For a long time, horse owners, veterinarians and farriers, have been confronted with this difficult problem: treating, monitoring and helping so called navicular horses. Today the term has become taboo because it represents repeated lameness and it is often a major handicap for the subject's sports career. The term podotrochlear syndrome has replaced it, but this troubles people's minds and quickly ends any discussion because it is not yet part of the horseman's vocabulary or jargon.
The problem remains difficult for both veterinarians and farriers alike. Horse owners for their part have to accept certain conditions; the use of the horse must sometimes be revised since certain exercises are very inadvisable in case of this pathology (1)(2). The budget can sometimes be very significant for investigating and treating this syndrome in veterinarian terms, as well as for the special shoeing which is often costly and renewed more frequently.
In order to update my knowledge and transmit the most up-to-date information to veterinarians and my colleagues, I sent out a very precise questionnaire to many farriers and also veterinarians specialising in lameness of horses around the world.
The responses are interesting and converge very significantly around the techniques that should be adopted in order to help horses suffering from podotrochlear syndrome. This is proof that information circulates rapidly and that new ideas with positive effects are immediately adopted by competent veterinarians or farriers.
I had the occasion to analyse navicular disease a few years ago ( 1994) and review the shoeing methods that should preferably be applied to these horses. Looking back through my notes, I can see that certain of today's new techniques give us more resources and interesting results.
Veterinarians have fine tuned their diagnosis and differentiate between three forms of the illness:(3)
-The articular form
-The ligamentary form
-The tendonous form
This degree of diagnostic precision requires advanced medical methods and will be difficult to achieve outside of well -equipped facilities.
The identification of one or several of these three forms will help the veterinarian and therefore the farrier to observe the hooves and define the appropriate type of correction.
However, we have to remain realistic and keep our corrective actions simple. Above all this involves stressing the basic principles. Negligence of owner but also of farriers leads to veterinarians diagnosing the damage too late in the day.
We will help the horse move easier initially by trimming and then by shoeing.
A navicular horse is always an animal that is very difficult to manage in terms of his lameness because neither the veterinarian nor the farrier can help on their own; under such circumstances, the complementary nature of our two professions is obvious. Owners or riders also have a role of prime importance in order to achieve a satisfactory result. Indeed, rigor in using and caring for the horse are also necessary in order to prolong the career of a sports horse or simply the life of a hacking companion.
Of course the farrier has a significant responsibility in terms of results because his work will partly involve respecting or re-establishing the ideal phalangeal alignment. In other words, correcting the line at the toe of the hoof. This will directly influence the angle of the pedal joint. He will also take care to ensure that the shoe exerts as little stress as possible in the various phases of the horse's stride.
Specialists in the biomechanics of the foot have shown us in great detail that by reducing the angle of the hoof (long toes, low heels) (4) we greatly increase the proportion of forces to which the hind -most regions are subjected during the weight-bearing phase.
In the propulsion phase, it is mainly the length at the toe and the leverage that this cause during breakover of the foot will determine forces in the podotrochlear region ( long toe high increase in forces and prolonging of the phase, short toe, reduction in forces and reduction in the phase). The farrier should therefore concentrate his attention on shortening this phase.
Recommendations for observing the horse
Nowadays, too many farriers underestimate their responsibility in changing certain aspects of limb conformation, the shape of the hoof capsule, and even the appearance of certain pathologies.
Observing the horse should be a systematic procedure before shoeing. It is at that time that limb conformation anomalies or shoeing errors will become apparent and that we will determine the main lines of our strategy.
The horse should be observed at halt and then in movement,(5) analysing his gaits, at walk and at trot on a circle (on both reins). It is a procedure that must not be neglected as it provides precious information on the horse's comfort on his hooves or on his shoes.