Illnesses 4 of 25


Anhydrosis is the scientific term for the inability to sweat. This condition appears to be becoming more common in horses. Affected horses sweat normally during the cooler months, but lose that ability when the weather turns warm and humid. Racing and competition horses are the most commonly affected. These horses cannot cool themselves, so they must be worked very carefully, if at all, during warmer months.

There is no scientifically proven explanation for anhydrosis and no effective conventional treatment other than moving to a cooler climate. My theory, which I describe below, is that anhydrosis develops because the immune system is weak. This theory is based on Traditional Chinese Medicine (TCM).

At the basis of TCM is the concept of Qi. Qi can be translated as “energy,” “life force,” or “vital force.” There are several types of Qi: Original Qi, Food Qi, Gathering Qi, True Qi, Nutritive Qi, and Defensive Qi. Nutritive Qi is in the Interior and nourishes. Defensive Qi is on the Exterior and protects. With anhydrosis the main concern is with the Defensive Qi or “Wei Qi.” Wei Qi circulates under the skin and its main function is to protect the body from attacks of external pathogens. Remember, in TCM the concern is not with viruses and bacteria, but with external pathogenic factors, such as Wind, Cold, Heat, and Damp. Wei Qi also warms, moistens, and partially nourishes skin and muscles, and adjusts the opening and closing of the pores, which regulates sweating and body temperature.

Let’s now look at how a horse could be set up for anhydrosis based on this theory. We take a horse and stress him with training and competition, and then we give him multiple vaccinations. This weakens the Defensive Wei Qi. Even on the “best” processed diets, nutritional deficiencies further stress his system. Another common practice is cooling down hot horses with cold-water hosing, which, while not a problem in a horse with strong Wei Qi, in a weakened horse could allow the pathogenic factor Cold to invade and contract the pores, inhibiting the proper function of the sweat glands within the pores. Weak Defensive Wei Qi can also allow pathogenic Heat to enter the body, causing excessive sweating initially, which then depletes the body fluids and eventually leads to the inability to sweat. Most horses with anhydrosis exhibit other signs of immune system weakness such as chronic cough, chronic lameness or stiffness, muscle pain, or allergies.

Treatment of Anhydrosis

To treat anhydrosis we must rebuild the immune system first and foremost. The diet should be improved by feeding whole grains rather than processed feeds. Extra Vitamin C and E may be indicated. Probiotics will help support good digestion and assimilation of nutrients. Electrolytes offered free choice, or fed to the horse that is sweating excessively, may help prevent anhydrosis. Blue-green algae has been proven to support immune function and would be a good addition to the diet. Homeopathic remedies can be used to help reverse the ill effects of vaccinations and rebalance the horse’s system. Acupuncture can be used to rebuild the Defensive Wei Qi and repel external pathogenic factors. In summary, to prevent anhydrosis you should feed a good whole food diet (including electrolytes if indicated), minimize training stress, vaccinate as little as possible, and sponge off hot horses rather than hose them down with cold water.

About the Author

Madalyn Ward, DVM, owns Bear Creek Veterinary Clinic in Austin, Texas. She is certified in Veterinary Homeopathy and Equine Osteopathy.

Memberships include American Veterinary Medical Association, American Association of Equine Practitioners, American Holistic Veterinary Medical Association, Texas Veterinary Medical Association and the Academy of Veterinary Homeopathy.

She has authored several books and publishes at her blog.

Madalyn Ward DVM