''Jarred Up'' horses - observations by a racecourse farrier

At the height of the flat racing season how many different terms are used to describe horses that lose their action? The description depends very much upon those that are explaining the condition and what is perceived to be the cause and the effect; the animal simply becomes scratchy and non free flowing in its movements. The exciting cause reveals itself as being “JARRED UP.”

At this early stage no observable foot specific secondary condition is presented. The physical condition I have become aware of horizontal striation of the dorsal wall which is rarely present in two year olds, but as a condition is fairly common in the older three year old plus groups, specifically when the animals have raced the previous season on firm ground. I feel there are several diagnostic constants which mix the primary causes of being “jarred up” with the secondary effects to form the description and source of the discomfort, these can be incorrectly described.

I feel the primary cause of the loss of action often relates to horses’ feet and acute inflammatory changes. The conclusions are drawn from physiological changes noted and only recently considered as being relevant to a loss of action some six to ten months earlier. The early foot changes are demonstrated by irregular growth patterns in the development of the dorsal surface of the hoof wall and related voids within the actual structure of the hoof. The above features progress downward locked in the structure of the hoof wall during normal growth from their area of formation, which was initially located within the tissues of the coronary crown down towards the hoof’s bearing surface. Voids are only revealed physically and visually when the attendant ridging and grooving reach ground level.

Without doubt the observations, when applied to flat racehorses, relate to an incident or repeated incidents of athletic output during the previous racing season on ground conditions unsuitable for the specific animal or its specific physiology. The animal often simply presents as not being free moving without any observable unilateral lameness. Often a few days on “The Walker” at rest and an analgesic course of medication will enable the animal to keep racing throughout the season and without any apparent loss of form, yet the animal’s action is changed and varies from slightly off to quite uncomfortable. To continue to race demonstrates just how adaptable a racehorse is.

I will attempt to describe the primary action modification most commonly noticed. My peers have long since suggested horses prepare their feet to land by lateral and medial adduction and abduction prior to their foot planting, a flaccid lower limb state, probably seeking out the nature of the ground surface and what adjustment the horse has to make to avoid injury. I have noted that the landing preparation aspect of the stride of sore / jarred up horses is dramatically visually bi-laterally exaggerated and the animal instead of abducting/adducting its feet actually assumes a base wide flight and its feet immediately prior to landing describe circular movements away from its axis, the left foot anti clockwise, the right foot clockwise. The movement described is bi-laterally matched, symmetric, which is felt is abnormal and forwards progress for the animal is somewhat mechanical [not free flowing], yet the animal is not exhibiting any unilateral [single leg] lameness. The above is felt is an outline of the noted condition, but what is actually happening? I feel there is strong evidence of coronary shunting, effected by the concussive forces transmitted through the dorsal wall of the hoof into the sensitive tissues of the coronary cushion due to a firm racing surface. It is these concussive forces that cause the coronary corium to lay down a protective fluid barrier, a “CORONARY SEROMA” [blister] or even in the most severe insults “HAEMATOMA” [blood blister], the fluids protect and buffer the vital horn growth area. It follows that this fluid area effectively becomes locked within the growing structures of the dorsal wall. The lymphatic system fairly rapidly mops up the fluid, a cellular, sometimes bloodstained and often linier void remains [non cellular] within the structure of the wall. The severity of the initial physiological insult determines the extent of the fluid, seroma/haematoma and the resultant defective area/void. The weakened hollow area now below the coronary ring is, I feel another of nature’s ways to effect an additional buffering/flexibility to dissipate any future or ongoing shunting trauma, firstly protected by a hydraulic action then an air buffered flexible space which remains within the horn tissue, a perfect and natural response for concussive protection.

The problems of shoe attachment to defective horn are at this stage are effectively still latent. How it affects the tradesman “Abraded feet” is a fairly loose term to describe the ultimate nightmare for the racetrack farrier. The distal edge of the hoof capsule has become flaky, cracked, underrun with cavities, to a greater degree loose from its underlying and adjacent supporting structures. The sole is consistently doubled, one of nature’s processes to protect the solar surface of the distal phalanx [P3] and its related soft tissues. This thickened sole is often not sufficiently matured to be mechanically exfoliated, yet it hangs below the level of the wall.

Nature takes no account within its physiological blueprint for the need of the farrier to attach a metal shoe as a base plate. The increased thickness of the double sole creates stressing forces of its own, demonstrated by the perfectly natural sideways loading on the weakened wall and to complete natural the separation of the already partly separated base structures prior to rebuilding them, which often is further demonstrated by the presence of a dorsal depression in the wall.

This is saying nothing of the now inflexible nature of the doubled sole constricting the natural processes of the sole connective tissues. It must be remembered in the wild state this horse would be somewhat in a recovery state and acutely in danger of predation. The problem is these feet seldom support a shoe in a satisfactory way. Racing plates tend to become easily detached especially during transit to the racecourse. This is a headache for the racetrack farrier, as in order to reattach a shoe, which he is employed to do, the loose unviable horn and great deal of the remaining poorly integrated glue has to be removed, just as is outlined as one of nature’s processes in the above paragraph in order to get a satisfactory layer to load a shoe onto and re-attach, nail the plate into. The problem here is that often after the defective horn is removed there is left insufficient wall horn, both in quantity and quality, into which a nail can be driven, certainly other than in the most forwards toe area and maybe one nail in each heel area. Otherwise, no viable nail supporting wall horn remains.

The thickened solar plate can in the very short term be used by a farrier to assist with a semi-secure nail attachment, as is demonstrated by the system of very low nailing and close shoe fitting sometimes seen in US stock. With ingenuity, stealth a great deal of luck and some skill a failure to reattach a shoe for the purpose of a single race is extremely rare, in my case twice in twenty six years, once due to the extreme stroppy nature of the patient not permitting re-attachment without displacing the re-attached shoe by immediately kicking it off again. The other occasion the animal was still as lame after re-attachment as it had been with the shoe absent when it arrived at the track!

Just out of interest, occasions have arisen when horses have gone to post with the nailing supported with electrical insulating tape, a very useful tool to have in the van and at other times the shoe and nailing supported in place with multiple layers of vet wrap. What happens after the animal returns to the care of its yard is fortunately another’s worry. I have these problems at home in my own daily practice when time is not of an essence. This is why it has been necessary to attempt to understand the specified racetrack scenario.

I will attempt to suggest how the condition of voids within the horn structure described in part one lead to abraded feet. It is actually a simple matter where the voids represent a wall detachment/lock up cavitation, which when the affected wall area reaches the level of bearing is imperfectly attached so as to have a loss of integrity with the underlying and surrounding horny tissue. The remaining wall structure gradually and simply fractures away from a defective basal connection and then further disintegrates under the loading associated with the stresses of athletic performance and when any attempt is made to nail into it.

There is a complicating factor in feet containing dry seroma cavities which I will attempt to explain. The integrity of feet which are affected in this way remain fine, and SEEM to remain thus until the separated area grows down to a level of the white zone junction, when the farrier’s nails penetrate into the cavity in order to attach a racing plate. The action of nail penetration seems to trigger a secondary effect, an influx of bacteria and yeast infection, associated with loose wall, seedy toe and/or white line disease kick-off, all of which assist the weakening conditions related to shoe loss and separation of the hoof wall from its junction with the solar plate. The author feels infection in itself is an induced condition and secondary to the original insult. The breakdown of the wall sole junction is without doubt related to environment and compaction by the racing/training surfaces.

To identify the onset of the syndrome takes very close observation as the initial indication is masked by the covering racing shoe and is not unusually seen as an extremely thin linier fissure, on many occasions detected by little more that a gut feeling. Having said this, if the fissure is missed at a very early stage, during the course of a full shoeing cycle great horn destruction in the area of the white zone will take place. A seedy toe, yeast-induced wall separation will happen and will unless effectively dealt with, migrate up the bi-sulphide junction more quickly than the wall can grow downwards, creating a chronic and accelerating condition. This horn decay is fortunately something that can be today easily controlled and/or reversed with recently and specifically developed products which condition hoof horn and destroy hoof related infection. I have trialled a conditioning gel product over the past two years with fantastic results.

There is when addressing problem feet today a distinct move towards the early use of hoof rebuilding materials and the attachment of alloy plates with glue products, from my viewpoint somewhat of a cop out and the equivalent of a band-aid exercise, undoubtedly. “Glue destroys the integrity of viable and healthy hoof horn.” This rebuild/attachment method is a nightmare to the racecourse farrier as these rebuilt feet and shoes attached with glue seem to be easily rejected. During the course of a year several reinforced feet / glue-on shoes are lost at the racecourse prior to racing; in fact it is fair to say the majority of front feet presented have evidence of glue/rebuild materials present. The shoes seem predisposed to falling off for many reasons. When this happens most of the lower hoof wall falls away with the polymer and /or acrylic. There is never sufficient time for the racecourse farrier to re-glue or rebuild a foot so the retained farrier has to find a way to replace the glue-reinforced/attached shoe using the traditional nailing method. There is no crisis more critical than getting a horse to the starting gate sound once it is at the racecourse premises. It is a very stressful time for everybody involved, and damaged feet are conditions best avoided wherever it is preventable.

So how can feet be made to regenerate sufficiently after having been subjected to treatment with re-enforcing material? The basic conclusion seems to be getting back to common sense methods, good diet, working on suitable surfaces (sea sand is not one of these), good husbandry, a regular shoeing cycle, sufficient hygiene, suitable bedding, pre-racing foot conditioning and the essential observant farrier. I feel a most important aspect is conditioning of the animal and its limbs in a way to assist sufficient horn keratinisation, which possibly is effected by training on suitable surfaces.

Steeplechase horses subjected to an element of road work in their preparation seem to have less hoof problems, yet this may simply be that they do not race on very firm ground, a seasonal influence. For the future, should we consider fitting a rolled toe shoe when animals are going to be asked the perform on really hard ground? There seems to be no place for the square toe being used on racehorse due to a lack of traction during the acceleration phases, but a very light roll, who knows? We will, in the next couple years no doubt! I feel there will be a niche for the rolled toe during the recovery stage from this condition but as a preventative measure? As a training aid? I will undertake such a study now that it has been suggested.