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Coastal
Bermudagrass Hay:
Equine Culinary Delight or Killer?
By Dr.
Bob Mowry, PhD, Extension Horse Commodity Coordinator, North Carolina
Cooperative Extension.
Coastal
Bermudagrass hay has been a predominant forage in the diet of North
Carolina horses for several decades.
Of the 225,000 equine in NC, it is estimated that over 100,000
head annually consume coastal bermudagrass hay.
Although
Coastal bermudagrass forage has traditionally been fed to equine,
skepticism among owners and veterinarians still exists on health
problems and specifically the implication of bermudagrass colic.
Several NC veterinarians have reported a higher percentage of
ileocecal impaction colics occur in horses fed coastal bermudagrass as
compared to other forage species. This specific type of colic occurs near the junction of the
ileum of the small intestine and cecum, located at the beginning of
the large intestine. Impactions
in this location are extremely difficult to treat.
There
has not been a well documented, scientific study to clarify the role
of coastal bermudagrass in the problem.
The University of Georgia recently conducted a survey of all
equine practitioners within Georgia to gain additional insight into
the bermudagrass, colic related question.
The results of the survey provide several key items that help
to clarify potential factors involved in colics.
Only
9% of the colic cases treated at the University of Georgia were
classified as ileocecal cases. Of
these, 85% were associated with bermudagrasses.
24%
of the veterinarians indicated their belief that coastal bermudagrass
hay is not a cause of ileocecal impactions.
63% believe coastal bermudagrass is a contributory cause, but
not the only cause. Only
13% of the equine practitioners believe that coastal bermudagrass is
the sole cause of ileocecal colics.
Practitioners reported ileo impactions for horses fed all species of
forages.
Horses changed quickly from an alfalfa or cool season grass hay to
coastal bermudagrass increased the incidence of colic.
More mature, less digestible hays were more often implicated in colic
cases.
The
presences of tapeworms in horses with ileocecal impaction colics has
raised questions concerning the impact of deworming programs and
rotation of dewormers on the occurrence of this type of colic.
The
University of Georgia survey represents an attempt to clarify the role
of coastal bermudagrass as a potential cause of impaction colic.
Obviously additional research is required to further determine
the cause of ileocecal colics. The
survey indicated all forages could cause impaction if fed in a mature,
less digestible growth stage. All
forages, whether fed as a hay or grazed in a pasture, should be
consumed at an immature growth stage.
Impaction colics which occur in the ileocecal region of the GI
tract are associated with Coastal bermudagrass forges and are
extremely difficult to treat. Horses
with a history of impaction colic should not be fed bermudagrass hay.
The
North Carolina Department of Agriculture Feed Testing Laboratory
provides a feed analysis service that tests for 14 nutrients, nitrates
and, if requested, mycotoxins in forage samples.
Feed testing kits can be obtained from each county extension
office. The analysis cost
$10.00 per sample. The
nutrient analysis reports the acid detergent fiber (ADF) content of
the forage. The ADF value
indicates reduced forage digestibility and energy content.
Forages with ADF values in excess of 35% are considered overly
mature and are more likely candidates to trigger impaction colics.
Immature forages with ADF values under 35% are recommended.
The
following forage feeding practices are recommended to limit the
occurrence of colic:
Feed
hays that are immature containing low ADF values.
Switch
hays gradually over a 7 to 10 day period.
Feed
mold-free forages. Test
suspect hays for mycotoxins prior to feeding.
Provide
at least 50% of the total diet as hay or pasture.
Adjust
horses gradually over 7 to 10 days to fresh, rapidly growing pasture.
Rotate horses off mature overgrazed pastures. |
