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How Do Horses Regulate Their Body Temperature?

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When temperatures rise, it’s vital for horses to effectively release excess heat to avoid overheating and heat stress. Like humans, horses rely on several mechanisms—radiation, convection, conduction, and evaporation—to regulate their body temperature. Understanding these processes is crucial for keeping your horse healthy, especially during intense physical activities or hot weather. But how do you know when your horse is too hot? Let’s dive into the details of thermoregulation in horses and how you can help them stay cool.

Understanding Thermoregulation in Horses

Thermoregulation is the process by which horses and humans regulate their body temperature. During physical activity, a horse generates heat as a by product of muscle activity. If this heat isn’t efficiently dissipated, the horse’s body temperature will rise, potentially leading to dangerous levels. (Clayton, 1991). Elevated temperatures can lead to reduced muscle performance and, at even higher levels, to protein denaturation such as enzymes, muscles, and tendons— which can lead to significant health risks.

Humans Are Better at Temperature Regulation

As riders, it’s essential to recognize that horses are not as efficient as humans when it comes to thermoregulation. Horses can overheat more quickly, particularly in warm and humid conditions. This is because their bodies are much larger and have in ratio to their body mass they have less surface to use for heat dissipation. That in itself make horses, and all large mammals, less effective at dissipating heat compared to humans. While we might feel comfortable in certain temperatures, horses could already be nearing their heat tolerance limits. Being aware of these differences is crucial in preventing overheating and ensuring your horse’s well-being.

Watch the video (NL) of KNHS x Carolien Munsters about thermoregulation in horses!

Ideal Temperature Ranges for Horses

The ideal temperature range for horses, known as the thermoneutral zone, is between -5°C and 15°C. Within this range, horses can maintain their body temperature without needing to too much extra energy on cooling or heating. However, when outdoor temperatures reach 20-25°C,  and with moderate to high humidity, what feels comfortable to us might already be outside a horse’s comfort zone. As temperatures rise further, especially beyond 25°C, horses may struggle to lose heat effectively. At 30°C and above, immediate and aggressive cooling methods, such as dousing the horse with cold water, become necessary to prevent heat stress.

Mechanisms of Heat Loss in Horses

·      Radiation

Radiation is the transfer of heat without direct contact, such as the warmth you feel from the sun. Horses can lose a significant amount of heat through radiation, especially in cooler conditions. For example, on a cloudy day with temperatures around 10-15°C, a horse can lose about 60% of its heat via radiation(Lindinger & Marlin 1995; Sloet 2014). However, in hot, sunny weather, this method becomes less effective as the horse absorbs more heat from the sun than it can lose. Providing shade on sunny days is essential to minimize heat absorption.

·      Convection

Heat loss through convection occurs when heat is transferred between the horse’s skin and the surrounding air. The process is more effective with stronger winds or when the horse is moving, as it increases air circulation around the body. The faster a horse moves, the more heat it can lose through convection. (McCutcheon & Geor, 2008). Convection can account for about 15% of a horse’s heat loss (Lindinger & Marlin, 1995).

·      Conduction

Conduction refers to heat transfer between surfaces in direct contact. For horses, this is limited to contact points of their hooves on the ground, so heat loss through conduction is usually minimal (Lindinger & Marlin, 1995; McCutcheon & Geor, 2008). Lying down on cool ground can increase heat loss via conduction, but overall, this method is less efficient than others. Cooling techniques involving conduction, such as cold towels or cooling blankets, may not be as effective and can even hinder more efficient cooling processes like convection and evaporation.

·      Evaporation

Evaporation is the most important method for thermoregulation in horses, primarily through sweating(Lindinger & Marlin, 1995). Under thermoneutral conditions at rest, evaporation accounts for about 25% of heat loss. During exercise or heat stress, this can increase to 50% (Lindinger & Marlin, 1995). This makes it a very important way for horses to cool down! However, in humid weather, the effectiveness of evaporation diminishes as the air becomes saturated with moisture, reducing its capacity to absorb sweat(Marlin, Misheff & Whitehead, 2018). In such conditions, active cooling with cold or ice water, combined with movement, becomes essential for quickly reducing heart rate and body temperature (Bongers, Hopman & Eijsvogels, 2017; Marlin & Lindinger, 1995). 

In addition to sweating, horses can also lose heat through panting (rapid, shallow breathing similar to a dog’s panting). Panting accounts for about 15% of a horse’s heat loss (Sloet, 2014) it could indicate that the horse is struggling to cool down and may need immediate help through active cooling.

Conclusion

To keep your horse healthy and performing well in hot conditions, it’s essential to understand and support their natural thermoregulation processes. Horses generate significant heat during physical activity, and if they can’t cool down effectively, it can lead to overheating and severe health issues. While humans manage heat more efficiently, horses rely heavily on evaporation and other methods like convection and radiation to release heat. As temperatures rise, especially in humid conditions, proactive cooling measures become crucial to prevent heat stress and ensure your horse’s well-being.

 

   Sources

  • Bongers C.W.G, Hopman M.T.E & Eijsvogels T.M.H (2917). Cooling interventions for athletes: An overview of effectiviness, pshysiological mechanisms, and practical considerations. Temperature,4(1), pp. 60-78
  • Clayton H.M (1991). Conditioning Sport Horses. Sport Horse Publications
  • Lindinger M.I & Marlin D.J (1995). Heat stress and acclimation in the performance hors: where we are and where we are going. Equine vet. Educ, 7(5), pp. 256-262
  • Marlin D (2017). To scrape or not to scrape when cooling hot horses
  • Marlin D, Misheff M & Whitehead P (2018). Optimising performance in a challenging climate: Preparation for and management of horses and athletes during equestrian events held in thermally challenging environments. FEI Sports Forum
  • McCutcheon L.J & Geor J.R (2008). Thermoregulation and exercise-associated heat stress. Equine Exercise Physiology, pp. 382-396),
  • M (2014). Hittestress bij het paard. Dier en Arts
  • M (2014). Oververhitting. Paard&Sport

 

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