Vital Signs
This area is a reference for the normal vital signs for adult
horses. Determination of these parameters can be essential in an assessment of a
patient's health. Even horses with what might appear to be only a mild depression
may be in critical condition. Knowing your horses baseline values, and comparing
those to times when one might suspect that he is ill, can be a VERY helpful aid in
triaging the priority level of a veterinary response.
General Assessment: Emergency medical
technicians are trained to first look at a persons mental status before ever touching the
patient. This can be very important in horses as well. Although this aspect
may not always considered a "vital sign", whether the horse is excited or
depressed can be an initial first clue on the horse's overall condition. Whether he
is interested in feed or grass or not will tell the owner very quickly if the horse is
ill. Generalized shaking, abnormal rolling, or on the other hand, a good mental
status of frolicking through the pasture should be taken into consideration.
Temperature: The normal temperature for
the horse is 100.0 degrees. However, a horse's temperature can vary somewhat with
the season. During the winter, it is not uncommon for the temperature to drop to as
low as 97. But usually, we are not concerned with temperature that are low, but
rather, trying to determine if he is running a fever from an infection. During the
winter, any temperature above about 100.5 should be suspect, with average fevers normally
running from 101.5 up to 104. The summer heat, as well as any exercise, can often
raise the core temperature upward even without a fever. This must be taken into
account when the assessment is made. A race or show horse, after intense
competition, can have a core temperature up to 105!! Even at rest, in the summer
heat under a tree, a temperature of 101 would not be considered abnormal. So events
preceding the acquisition of the temperature must be taken into account before it is
interpreted. Taking a horses temperature is usually done rectally with either
a standard glass or digital thermometer.
Pulse: The normal pulse rate, most often
taken by listening to the heart on the left side of the chest just behind the left elbow,
is 40 beats per minute. Horses that are fit may have rates as low as 28, and this is
not considered abnormal. However, ANY rate above 40, even 44, should be looked in
the context of how the horse is feeling. Rates between 40-60 are considered
"serious", but may be explained by an elevated temperature. However, rates
above 80 are considered "critical" and indicate a very serious problem. Of
course, these rates apply to a horse at rest, and any exercise just before taking the
pulse should be taken into consideration. Also, if the horse is suddenly excited, it
may be elevated on a very temporary basis. Listen to the rate for at least a minute,
checking to see if it comes down, before recording the final rate.
Respiration: The normal rate for horses is
the same for adult humans, that being between 12-20 breaths per minute. However,
many things can effect this that must be taken into consideration before considering
whether it is abnormal. One common factor is his temperature. Other
characteristics of breathing, rather than just the rate, may be more of an overall
indicator of problems. Deep heavy breathing, or breathing with an extra abdominal
effort, abnormal noise, labored breathing, or gasping are all indications of a very
serious problem. Report any observations that are anything but quiet and easy
breathing.
Mucus Membrane Colour: The normal colour
is pink. Gums that are pale, deep red, purple, overly yellow, or streaked with the
appearance of small broken blood vessels are abnormal and should be recorded. Some
of the causes for abnormal appearance are listed below:
Pale: Low perfusion of blood indicating a "shock" condition.
Deep red: Congested membranes, also a shock type condition with toxicity.
Purple or blue: Low oxygen levels or serious toxicosis.
Overly yellow: Gums are normally slightly yellow, but very yellow may be a liver
problem.
Petecial hemorrhages: Certain types of toxicosis.
Capillary Refill Time: After depressing
the gums, the colour should return withing 1-2 seconds. Delayed return of colour, 3
seconds or more, is an indication of poor blood perfusion, often brought on by serious
dehydration, shock, or other toxicosis.
Borborygmus: This refers to the sounds
that the gut makes in digesting the feed. A horse should have a normal gurgling
sound on both sides of the abdomen back near the flanks. Several horses should be
assessed before making a determination of what can be considered "normal",
"none", "low", or "hypermotile". During colic
episodes, horses with little or no gut sounds may be in serious condition. A
hypermotile gut may be indicating an irritation, and this may be coupled with a loose
stool or diarrhea. Assessing the gut sounds from one moment to the next may indicate
whether a horses condition is improving or deteriorating. Take this, and all of the
vital signs, frequently.
Hydration State: The best way to determine
hydration is through an assessment of the horses blood parameters. However, using
the "skin turgor test" can often be a quick field aid. The skin over the
shoulder should be pinched with some elevation of the skin. If it snaps back into
place very quickly, the horse may be considered to be adequately hydrated. Any delay
should be suspect and assessed along with the other vital signs. Older horses tend
to have a more relaxed skin, so this should be taken into account. Again, assessing
this parameter when the horse can be considered healthy will help determine if this is
abnormal.
Conclusion: It is important to state that
in a patients assessment, the vital signs must be taken as a whole. One parameter
that may be outside the normal boundaries may not be overly significant when all of the
others are within normal bounds. Also, some signs may adequately explain why others
are abnormal, such as an increased pulse rate associated with a fever. However,
reporting all of the signs before veterinary help arrives can often give a much clearer
picture on the level of concern and the response rate.
Red Maple Leaves are Toxic to Horses
We are sad to have to report that one of our patients recently died to apparent
ingestion of Red Maple Leaves (Acer rubrum). This occurred when the horse
ate the downed leaves that had fallen into his pen. The toxic principle is unknown,
and there is no known antidote. The clinical signs include a hemolytic anemia.
That is where the red blood cells are broken down and the patient looses the
ability to transport oxygen in the blood. Even if the blood can be replaced with a
transfusion, there is a further concern of renal failure due to the destroyed red cell
components. Take time to check pastures to see if red maple trees exist. If
they do, gather the leaves so that the horses will not be tempted to eat them.
This Page:
25 October 2004
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