Dr Tania Cubitt & Dr Stephen Duren – Performance Horse Nutrition & LMF Feeds
California horse owners know that summer brings more than sunshine. From the dry heat of inland valleys to the humidity of coastal regions, rising temperatures can challenge a horse’s ability to stay comfortable, hydrated, and performing at its best. Add in long trailer rides, competition schedules, and even wildfire smoke, and the demands on the equine athlete can increase significantly.
While most horse owners recognize the importance of providing water and shade during hot weather, heat stress is about much more than preventing overheating. It affects hydration, electrolyte balance, energy metabolism, recovery, and overall performance.
How Horses Handle Heat
Unlike humans, horses generate a tremendous amount of heat during exercise. In fact, as much as 75–80% of the energy produced by working muscles is released as heat rather than being converted into movement. To prevent body temperature from rising to dangerous levels, horses rely primarily on sweating.
Sweating is an incredibly effective cooling mechanism, but it comes at a cost. Along with water, horses lose substantial amounts of electrolytes, including sodium, chloride, potassium, calcium, and magnesium. During intense exercise or prolonged exposure to high temperatures, these losses can become significant.
When fluid and electrolyte losses are not adequately replaced, horses may show signs of dehydration, fatigue, slower recovery, reduced appetite, or decreased performance. In severe cases, heat exhaustion and heat stroke can occur.
Recognizing the Signs
Heat stress doesn’t always present as a dramatic emergency. Often, the first signs are subtle.
Horse owners may notice:
- Increased respiratory rate after exercise
- Prolonged sweating or, conversely, reduced sweating
- Elevated heart rate during recovery
- Reduced energy or willingness to work
- Longer recovery times between workouts
- Decreased water consumption
- Reduced feed intake
Monitoring recovery after exercise can provide valuable insight. A horse whose breathing and heart rate remain elevated long after work may be struggling to dissipate heat effectively.
California Challenges
California presents unique environmental stressors for horses. Summer temperatures regularly exceed 100°F in many inland areas, while wildfire season can create poor air quality that places additional stress on the respiratory system.
Transportation is another factor. Many horses travel long distances to competitions, clinics, or trail destinations. Hauling itself is a recognized stressor that can increase fluid losses and contribute to dehydration, even before a horse begins exercising.
In these situations, proactive management becomes essential.
Supporting Hydration and Recovery
The foundation of any heat-stress management program begins with water.
Fresh, clean water should always be available, and horse owners should encourage drinking before, during, and after exercise whenever possible. Horses often drink more readily when water is familiar, which is why some owners bring water from home when traveling.
Electrolyte supplementation may be beneficial for horses that sweat heavily or work regularly in hot conditions. Replacing the electrolytes lost through sweat helps support hydration and normal muscle function.
Forage also plays an important role. High-quality forage provides a reservoir of water within the digestive tract and supports healthy gastrointestinal function. Maintaining consistent forage intake is especially important during periods of heat stress.
Management practices such as exercising during cooler parts of the day, providing shade, maximizing airflow, and using cold-water cooling after exercise can further support a horse’s ability to regulate body temperature.
The Metabolic Side of Heat Stress
One aspect of heat stress that often receives less attention is its effect on energy metabolism.
When horses are exposed to environmental and exercise-related stress, their bodies must work harder to maintain normal physiological function. Efficient utilization of glucose becomes increasingly important because glucose serves as a primary fuel source for working muscles.
Chromium is a trace mineral involved in supporting normal insulin function. Insulin helps move glucose from the bloodstream into cells where it can be used for energy production.
Research has shown that supplemental chromium may help support glucose utilization and metabolic efficiency during periods of physical stress. This may be particularly valuable for performance horses, horses in training, and those exposed to environmental challenges such as heat.
A Complete Summer Strategy
No single nutritional ingredient can eliminate the effects of heat stress. Successful management requires a comprehensive approach that combines proper nutrition, hydration, electrolyte replacement, and thoughtful management practices.
By providing horses with abundant fresh water, quality forage, balanced nutrition, and appropriate support for energy metabolism, owners can help their horses remain comfortable and resilient throughout the summer months.
As temperatures climb, remember that heat stress begins long before a horse appears overheated. Recognizing the early signs and implementing proactive management strategies can help support health, recovery, and performance all season long.
All LMF Feeds contain Kemtrace Chromium, the ONLY FDA approved chromium for use in horses.