Vital Signs (Book Excerpt)

Editor's Note: This is an excerpt from Understanding Equine First Aid by Michael A. Ball, DVM. This book is available from

The physical examination should assess any changes in the horse's demeanor, respiratory system, cardiovascular system, body temperature, evidence of shock, and hydration status.

For a moment, usually from a distance and outside the stall, I like simply to observe the horse. Is the horse abnormally anxious or depressed? Is the horse exhibiting signs of pain such as flank watching, pawing, or stretching? Is there evidence that the horse has gotten down and rolled? Is there bedding on its coat or in its mane and tail? If so, make a note about the abnormal posture or activity. Such changes in the general demeanor of a horse can be significant.

Don't just evaluate the horse--evaluate its environment, too. Is there evidence that the horse has been drinking and eating? How many piles of manure have been produced today and what is the consistency? Obviously, if the horse is violently thrashing in pain or if it is bleeding severely, you do not want to spend an hour collecting this sort of information before you call in the veterinarian. But if this examination process becomes part of you daily routine, you'll be able to note the changes in the horse's condition in a matter of minutes.

To establish a baseline set of measurements when the horse is healthy, do your "hands-off" observations first. Then after watching the horse, measure its heart and respiratory rates. I usually insert a livestock thermometer into the horse's rectum and wait the appropriate time (three minutes) before removing and reading it. During the "thermometer time," you can perform most of the other parts of your examination. Remember that if the horse is difficult about the thermometer, and a fight ensues, its heart rate can increase. Let the horse relax for a minute or two before rechecking the heart rate, or check it after the thermometer is removed.

The use of a stethoscope can make it easier to determine the heart and respiratory rates, but is not essential. The heart rate can be determined by feeling for the pulse along the lingual artery. It can be felt under the jaw, where it lies just under the skin and on the bone. I once heard a 4-H leader describe it as feeling for something like a thick piece of spaghetti. The pulse, or heart rate, also can be assessed by listening to the heart at the point of the elbow on the left side with a stethoscope. The normal heart rate for a horse is approximately 30 to 40 beats per minute.

The respiratory rate can be determined by watching the rib cage, feeling for the breaths at the nostrils, or listening to the breaths in the windpipe with a stethoscope. At the same time that the respiratory rate is determined, the character of the horse's breathing should be noted. Are the horse's nostrils flared when it inhales? Is there air moving through both nostrils? Is there any noise being generated as the horse breathes? The normal respiratory rate for a horse is eight to 12 breaths per minute.

After determining the heart rate and respiratory rate, assess the color, moistness, and capillary refill of the gums. Normally, a healthy horse has gums that are pink and moist. It should have a capillary refill time of about two seconds. The capillary refill time is determined by pressing hard on the gum line next to the teeth and determining how long it takes for the blood you squeezed out to rush back into the area, making the blanched white spot you created go away. Gums that are abnormal in color (bright red, dark red, bluish, or white) and a capillary refill time greater that two seconds can be an indication of various forms of shock.

Don't forget about the thermometer reading. A horse's normal body temperature varies between 99.5 and 101.5 degrees Fahrenheit.

These physical parameters and how different disease processes or injury affect them will be discussed in subsequent chapters.

I emphasize that each horse responds to physical problems differently. For example, not all horses experiencing pain have an elevated heart rate.

Sometimes when you look over your horse, "alarm bells" will go off simply because you know your horse so well. That's the time to pull out the notes you first made as a baseline when your horse was healthy and compare them to the horse's vital signs taken when you suspect there might be a problem. Such notes will provide you and your veterinarian with a useful guide in assessing a potential problem.

About the Author

Michael Ball, DVM

Michael A. Ball, DVM, completed an internship in medicine and surgery and an internship in anesthesia at the University of Georgia in 1994, a residency in internal medicine, and graduate work in pharmacology at Cornell University in 1997, and was on staff at Cornell before starting Early Winter Equine Medicine & Surgery located in Ithaca, N.Y. He is also an FEI veterinarian and works internationally with the United States Equestrian Team.

Ball authored Understanding The Equine Eye, Understanding Basic Horse Care, and Understanding Equine First Aid, published by Eclipse Press and available at or by calling 800/582-5604.

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