How to measure your horse's temperature correctly

Which thermometer should you use?

Always use a digital thermometer, preferably one designed specifically for animals. This type of thermometer delivers a reliable reading within 30 to 60 seconds and beeps when it's done. A glass mercury thermometer also works, but is slower and more fragile — not ideal in a stable. Choose a thermometer with a cord or clip that you can attach to the tail base so it doesn't fall out or slip inside. Store it in a protective case in your first-aid kit and discard it if it has been dropped or damaged.

Step by step: how to measure correctly

Follow this sequence for a safe and accurate reading:

• Secure your horse in a safe spot and let it stand calmly — stress raises the temperature.
• Lubricate the tip of the thermometer with petroleum jelly or lubricant.
• Stand beside the hindquarters, never directly behind, and gently lift the tail.
• Slowly and carefully insert the thermometer into the rectum to a depth of about 4–5 cm.
• Wait for the beep (digital) or hold it in place for 2 minutes (analogue), note the value, and gently remove it.
• Clean the thermometer immediately with an antiseptic wipe or alcohol, and save the reading in your horse's profile in EquiSight.

What are normal values by age group?

Temperature varies slightly by age and circumstance. Use these reference values as a guideline:

• Adult horse: 37.5 – 38.5 °C
• Foal (0–4 weeks): 38.0 – 39.0 °C
• Young horse (1–3 years): 37.5 – 38.8 °C
• After intense exercise: temporarily up to 39.5 °C, normally drops within 30 minutes
• In hot weather or high humidity: readings can be 0.3 to 0.5 degrees higher

When should you call the vet?

A one-off reading of 38.8 °C in a resting horse is not necessarily cause for panic. However, there are situations where you should contact your vet immediately. Call if the temperature exceeds 39.5 °C, especially if the horse also shows other symptoms such as lethargy, loss of appetite, nasal discharge, or lameness. Also call if the temperature is below 37 °C — hypothermia can indicate shock or severe dehydration. If in doubt, take two readings half an hour apart and record both values. In EquiSight you can track this via the horse profile, giving your vet a clear overview.

Common mistakes when measuring temperature

• Measuring right after exercise: wait at least 30 minutes after riding.
• Inserting the thermometer too shallowly: you'll be measuring outside air rather than body temperature.
• Taking a reading from an anxious horse: excitement can raise the reading by 0.5 degrees.
• Only measuring when illness is visible: also take a baseline reading when your horse is perfectly healthy.
• Not recording the result: without reference values, a single reading has little meaning.

Tracking readings with EquiSight

A single reading says very little on its own. The value lies in the pattern over time. Save every reading in your horse's profile in EquiSight, including the date, time, and circumstances. If your horse has been ill more often or has a chronic condition, you can use EquiCoach to review trends and patterns in health data. This helps you spot abnormalities sooner and puts you in a stronger position when speaking with your vet.