Among the most valuable pieces of information you can know about your horse are his individual normal vital signs: temperature, pulse and respiration (TPR).
• To determine normal ranges for your horse, take the TPR measurements for several days straight and record the results.
• Check both morning and evening, same time each day, same time in relation to any exercise, turn out or feeding. Check a few times after what would be a fairly standard or average ride.
Knowing your horse’s regular TPR may help when you have a nagging suspicion something might be wrong. Let’s say you come into the barn and your horse just looks a bit “dull” or “flat” to you. If you find an abnormal rise in pulse, respiratory rate or temperature, you’ll know to look further. It also makes your vet’s job easier if you can tell him your horse’s pulse is 48 when it’s normally never over 35, than if all you have to report is a pulse of 48.
The horse’s pulse can be taken either using a stethoscope positioned slightly forward of the horse’s left elbow (actually a heart rate rather than a pulse, but they should be the same), or by gentle pressure over the facial artery which crosses over the lower edge of the jaw bone, about halfway along its arc, or over the digital vessels, which are two arteries that cross over the top of the sesamoid bones at the ankle.
Take a respiratory rate by watching the horse’s chest for the rise (inspiration) and fall (expiration) that occurs with each breath. Count only the rises or only the falls, not both.
If you have a stethoscope, an easy way to get the rate is to position it directly over the horse’s trachea (windpipe), high in the neck. Note: When using a stethoscope, wait for the horse to stop fidgeting and calm down before you start to count. Simply keeping the pressure from the stethoscope in place will cause temporary elevations.
For body temperature, use a large-animal thermometer in the rectum. Shake it down and then insert it a distance of between half and 3/4 of its length and it leave in place for 2 minutes.
Thermometers inserted into manure balls may give falsely low readings. If the horse wants to pass manure when you insert the thermometer, let him do that first. Then record the reading.