted by the liver to fat.
2. Butyrate is mostly used as energy source by the cells lining the digestive tract but excess can also be converted by the liver to fat.
3. Propionate is either converted by the liver to glucose and then transported to muscle for use or storage as glycogen or it is converted by the liver to amino-acids and/or fat. Estimates suggest as much as 50% of blood glucose is derived from propionate.
So you can see, we need to take VFAs seriously.

Free Fatty Acids (FFAs) come from the breakdown of fat, either long-chain dietary fat in the digestive system or adipose fat from body stores, and are moved by the circulatory system to muscle, where they can be used as fuel for aerobic exercise.

The Good
Horses don’t eat, or need, much fat. The evolved diet (grasses, forbes, shrubs) was low in fat, no more than 5% of total calories. This explains why horses don’t have gall bladders: instead a continuous but very small amount of bile, important for fat digestion, trickles in to the small intestine.

Green pasture fulfils your horse’s total dietary requirement for fat, including the EFAs Omega3 and Omega6. Anything in the evolved diet that was rare and essential is processed very efficiently by the digestive system, including EFAs (as are sugars/starches and sodium, which were also rare in the environments where horses evolved). Green grass has a Omega3:Omega6 ratio of 4:1 or higher .That is, green grass is very high in anti-inflammatory Omega3 - which is one of the reasons why ‘poorly’ horses are turned out for a dose of Dr. Green.

Your horse on 24 hour pasture is getting around 16grams of Omega3 and 4 grams of Omega 6 each day. EFAs are lost when drying grasses into hay- about half the overall fat is lost but almost all Omega3 is lost - and need to be supplemented to meet dietary requirements. The easiest way replace lost EFAs is to add a 100g of ground flaxseed/linseed (grind seeds in a coffee grinder immediately prior to feeding) or 30mls of cold-pressed flaxseed/linseed oil to the daily ration (See Carol Layton’s article for more information on the various aspects of feeding linseed).

Fat is calorie dense. This is mainly because fat, unlike other energy substrates, is hydrophobic: no water is stored with it. If you could pull from your horse a kilo each of fat and glycogen (remember, glycogen is stored carbohydrate, as discussed in Carbs: The Good, The Bad And The Ugly), the fat has more than six times the amount of stored energy.

The Bad
Calories excess to needs get stored away. When the excess calories arrive as carbohydrates, for example, as sugars in spring pasture, first they are stored as glycogen in the muscles and liver and then, when the glycogen storage limit is reached, they are converted and stored as fat (IMTGs and adipose fat). Excess calories from dietary fat can only be stored as fat, first IMTGs are replenished then the rest stored as adipose fat. However, if you provide the same amount of excess calories from a carbohydrate source or from a fat source, the fat source will yield higher body fat because the conversion process for fat sources only uses up 3% of the calories where the conversion process for carbohydrate sources uses up nearly 25% of the calories. Feeding your horse fat makes him fat!

For this reason, some additional fat supplementation might be useful but only in VERY HARD WORKING endurance horses where fiber and grain can not provide sufficient calories. Generally, all horses require up to 5% of their total daily calories provided by fat (easily met by horses on green pastures) and this can be boosted to up to 8% for very hard working horses (NB, very few horses actually work hard enough that energy requirements can not be met by fiber and grain).

Do not feed fat at levels higher than 10% of total calories. Remember, structural carbohydrates, what we commonly call fiber, in pasture and hay are fermented by microbes in your horse’s hindgut into VFAs; an important, natural source of fat. With high-fat diets, excess fat that is not able to be absorbed by the small intestine leaks into the large intestine and disrupts this microbial fermentation, reducing the VFAs produced.

Rachel Reid on Shar and me on Ginge at about 120km into the 2007 Cob and Co 160km ride to take equal first in 10: 33 with Ginge awarded Best Conditioned. As an experiment, following a conversation with Jim Autio (who wrote The Digital Mantrap, one of the most interesting books I have read on human nutrition and exercise physiology) and who suggested that with dietary manipulation VFAs might be able to supply 40% or more of equine energy needs, Ginge was fed only fiber (pasture, hay, beet pulp) in the week up to and during the actual ride - no grain, no fat. His glycogen stores ran out at about 130km into the ride, after which our paced slowed significantly, down from an average of 16km/hr (10m/hr) to just over 12.5km/hr (7m/hr) from there. Still, in my books, that is a pretty good effort for a simple gutful of fiber - be sure to look after those microbes!

The Ugly
Remember, it is carbohydrate, stored as glycogen in muscles and the liver, that, energetically speaking, limits performance. This is true for both high-intensity speed-work and for lower-intensity endurance-work. Fat, as an energy source, is NEVER in short supply. For riders of performance horses the main problem with feeding diets high in fat is fat’s effect on carbohydrate uptake and utilisation. Muscle glycogen stores in working horses fed high-fat diets have been shown to be only 1/3 to 1/2 that of horses on low-fat diets.

There are countless studies concerning working horses adapted to high-fat diets and they universally demonstrate that these horses perform like unconditioned horses when compared to their low-fat diet counterparts. This is because a high-fat diet induces metabolic changes that compromise the entire process of carbohydrate utilisation, from digestion to muscle use. We know that glycogen availability is the energetic limiter of performance, including the sustained performance of endurance horse. Don’t confuse glycogen compromise with ‘glycogen sparing’ (as some equine feed manufacturers euphemise).

The simple way to ensure your endurance horse spares glycogen, by instead utilising those energy-rich IMTGs, is to work him. Because glycogen is the limiting energy substrate, exercising your horse, whether with speed work or with endurance conditioning, has the basic response of maximising the efficiency of glycogen fuel use. For endurance exercise, this means increased utilisation of and reliance onIMTGs and at increasing levels of work intensity. Then make sure you feed the work by providing adequate calories. To ensure that both glycogen and IMTGs stores are replenished, first ensure your horse is receiving sufficient fiber, both for gut health and to provide the raw material for VFAs. Remember, some VFAs are converted to glucose and can be used to replenish glycogen stores, others are converted to and replenish fat stores. If more calories are required, as they likely will be for any hard-working endurance horse, add grain safely (as described in Carbs: The Good, The Bad And The Ugly) - your horse can easily convert excess carbohydrate to fat once glycogen stores are replenished. The only dietary fat you need be concerned with is replenishing those EFAs if your horse lacks access to sufficient pasture.

More Info
Everyone interested in managing/riding performance horses should undertake Eleanor Kellon’s courses: NRC Plus and Nutrition For The Performance Horse.

Soft Country Feet Revisited

Some months back I wrote an article, Soft-Country Feet?, where I suggested that hoof ailments such as hoof cracks, white-line disease and thrush, common to horses living in soft, wet environments could be reduced or eliminated with regular, biomechanically-sound trimming.

Generally my horses get trimmed every three weeks. However, recently I have been travelling and it has been just on 10 weeks - 3 trim cycles - since my herd of eight were last trimmed. I was prepared for the worst but fortunately it wasnt that bad. All of them had grown really long (none of the working horses were even closte to fitting into their Easyboot Gloves!), a couple had developed some cracks on the dorsal wall, a couple had hoof-wall separation in the quarters, and those usually in work had lost some robustness of the frog. Otherwise they looked pretty good. It was just a case of removing excess length and correcting breakover. Here are some before, after and comparison shots of their near-fore feet:



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The last two sets of photos are of my two rising three-year olds. As I was by myself, and they are not well halter trained, I just trimmed them at liberty in the paddock. I forgot to take post-trim shots of the filly but still got the comparison shot.

Basically, despite the long interval between trims and the, not unexpected, excessive growth, I could still treat these as basic maintenance trims, achievable by any owner trimmer. For this straightforward kind of work I tend to follow a simple process.


Dorsal and lateral views of untrimmed near-fore hoof.


Solar view of near-fore untrimmed and then with excess bar and sole removed.

1. Remove any solar structures (sole, bars) if necessary. On healthy, exercising feet this is not always, in fact very rarely, required. However, bars and all but the outer circumference of the sole should be pasive to the wall when standing on flat, hard ground. So if I know I am going to  have to take down the walls a fair amount (as is the case here), then I will remove solar structures now. I very rarely remove frog; only if it is diseased. Frog stimulation and loading is required for the development of the the digital cushion and lateral cartilages necessary for horses undertaking performance work (underlying theory for a performance horse hoof can be found here).


Use nippers to remove excess wall. Use the rasp to establish vertical hoof height at the heels and toe.

2. Establish the vertical height of the hoof. The vertical height is the height of the coronary band above the ground when the horse is standing normally. In domestic horses it is pointless to put some arbitrary measurement on this - rather, use landmarks of the hoof to guide you as to where the coffin bone is positioned in the hoof and trim to optimise coffin bone location. If you are unsure of how to do this, ask your trimmer to show you. For many, if not most,  domestic horses, the coffin bone is too low in the hoof capsule and there is little scope to reduce vertical height.

In this example I have used nippers to reduce wall length. Generally this will not be necessary for maintenance trims - a regular 2-3 week maintenance trim will prevent such gross wall growth.  I then used the rasp to establish a plane across the heels and toe to set up the vertical height of the hoof.


Scoop the quarters to ensure they are passive to the heel and toe. Add a bevel around the hoof.

3. Rasp the quarters until they are passive to the heel and toe. Scooping the quarters enables the heels to more easily expand on weight-bearing. I often see otherwise well trimmed feet lacking quarter scoops. Then apply a bevel around the front half of the hoof. There are a multitiude of approaches to bevelling. I prefer a 45 degree angle around the hoof from 9 to 3.  If the toe needs backing up futher, I will apply a steeper bevel so I can go back behind the white line - this is not something that would generally be done in a maintenance trim. I rarely bevel into or behind the quarters unless there is a quarter flare. Finish with a rasp around the distal hoof wall to complete the trim.




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So lets just repeat that process another time to be sure.


Untrimmed near-fore hoof: dorsal and solar views.


Remove only those solar structures that will not be passive once the excess wall has been removed. Note: the frog and the outer cricumference of sole need not be passive.


Remove excess wall with nippers: this will rarely be necessary for regular maintenance trims. Use the raps to establish vertical height of hoof  by establishing a heel and toe plane.


Rasp the quarters scoop to ensure the quarters are slightly passive to the heel and toe. Apply a bevel around the front half of the foot. Generally the outer wall should be passive to the inner wall and outer sole perimeter. When addressing flare, at the toe - as is the case here - or quarters, the whole wall can be passive to the sole. Finish with a rasp around the distal hoof wall to complete the trim.




Keep up your regular maintenance trims - your trimmer will love you for it.




That Big Trot

Endurance riders love a BIG trot. When looking at your upcoming superstar or admiring how your favourite horse trucks down the trail, nothing excites more Oohs and Aahs amongst endurance riders than that big trot. Many endurance horses, maybe yours, undertake most of their competition miles in that big trot. I would like to suggest there are a number of reasons why the big trot is not the be-all and end-all and that more canter should be included when covering distance, for a number of reasons including:

1. Energy efficiency;
2. Scapular inhibition; and
3. Lumbar/sacral strain.


This horse clearly demonstrates all the hallmarks and pitfalls of a big trot. Although momentum plays some part in his extravagant movement, this degree of limb hyperextension requres a significantly higher degree of muscular effort than would a more modest stride. His scapular (the large bone of the shoulder) is forced through an excessive range of motion with the scapular cartilage (at the top of the shoulder blade) hitting the saddle with each stride. His hind legs are widely separated - one forward, one backward - placing excessive strain on the joints of the pelvis/sacrum and the lumbar region of the back. For these reasons, his neck is short, his back is hollow and his hindlegs show minimal joint flexion at hip, stifle and hock; instead they swing, pendulum-like, outside the path of the forelegs.

1. Energy Efficiency
When your horse moves in hyperextension, that is lengthening more than provided for by momentum, excessive muscular effort is required: extended gaits are not energy efficient. The further forward the hoof lands relative to the body mass, the more braking action occurs. Generally, a hyperextended hoof also stays on the ground for a longer period of time; tempo decreases as stride length increases. Muscular effort is required to overcome both the increased braking action and the inertia of the grounded hoof. From an energetic point of view, for most horses, any work faster than 15km/hr (ca 9mph) should ideally be performed at the canter rather than trot.

Unlike the canter, the trot lacks respiratory coupling. The up and down motion of the canter causes the substantial mass of the digestive system to move backward and forward within the body cavity with each stride. This piston-like motion activates your horse's diaphram, automating the breath with each stride, with almost no effort - an incredibly efficient way to move. The only time cantering is less effecient than trotting at fast speeds is travelling up very steep hills. Here, gravity works to push the digestive tract backward so respiratory coupling is not activated and the tempo of the canter is too slow to provide sufficient oxygen with each breath/stride and your horse quickly moves into an anaerobic work state. Although breathing at the trot requires more energy, your horse can choose to take a breath with different numbers of strides: increasing available oxygen and removing carbon dioxide.

2. Scapular Inhibition

This photo shows what happens to your horse's shoulder when he trots with lengthened strides for extended periods of time. Note the bulging scapular cartilage at the top of the shoulder blade from repeated trauma as it impacts the saddle and the 'hollows' immediately in front of and behind the wither as the horse tries to protect his shoulder from bruising by the saddle.

The shoulder of your horse has no bony attachment to his body: rather, his thorax is supported between his fore-legs within a sling of muscle and connective tissue. As a consequence, the shoulder blade (scapula) is very mobile, with a wide range of motion. As your horse extends his leg, the scapula rotates backward: the greater the extension, the greater the degree of scapular rotation. The top of the scapula consists of a cartilagenous area and this will commonly impact against the front of the saddle.

Over time, repeated impact results in congestion of the scapula cartilage - trauma. In an attempt to protect himself from more trauma, your horse braces the muscles around the top of the shoulder - in particular the trapezius muscles but many of the muscles of his topline are impacted - giving rise to the classic endurance musculature where there is a dip in front of the wither at the base of the neck and a hollow behind the wither. Flexible and semiflexible saddles that allow the scapula to move underneath them without impact greatly reduce this issue and, combined with appropriate body work and body-use reconditioning allow this issue to be addressed and enable normal scapular function.

3. Lumbar/Sacral Strain
In the trot, your horse's hind-legs are widely separated with each stride, with one hind-leg reaching forward and the other hind-leg reaching back. The pelvis and in particular the sacrum come under increasing stress with increasing stride-length at trot. In this configuration, it is difficult for the lumbar region of the back (the area directly under and behind the back of the saddle) to remain supple as one side of the horse is in extension while the other is in flexion. Inevitably this leads to lumbar strain and pain. Again your horse braces his muscles in this area in order to protect himself from lumbar pain, leading to further back stiffness and hollowing.


In the first picture the hind-legs are widely seperated in the lengthened trot, which, over time, leads to sacral strain and lumbar bracing. In the second picture the hind-legs move closely together at the canter enabling the sacrum and lumbar region to tuck freely, mobilising the horse's back.

These three issues inevitably combine - the result is your endurance horse has a hollow back.


The photo shows back and hind-quarter musculature typical of endurance horses, though this is a more extreme example than commonly encountered. For the reasons discussed here, rehabilitation requires that big trots are totally avoided. The thermograph of the same back shows how extensively circulation through the musculature has been disrupted. Note the relatively cold area (green) where the saddle sits as the muscle fascia has thickened. The lumbar area (immediately behind the saddle area) is very restricted with little blood flow whatsoever (green and blue) and has put excessive strain on the sacral tuberosities (the pointy lumps at the top of the croup). A horse with this degree of muscular shut-down will not be able to use the hindquarters in any meaningful way.

By all means, use all the gaits available to you when training and competing your horse. Just dont get bogged down with the idea that a big trot is the be-all and end-all. Break the trot up with canter wherever appropriate and your horse will go much farther for less effort.


Manilla Tom Quilty 2010 - Booted Horses are More Likely to Finish!

Last weekend saw endurance riders from all over the Australia and from around the world gather at Manilla, NSW for this years Quilty. The Quilty is Australia's oldest and most prestigious endurance ride. 11 booted horses were entered in the event and 8 were successful, for a 73% completion rate (compared to the 54% completion rate overall). The successful combinations were:

  • Carol Layton on Omani Mr Squiggle;
  • Deanna Trevena on Warr of the Roses;
  • me on Jupiter Mikeno;
  • Virginia Dodson on Qmriya Raheema;
  • Ann Batt on Roxborough Nato;
  • Donna Tidsdale on Karrana King;
  • Jane Martin on Blake's Heaven Dubbonet; and
  • Rebecca Hayes on Summerzar M'zigye.
  • (Commiserations to Rachel, Colleen and Darryl)

Carol's Squiggle was the first booted horse over the line and picked up a lovely kersey rug and generous gift voucher for their efforts, awarded by barefoot proponent Jill Moss. Photo curtesy of Jill Moss.

My ride, Jupiter Mikeno is owned by Virginia Dodson and we rode together. V is a long-time endurance friend and, more recently, one of my trim clients. Aside from doing their hoofwork, I have ridden each of the three horses V brought to this year's Quilty in 100 mile rides, so I know them pretty well.

Some photos and thermograms of Jupiter Mikeno's near fore and off hind feet, the day prior to applying EasyBoot Glue-Ons. My boots were kindly supplied by Chris and Mike from EasyCare DownUnder. Mike is the most experienced and helpful boot retailer in Australia.

As far as I am aware, all the booted horses were wearing EasyBoot Glue-Ons with Goober Glue. For the Quilty I asked another barefoot trimmer, and endurance rider, Rob Howden, to glue the boots on for us. A few weeks back, I rode Bec Hayes' mare Summerzar M'Zigye on a 50 mile ride and Rob had glued the boots on for her. The mare managed some acrobatic leaps in and out of a puddle and the boots were glued so nicely there was no issue - so who better to apply the boots for the Quilty. Of course, Rob also applied the boots for his partner Carol Layton (together they are the very successful Balanced Equine team).

It was interesting watching Rob apply the boots. He is more fastidious in the hoof preparation, scrupulously removing all dirt and exfoliating lose horn, than anyone else I have watched (much, MUCH more thorough than myself!). He also has an interesting technique after applying the glue to the boot and the boot to the hoof: using a hammer to tap the glue up from the bottom of the boot wall, until the Goober Glue just shows above the top of the boot wall. Here Rob uses an EasyBoot Glove, minus gaiter, and white Goober Glue to better demonstrate the process.

The Quilty travels from State to State, a different location each year. Generally, the track is pretty easy as the infrastructure and bureaucracy required for a prestigious ride with close to 300 hundred horses competing limits possible locations. This year's track was mostly flat to undulating dirt roads, with the 34km third (of five) legs having a few hills. The first horse across the line did so in 8 and a half hours neat. Slower competitors had a harder time as the rain started about seven hours into the ride, and much of the ride was over clay soils which became, in turn, slippery, then tacky.

1. Me and Mikena vetting in after the second leg (@86km), the rain was just starting. 2. Tacking up in the rain for the third leg. 3. Vetting after the third leg - the horses were 'over' the rain and we riders were 'over' the mud - my poor shiny sneakers! Photos courtesy of Chrissy Cooper.

1. Hamming it up for the camera going out on the fourth leg while waiting for Virginia to catch up. 2. Virginia and Raheema: no probs on the slippery tar with Easyboots. 3. Finally we are on our way... Photos courtesy of Chrissy Cooper.

I also spent some time playing around with the thermal camera, trying out different protocols and timings to determine the way to get the maximum amount of information about heat patterns, circulation and feet in competing horses. Here are a couple of thermograms of Mikena's feet in her Easyboot Glue-Ons, dorsal shot of near fore and lateral shot of off hind, the morning before and the morning after the ride.

We will continue the thermography work in the US over the next few months. Keep posted via EasyCare's Newsletter and FaceBook pages.

Carbs: The Good, The Bad And The Ugly

(Or, does my endurance horse have sub-clinical laminitis?)

So, before we begin, some terms:

Carbohydrates, or ‘Carbs’, come in a variety of forms. They can range from simple structures (glucose and fructose) to slightly more developed forms (sucrose, maltose, lactose), all known as simple-carbs (sugars). There are also more intricate carb structures – complex-carbs - that are utilized and stored by animals (glycogen) and plants (starch). Plants also create and utilize some other carbs (cellulose, hemi-cellulose, lignin) as building blocks – these carbs are known as structural-carbs (fiber).

Sub-clinical laminitis is an oft-used term in barefoot circles. The idea is that your horse is experiencing an ongoing, mild – that is, 'not clinically significant’ – laminitic event. Generally, anytime your trimmer can’t get your horse moving comfortably barefoot in a reasonable time frame and your horse remains stubbornly tender footed to ride, he is assumed to have sub-clinical laminitis. I often think we are at the stage where sub-clinical laminitis is for barefooters what navicular syndrome is for shodders – a debased catch-all term used whenever your horse isn’t traveling right.

Horses are, more than almost every other mammal, a walking digestive tract. The evolution of a trickle-fed, hind-gut fermenting digestive system has enabled wild (and feral) horses to survive and thrive eating energy poor – that is, low in sugars/starches, high in structural-carbs/fiber - forage on which most other herbivores would starve. Think frozen Mongolian steppe, harsh Shetland Isles, dry Middle-East desert. Remember the digestive capacity of an average size horse approaches 200 liters, some 65% of that is the fermentation vat that is the hind-gut.

Horses can digest carbs in the form of sugars/starches directly. These are digested almost completely in the small intestine. Structural carbs cannot be digested directly by your horse, indeed by any mammals. Instead, microbes in the hindgut ferment structural carbs, producing volatile fatty acids (VFAs), which are then absorbed by the horse and are a significant source of energy.

So what is all the fuss about carbs? And how do carbs affect your horse’s feet?

The Ugly

There is a limit to how much sugar/starch your horse can digest in the small intestine before it becomes overloaded. Typical examples of carb overload include 1).where your horse breaks into the feed room and eats a bag of grain and 2). a high-sugar flush in spring pastures. Sugar/starch not absorbed in the small intestine moves through to the hind-gut. Amongst the many species of microbes living in the hind-gut are Streptococci species. These guys feed on the sugars/starches (and also the complex carb fructan) that overflows from the small intestine, with lactic acid produced as a by-product. Normally this lactic acid is utilized by other bacteria but if the levels of sugar/starch/fructan is high, the Streptococci are favored and multiply quickly, so lactic acid levels rise very quickly. The hind-gut becomes acidic, with massive die back of other gut microbe species. The gut lining is damaged and endotoxins and lactic acid enter the blood stream. Your horse becomes systemically ill: cardiovascular shock, colic, fever, diarrhea and laminitis may result. How these laminitis trigger factors in the blood stream following carb overload cause laminitis is still unclear, despite extensive and ongoing research.


Pharmaceutical preventatives to carb overload induced laminits include Foundergaurd and Equishure. Foundergaurd is a selective antibacterial drug that targets Streptococci and effectively prevents laminitis but needs to be fed 4 days prior to a carb overload event to ensure it is thoroughly mixed in the contents of the hind-gut. Equishure is a pH buffer – a delayed release of bicarbonate that neutralises hind-gut acidity. Again, it needs to be already in the digestive system to be effective against carb overload. Perhaps you might ask: if I am going to the effort (and expense) of drugging my horse to prevent laminitis, shouldn’t I instead improve my horse-management and simply remove the risk of carb overload?

The Bad

If your horse experiences ongoing, high levels of dietary sugar/starch he will, like you, develop high levels of circulating insulin (commonly termed insulin resistance). Again, the trigger is unclear, but high levels of circulating insulin correlate strongly with laminitis. Breeds renowned as being ‘good doers’, such as Arabians and the pony breeds, are more prone to insulin resistance. Remember, your horse’s ancestors evolved to thrive in biomes where calorie rich forage is rare. When he did come across a cache of sugar/starch, the subsequent rise in blood glucose was met with an oversupply of insulin. This oversupply of insulin induces glucose to be quickly laid down as fat (both intramuscular triglycerides and adipose fat). Arabians, ponies and other thrifty breeds have retained this ability: the ongoing availability of sugar/starch-rich forage for contemporary domestic horses means they often display insulin resistance and, hence, laminitis.

The Good


How did your horse’s ancestors, in the absence of lush pastures and grain-feeding owners, get sufficient carbs to make enough glycogen to fuel his daily movement? Through that wonderful hind-gut fermentation process! Fermentation of structural carbs like cellulose and lignin – that is, fiber – results in VFAs that can be absorbed by your horse. Some VFAs can be used directly as energy, other VFAs are converted to fat and amino-acids. And some VFAs are converted to glycogen. Enough glycogen for your horse to cover 20-40km daily, mostly at a walk but with enough reserves to escape predators and for the occasional amorous encounter. Here, Shetland ponies on coarse grazing show good health, including feet, thanks to effecient digestive systems.

Exercise increases insulin sensitivity; circulating insulin levels are reduced. This is true in 'normal' and (so called) 'insulin resistant' horses. The best thing you can do to reduce the risk of sub-clinical laminitis is to exercise your horse. He needs to be covering at least 20km per day in turnout and/or structured exercise. The more work you give him, the higher his requirement for glycogen will be: remember, glycogen is the complex carb created by animals to utilise and store energy. Most hard-working horses, like your competitive endurance horse, are not able to replenish their glycogen needs from hind-gut fermentation alone: those hard working muscles are hungry for carbs and your competitive endurance horse is likely in a state of chronic glycogen deficit.

You can deliver carbs to your horse safely. Let the bulk of carbs enter as forage (pasture/hay) for fermentation in the hindgut. For hard-working horses supplement with readily digestible sugar/starch within two hours of work. Following work carbs are rapidly absorbed as the muscle wants to refuel and rebuild. Giving sufficient carbs (eg up to 2kg of grain) immediately post-work facilitates muscle recovery and development.


When this photo was taken, this horse was training a minimum of 80km, usually 100km and up to 150km/week, each week for several months. To provide enough sugar/starch to sustain that kind of workload he ate 6-8kg of grain (whole oats and extruded corn) mixed with beet pulp daily. Spread over 5 meals, with about 1.5kg grain per meal, carb overload issues were avoided. This on top of ad-lib pasture and hay. After several months, I had to reduce the workload: it was not possible for him to eat enough grain to replenish his glycogen needs. No suggestion of sub-clinical lamintis here.

Given that work reduces insulin levels and depletes glycogen stores, it is extremely unlikely that your competitive endurance horse, indeed any hard-working horse, is experiencing carb induced sub-clinical laminitis. I suggest you look instead to the mechanics of his hoof and your trim to explain any ongoing tenderfootedness...

More Info

Everyone interested in managing/riding performance horses, should undertake Eleanor Kellon's courses: NRC Plus and Nutrition for the Performance Horse

Katy Watts site, Safergrass, is the benchmark for information on pasture triggers for laminitis.

The most comprehensive survey and analysis of the relationship between carb and equine performance is available free in Tom Ivers' eBook Optimised Nutrition For The Athletic Horse.


Ongoing Education

Thanks to EasyCare, I recently had the opportunity to attend a four-day equine thermography course with Donna Harper DVM. Dr Harper is one of the pioneers of equine thermography and has a wealth of knowledge to share, which she does very generously. Thermography uses an infra-red camera to translate skin surface temperature into colour screen-images. This enables us to look at the heat patterns on a horse and detect any anomalies in those heat patterns. I am really looking forward to playing around with thermography - wouldn't it be nice to get some controlled comparisons of heat patterns in barefoot, booted and shod horses?


This is a thermograph of the right front sole of one of my horses after day three (150 miles) of a five day (250 miles) ride back in 2006. The horse was booted in Easyboot Bares for the entire ride. It's hard to argue with such a nice heat pattern. Image by Jean Koek.

In the course, Dr Harper covers not only theory and practice for the thermograph technician but also stresses the need to understand, limit and correct for 'artefacts' that will compromise the integrity of the image. She also emphasises that correct reading of images requires an in-depth understanding of anatomy and physiology.


This image has been doing the rounds for years. Usually it is suggested to represent what happens to limb circulation when a horse is shod (front right) compared to unshod (other three feet). In fact, what it actually shows is a heat pattern absolutely consistent with cervical nerve dysfunction - that is, the shoe on the front right is largely irrelevant to the cool temperature pattern seen here.

Dr Harper has a wide range of interests on top of her equine thermography practice/instruction and her regular veterinary work. Amongst other things, we looked at and discussed an interesting horse-shoe she concieved, developed and tested on her own gallopers. She outlined her ideas on the characteristics of a saddle-pad that would actually work at protecting the horse's back from less than perfect saddle-fit or rider equitation. And of course we discussed prosthetics for equine amputees, a topic close to her heart.

Here is Dr Harper's thoroughbred amputee mare, Oink, nursing a couple of foals. Oink wore a prosthetic limb and raised five foals of her own and an additional two orphans to boot. Her only foal that was taken to the race track won its first race. Oink was only recently put to sleep after seventeen years as an amputee.

You can see here a prosthetic hoof Dr Harper made out of an Easyboot.

Thanks Dr Harper for a stimulating four days and thanks EasyCare for facillitating my attendance.

Duncan McLaughlin

 

 

Is Concussion Really A Problem?

"Your eye and ideas are not nearly as good as nature’s."  James Rooney

We have all seen them, those insidious concussion rings that appear in the hoof wall following an endurance ride, gradually moving down with the growing hoof capsule. Sometimes they even manifest as horizontal concussion cracks. They look ugly and they scream: Damage! And then, there is all that long-term concussive wear and tear on joints leading to inevitable arthritic change. Not surprisingly, managing concussion is often considered the primary soundness issue for your endurance horse over his career.

But need it be so?

To answer this question, let’s first consider how the hoof functions. Of course, as any internet search soon shows, there are about a bazillion or so theories on how the hoof functions and how to best manage and dress the hoof for optimal performance. For any one theory of hoof function you will soon find another in complete contradiction. However, all the different theories can be categorised into two basic models based on the distribution of weight through the hoof.

1. Whole Of Foot

Under this model, your horse's weight simply falls, via the skeleton, to the ground through all components of the hoof (wall, sole, bars, frog), which share in the distribution of that weight. The coffin bone is the load-bearing structure. Under this model, factors external to the hoof, such as the amount of daily movement, the living and working terrain, conformational traits, and the presence/absence of hoof protection, are considered to determine which hoof structures are trimmed and which left untouched. The aim is to distribute weight across all hoof components, including the caudal hoof (digital cushion, ungual cartilages), to optimise correct coffin bone loading within the hoof, both in motion and at rest.

2. Lamellar Sling

Under this model, your horse's weight falls through to his coffin bone, which is in turn suspended in a 'sling' by way of the close interweaving of the epidermal (hoof wall) and dermal (inner hoof) lamellae. Under this model, the hoof wall is the primary weight bearing structure, and the focus is on angles and measurements of the hoof in isolation to both your attached horse and his living environment. Obviously this model is implicit in all farriery: attaching a shoe mandates the hoof wall as the only weight-bearing structure. Some vets and researchers also use this model. For example, the work of much-quoted laminitis researcher Chris Pollitt DVM is based on this model, which he describes as the 'lamellar corium - distal phalanx attachment apparatus'.

Most schools of barefoot trimming use methods based on the Whole Of Foot model. Rightly so - there is good reason to be skeptical of the Lamellar Sling model:

1. Despite the extensive area of interconnecting epidermal (hoof wall) and dermal (inner hoof) lamellae, around about a square meter per hoof, there is no reason to believe that, as the primary (or singular) weight-bearing mechanism, this soft tissue connection is able to withstand the repetitive forces generated by a moving horse over a long term performance career.

2. Horses are not intergalactic visitors, without an evolutionary history. No other terrestrial mammal suspends its weight from its epidermis! Horses evolved from three-toed ancestors that distributed weight through the whole of each of their three toes. It is hard to imagine, given this starting point, any type of selection pressure under which a ‘lamellar sling’ would or could evolve.

Like your horse, giraffes evolved by fusing and lengthening of the bones of the lower limbs but the giraffe has two toes encased in horn instead of one.

3. More pragmatically, schools of barefoot trimming based on the Lamellar Sling model, for example those based on Hiltrud Strasser DVM’s theory of ‘ hoof mechanism’, continue to be spectacularly unsuccessful at producing sound horses able to perform any useful amount of work.

Bone requires loading – it loves to be stressed. But it needs to be stressed along the line(s) of compression for which it evolved. Your horse’s coffin bone is his loading hoof structure: trimmers of successful barefoot performance horses trim to the coffin bone. In particular they look to maintain/develop a hoof where the medio-lateral and anterio-posterior balance facilitate quick and easy rotation of the coffin bone during the support-phase of movement (see the previous post on positive dissociation for a reminder on why short stance phases are important) and where the coffin bone sits high in a short hoof capsule.

Trimmed (or shod) in accordance with the Lamellar Sling model, your horse’s weight is suspended primarily or solely from the hoof wall. The soft tissue, the epidermal and dermal lamellae, connecting the hoof capsule to the internal hoof are not able to withstand repetitive pressures associated with movement and the hoof capsule is pushed (by the ground) up higher and higher around the coffin bone; the hoof becomes longer and longer. In the absence of ground stimulation, the thin sole and under-developed caudal hoof (frog, bars, digital cushion, ungual cartilages) results in a coffin bone that sits low (digital descent) in the already elongated hoof capsule. There is no compression of the coffin bone, via the sole. Instead, it is placed under tension from the lamellar sling – a quite different force than the compression forces the coffin bone evolved to cope with. The distal phalangeal joint (between the short pastern and the coffin bone) is encased within the long hoof capsule, reducing range of motion.

Further, to move optimally, the coffin bone pivots over a specific balance point in the hoof, above the pericuneal cortex, during the support-phase of movement. When your horse has a long toe, the palmer processes of the coffin bone elongate in an attempt to rebalance the hoof and so maintain position of this pivot point. This results in what we commonly call under-run heels: It is not necessarily that the heels are actually under-run but that the palmer processes of the coffin bone have elongated backward, over the heel, in an attempt to balance the long toe.

 

Trimmed in accordance with the Whole Of Hoof model, your horse will have increased concavity, sole thickness and caudal hoof (frog, digital cushion, ungual cartilages) development within a relatively small hoof capsule. The coffin bone sits high in the hoof capsule with the happy consequence that the distal phalangeal joint is about level with the coronet band, enabling that very fluid movement peculiar to barefoot horses.

The focus using the Whole Of Foot model is not how much the hoof wall (or any other hoof component) is loaded or unloaded, this depends on a range of factors, but to ensure the coffin bone is correctly loaded. As a rule of thumb, we want the hairline above the extensor process of the coffin bone to be around 10mm distance (or less!). If this distance is 14mm or greater, your horse clearly has a descended coffin bone (digital descent).

 

Despite the very long walls on the foot of this soft-terrain living Cumberland Island feral horse, correct anterio-posterior balance is maintained. The long heels balance the long toe to ensure correct pivot point and the coffin bone is still loaded as the very soft terrain provides a ‘solar plug’ which fills in the area under the sole between the wall. In addition the wall at the toe cuts into the soft ground, allowing full range of movement without excessive dorsiflexion of the fetlock. I pinched this photo from Cindy Sullivan’s Tribe Equus website.

Our discussion about concussion and hoof structure must include mention of the bars. For our performance horse, we want short, straight bars that bear load during support-phase. In a well developed hoof the ungual cartilages are thickened with fibrous cartilage that sits over the bars. On weight-bearing the bars are pushed up and work in conjunction with the ungual cartilages to expand the top of the hoof. Loaded bars are also involved in the transfer of energy to the digital cushion. Bar loading is vital for reducing concussion (as your good footed horse actually experiences negative pressure in the hoof on heel strike, it sucks onto the ground – refer to Prof. Robert Bowker’s work on good footed horses for more detailed explanation). Those trimmers who are misguidedly excavating bars in order to relieve ‘navicular syndrome’ or wall flares at the quarters, are actually increasing concussion and preventing caudal heel development. No amount of trimming can develop short, straight, functional bars. Functional bars result, as if by magic, when the coffin bone is carried high in the hoof capsule; a result of well developed soles and caudal hoof structures.

Similarly, it is not possible to trim concavity into the sole. Again, concavity arises when the thick sole and well developed caudal hoof push the coffin bone higher in the short hoof capsule. Carving out concavity in a parody of correct hoof function simply thins the sole further, preventing your horse from performing any useful amount of work. In particular, the sole under the coffin bone, rich in proteoglycans that function to hydrate the solar tissue and so absorb concussion, should not be compromised.

So, trimmed by methods that accord with the Whole Of Hoof model, your horse will move in a biomechanically correct and comfortable manner. But what do we mean by ‘moving comfortably’? In a recent internet chat-group discussion, one observer of Australia’s desert brumbies mentioned that some of these horses would take ‘ouchy’ steps when trotting on rocks and gravel. This is  what should happen and demonstrates extremely effective hoof function. When I take my shoes off and go for a run, I can stride along quite comfortably but if my foot begins to land on a sharp rock, I immediately take an ouchy step - I limp- as sensory nerves instigate a reflex action to prevent my foot from weight-bearing. The ouchy step is the perfect (though energetically inefficient) way to move when treading on a sharp rock and prevents both me and the brumby from getting a bruised sole. It certainly does not mean either of us are unsound or in pain. Indeed, failure to take an ouchy step when treading on a rock is, or should be, the real concern; go watch the shod horses at your next endurance ride…

The same sensory mechanisms explain why terrestrial mammals take longer steps on soft ground compared to shorter steps on hard ground. When landing on a soft surface the hoof instinctively comes down harder in order to load the coffin bone and to find a stable platform for support: cushioning (turf, sand, padded boots or shoes) reduces sensation, not concussion. Your barefoot horse, trimmed to appropriately load the coffin bone, trotting with shorter strides on an tar road demonstrates the correct biomechanical form and function to dissipate concussion. On a softer surface, say a grassy field, he will need to move with a more lengthened stride – that is, increased force - in order to correctly load the coffin bone and reach a stable suport surface.

Accepting that his movement will change on different surfaces, you should always remain alert that your barefoot horse travels in a comfortable manner. Anytime your horse is not moving comfortably, for example, continuing to tip-toe along a gravel road, he is using muscular effort to change his way of going. This is not only an incredible waste of energy, with potential for muscular overuse injury, but also puts improper stress on bones and joints: joint injuries are not overuse injuries, they are improper-use injuries where muscles, via tendons, inappropriately strain the bones comprising the joint. If your barefoot horse is struggling in anyway with the distance or terrain you ride him over, you should boot him.

A number of boot models are appropriate for endurance horses. I prefer the Easyboot Glove for endurance (and whenever possible for rehabbing horses with laminitis, ‘navicular syndrome’, and similar hoof pathologies). I particularly like the Glove because:

1. Rubber is the ideal surface to encourage perfusion of blood through the hoof. In his lecture to students in the 2009 Diploma of Equine Podiotherapy, Prof. Bowker discussed how the hoof interacts with a rubber surface, increasing surface area (more than on any other substrate). Even small increases in surface area will drastically reduce overall pressure.

2. The firm rubber surface evens out the actual terrain the horse is moving over. On soft terrain such as deep turf or sand, the rubber provides a more resistant landing preventing the limbs from hyper-extending in an attempt to find a stable landing place. On very hard terrain such a rock or tar, the rubber creates a more cushioned landing, allowing your horse to move out comfortably with lengthened stride, which is much less fatiguing for the rider.

3. There is a good breakover, relative to the solar area, moulded into the boot (the breakover is much better than the breakover of the actual hoof for the majority of domestic horses). As discussed previously, a quick breakover ensures correct biomechanical action, including heel first landings. Comfortable heel first landings are the way to develop the caudal hoof. Stimulation of receptors in the frog, heel bulb and ungual cartilages encourage development of the digital cushion. The digital cushion of horses with no frog, sole and heel stimulation is a weak mass of connective tissue. By contrast, stimulated with whole-hoof ground-contact and heel first landing, the digital cushion develops a web of fibrous cartilage that radiates out and up from its origin near the junction of the deep digital flexor tendon with the coffin bone. On a well developed hoof this fibrocartilagenous web extends up past the navicular bone and creates a resilient floor across the entire base of the digital cushion. More fibrocartilage means more energy dissipation and less concussion. Further, the ungual cartilages of the coffin bone also lay down (thicken with) fibrocartilage in response to stimulation. Well developed ungual cartilages approach an inch in thickness and are crucial in reducing concussion as only thick ungual cartilages encase intricate complexes of blood vessels within: these act as hydraulic energy dissipaters. When these complexes merely sit along the internal edge of thin ungual cartilages, their function as shock absorbers are compromised. Ideally, you want your horse to have close to one third of its hoof volume taken up by these caudal hoof components. In shod horses the caudal hoof volume is commonly less than 20% and sometimes as little as 10%. Used on a horse with a well developed caudal hoof, as found with many barefoot endurance horses, I will further rasp back the Glove breakover a few millimeters more to create an improved boot breakover for working horses – this saves waiting for the breakover to wear in over time.

4. The comfort provided by the boot means the horse can be ridden more. More steps means more blood perfusion through the hoof and more development of the caudal hoof. In effect, you can ride your horse to increased soundness (the opposite of the traditional view that an endurance horse only has so many miles in him).

GE Lady, at the end of a hundred mile ride, wearing Easyboot Glue-Ons with solar packing. Despite a strenuous and rocky 100 miles, Lady continues to move with positive dissociation. Her soft and relaxed musculature, in particular the raised withers and forward reaching poll, indicate continued excellent biomechanical form despite her exertions.

Of course, it is not all sweetness and light. All hoof boots have a flat inner-sole. If most of your horse’s time in action is spent in boots (as is often the case for endurance horses, who cover much more ground in training than when loafing around the paddock), you will see the hoof adapt to this flat surface; primarily by losing concavity. The coffin bone does not want to ‘bottom out’, that is, over-descend (and come into tension as per the Lamellar Sling model), as is possible with a concave foot on the harder, flat rubber boot surface. The sole will thicken further, particularly in toward the frog, filling in the concavity. Not in itself a problem except that this extra thick sole has potential to overload the coffin bone when your horse is unbooted. For many boots, the issue is avoided completely by using a dome pad as a ‘solar plug’, providing an artificial terrain that maintains concavity (in fact dome pads are so effective at this I have often incorporated them in the recovery of laminitic horses to riding soundness). Dome pads are not yet available for the Glove but it is easy to create custom pads for your horse using Goober Glue.

Further, cushioning reduces sensation not concussion. Booting, and particularly booting with pads (of whatever form), reduces the sensory feedback from the hoof. More than likely your horse will want to really stride along when booted. It is appropriate for you, as the rider, to slightly temper this more extravagant movement and somewhat contain his length of stride. But don’t worry too much. So long as the boot allows (or improves on) correct movement (reducing support-phase, lengthening flight-phase) then any increased concussion forces are easily dissipated according to nature’s design.

Remember, it is correct biomechanical form and function that dissipates concussion – get these right and concussion simply ceases to be an issue, no matter how many miles you ride.

Positive Dissociation Indicates Effecient Movement

Clip-clop, clip-clop, clip-clop. Generally, we think of the trot as a two-beat gait. First, one diagonal (near-fore and off-hind) hits the ground followed by a moment’s pause before the other diagonal (off-fore and near-hind) hits the ground. But this isn’t always the case. Often, the legs of a diagonal pair do not move in unison. We call it positive dissociation when the hind-foot hits the ground before the diagonal fore-foot and negative dissociation when the fore-foot hits the ground before the diagonal hind-foot.

 

 An off-the-track galloper, in the arena in preparation for his new life as a companion and trail horse, clearly shows positive dissociation.

 Positive dissociation indicates stride efficiency. Generally, superior performance horses move in positive dissociation. Negative dissociation indicates poor efficiency and biomechanical imbalance. So we can use dissociation as an indicator of the efficiency and biomechanical correctness of our horses. Efficient movement is about covering more ground with less energy expenditure. Racehorses and endurance horses need to be efficient. Dressage horses and showjumpers do not: Indeed, these disciplines can develop some qualities in movement that are very inefficient.

 To understand how trimming and conditioning affect stride efficiency, and how this is demonstrated by positive dissociation, we need to understand the component phases of each stride:

1. The flight phase is entire period of the stride where the hoof is in the air.

2. The support phase is the period where the hoof touches the ground. The support phase is further divided into three sub-phases: breaking phase, stance phase and propulsive phase.

We want our efficient horse to spend more of each stride in the flight phase and less in the support phase.

 

 

This bare hoof will aid efficient movement: good anterior/posterior balance with short toe and clearly scooped quarters.

 

A physiologically correct barefoot trim aids efficiency for a number of reasons, including:

1. Correct hoof form maintains healthy stay apparatus and allows for efficient foreleg protraction during movement;

2. Heel first landings allow the hoof to flow through the entire support phase more quickly;

3. Scoops in the quarters and toe add biomechanical efficiency; and

4. A shorter toe has greater surface area for propulsion and ensures a more efficient flight path.

Let’s look at each in turn.

 Healthy Stay Apparatus

When at rest, your horse employs his stay apparatus to maintain a standing position with minimum effort. The stay apparatus, in both the forelimbs and hindlimbs, involves ligaments, tendons and muscles that align in unison to counterbalance both gravity and bodyweight. Incorrect hoof alignment will misalign the stay apparatus, reducing its effectiveness: your horse must now employ muscular effort even when resting. Obviously, this reduces his overall efficiency. By barefoot standards, nearly every shod horse shows anterior/posterior imbalance and some degree of digital descent: these horses are working harder, even at rest.

 In movement, horses are not able to protract the foreleg quickly enough to position the hoof for the support phase by muscular contraction alone. Instead, protraction results from a catapult type action of certain muscles, like the biceps muscle of the forelimb, that store and release energy like an elastic band - they function like tendons. These very same muscles are also involved in the stay apparatus. So dysfunction of the stay apparatus due to hoof imbalance also reduces the elastic action of the muscles protracting the limb. The horse must engage more muscular effort, which is very fatiguing.

 Heel First Landings

 

Bare or booted, a correctly trimmed hoof with associated heel first landing enables increased efficiency of movement.

 Pretty well everyone in the barefoot movement understands and agrees that heel first landing is a good thing (if you want a recap, there is a nice summary at www.barefoothorse.com/barefoot_Breakover.html). But don’t confuse ends with means. We don’t want a well trimmed hoof in order to achieve heel first landings. We want our well trimmed hoof, with associated heel first landing, to increase stride efficiency. However, the following caveats apply when using heel first landings as an indicator of correct biomechanical movement:

1. On uphills horses land toe first. This is because there is less time for flight phase, so the foreleg never fully extends;

2. On downhills most horses land heel first. There is more time for flight phase, so the foreleg more fully extends;

3. The degree of heel first landing is dependent on momentum. A horse faster moving horse will show more heel first landing than a slower moving horse. Flight phase is largely influenced by the power coming from the hindquarter, more flight time = more forelimb extension = increasingly heel first landing. Horses moving with little momentum may not show clear heel first landings, even if they have good hoof form and correct movement.

 A heel first landing, with heels expanded due to the scooped quarter, allows the breaking phase to flow more smoothly and quickly into the stance phase of support. This reduces the overall time spent in the support phase and increases the time spent in flight phase.

 Quarter and Toe Scoops

As just mentioned, the scooped quarters allow the heels to expand on hoof impact, expediting flow through the support phase of a stride. That scooped shape also provides your horse with increased power when travelling on yielding terrain such as turf, sand or steppe, in the same way that your cupped hand increases your power when swimming.

 During the breaking and stance components of the support phase, the quarters experience increased abrasion as the heels expand on hoof impact. Similarly, the toe experiences increased abrasion during the break-over and the propulsive components of support phase. High-mileage barefoot (unbooted) horses often develop a toe-scoop on their front feet: a slight depression of the hoof wall and sole at the toe between (roughly) 10 and 2 o’clock. Like the quarters, this toe scoop simply reflects an area of high wear.

 On firm but yielding surfaces such as turf, gravel, sand or steppe, the slightly longer toe at 10 and 2 o’clock displaces substrate from the side toward the hoof midline. This increases the surface resistance to the hoof at the end of the propulsive phase resulting in increased efficiency: the hoof moves over the surface rather than through it. Conceivably, you could design a desert racing boot, with the break-over further back and a toe scoop that mimics these natural characteristics, for those UAE horses racing 100 miles at fast speeds and requiring the protection a hoof boot provides…

 A Short Toe

An efficient mover will show less vertical displacement through the stride. A shorter toe promotes a lower foot path with less vertical displacement: during support, the hoof spends less time in the breaking phase and more time in the propulsive phase. As the degree of vertical displacement in the stride reflects the degree of downward directed force, the efficient mover is also less prone to stress/concussive injury.

 In the absence of slow-motion video, the easiest way to assess vertical oscillation is to tack your horse up trot him out: take note of vertical (up and down) movement of both his head and his saddle. The head or saddle moving up or down, relative to the ground, indicates wasted energy and increased likelihood of injury.

  

A typically shod endurance horse demonstrates a flight path that is inefficient and increases the likelihood of long-term injury.

 Your long toed horse has a longer stride. This is because the long toe, with flat or toe first landing, does not roll smoothly from the breaking to stance phase and experiences a delayed break-over for a longer support phase. So the flight phase begins with the leg further back under the horse. This is inefficient. It is also associated with a slower tempo (due to increased support phase and inability of the protractor muscles to work elastically as tendons).

 So it is clear that for a number of reasons a correct barefoot trim will increase the time in flight phase and decrease the time in support phase. The foreleg will break-over more quickly, which is reflected in increased positive dissociation. However, even well trimmed and managed horses can be seen to move inefficiently.

  

A well trimmed endurance horse showing negative dissociation, the right-fore is going to hit the ground before the left-hind. You need to assess if this is simply a momentary loss of balance or a habitual way of going.

 

 

Dissociation also applies to the diagonal that makes up the second ’beat’ of the canter: we want to see positive dissociation here too. This green horse is travelling on the forehand - we see negative dissociation of the off-fore landing before the diagonal near-hind.

 A horse that travels to much on the forehand, either as a general way of going or as a momentary loss of balance, will demonstrate negative dissociation.

  

This horse is developing piaffe, a movement requiring a high degree of collection. However this photo captures a decided lack of balance, with too much weight on the forehand and the horse is triangulating with the foreleg well back under the body and the hoof stuck in support phase.

 Another way to increase stride efficiency, with resulting positive dissociation, is to train your horse to both push and carry more from the hindquarter and so allow the foreleg to cycle through the support phase more quickly. Correct dressage training is an excellent way to do this. Accelerations at trot are also effective: trot steadily and then, suddenly, trot much faster for a short period before resuming the steady trot - repeat several times. Indeed, accelerations are commonly employed by standardbred trainers to improve the performance of their racehorses, to the extent that some trotters, travelling at race speeds, reach and carry so much with their hind end that for some strides the foreleg simply cycles through the air and doesn’t touch the ground at all. Hill work is also advantageous for developing stride efficiency. When travelling uphill, the weight shift from gravity mostly increases the demand on the hindquarter but also on the foreleg extensors. Extra strength developed on hills means increased efficiency on the flat. Also, when travelling uphill, the support phase is shorter, mostly because the breaking phase is reduced or eliminated completely and the propulsive phase increased.

 So there you have it, a barefoot trim and a little specific conditioning will enable your horse to move more efficiently down the trail. And you will see this increased efficiency by watching for positive dissociation.