06/07/2024
Happy Tuesday y'all! With the rising temperatures, we wanted to provide an educational post on Anhidrosis. Knowledge is power!
Anhidrosis, or the lack of sweating, is a common problem encountered in the horse population of Florida. Just like humans, horses rely heavily on their body's ability to sweat in order to keep cool. However, the perpetual and excessive heat in Florida can play a damaging role on the horse's ability to sweat.
For a normal horse, the brain senses when the body's temperature is rising and via an intricate hormonal signaling system, causes the skin to release sweat which carries heat to the surface of the skin and then evaporates, taking the heat with it.
When the sweat glands can not respond to the brain, the heat continues to build up in the body. The horses then attempt to "pant" or "blow" in order to cool themselves. Horses are unable to breathe through their mouths normally so they flare their nostrils out and breathe shallowly at a very quick rate. Some owner's report that their horse's appear like they just ran a marathon but haven't left their stall!
The persistent heat in Florida wears out the body's ability to respond to the stimulus to sweat. Researchers are still working on the exact source of where things go wrong but we believe that it is based on the hormones and sweat glands. Some horses can become non-sweaters it seems like overnight. While others gradually reduce their amount of sweating slowly until they completely stop. Some horses can be considered partial non-sweaters if they sweat a bit under their saddle pads but not as much as should be expected. Elderly horse's are prone to anhidrosis, even if they have sweat well all of their lives.
In Florida's extreme heat, a horse's body temperature can climb quickly just by standing in the sun or a warm barn without sufficient airflow. A horse suffering from anhidrosis typically appears dull and uninterested in their surroundings, blowing or painting with flared nostrils, some may develop poor hair coats or lose some areas of hair. Horse's that fail to sweat are at severe risk of heat stress and stroke if their temperature climbs too high. Frequently these horses have a re**al temperature of 103-105 deg F and if their temperatures continue to climb they are at risk for brain and multi-organ damage.
The only known cure for anhidrosis is to relocate the horse to a cooler region. However, even if that horse lives in a cold region for 1 year and experiences cool/cold temperatures during the winter but returns to Florida, those horses frequently stop sweating within 6 months.
Many owner's have attempted a variety of treatments for non-sweaters. This includes Stout beer daily and a variety of supplements. Many owners report favorable results with the One AC supplement. All other treatments are aimed at controlling the horse's body temperature. Keep all non-sweaters in a stall or shade during the day with fans to provide air flow. Frequent cold-water baths to help bring down their temperatures. Sweat scraping after the baths will help remove the water that has heated up on their skin. Body clipping to remove as much hair as possible from the horse's coat can also help. In severe cases, diluting rubbing alcohol in a bucket of water and sponging the mixture over their necks and backs can help dissipate the heat even faster (do not use on their face). Every horse should have clean and inviting water available to them at all times and should have a salt block or given electrolytes.
Once a non-sweating horse has been given a cold water bath, his temperature should begin to return to normal. If it does not, call Central Florida Equine Hospital to make sure that your horse does not have a fever for other reasons!
Dr. Becca Adkins, DVM
