The most adventurous opinions circulate about horn splits and their treatment. On the internet, in particular, you can find praiseworthy treatment approaches as well as very medieval-looking procedures with the most adventurous shoeing.The majority of veterinary medicine and farriery textbooks are from the 1980s or older. However, there are now excellent new, scientifically sound studies and findings on these topics.
The materials used in farriery in particular have modernized. Plastics, adhesives, fibers and fiber composites have found their way into shoeing over the last 10 to 15 years. They offer much more elegant treatment options for hoof problems than the perforated plates, screws and clamps made of steel used to.The force-elongation behavior of selected polymer materials is very similar to that of the hoof horn.
In this way, horn defects such as hollow walls or fissures can be reconstructed in such a way that the hoof regains the characteristics of a healthy hoof and then grows back in the same way. The hoof is practically tricked into believing it is healthy. Nature then acts accordingly. Iron plates and screws on the hoof do not last very long due to the extremely different material properties. Furthermore, horses with such "prostheses" can hardly be loaded.However, this does not mean that everything was done wrong in the past, but that there was simply nothing better.
Today's treatment options should be seen as a supplement to good hoof care and make the work of the farrier, hoof trimmer or attending vet easier and shorten the horse's convalescence time. Many hoof trimmers have already recognized these opportunities.
Fig. 2 + 3: Horn split glued with aramid fibers in a top jumping horse.
The hoof wall grows back closed under full load in sport.
What is a horn split in horses?
Horn splits are longitudinal separations in the area of the horn wall, which run parallel to the horn tubes from the coronet band towards the bearing band. True horn splits are always located at 2 characteristic points on the hoof, at the front in the middle of the toe or at the side at or just behind the widest point.
Superficial cracks run in the glaze layer and only on the outer surface of the tube layer (radially distributed air cracks). A distinction is also made according to location and depth. A deep crack from the crown edge to the supporting edge is the penetrating-through horn crack. A transverse horn defect is called a horn fissure; these are caused by former bruises or injuries to the ligament and do not normally pose a major problem.
Real horn fissures often extend to the ligament, the growth zone of the horn wall. If this is damaged, these fissures can bleed again and again. But don't panic, even these fissures can be treated in the vast majority of cases. In very few cases is the ligament actually severely injured. This actually only occurs in the case of kicking injuries or when shoes or studs are worn.
Horn splits are always worth treating, as they mean instability of the horn capsule and therefore lead to changes in the shape of the hoof in the long term. Horses with horn splits often have pain due to bruising and straining of the sensitive, heavily innervated corium, often associated with lameness.
Another problem is rotting processes in the crack caused by bacteria and fungi, which colonize the crack in symbiosis shortly after the crack has formed. The notch bottom of the crevice is the ideal environment for these germs to multiply. Warm, damp, dark and an alkaline pH value from the stable bedding. These putrefaction processes often lead to further complications in the form of material loss and infections with possible abscess formation
How does a horn gap develop?
Very few genuine horn splits are caused by external injuries, as is often claimed, but result from high tension in the horn capsule. The frequently heard explanation "the horse just jumped on a sharp stone" is almost always wrong.
Conceivable external injuries result from grazing with the opposite hoof or gripping with the iron of a hind leg. External injuries caused by wire or other fencing material are also conceivable. However, these types of injuries are easy to distinguish from those caused by the formation of a split due to non-physiological tension.
The majority of all fissures are found on the front hooves. They occur in two very specific places: The toe wall center, and laterally just behind the widest part of the hoof on both the inside and outside. There are, of course, reasons for this.
In the vast majority of cases, horn splitting is due to unphysiological tension in the horn capsule. The hoof wall then cracks at the point of highest tension, similar to a wire that is bent back and forth at the same point many times and finally breaks simply due to material fatigue.
Where do these destructive tensions come from?
After years of discussions about the advantages and disadvantages of shod or unshod hooves, the term "hoof mechanism" should be familiar to anyone interested by now.The normal adult, medium-weight warmblood horse weighs approx. 500 to 600 kg on average. This load must be carried by the 4 hooves. When trotting, only 2 hooves are loaded at the same time.
The forces and therefore also the tension in the hoof also increase many times over due to the speed of movement. The highest tensions are therefore to be expected, for example, when landing after an obstacle or when galloping fast on hard ground. This means that a hoof can briefly bear up to 6 times its own body weight. In figures, that is over 30,000 N. (Source, Dr. vet. Christine Hinterhofer 1997, University of Vienna), i.e. 3 tons on one hoof for a short time. Uneven ground and the weight of the rider additionally increase the deforming forces.
All these forces generate the normal hoof mechanism in a healthy, correctly shaped hoof, whether shod or barefoot. The hoof stretches under load and returns to its original shape when the load is removed. These elastic deformations of the hoof reduce the stress peaks below the level of horn damage. If this ability of the hoof to expand is hindered or partially reduced, stresses occur which can then cause cracks in the horn.
Is the shoeing to blame?
The fact is that most horn splits are found on shod front hooves, much less so on barehoofed horses. Now it would be too easy and unfair to simply blame the farrier. In fact, a combination of many factors often leads to the formation of a split. It starts with the genetic predisposition of hoof shape, position and horn quality, continues with negligent correction appointments at foal age, environmental and husbandry conditions and ends with the horse's current eating habits. Excessively long shoeing intervals with only cautious corrections also often play a major role. The current hoof shape and function is therefore a product of the horse's genetics, load cases and environmental conditions.
Hoof with horn split
Due to the many factors that influence hoof shape, here is an overview of some important deviations from the ideal hoof shape that can lead to splits, either individually or in combination with the factors described above.
Hooves with long toes and low heels
This hoof shape leads to an extremely high "rolling resistance" during heel strike and thus to a strong elastic deformation of the toe wall, especially at the coronet band. Furthermore, the point of incidence of the load slips backwards towards the heels. As a result, the heels are subjected to high loads and are squeezed; this is referred to as under-pushed and also curled heels. The course of the tube in the horn wall is then no longer parallel between the toe wall and the heel. This often results in gaps in the side wall that tear from top to bottom. This is often exacerbated by a forced heel with tight hoof pads.
Extremely flat, wide hooves
Extremely flat, wide hooves are often accompanied by an outwardly curved hoof wall. The load-bearing hoof wall is formed by the coronet band at the coronet band and should grow in a straight shape towards the bearing edge. Pressure forces from heel strike can only be fully transmitted in straight walls. Any outward bending of the wall (trumpet-shaped) means that the load of the horse's weight is no longer transmitted in a straight line to the coronet band. The curved walls cause bending stresses that lever the hoof wall further and further outwards, as shown in Figure 7.
The resulting fissures tear radially from below, usually to the middle of the hoof wall, i.e. to the crease in the wall, and sometimes grow out again to tear again. This continues until the farrier or hoof trimmer straightens the horn wall, making it more resilient. This can take several shoeing periods, as the correction must be made gradually.
Fig. 7: Radially distributed fissures due to outwardly bent hoof walls
Hooves with uneven wall length and one-sided footing
In this case too, side wall gaps often occur. The hoof is loaded completely asymmetrically with each loading cycle due to the one-sided tipping. The hoof first heels on the outside and tilts onto the inner wall. The inner, steep wall is overloaded and cracks.
Side wall gap due to uneven load distribution
In this case, the hoof mechanism is impaired. The flat outer wall can stretch in line with the hoof mechanism. The inner wall stands vertically immobile on the shoe or ground and tilts inwards and outwards under load in the coronet area. The resulting shearing forces can lead to the formation of fissures. Such splits always tear from top to bottom.
Fig. 8: Horn gap due to uneven load distribution
Treatment of a split horn in horses
In principle, a split horn can only grow out from the top downwards. Healing from the inside is anatomically impossible (as is the case with fingernails). This is why horn splits that originate at the coronet band take almost a year to grow out completely - provided that nothing tears again.
To begin with, the hoof trimmer, whether farrier or hoof trimmer, must first recognize what the problem is. Accordingly, when working on the hoof, he must ensure that the tension in the hoof tends to be less, i.e. "normalized" and better distributed. This is generally achieved by approximating a regular, symmetrical hoof shape with normal wall angles and a flat footing.
In most cases, this can only be achieved over several shoeing intervals. Only rarely does a single hoof correction lead directly to complete success. Orthopaedic shoes with plates, silicone inserts or shoes with bars are often necessary. Only in this way can the load on the hoof be evenly distributed, the damaged wall relieved and the sole of the hoof supported.
In principle, this also works with bare hooves. However, this always involves the risk of severe vertical hoof deformation on uneven ground. This increases the risk of the hoof tearing again. In addition, the aim of the treatment is actually to keep the gap quiet, i.e. little movement in the affected wall section. A metal fitting therefore normally makes sense. It distributes the load across all sections of the wall. Pure plastic fittings cannot do this! It also always makes sense to use the same fitting on each axis.
Fig. 10: Same horse in the 2nd shoeing period
Gluing horn splits
As a result, the forces are transmitted over a large area and the hoof can function like a healthy hoof. During the healing phase, the horse can be loaded normally in most cases, which is not possible with metal joints and screw connections. It is important that the horn wall is clean and germ-free before gluing in order to prevent rotting.
Fig. 11-13 : Hoof with heel wall gap, after corrective shoeing and gap glued with fiberglass mesh
Diagnosing a cleft horn
A split horn is usually diagnosed by visual inspection of the hoof. Typical symptoms are visible cracks in the hoof wall, lameness and sensitivity when trotting forward or palpating. Horn splits can occur in various places on the hoof, particularly in the middle of the toe wall or on the lateral hoof wall. An experienced farrier or vet can examine the horn split in more detail and determine the severity and treatment options.
Keralit hoof strengthener against rotting
The following is suitable for treating rot in the split Keralit hoof strengthener is excellent. This product strengthens the horn and counteracts the formation of rot. Using the hoof strengthener improves the quality of the horn and makes the hoof horn more resistant to external influences.
Keralit laurel ointment for crown edge care
For the care of the crown edge we recommend the Keralit laurel ointment. This ointment supports the regeneration of the coronet band and promotes the growth of healthy hoof horn. Regular use helps to maintain horn quality and prevent further horn damage.
Tips for supporting the healing process
The following measures should be taken to support the healing process of cleft horns:
- Feeding: A balanced diet with sufficient nutrients such as biotin, zinc and amino acids promotes horn quality.
- Protection: Avoid excessive strain while the affected hoof is healing
- Check-up: Regular checks and care by a hoof expert are essential to monitor the healing process and adjust the treatment if necessary.
Preventing horn splitting in horses
Preventive measures can help to prevent horn splitting and promote healthy hooves:
- Regular hoof care / hoof trimming: Make sure that the hooves are regularly trimmed and corrected by an experienced farrier.
- Shoeing: If necessary, orthopaedic shoes should be used to distribute the load evenly over the sole and hoof walls. This is the only way to achieve a load-bearing hoof shape adapted to the case in the short term.
- Environmental conditions: Provide dry and clean stalls and runs to protect the horn from excessive moisture.
- Nutrition: A balanced and nutritious diet supports horn quality and hoof health.
A split horn in a horse is a serious problem that requires careful diagnosis and treatment. With regular hoof care, suitable shoeing and a balanced diet, you can promote your horse's hoof health and prevent horn splits. In the case of existing horn splits, it is important to support the healing process with suitable measures and products and to have it closely monitored by a hoof expert.