You might be asking, "Why does my horse need an exam like this? He seems perfectly healthy." For the same reasons that your physician recommends a yearly examination for you, your horse (and dog, and cat, and goat, too!) should be examined at least once yearly by a vet, even if nothing seems to be the matter. In our opinion, it's even more important for your animals to receive this routine exam than it is for you! Our domestic animals don't live as long as humans, which means they age faster than we do. More things change from year to year, making an annual exam even more crucial. Not to mention, our animals can't tell us in words what might be troubling them - finding an abnormality on a physical exam might be the first sign of disease.
1. Heart auscultation: We listen to the heart with three things in mind - rhythm, rate, and the heart sounds themselves.
Rhythm is the steady, consistent beat of the heart. When the rhythm is interrupted, we are able interpret the change in timing of beats. Think of a drummer that doesn't match the band. This is called an arrhythmia. A couple arrhythmias we hear are:
Second Degree AV Block: The horse's heart rate is slow at rest, and their heart
is so large that they sometimes "drop beats." This is known as "second degree AV
block", which is a fancy term for "every so many heartbeats, one is skipped." It's
very common in horses, and usually no reason to worry
Atrial Fibrillation: A -Fib, as it's known in the industry, is an uncontrolled
fluttering of the atria (the top two chambers of the heart). A-fib causes a
completely random heart rhythm, which can be dangerous.
Heart Rate is the number of times the heart beats in a minute. A horse's normal, resting heart rate is 32-44 bpm. (This can vary up or down slightly.) A high resting heart rate can indicate heart abnormalities, sickness or pain.
Heart sounds are ausculted on both sides of the thorax to detect murmurs. Murmurs are generally caused by imperfections in how the heart valves open and close. Some heart murmurs are very common in horses, and can be insignificant, but others can indicate a problem. We document any murmurs we hear, and if they worsen from one year to another, or are otherwise concerning, we may recommend a cardiac ultrasound to diagnose the specific problem.
2. Lung auscultation: We listen carefully to both sides of the chest, and in all "lung fields". Generally, we divide the lungs into left and right "ventral lung fields" (which surround the heart and just above it), "middle lung fields" (which are in the center of the chest on both sides), and "dorsal lung fields" (closer to the spine). We are listening for abnormal sounds, which is pretty much anything that doesn't sound like a soft breath. "Crackles" and "wheezes" are the most common abnormal sounds, and indicate inflammation in the lungs. We may also listen over the trachea, for mucus in this structure.
4. Temperature: This simple test is always performed rectally in a horse (can you imagine taking it orally?). A horse's normal rectal temperature is 99.5-100.5 F, but mild elevations up to 101.5 F may be seen due to exercise, trailering or excitment. We diagnose a temperature around 102 F or higher to be a "fever" in a horse. A fever can indicate inflammation or infection.
5. Weight taping and Body Condition Scoring: Tracking the weight of a horse from year to year is important to detect trends in weight gain or weight loss. A scale that will tolerate the weight of a horse, however, is a little hard to come by. So, various calculations for estimating the weight based on other measurements have been devised. The best calculation so far that we've found is one that takes into consideration the "heart-girth" (the circumference of the horses' chest, just behind the elbow) and the length of the horse from shoulder to hip. (There's a good website which helps with the calculation, and a few smart phone "apps" exist as well.) Even more important than the estimated weight of the horse, however, is the body condition score. This is a number from 1 to 9, 1 being emaciated and 9 being obese, which gives an indication of how appropriate the horse's weight is for his size. It is determined by the amount of fat over a horse's ribs, hips, spine and crest of the neck.
Wow! That does seem like a lot, doesn't it? Fortunately, we can be doing a lot of this while we're chatting about your farm's deworming program, or what your plans are for the show season... so it doesn't seem to take that long. A good, thorough routine examination can usually be completed in about 5-10 minutes, but the information we gather can be very helpful! So, the next time you're having us out to vaccinate, or do some dentals, think about adding a wellness exam to the visit - your horse may thank you!