TPR stands for the vital signs temperature, respiration and pulse. They tell you if your horse is healthy. Memorize the values, this will help you if you need them quickly in an emergency situation. Especially the pulse rate at rest varies from horse to horse, depending on breed, age and weight. It is best to determine the values once for your horse when it is healthy.
The normal pulse values of a horse are between 28 and 40 pulse waves per minute, which can best be felt on the underside of the gait. It is best to count 15 seconds and multiply by four and you will have the correct value.
The number of breaths is 8 to 16 breaths per minute. This is observed by the movement of the flanks.
Lastly, the body temperature. This is between 37.5 and 38.2 °C in horses, and somewhat higher in foals at about 38.5 °C. Usually, the temperature is measured with a clinical thermometer in the anus. The thermometer is best attached to the tail with a string and a clothespin so that it cannot simply disappear.