Horse Vital Signs 

Three standard indicators of a horse's health are temperature, pulse rate and respiration. These can be used not only to determine if your horse is ill but also can indicate the type of illness.

Horse's Temperature

The normal temperature for a horse is about 38C (100.5F). Individual horses may vary half a degree either side of this, so you may want to take your horse's temperature when it is healthy so you know what its healthy temperature is exactly. There can also be a variation of up to half a degree due to time of day and activity. Variations of more than one degree indicate a problem, which should be treated accordingly..

An elevated (abnormally high) temperature usually indicates that the horse has an infection. In such cases, keeping the horse warm and comfortable is important. In particular, one should protect it from being chilled by cold, wet or windy weather. The higher the temperature is, the more serious the condition, and the more likely that veterinary assistance or antibiotics may be required.

A depressed (abnormally low) temperature is unusual, but can occur in cold weather (especially if it is wet or windy) if the horse is unable to maintain its temperature. Horses which are old, sick or weak can be chilled easier and faster in cold conditions. A drop in temperature should be taken seriously as even small changes can easily result in secondary issues such as colic, or even be fatal. The horse should be moved to shelter and covered with a warming rug. If you have mash, mixing a small quantity with some warm water (but not hot!) and feeding it to the horse can help it warm up, partly due to the warming effect of the water and partly from the quick energy of the mash. The horse should be closely monitored until it warms up and fully recovers. To prevent a reoccurrence, one should ensure that the horse has adequate shelter from the weather, consider using a horse rug on colder days (especially if wet or windy) and consider giving it a quantity of high-energy food (such as mash or grain) during cold periods (note that any dietary changes should first be discussed with a veterinarian to avoid potential dietary related problems such as laminitis).

If a horse shows signs of illness or abnormal behavior, but does not have a temperature, the problem is probably not infection related. In other words, it could be an injury or a non-infection illness such as colic or laminitis. Consequently, even a normal temperature is is useful diagnostic tool, as it helps to eliminate infections (e.g. strangles) as possible causes of the problem symptoms.

If you are not experienced in taking a horse's temperature, you should first do this with an experienced person, to minimize risk of injury to yourself or the horse. Some tips:

  • An electronic thermometer is better than a glass thermometer, as it is faster and does not have the risk of breaking and associated injury. If you only have mercury thermometer available, first shake the mercury below 37.4 and take care that it does not break when inserting into or removing from the horse.
  • If possible, have someone at the head end to distract the horse with a bit of food. If working on your own, consider first tying up the horse to minimize movement or risk of it running off.
  • Put some lubricant on the bulb-end of the thermometer to make insertion in the rectum easier.
  • Raise the tail with your left hand and insert the bulb into the rectum with your right (if you are left-handed, hold tail with right and insert with left). With mercury thermometers one needs to wait about half a minute and not remove until the mercury stops moving. With electric thermometers readings are normally quicker and depending on type it may beep to tell you that the reading is complete.
  • Horses can be startled by this procedure and may kick, so one should watch and be careful of the horse. Standing slightly to one side rather than directly behind the horse is a safer position.
  • Make sure that you hold onto the thermometer firmly, as otherwise movement of the sphincter muscle could draw the thermometer inside the horse.
  • Wash the thermometer and if possible wipe it with alcohol (or appropriate disinfectant) to sterilize it before putting it away.

Horse's Pulse 

A horse's pulse rate should be taken when it is resting, as the pulse rate during exercise or shortly thereafter is not a good indication (unless one is using pulse recovery rates and maximum pulse rates as part of a fitness evaluation). The normal pulse rate for a horse is depends on various factors such as breed (e.g. ponies tend to be faster), age and physical fitness. Consequently, it is wise to take your horse's pulse rate when it is well and write this down, so that you know the normal pulse rate of your horse. Then, if you suspect illness, you will know the normal pulse of your horse which you can test against. If you don't know your horse's normal pulse rate, consider the range of 36-42 beats per minute as normal.

To take the pulse, gently press your fingers against an artery and count the number of beats. You will need a watch with a second hand to measure the time. The easiest places to feel the pulse are:

  • Under the top of the lower jaw, gently pressing the artery against the underlying bone
  • On the horse's cheek, just above and behind the eye
  • The inside of a foreleg, level with the knee, where the artery runs over the bone.

One can also use a stethoscope, pressed gently against an artery, to listen for the pulse rather than using one's fingers to feel for it. 

An elevated pulse rate can be associated with illness or pain (as well as exercise or fear). A high pulse rate combined with a normal temperature indicates a non-infection illness. A high pulse rate combined with a high respiration rate but a normal temperature is often associated with pain.

Horse's Respiration

The resting respiration rate of an adult horse is 8-15 times per minute. This is a wide range as the normal respiration rate for an individual horse is dependent on its breed, age and general condition. Consequently, it is wise to take your horse's respiration rate when it is well and write this down, so that you know the normal respiration of your horse, which you can then test against if at a later date you suspect illness.

The easiest way to measure a horse's respiration is to stand behind it and watch its flanks, while timing with a watch. You may need to first move the horse into an area where it is quiet and away from other horses, as excitement or sniffing can make an accurate count difficult. Likewise, on a hot day you may need to move it out of the sun, as a hot horse breaths faster.

An elevated respiration can be associated with illness or pain (as well as exercise or fear). A high rate combined with a normal temperature indicates a non-infection illness. A high respiration rate combined with a high pulse rate but a normal temperature is often associated with pain.