EQUINE | Equine Disease Update
in December 2016 with a local veterinarian indicating he
was seeing an increase in cases. UKVDL pathologists and
epidemiologists noticed an increase in cases submitted
to the lab in January 2017 and alerted local practitioners
and farm managers through listserv and social media.
Typically, nocardioform cases are first noted as early as
October and run through May of any given year. The ma-
jority of cases are diagnosed from December through
April, usually peaking in mid-March (Figure 2). Through
the third week of February 2017, UKVDL has confirmed
44 cases of nocardioform placentitis. Of these 44 cases,
31 have resulted in abortion, 12 in viable foals, and in
one case a live but non-viable foal.
The means of transmission is not yet identified. Nocar-
dioform lesions are not similar to those of other types of
bacterial placentitis or septicemic bacterial placentitis.
Environmental factors are being investigated thorough-
ly and early analysis indicates an increase in nocardio-
form placentitis cases after a summer of hot, dry weath-
er. Nocardioform placentitis cases are almost always
lower in years associated with a high incidence of lep-
tospiral abortions, which is correlated with weather that
is wetter than normal. Analysis of farms affected with
nocardioform placentitis indicates larger farms with
more pregnant mares and higher stocking densities are
at greater risk. Preliminary data indicate that mares that
spend more time in the barn are at risk of developing
the disease; increased grazing times appear protective.
There is a statistical indication that pre-breeding treat-
ments with NSAIDs or progesterone could be protective,
but this needs further study. Mares that are given post-
breeding human chorionic gonadotropin (hCG) are at
significantly lower risk, but this also requires further
study.
Based on cases of nocardioform placentitis received
by UKVDL from January 1, 2010, through February 21,
2017, there is little evidence that the disease recurs in
particular mares. One exception is a mare that had a pla-
centa submitted in 2011 that was positive for nocardio-
form and a fetus submitted in 2016 that also was diag-
nosed with the disease. The likelihood of recurrence of
the disease in previously affected mares would appear
extremely low.
Contact: Jackie Smith, PhD, MSc, Dipl AVES jsmit8@uky.
edu (859) 257-7559 University of Kentucky Veterinary
Diagnostic Laboratory Lexington, KY
Equine Cardiac Disease
Equine cardiac disease is an uncommon but potentially
serious condition. Clinical signs range from poor per-
formance to sudden death. Causes of cardiac disease in
horses include congenital malformation, chronic valvu-
lar degeneration, cardiomyopathy, inflammatory or in-
fectious disease, ruptured chordae tendineae, and car-
diotoxins. This article describes common cardiotoxins
that have been implicated in affecting horses in Central
Kentucky.
Ionophores (e.g. monensin and lasalocid) are common
feed additives and supplements intended for cattle,
pigs, or chickens. Exposure occurs when horses have ac-
cess to concentrated mineral premixes containing iono-
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• Equine Health Update •