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By
Michael Lowder, DVM, MS
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'Colic' is one word the horse owner finds objectionable on any
given day. It is generally used to refer to an acute onset of
abdominal pain in the horse. Frequently, colic will require the
horse owner to seek emergency treatment for her horse from a
veterinarian.
Most colics can be managed medically, but some do require surgical
treatment. Treatment cost can range from a few hundred dollars to
thousands for surgery and aftercare. In order to prevent an
episode of colic occurring on one's farm or with one's horse, it
is helpful to know what causative factors are associated with the
disease.
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Colic is known to have
multiple causes in the horse, and the epidemiology of colic is
important in identifying and reducing the risk factors for colic.
Some of the most common factors known to date include the
following:
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Change in diet
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Change in batch or type
of hay
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Level of activity
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Stabling conditions
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History of a previous
colic
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History of a previous
abdominal surgery
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There are many theories
as to why each of the above listed factors may influence an
episode of colic. The one dominant factor that seems to be
repeated in several epidemiological studies is a change in hay or
batch (cutting) of hay. The incidence of colic seems to be the
highest within approximately two weeks of changing the hay. This
could be due to several factors including hay maturity (what
height the hay was cut at), type of hay (switching from grass to
legume), drying and handling of the hay during harvesting, and
type and duration of storage.
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Poor quality or moldy hay
may affect the way hay is chewed and processed by the horse. If
the hay has a poor taste, the horse may not chew it properly. This
may lead to the swallowing of long stems, ultimately predisposing
your horse to impaction colic.
Hays that have more stem
and less leaf will have a higher percentage of fiber. While fiber
is needed in the diet, there is a point where it is not beneficial
to have more. As the fiber content of the hay increases, the
digestibility of the hay decreases.
Colic is not associated
as much with hay when a horse is being fed alfalfa, coastal
Bermuda or Bermuda hay. In contrast, when feeding wheat hay, Bahia
grass hay, oat hay, Timothy hay, cane hay or Alicia hay, the
chances for a colic increase as these hays are higher in fiber and
lower in protein. Feeding hay from round bales has been associated
with a higher incidence of colic as the method of storage usually
yields a lesser quality hay with more stem and greater propensity
for mold. Have you ever noticed that horses always seem to eat the
center of the round bales? The center of the bale has less
exposure to the elements and is better tasting and more
digestible. In addition, your horse has indiscriminate ingestion
of hay with round bales. This may lead to colic due to over
consumption (impaction colic from eating very dry hay). Another
drawback to feeding round bales is that when horses attempt to
feed from the center of the bale, there is a greater chance that
they might injure their eyes from the hard stems of hay.
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Switching from stem hay
to cube hay may decrease the incidence of colic in older horses
with poor dentition if the change is made gradually. It is often
helpful to soak the hay cubes (for 5-10 minutes) prior to feeding
to geriatric horses to reduce the duration of chewing (gumming!)
by some. Hand in hand with changes in hay, changes in grain
are often made and can be associated with an increased risk of
colic. These changes include both concentrate [sweet feed and
pellets] and grains (e.g., oats, corn, etc.). Most horses like a
change in their grain diet, and subsequently rapidly ingest their
new grain, which may lead to gastric distension. The microflora of
the digestive tract may also be altered by changes in their grain
diet leading to a digestive upset.
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Part II examines
changes in type of grain, amount of grain fed, pasture availability,
breed of horse, de-worming schedule, feeding practices, and changes
in the weather. |
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