Photo: The Horse Staff
Temperature, pulse, and respiration (TPR)--are the absolute basics every horse owner or caretaker should know if they want to take the best care of their animals. These three vital signs are just the bare bones of a physical examination, but they can greatly help you--and your veterinarian--when you think your horse might be sick. Just knowing these three values for your horse can give your veterinarian great insight as to just how sick or injured your horse could be.
For example, say this morning while feeding you found a boarder's horse standing in a small puddle of blood in the pasture. The blood evidently came from a wound near the pastern. The horse is acting tired, but looks OK otherwise. The wound isn't deep, but the lower leg has a fair amount of blood on it. You call your vet and tell him it's not serious. "He looks all right to me," you say.
But is he?
Three hours later your vet finds him dead in his stall. What went wrong?
If you had taken his TPR when you found him, you would have known that his heart rate was over 100 beats per minute (almost three times the normal rate), and your vet would have known that the horse was in shock from severe blood loss. Later you find the fence wire he got tangled in and the tremendous amount of blood he actually lost.
I apologize for the graphic nature of this example, but it is necessary to awaken readers to the reality of dealing with life and death issues for horses. I've heard too many people say "if only" who could have made a difference in their horse's survival by becoming educated in the basics of a physical examination for a horse. Hopefully, you won't have to say "if only..."
No, this is not a home repair project, but you will need a few supplies to perform a basic physical examination--a thermometer, a stethoscope, and a watch that allows you to count in seconds. The thermometer should be digital. The glass (mercury) types are not recommended because of the risk of toxic mercury vapors escaping if the glass thermometers break. Furthermore, most lay people like the digital types because the time for a reading is much less (about one minute) for a digital compared to three to five minutes for a glass thermometer. In the case of foals, it is probably kinder and possibly safer to use the soft digital ones rather than the rigid glass types, especially if the foal is particularly rambunctious.
Any thermometer you use should have a small hole constructed at the end so a long piece of brightly colored suture material, string, or tape can be applied in order to help find the thermometer if it's lost in the stall. A small clamp or clothespin can be placed at the end of the suture material so that it can be clamped to the horse's tail and left in place until the temperature can be read. In that way, you do not have to hold the thermometer in place, and if the horse defecates, the thermometer is easy to find since it is attached to the horse's tail. You can purchase these types of thermometers in any drug store.
The stethoscope, of course, magnifies sound, so you can clearly hear the heart beating and the sounds of breathing. There are many different types of stethoscopes. For your purposes, a very inexpensive one can be purchased at a drug store or through horse supply catalogues, often for under $20. These inexpensive stethoscopes are sufficient for enabling you to hear the heart beat and determine a heart rate and respiratory rate.
The Powers of Observation
I have always believed that the beginning of a really good physical examination begins with observation. This applies to veterinarians, physicians, and horse owners. A great deal can be learned about your horse just by observing his posture, attitude, and environment. It is a skill that usually must be learned, as not all of us are naturally observant. Most of the time, it just entails learning what to watch for--patterns of lying down to rest, normal response to exercise, normal appetite, etc. Observation from outside the stall or paddock can give valuable information. For example, did the horse eat or drink last night? How many piles of manure were passed? If a problem is suspected, is there mild pain (flank watching) or are there paw marks and evidence of rolling on the horse or in the stall?
By observing your horse closely, you can determine his normal and abnormal behavior. And, by observing every day, it can become an almost unconscious part of your daily routine, which can help you decide when there is a problem with your horse.
Determining "Normal" TPR
When will you need it? Any time you think one of your horses might be ill or injured is an appropriate time to measure TPR as long as your horse is at rest. (It can also help you judge your horse's condition.) But first you should perform a TPR when your horse is healthy, then you will have that horse's "normal" vitals. For example, although the normal heart rate for most horses is 32-36 beats per minute, some horses are lower--24 beats per minute--or maybe slightly higher--40 beats per minute. This can be a significant value for comparison when your horse is sick, so write it down and keep it where you can access it easily.
The rectal temperature can be easily taken on most horses. Shake the thermometer down if using the glass/mercury kind, and place a small amount of lubricant (petroleum jelly or KY Jelly) on the thermometer. Approach the horse from the side--do not stand directly behind the horse in case he decides to kick! Raise or move his tail and insert the thermometer into his anus. If the thermometer has a clip, clip the string to his tail. While waiting for the temperature reading, you can measure the heart and respiratory rates.
The normal rectal temperature of a horse is 99.5-101.5°F (37.5-38.6ºC). Neonatal foals (foals less than one month of age) have a normal temperature of 100.0-102.0°F (37.7-38.8ºC). Remember, newborn foals can easily suffer from hypothermia (low body temperature), so if the foal's temperature is below 98.0°F (36.6ºC), call your veterinarian and rub the foal with towels or blankets to stimulate blood flow and/or dry his coat.
Note--If the horse's rectal temperature is above normal, it's called a fever, not a temperature. All horses have a temperature--either above normal (fever), below normal (hypothermia), or normal.
Pulse and Respiration Rates
The heart rate (pulse) and respiratory rate can be taken without a stethoscope, but having a stethoscope makes the job easier. If a stethoscope is not handy, the pulse can be taken from the lingual artery, which is on the bottom side of the jaw where it crosses over the bone. The pulse can be taken for 15 seconds, then multiplied by four to achieve the heart rate in beats per minute. If a stethoscope is available, then listen to the heart on the left side of the horse's chest, just behind the elbow. Each "lub-dub" of the heart is considered one beat. The normal heart rate for an adult horse is about 32-36 beats per minute. The heart rate for foals varies depending on age. Newborn foals have a heart rate of between 80-100 beats per minute. Foals which are a few weeks to a few months of age will have heart rates of 60-80 beats per minute.
The respiratory rate can be taken by watching the horse's chest move in and out (each inhale or exhale is one breath) or feeling the air come out of his nostrils. The stethoscope can be used to listen to the breaths as the air travels across the trachea when the horse inhales and exhales. This should sound clear.
The characteristics of his respiration should also be noted. Is the horse taking shallow or deep breaths? Are there abnormal squeaky or crackling sounds associated with the breathing?
The normal respiratory rate for adult horses is eight to 12 breaths per minute. Newborn foals have respiratory rates that are quite high (60-80 breaths per minute). Neonatal foals have resting respiratory rates from 20-40 breaths per minute. Please remember that if your horse or foal becomes excited for any reason during the examination, it can elevate his heart and respiratory rates temporarily.
Another indicator of health is the mucous membrane color, or gum color. Healthy horses have nice pink gums that are moist to the touch. Capillary refill time can also be checked while looking at your horse's gums. Press your finger firmly on the gum line, then take it away quickly. The time it takes for the area to turn from white back to pink is the capillary refill time and should be around two seconds. Gums that are dark red, bright red, brick red, blue, or even white with a prolonged capillary refill time usually indicate one of the various forms of shock, and your veterinarian should be summoned immediately.
An owner's or caretaker's basic physical exam should never take the place of a veterinarian's exam. However, if you become familiar with these techniques, you can help recognize a problem and be able to relay the information to your veterinarian. This basic information can save time and potentially save your horse's life.
Above all, talk to your veterinarian. Make sure he or she understands that you are interested and want to learn how to better care for your horse. Furthermore, have your veterinarian observe you while you perform a basic physical examination, and ask what information he or she would like the most in the case of an emergency. Good communication is the key to a successful veterinary/client relationship!
If you ever perform a TPR exam on your horse and think there might be a problem, call your veterinarian. When your veterinarian arrives, he or she will perform a more detailed examination. The veterinarian will not just listen for the respiratory rate, but evaluate the entire lung field for abnormal sounds. His evaluation of the heart includes not just checking the heart rate, but he will also listen to the rhythm for the presence or absence of a heart murmur. The abdomen will be listened to for sounds of a normal moving gastrointestinal tract or for the more ominous silence of a GI tract in stasis, which happens in some serious forms of colic. Depending on the problem, your veterinarian will perform many other procedures to determine the true extent of the problem and the treatment necessary for resolution.
By being knowledgeable of your horse's normal vital signs and able to take his vital signs in an emergency, you greatly increase your horse's chance of surviving a serious illness or accident. Your horse's first line of defense against health problems is your knowledge and vigilance.
Ball, Michael. A. Understanding Basic Horse Care. Lexington: Eclipse Press, 1999.
Ball, Michael. A. Understanding Equine First Aid. Lexington: Eclipse Press, 1998.
About the Author
Christina S. Cable, DVM, Dipl. ACVS, owns Early Winter Equine in Lansing, New York. The practice focuses on primary care of mares and foals and performance horse problems.