Last month, we looked at attention to hoof care and recognition of common foot problems in older horses, using an overview of hoof facts and foot-related nutrition followed by a look at laminitis.  This month, we continue with three more of the hoof problems common to older horses and what you should look for to recognize problems and correct them before permanent damage can occur.

Subsolar Abscesses

A subsolar abscess is probably the most common cause of lameness in the horse.  The pain from the pressure generated by the pus within abscesses trapped under the hard shell of the hoof can be tremendous.  Some cases can be so extreme as to lead to the complete inability to bear any weight on the affected limb, resembling the behavior of a horse with a broken leg.

For bacteria to gain access to the subsolar tissues, there has to be some sort of opening in the outer shell of the hoof.  Trauma to the sole can cause a small, possibly not even visible, break in the sole.  A misdirected shoe nail can do it.  Hoof cracks, seedy toe from founder, and white line disease (an infection of the white line by microbes, bacterial or fungal, that feed on the softer horn tissues in the foot) are other examples of problems that create an avenue for bacteria to penetrate into the subsolar tissues. 

The body responds to the bacterial infection by flooding the area with white blood cells to kill off the bacteria and by walling off the infected pocket, forming the abscess.  As pressure builds, the horse rapidly becomes more lame.  The pain is greatly relieved once the abscess finally opens and drains.

Thrush

Thrush is a bacterial infection of the frog of the hoof.  It results in an accumulation of foul-smelling, black, necrotic material on the frog.  A mild case involves only the superficial layers.  Severe cases penetrate to deeper layers, undermining the frog and surrounding sole, causing considerable pain and lameness.  The responsible bacteria actually feed on the soft horn of the frog and are normal soil organisms.  The infection is most often caused when horses are subjected to wet, muddy, swampy conditions or heavily soiled, unhygienic stalls.  Poor hoof conformation,  neglected feet, and feet shod with full pads are at higher risk, as they will more likely trap dirt and moisture.

Prevention includes:

·    Daily hoof care - picking out the feet daily before putting the horses up for the night will give the feet a chance to dry out and eliminate a large number of the pathogenic microorganisms.

·    Provide clean, dry bedding in the stall so there is a good environment for part of the day.

·    Regular exercise - the smaller and muddier your daytime turnout, the more important this becomes.  Exercise will promote a stronger hoof that is more resistant to infection.  Also, exercise causes motion that helps the hoof to clean itself.

·    Avoid the use of full pads during wet months.

·    Regular trimming helps, as does correction of hoof problems when possible, such as sheared heels and contracted heels.

·    Prophylactic use of foot baths (2 ounces of bleach mixed with 3 gallons of water) or dressings (Koppertox) can help to help destroy the offending microorganisms.

Hoof wall cracks

Hoof wall cracks are a common hoof problem.  They can be very minor and of little significance.  Other times they are very serious, causing severe lameness, infection, and debilitation for long periods of time.  Hoof wall cracks should be characterized according to:

·    Location - cracks can be found on the toe, quarter, bar, or heel

·    Depth - they can vary from very superficial to full thickness with bleeding

·    Length – the extent of the crack from top to bottom

·    Starting point - does it begin from the ground surface or from the coronet?

·    Degree of infection

Like all problems, hoof wall cracks have many causes.  Long hoof walls, thin hoof walls, dry feet, and unbalanced feet are more prone to cracking.  Damage to the coronary band can lead to a defective hoof wall that cracks.  Very frequent shoeing can result in greater damage to the hoof wall from the nails; this weakens the wall, allowing cracking to occur. 

Treatment of hoof wall cracks depends upon the type of crack.  For instance, a simple, superficial, incomplete quarter crack may only need a good trim and a bar shoe with quarter clips.  However, a deep, infected, unstable quarter crack will need extensive treatment to remove the dead tissue and clean up the infection.  These deep cracks require more elaborate stabilization, such as wire fixation or acrylic, to prevent the crack from self-perpetuating. 

Regular hoof care is extremely important to promoting healthy, stable, functional feet.  Equally important are providing proper nutrition, a safe facility, a clean environment, and regular exercise.  All of these, along with a little regular grooming and a lot of kindness and love, will help your horse step into a healthy, ripe old age on all four feet.