Expert Exchange

Martha Olivo on the Hooves

Q: I have heard that the horse "has five hearts". What does that mean?

A: When blood is pumped from the heart, it flows into elastic-like arteries. With each pump of the heart, the arteries expand to accept the surge of blood, and then they shrink back down to their 'normal' size again. Blood travels in this manner, branching again and again until it is pushed into capillaries. These tiny little vessels are where the blood actually performs its duties: it provides nearby cells with oxygen and food, and removes waste and carbon dioxide.

As more blood surges behind it, the capillary blood is pushed into venules, which branch into larger veins. Veins are not elastic. Their adaptive quality is that they have little valves. These valves prevent the blood from sloshing backwards, as the pressure is no longer quite as intense as it was earlier in the circulatory journey.

The circulatory system functions much better if the veins have a little help in their task of getting blood back to the heart. This is one of the roles of muscles. Each time a muscle contracts, it squeezes blood through the vein toward the heart. The veins' valves trap the blood in its new location, and it waits there until the next surge of blood pushes it along or until the muscle contracts again. And so, with each squeeze of a muscle, the veins are provided with a little assistance in their daunting task of returning blood to the heart.

In the course of their evolution, horses have lost muscular structure in their lower legs. Through millions of years of evolution, these muscles have become tenuous straps. Therefore, the muscular function of aiding blood in its journey back to the heart has been minimized. And this is where the hoof comes into play.

When a hoof has proper mechanism, it both widens and flattens when bearing the horse's weight. This mechanism allows the blood into the corium that 'lines' the hoof wall and coffin bone. When the horse lifts his foot, the wall contracts, the sole becomes concave, and the coffin bone lifts slightly into the neck of the coronary band. Like the action of the heart, this action effectively pumps blood out of the foot.

The horse's hooves, or four 'auxiliary hearts', are paramount to his health. The function of each heart, including his real heart, depends upon proper hoof mechanism.

About the author:
Martha Olivo was a farrier for 25 years before hanging up her hammer and committing herself to the Whole Horse Trim™. The Whole Horse Trim™ is a physiologically correct hoof trim that duplicates the parameters found in feral equine hooves. As an accomplished hoof care clinician, Martha currently tours the US holding clinics that help horse owners, farriers and veterinarians understand the benefits of High Performance Barefootedness. Martha is a Strasser Certified Hoofcare Specialist and founder of United Horsemanship, a membership organization committed to the application of natural equine care.

United Horsemanship is a growing company dedicated to advocacy, natural horsemanship and "helping horsemen become better horsemen." With her business partner, Tara Felder, Martha networks to support and educate people involved in the natural horse movement. Although United Horsemanship focuses on the care of horses' feet, it isn't just about trimming feet. It is a solidarity movement and a nationwide, for-profit membership organization that was born out of love for and dedication to horses.

Committed to their company's vision - "to form a commonwealth of support, education, advocacy and information among those individuals and organizations who regard natural horse care as a sensible, humane and preferable way to initiate and sustain optimal health and well being in horses," Martha, Tara and a team of enthusiastic helpers work tirelessly to make United Horsemanship a self supporting organization. For Martha's clinic schedule and to learn more about United Horsemanship, log on to their website at To schedule a clinic, call (360) 647-7503 or drop an email to