Is my horse normal?
What can we do (or ask a veterinarian to do) to determine if our horse is normal or not?

First lets assess behaviour. You know better than most what your horse does and does not like to do. Is he/she behaving as usual? Is he/she alert, eating or showing signs that we don’t like to see such as pain or depression? In general, if a horse is eating there is usually not much wrong of great importance.

What is the environment like?
Is the bedding in the stall markedly disturbed as might be expected from a horse with colic? Is there evidence of other problems such as chewing of the fence rails?

What steps are there in examining a horse?
Take your horse's temperature! How many people know the normal body temperature range for their horse?  It is 37 - 38.5 ⁰ Celsius (⁰C). The temperature is taken by a thermometer inserted into the horse’s rectum (bum). What a nuisance eh? Pity we couldn’t use the gadgets seen in human medicine like the skin and ear probes. Anyhow, the thermometers now come in digital units as well as the old mercury ones. If the temperature is high, around 40.0⁰C, then we would usually think of an infection. Sometimes a horse’s temperature may be elevated because of recent strenuous exercise, such as a gallop, but if this is the case, it will not stay elevated for more than a 5-10 minutes. Low temperatures commonly occur as a result of shock and may be seen in colic cases that have been going on for a a while and with horses that have been down on the ground with a problem.

What other parts of the horse should be examined?
What do the vets look for?
First the heart. The heart pumps blood around the body and the blood takes nutrients and oxygen to the most distant extremities. The normal heart rate for a fit racehorse will be low ~ 35-45 beats per minute (bpm) and higher if the patient is not athletic. A heart rate of greater than 50 may signify a problem (providing it isn’t a quick acceleration associated with nervousness of the exam). If the heart rate climbs above 60 bpm then there is generally cause for concern. If the heart rate is over 100 bpm, then we are very concerned about the patient’s short and long-term survival.

The heart rate is best identified by examination with a stethoscope at the point of the elbow on the left hand side. In addition to the heart rate, the hearts’ rhythm and sounds are evaluated. Irregular rhythm can occasionally be noted in horses and may be associated with problems and murmurs, especially if accompanied by a vibration (thrill), are less commonly noted but potentially serious problems.

After the heart we look at the respiratory system. The respiratory system involves the nostrils, nose, pharynx and larynx, trachea and lungs. The lungs are examined by placing the stethoscope above the heart (on both sides) and following a line drawn from the bottom of the elbow to the horse’s hip. Everything above that line is an area where the lung sounds may be heard.  Sounds heard through the stethoscope may identify pneumonia, allergic airway disease, chronic obstructive pulmonary disease etc and may be facilitated by placing the horse in a quiet environment, especially not in the wind. The normal respiratory rate is between 10-20 breaths per minute. A horse that consistently has an elevation should be examined more specifically. A horse that is breathing hard may often display flaring of the nostrils

Another instrument used to examine the respiratory system is a fiberoptic endoscope, which lets us look in to the upper and lower respiratory system. The picture (above right) shows the horses’ upper respiratory tract (the larynx) and we can see the vocal cords and epiglottis as well as the opening into the trachea (you will also note that there is an asymmetry- more on that later). The nostrils are evaluated by placing both hands in front of the nose to detect any airway disturbances.

Next we evaluate the gastrointestinal system. This begins at the mouth and finishes at the rectum. It is a long and complex set of organs. The digestive tract is examined initially by looking at the shape of the head, in particular looking for abnormal swellings (as seen in the picture below left) and examination of the teeth.

Further examination can be performed using a mouth gag to hold the mouth open and prevent you getting bitten. The digestive tract inside the abdomen is examined with a stethoscope, by rectal exam or with an internal and/or external ultrasound. The last part of the digestive tract is the anus, which is under the tail.

This horse (pictured left) had nasty skin cancers hiding there, which are called melanomas.

After the ‘Big Three’, which are the heart, lungs and abdomen there are a variety of other systems and organs that need to be examined. Starting at the head, lets look at the eyes. The eyes can be viewed with a penlight or a variety or more specific instruments.

The eye should be clear and not have any hint of tearing, discharge, swelling, colour change or pain. The eye in the above right picture has slight pain, some discharge and is not clear. The blueness comes from oedema (fluid) that has infiltrated the cornea (which is the clear surface of the eye ball).

The ears are examined manually or on occasion with a light or even by x-rays. The throat and upper neck are next and mostly examined manually. After we have done a general physical exam of the upper part of the horse it is time to look more carefully at the musculoskeletal system. This includes examination for conformation, lameness and the nervous system.

Conformation: This refers to our appraisal of what shape and alignment the feet and limbs should have. Some of this exam is based on personal preferences however; some problems identified have been to show consistent relation to ongoing lameness problems. The ideal conformation for a horse varies according to the breed. Clearly,  a racing Thoroughbred would not be expected to have the same shape or limb conformation as a Clydesdale or a Tennessee Walking Horse. They are bred to do different jobs and the conformation usually reflects this.

For most horses we recognise some basic philosophies and they are that the limbs should be symmetrical and reasonably straight when viewed from in front and behind and when viewed from the side that the desirable attributes are refected in a foot/shoulder angle that is almost equal.

The experienced person relatively easily identifies abnormalities of shape and or function such as this bone growth on the inside of the cannon bone (termed a splint). This may be a simple growth as a result of irritation of the splint bone or a kick or it may represent a fractured splint bone.

Lameness is evaluated by watching the horse walk and trot. In addition, aids such as hoof testers and flexion tests are used to try to identify areas that are more painful than they should be. The old adage "No Hoof - No Horse" is very true.  Particular attention is paid to the hoof itself, the shape of the foot, how the horse has been shod.

 It is a pity that horses can’t talk, they could tell us where they hurt and things would be so much easier.  However, they can't!  So we have developed a series of intricate and sometimes difficult to perform manoeuvres and tests that help tell us to identify where the horse is feeling pain. Sometimes this even means injecting local anaesthetic into an area and recognising the source of pain must be there if the pain is eliminated after the injection. This technique is known as a nerve block. 

Examination of the nervous system can be quite complex and involves a series of tests that are designed to determine if the horse has proper control over its actions and feet placement. The simplest and most common test to perform involves spinning the horse in a circle and watching how it places it feet.

Finally, If the horse being examined is intended as a breeding animal then external and internal evaluation of the reproductive system will need to be performed. The external conformation of the mare can relate to her ability to have problems getting into foal. The mare in the picture below left would clearly have problems preventing manure and air from entering her vagina.

Internal reproductive tract examination of the mare involves a rectal exam with or without an ultrasound and may involve a look at the cervix and vagina using a speculum (above right) . Examination of the stallion certainly involves making sure he can get an erection and breed and should involve collecting semen a visualising it under the microscope .  

© Cyberhorse 2003 Angus McKinnon