EQUINE | Equine Disease Update
cases of salmonellosis in a number of states, all of which
related to infection with serogroup C1 Salmonellae.
A limited number of outbreaks of clostridial enteritis
due to Clostridium perfringens Type A/β-2 toxin geno-
type, were confirmed in Kentucky, USA. Several cases of
proliferative enteropathy (Lawsonia intracellularis) were
recorded in Kentucky and Michigan, USA.
The fourth quarter of 2016 saw an additional 15 cases
of Eastern equine encephalomyelitis confirmed in five
states in the USA, nine of which were in Wisconsin. West
Nile encephalitis was reported by Spain (nine cases) and
the USA (20 cases involving six states of which 11 were
in Oklahoma). The majority of cases in the USA were in
unvaccinated horses.
The USA continues to record outbreaks of rhodococcal
disease in numerous states; a limited number were re-
ported in the period under review. The fourth quarter of
2016 also saw recorded cases/outbreaks of several other
diseases: ehrlichiosis in Switzerland (one outbreak), Ge-
tah virus infection in Japan (single case), and equine en-
cephalosis (single case in the Western Cape Province of
South Africa).
The University of Kentucky Veterinary Diagnostic Labo-
ratory (UKVDL) plays an important role in its support of
Kentucky’s horse industry. Between June 1, 2010, and
June 30, 2012, onehundred and thirteen horses aged
fifteen years and older were submitted for necropsy to
UKVDL. Review of these necropsy cases revealed that
the main organ system contributing to the death of this
group of aged horses was the digestive system, followed
rather closely by the cardiovascular system.
Specific diagnoses of the digestive system that were
noted in this group of geriatric horses included but
were not limited to: strangulating lipoma; small intes-
tinal entrapment, devitalization, and/or rupture; gastric
rupture; large colon displacement, torsion, impaction
and/or rupture; and necrotizing colitis of bacterial or un-
known etiology.
Causes of Mortality in Aged Horses in Ken-
tucky Although prevention of these disorders is not generally
possible, certain steps can be taken by owners to im-
prove the digestive health of t heir horses. A consistent
diet with sufficient roughage promotes a healthy diges-
tive system for horses of all ages. However, as horses age,
their teeth can wear unevenly and crack or break, pre-
venting proper mastication and hindering the digestion
of food. Therefore, proper dental care is crucial for older
horses, along with appropriate nutritional substitutions
for horses that can no longer chew forage adequately.
Over the last century, the place of the horse in society
has shifted from that of an absolute necessity, primarily
used for transportation and labor, to more of a pleasure
animal. Today, horses are most commonly companion
animals, lesson horses, breeding stock, and sporting
competitors, with more limited use for farm and ranch
work. This change in usage has resulted in an increasing
geriatric horse population, and accordingly, the need to
better understand the complexities of geriatric horse
health. Maintaining an appropriate deworming regimen for
horses of all ages can also go a long way to preventing
digestive dysfunction. For example, Causes of Mortality
in Aged Horses in Kentucky poorly-managed parasitic
infections can contribute to the formation of adhesions,
leading to intestinal obstruction, and tapeworm infec-
tion can lead to colic due to cecal impaction. Once an
owner notices signs of colic and digestive distress, time-
ly veterinary intervention can sometimes improve the
outcome for a horse, particularly if corrective surgery is
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• Volume 19 no 2 • June 2017 •
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