Eccentric opinions circulate about hoof cracks and their treatment. On the internet, in particular, you can find praiseworthy treatment approaches as well as very medieval-looking procedures with dubious shoeing protocols.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 wall seperations or fissures can be reconstructed in 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. Metal patches and screws on the hoof do not last very long due to the extremely different material properties. Furthermore, horses with such "prostheses" can not be exercised properly.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: hoof crack glued with aramid fibers in a top jumping horse.
The hoof wall grows down without crack under full work load in sport.
What is a hoof crack in horses?
Hoof cracks are longitudinal separations in the area of the horn wall, which run parallel to the horn tubuli from the coronet band towards the weight-weight bearing edge. Genuine hoof cracks are always located at 2 typical locations 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 periople layer and the external surface of the tube layer (radially distributed air cracks). A distinction is also made according to location and depth. A deep crack from the coronary band to the supporting edge is considered a hoof crack. A horizontal crack usually is caused by trauma or injurie to the coronary band and mostly do not pose a major problem.
Real horn fissures often extend to thecoronara band, 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 the coronary band is severely injured. This actually only occurs in the case of overreach injuries or when shoes or studs are worn.
hoof cracks 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 hoof cracks often have pain due to bruising and sexercise of the sensitive, heavily innervated corium, often associated with lameness.
Another problem are infectious processes in the crack caused by bacteria and fungi.They 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 hoof crack develop?
Very few genuine hoof cracks 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 cracks 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, hoof cracks 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 hoof cracks 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 hoof crack
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 a concave 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 weight bearing edge. Pressure peaks occuring during the landing phase can only be processed properly in straight walls. Any concavity of the wall 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 concave 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 flatter 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 cracks always tear from top to bottom.
Fig. 8: hoof crack due to uneven load distribution
Treatment of a split horn in horses
In principle, a hoof crack can only grow out from the top downwards. Healing from the inside is anatomically impossible (as is the case with fingernails). This is why hoof cracks that originate at the coronet band take almost a year to grow out completely - provided that no further damage occurs.
To begin with, the hoof care specialist, whether farrier or hoof trimmer, has to recognize the cause of the problem . Accordingly, when working on the hoof, he must ensure that the detrimental tension in the hoof is minimized, i.e. "normalized" and better distributed. This is generally achieved by approximating a regular, symmetrical hoof shape with normal wall angles and a normal landing pattern.
In most cases, this can only be achieved over several shoeing intervals. Only rarely does a single hoof correction directly leads to complete success. Orthopaedic shoes with pad and packing or bar shoes are often necessary. This sometimes is the only way to distribute weight and load evenly on sole, frog and wall in order to relieve the damaged hoofwall.
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 shoe therefore normally makes sense. It distributes the load across all sections of the wall. Pure plastic plastic cannot do this! It also always makes sense to use the same kind of shoe on each axis.
Fig. 10: Same horse in the 2nd shoeing period
Gluing hoof cracks
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 exercised normally in most cases, which is not possible with metal sheets and screw connections. It is important that the horn wall is clean and germ-free before gluing in order to prevent any kind of infection.
Fig. 11-13 : Hoof with heel wall gap, after corrective shoeing and crack glued with fiberglass mesh
Diagnosing a hoof crack
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. hoof cracks 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 hoof crack in more detail and determine the severity and treatment options.
Keralit Hoof Strengthener against rotting
The following is suitable for treating rot in the gap 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 a hoof crack:
- 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 hoof cracks
Preventive measures can help to prevent hoof cracks 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 hoof shape adapted to the case in the short term.
- Environmental conditions: Provide dry and clean stalls and paddocks 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 hoof cracks. In the case of existing hoof cracks, it is important to support the healing process with suitable measures and products and to have it closely monitored by a hoof expert.