🌡️ Vet Guide to Fevers in Horses | 2025 Temperature Monitoring, Hyperthermia & When to Call the Vet 🐴

By Dr Duncan Houston, BVSc

Your horse’s temperature is one of the most important indicators of their health. But not all elevated temperatures mean fever—and knowing the difference between a **true fever** and **hyperthermia** (overheating) is crucial for timely care. 🧠🐴

In this 2025 guide, I’ll explain how to monitor your horse’s temperature, recognize fever versus heat stress, and determine when veterinary attention is needed. 📋🌡️

🧪 What Is a Horse’s Normal Temperature?

A healthy horse typically has a rectal temperature between 99.5°F and 101.5°F (37.5–38.6°C). But every horse is different. That’s why it’s important to know your horse’s personal baseline. ⚖️

💡 Pro Tip:

• 🌡️ Use a **digital human rectal thermometer** to check your horse’s temp
• 🕒 Record readings during normal rest at the same time of day
• 📊 Create a log using the Ask A Vet app

For some horses, 99.5°F might be “normal.” So a reading of 101.5°F—even if within the general range—may still represent a meaningful rise for that individual. 🧠📈

🔥 Fever vs. Hyperthermia: What’s the Difference?

Both result in an elevated body temperature—but they occur for very different reasons and require different responses. 🧐📚

🌡️ What Is a Fever?

A **fever** is a regulated rise in body temperature triggered by the brain. It occurs when the **set point** in the brain's thermoregulation center increases in response to:

• 🦠 Infection (bacterial, viral, fungal)
• 🧬 Inflammatory conditions
• 💉 Vaccine reactions

Because the body “wants” to be warmer, it suppresses cooling efforts—like sweating or seeking shade. ❌💧

🌞 What Is Hyperthermia?

**Hyperthermia** is an unregulated temperature rise due to external or internal heat load. The body’s set point stays the same, but the horse can’t shed heat fast enough. Common causes include:

• 🏇 Intense exercise in hot/humid weather
• 🌡️ Environmental heat + poor ventilation
• 🧬 Anhidrosis (inability to sweat)
• 💊 Certain drugs or toxins

Once cooled, the temperature should return to normal. If it doesn’t, call your vet. 🚨🐴

🧠 Why It Matters: Treatment Plans Differ

Fever and hyperthermia may both present with a hot horse, but how you respond is critical. ❗

🧊 Hyperthermia Treatment:

• 🧴 Hose with cold water, especially large veins (legs, neck)
• 🌬️ Use fans, shade, or misters to aid cooling
• 💧 Offer cool water and electrolytes
• 🧪 Monitor recovery—temp should drop within 15–30 minutes

💊 Fever Treatment:

• 📋 Evaluate for infection or inflammation
• 💉 Use anti-inflammatory medications (as directed by vet)
• 🩺 Further diagnostics (bloodwork, imaging) may be required
• 🚫 Don’t cool a feverish horse aggressively unless directed—it may impair immune response

🩺 When to Call Your Vet

If your horse’s temperature rises above 102°F (38.9°C) **without a clear reason**, contact your vet. Likewise, **sustained fever** or failure to cool down after exercise requires attention. 📞👨‍⚕️

🚨 Call Immediately If:

• 🌡️ Temperature exceeds 103°F (39.4°C)
• 💦 Horse is sweating profusely—or not sweating at all
• 😴 Lethargy, depression, or not eating
• 😓 Labored breathing or rapid pulse at rest

📊 Monitoring Daily Temp Is a Must for Show Horses

If your horse travels, competes, or is boarded at a high-traffic barn, check temperature **daily**. Shows and clinics expose horses to new environments and pathogens. 🚛🐴

Early detection of subtle temperature changes can stop a contagious outbreak in its tracks. 🌡️⛔

📲 Use Ask A Vet for Fever Concerns

The Ask A Vet app offers quick, professional guidance when your horse runs hot. Use it to:

• 📸 Share temperature logs and photos
• 📱 Chat live with a vet about fever vs. hyperthermia
• 📊 Track trends with wellness logs
• ⚠️ Get treatment recommendations for fevers or heat stress

It’s peace of mind in your pocket, especially when your vet isn’t immediately available. 🐴📲

✅ Quick Tips for Managing Horse Temperature

• 🌡️ Know your horse’s baseline temperature
• 📈 Watch for rises—even within the normal “range”
• 🧊 Don’t confuse post-workout heat with a fever
• 🧪 Use digital thermometers and keep a log
• 🩺 Call your vet if temperature exceeds 102°F or stays high

📲 Final Thoughts from Dr Duncan Houston

Temperature monitoring is one of the simplest and most valuable things you can do for your horse’s health. Whether it's an early sign of illness or a red flag of overheating, acting fast makes all the difference. 🧠💪

Keep a thermometer in your tack box and the Ask A Vet app on your phone. Together, they’re your front line in protecting your horse in 2025 and beyond. 🐎📱