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🔥 What Is Heat Stress in Horses?

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Heat stress occurs when a horse’s body cannot dissipate heat effectively, causing their internal temperature to rise dangerously. It often results from high ambient temperatures, humidity, poor ventilation, overexertion, or inadequate hydration.


🐎 Early Signs of Heat Stress

1. Increased Respiratory Rate

  • Normal: 8–16 breaths per minute.

  • Sign of stress: Rapid or shallow breathing, panting even at rest.

2. Excessive Sweating

  • Heavy sweating over the body, especially on the flanks and neck.

  • Later stages may show reduced or no sweating, which is more serious.

3. Elevated Heart Rate

  • Normal: 28–44 beats per minute.

  • Sign of stress: Persistently high pulse even after rest.

4. High Rectal Temperature

  • Normal: 37.5–38.5°C (99.5–101.3°F).

  • Early warning: Above 39.4°C (103°F).

  • Emergency: 41.1°C (106°F) or higher.

5. Lethargy or Depression

  • Horse may seem unusually tired, disinterested, or slow to respond.

6. Dehydration Indicators

  • Tacky or dry gums.

  • Capillary refill time longer than 2 seconds.

  • Skin loses elasticity (slow skin pinch test).

7. Uncoordinated Movements

  • Weakness, muscle tremors, stumbling, or swaying.

8. Reduced Water or Feed Intake

  • Reluctance to drink or eat may accompany early heat stress.

9. Dark or Scant Urine

  • May indicate dehydration or overheating.


🚨 When to Call a Vet

Contact a veterinarian immediately if your horse:

  • Has a temperature above 40.5°C (105°F).

  • Stops sweating despite obvious stress.

  • Appears disoriented, collapses, or shows signs of colic.


🛡️ Preventive Measures

  • Ride or work your horse during cooler parts of the day.

  • Provide shade and fresh water at all times.

  • Use fans or misters in barns.

  • Allow gradual acclimation to hotter conditions.

  • Consider electrolyte supplements during hot weather or heavy work.

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