3/24/2010 Normal Physical Exam

Vet tip of the Day: The Normal Horse
Key Words: Heart rate, Respiratory Rate, Temp, Gut sounds, mucous membranes

I performed a prepurchase examination for a new horse owner this week.  She had lots of good questions about her horse husbandry.  One thing she was interested in was learning normal physical examination findings, so I thought I would go over some basics which all horse owners should know.  In case of emergency, or if your horse simply isn't feeling well, being able to do a basic asssessment of your horse's physical parameters can be extremely useful.  Not only does it give you factual information to convey to your veterinarian over the telephone, it also gives YOU factual information to allow you to determine just how serious your horse's condition may be.

First you need some equipment.  Go to any nursing supply store and by a CHEAP stethoscope.  The most basic model is perfectly adequate for obtaining a heart rate.  To listen to your horse's heart, place the flat side of the stethoscope bell against your horse's chest just behind the point of the elbow, then push the stethoscope head forward as far as you can so it slides in underneath the triceps muscle.  Close your eyes and listen carefully.  The heart beat has two parts - lubdub...lubdub...lubdub.  Practice until you can hear it clearly.

Next go to the drug store and buy a regular old human digital thermometer - I prefer the non-flexible ones. 

Finally, purchase a small, LED flashlight and cheap watch with a second hand and store them, along with your stethoscope, thermometer, and a small notebook with a pen attached to it by a piece of string in a handy place in your feed or tack room or horse trailer.

Here are some normal numbers - write them down in your notebook so in an emergency you don't have to remember them. 

Heart rate: 28- 44 beats per minute.  I usually count the heart rate for 15 seconds and multiply by 4 to get beats/minute. Heart rates over 52 beats per minute are definitely abnormal.  Heart rates over 80 beats per minute indicate severe cardiovascular distress.  Remember, exercise, nervousness or excitement may cause your horse's heart rate to be elevated without any serious illness present.
Respiratory rate: 8-16 breaths per minute.  The best way to count the respiratory rate is to stand back from the horse and watch the abdomen just behind the ribcage.  In a normal horse you will see a gentle rise of the abdomen with each breath.  Taking an accurate resting respiratory rate in a normal horse can be difficult, because as soon as you approach them they begin sniffing and snuffling, thereby disrupting the quiet, resting breathing rate.  If your horse has a wide flare to the nostrils with each breath and an deep movement of the abdomen with each breath coinciding with the nostril flare, this is a sign of labored breathing and is abnormal.
Gut Sounds: Using your stethoscope, listen to your horse's abdomen in 4 places - up high and down low on each side, behind the ribs and in front of the hip.  Gut sounds vary tremendously even in a normal horse, but if you listen for 30 seconds in each location, you should hear at least one good, rumbling gurgle in each of your 4 listening zones.
Mucous membranes: Standing beside your horse's head (not in front), lift your horse's lip just enough to see the gums above the incisors on one side.  Normal gums are quite pale pink, with a glistening surface.  If you press against the gums firmly with your finger for a few seconds, when you remove your finger the gums should be white, and should refill with the normal pale pink color in less than 2 seconds.  This is called the capillary refill time (crt).
Attitude:  When I record my physical examination findings, I will often note: BAR.  This is code for Bright, Alert, and Responsive.  When you do your physical exam, note your horse's attitude, expression, head position and body position. Look in the stall or pen and check for fresh manure, or signs of distress such as areas where your horse may have been pawing or rolling.  Check to see if the water trough is full and if the last feeding has been consumed.
Gait/Posture:  Finally, move your horse around a bit and check for lameness and willingness to move forward.

Now you are prepared to do a comprehensive physical examination on your horse.  The best way to recognize abnormal is to know normal, so practice performing physical examinations on your horse frequently so that when you are concerned that something isn't right, you will be confident in your assessment.

Enjoy!