COOLING MECHANISMS

Here are the underlying mechanisms your horse uses to cool himself down. By knowing how they work, you’ll have a better understanding of current cooling recommendations. Convection: Heat (thermal energy) is carried away from your horse’s body as air flows over his skin, as in response to a cool breeze or fan. Radiation: Heat is lost into the environment because of a difference in temperature between your horse’s body and the surrounding air. Evaporation: Heat is lost when a liquid (sweat) is converted into a vapor. Conduction: Your horse’s warm body comes into contact with something cooler, such as a spray of cold water or an ice bag. The heat then conducts (transfers) to the cooler object.

So how do these mechanisms work? Here’s what happens in your horse’s body that allows heat to transfer from his core to the surface of his skin, where it’s then lost to the environment:

1. Your horse’s heart rate increases and tiny blood vessels in his skin and lining of his respiratory tract enlarge. This process improves blood flow to the surface of his skin to aid heat loss via radiation, conduction, and convection.

2. Your horse might start to breathe more rapidly or “pant,” allowing increased amounts of cooler outside air to pass by the blood vessels in his respiratory system. This process allows for heat loss through convection and radiation.

3. Your horse begins to sweat. Sweating allows for heat loss through evaporation and is your horse’s most important cooling mechanism.