Hoof cracks seem to occur more often in summer months.

The summer heat often spell problems for horse’s hooves.  Lots of factors get blamed, but sometimes it’s more a matter of guilt by association rather than a true cause.

Some horsemen believe that turning horses out at night in the summer subjects the hooves to too much moisture from dew on the grass. The theory is that the feet soak up all this moisture, swell, then shrink again when brought inside to dry stalls or worked during the day under dry conditions.

However, a study by Kempsom and Campbell of the University of Edinburgh found that sections of hoof wall could be baked in an oven or soaked in water for two weeks and still remain intact and sealed to the extent that the outer layers wouldn’t absorb anything past a depth of three to five cell layers. And dry conditions aren’t a problem for the healthy feet, either. (Note we said “healthy.”)

Heat may have a little to do with it, but it’s more heat from exercise than weather. A study presented at the 2001 American Association of Equine Practitioners (AAEP) meeting reported that feet remain abnormally hot on thermographic readings as long as 24 hours after a fast exercise session.  Even low-level exercise raises the temperature of the feet. 

Extremely high tissue temperatures, high enough to cause cellular damage, have been documented in some tissues (tendon) following exercise.  Since the hoof can’t be rapidly cooled (it doesn’t sweat and has no surface blood vessels), overheating could contribute to some of the hoof-quality problems that develop in summer, like white line separations/weakness, cracking and even sole bruising.

However, the most prominent reason for hoof-quality issues appearing in the summer is that the problem horse doesn’t really have healthy feet to begin with. The predisposing causes are there year round, but the horses are simply being worked more in the summer and that seems to bring the problems to the surface.

Fighting Back
If your horse’s shoes aren’t redone frequently enough, the nails can become loose and the shoes move more, further increasing the size of the nail holes and damaging the hoof wall around them.  Nail holes expose the more-susceptible inner layers of the hoof to moisture/drying and organisms just like cracks do. 

Even small cracks are chinks in the horse’s normal hoof armor that greatly increase the chances of both drying and moisture absorption, and provide a pathway of entry for damaging organisms.  The permeability study also showed that brittle hoof walls absorb much more moisture than hooves of normal, good quality.

We also disapprove of too much rasping, too, which may weaken the protection of otherwise normal and healthy hooves. Avoid the temptation to “smooth” out the hoof wall, removing ridging. This surface rasping along the hoof wall removes the natural waxy protection on the hoof, making it vulnerable to adverse effects of high moisture or excessive dryness.  A good farrier knows to rasp to the minimum amount of necessity.

What To Do
• Although it won’t give you results overnight, your horse’s diet is your primary weapon against poor hoof quality. Be sure all the nutrients key to good hoof quality are present in adequate amounts. You want to look at levels of trace minerals, fatty acids, protein and essential amino acids.

• Avoid rasping the hoof wall.  When upper layers of hoof wall have been removed by rasping, the hoof should be protected by use of a good hoof dressing like pine tar or Hawthorne’s Sole Pack Medicated Liquid Hoof Dressing(www.hawthorne-products.com, 765-768-6585). We also especially like Animal Legends Equine Hoof Dressing (www.animallegends.com 800-399-7387).

• If nail-hole cracks and loosening shoes are a problem, discuss the issue with your farrier. He may have solutions to offer, which may include temporary helps like filling in nail holes or using a hoof sealer. You may need to have your horse’s shoes redone more frequently or you may need to switch to a lighter weight shoe with smaller nails. If you’re not giving your horse’s feet a “rest” from shoes in the colder months, discuss the possibility. This helps old nail holes grow down and out of the hoof. Glue-on shoes are also a possibility for many horses.

• Icing or cold water whirlpools are a standard summer routine for many high-performance horse trainers, especially if the horse seems at all foot sore. Ice boots applied over the pastern/foot, or even the cannon bone, are another, mess-free, way to rapidly cool down overheated feet.  We’re especially impressed by the wraps by EZ Ice (www.ezice.net 386-423-1792), Reitsport (www.horsetech.com, 800-831-3309) and Dura-Kold (www.dura-kold.com, 405-943-8811). MacKinnon (www.mackinnonicehorse.com 800-786-6633) also makes a line of  cooling products, including hoof boots.