Article by Matt Randall, DVM
Temperature, pulse and respiration are the vital signs that everyone generally thinks about, but hydration status and even attitude can be considered a vital sign. While there are typical ranges for horses in general, it’s important to know what’s normal for your horse.
Almost every veterinarian will ask you questions about these vital signs when you place an emergency call. It can mean the difference between an after hours trip to the veterinary hospital or a cheaper, but sleepless, night of home monitoring.
Here are some general tips for measuring vital signs. It’s best to have your veterinarian show you how to properly check your horse’s vital signs.
Normal temperature range for a horse is 99-101 degrees Fahrenheit. “They don’t feel hot” is not an acceptable answer when the vet asks does your horse have a temperature on an emergency phone call.
The most reliable way to take a horse’s temperature is rectally. A simple digital thermometer from the drug store will do the trick. With a properly working thermometer, it’s extremely difficult, if not impossible, to get a false high reading.
It is, however, quite easy to get a false low temperature. Lack of contact with the rectal wall may give a false low reading. Fecal matter or an impending passage of gas may not allow sufficient contact to get an accurate reading.
Veterinarians usually save the term fever for when a horse has an infectious process going on, whether it is from a viral or bacterial upper respiratory infection, an infected wound or colitis. Hyperthermia is when the body temperature is elevated secondary to something such as the environment or exercise. If it’s 100 degrees outside, and you’ve worked your horse, his temperature is going to be elevated.
A fever is part of the body’s response to healing, so mild fevers indicate that the horse’s body is doing its job. When it’s over 104 for prolonged periods of time, it can start to have negative effects on other body systems, and your horse needs attention.
A good rule of thumb is to call your vet when the horse’s temperature is over 102 degrees.
The typical heart rate for a resting horse is 28-44 beats per minute for an average-sized horse. It’s faster in smaller horses, like miniatures. More fit horses tend to have lower heart rates between 28-36 beats per minute due to conditioning.
Here’s where having a stethoscope, even an inexpensive one from the drug store, is very handy. On the chest behind the elbow is the best place to take a reading. Bear in mind, you may have to play around with the placement to hear a good heartbeat. Once you’ve found it, count the number of beats for 15 seconds, then multiply by four. It’s important to note that “lub-dub” is one beat, and in a fit horse, the time between the “lub” and the “dub” can be surprisingly long.
Elevated heart rates generally go along with stress—whether its pain, shock or simply, ‘Oh my, what was that shiny thing that just went by?’ A standing heart rate of about 48-52 beats per minute or higher is noteworthy. Sixty beats per minute or more is most often cause for concern.
A resting horse will usually take eight to 16 breaths per minute. The fitter the horse, the fewer breaths they take at rest.
Taking a respiration rate is easy. Simply count the number of breaths your horse takes within a minute (or 15 seconds and multiply by four). Don’t be surprised if your horse appears to be holding its breath.
Generally, a low respiration rate isn’t what you’re worried about. It’s elevated respiration rates of 24 breaths per minute or higher that may indicate a problem.
With summer looming ahead, elevated respiration rates in resting horses can be warning sign for potential heat stress.
You can check a horse’s hydration status two ways—capillary refill, where you check a horse’s gums by pressing right above the teeth and seeing how long it takes the color to return to a normal pink color, and skin tent, where you pull the skin at the point of the shoulder to see if it sticks together.
With capillary refill, one second is normal. Two seconds is the starting line for questionable. A slow capillary refill time indicates lack of volume or low pressure in the circulatory system, which could be from dehydration, shock or colic, etc.
With skin tent, you want to see the skin pop right back in place. When checking skin tent in older horses, it’s important to remember the skin has lost some of its elasticity and won’t bounce back like in a younger horse and should be taken into consideration. However, capillary refill will be the same in all horses.
Gum color is also important. The gums should be a pale pink color. You might be surprised how pale they normally look. Blanched white, brick red and purple gums are the extremes you may see. Any one of these is often accompanied by an elevated heart rate, respiration rate and usually warrants an emergency call.
Gut sounds, too, can indicate hydration. If the gut is “moving” and sounds “gurgle-y,” there is generally adequate hydration for it to do so.
It’s not necessarily your classic vital sign, but it’s often the first sign you will notice if something is wrong. Say your piggy mare isn’t eating, or your energetic 4-year-old is oddly lazy or lethargic.
No single sign tells the whole tale. It’s all of them together that paints the picture of your horse’s well being.
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