Temperature, pulse and breathing rate, often shortened to TPR, are the three numbers a vet asks for first on almost any phone call about a horse who seems unwell. Learn the technique while your horse is healthy and rested, because fumbling for a pulse point for the first time on a sick horse wastes the minutes that matter. Work in a set order, breathing first, pulse second, temperature last, since those readings disturb him progressively more.
Before you begin: setup and resting state
Gather a digital rectal thermometer with a string and clip attached, water-based lubricant, a watch or phone timer, a notebook, and a headcollar and lead rope. Tie him or have a helper hold him in a familiar, quiet spot, standing square on level ground. Readings mean little unless he is rested: recent exercise, travel, feeding excitement or a hot afternoon all raise pulse and breathing, so wait until he has stood quietly for a good while before you start, and note the conditions beside the readings. Normal resting ranges for an adult horse are a temperature of 99 to 101.5 degrees Fahrenheit (37.2 to 38.6 degrees Celsius), a pulse of 28 to 44 beats per minute, and a breathing rate of 8 to 16 breaths per minute. Your own horse's usual figures within those ranges are his personal baseline.
Breathing rate first, from a distance
Stand where you can see his flank and nostrils without touching him, because contact and attention can quicken breathing. Watch the flank rise and fall: one rise plus one fall is one breath. Count for 30 seconds and double the figure, or count for a full minute if his breathing is irregular. Note whether breathing looks easy and quiet or noisy, laboured or accompanied by flared nostrils at rest, and write the number down immediately.
Pulse second, under the jaw
Run your fingers along the underside of his jaw until you feel the facial artery crossing the bone, a cord-like structure you can roll slightly under your fingertips. Press gently until you feel a clear beat; too much pressure flattens the artery and the beat vanishes. Count beats for 30 seconds and double it, checking that the rhythm feels regular as you count. If the jaw artery eludes you, the artery just inside the elbow or below the fetlock can serve with practice, though both are harder to find. Record the rate and whether the rhythm was steady or uneven.
Temperature last, and never let go
Shake down or switch on the thermometer, apply lubricant to its tip, and clip its string to his tail hair. Stand to the side of his hindquarters, never directly behind, lift the tail gently to one side, and insert the thermometer into the rectum with a slight twisting motion, angling it so the tip rests against the rectal wall rather than sitting in a ball of droppings, which reads falsely low. Hold it in place for the full reading time, usually until it beeps, keeping your hand on it throughout; a thermometer left unattended can be drawn in or expelled and lost. Withdraw it gently, read it at once, wipe it clean, and note the figure with the time. Wash and disinfect the thermometer before returning it to the kit.
What to do with the numbers
Write every set of readings down with the date, time and circumstances, and keep a run of normal-day baselines across seasons, since a horse whose usual temperature sits at the lower end of the range showing a reading at the upper end is telling you something a single figure against the textbook range would miss. Phone the vet the same day if resting figures fall clearly outside the ranges above, if breathing stays rapid at rest, if the pulse rhythm is irregular, or if the numbers accompany dullness, refusal of feed or any other change that prompted you to check. During any future colic scare, read the vet his trend straight out of KinsLe's Pet Passport instead of guessing from memory.