Mare Reproductive Loss
Syndrome
Daily Briefing,
May 17
Mare Reproductive Loss Syndrome Briefing
UK College of Agriculture
(Click here for audio
briefing)
Free
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The following information is provided with respect to progress of the
investigation into the Mare Reproductive Loss Syndrome.
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The coordinating group has been studying details of mare breeding records
for 2001. This identified more precisely the time of the critical
insult giving rise to the syndrome, between April 17 and 23. Based
on information provided, late abortions, the birth of weak foals, and early
fetal losses appear to be linked to the same causal event. The investigating
group is extremely appreciative of farms that have provided early fetal
loss information and will be requesting further data to assist in our research
investigation. Information on early fetal losses and daily figures
on submissions to the Livestock Disease Diagnostic Center (LDDC) indicate
the incidence has fallen over the last seven days.
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Studies undertaken at the LDDC on equine samples over the previous 3 weeks
have found no evidence whatsoever of an infectious or contagious disease.
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Examination of fetal and foal samples strongly support that the presence
of bacteria is secondary to a primary insult. Pathological findings
from early fetal losses are inconclusive. Gross and histopathological
lesions from late fetal losses are consistent with ergot toxicity but are
not characteristic.
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Detailed inspection of pastures grazed by affected mares has been undertaken
by agronomists from the College of Agriculture, University of Kentucky.
The investigations have so far revealed no clearly identifiable source
of the syndrome.
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The list of possible candidates including mycotoxins, fungal endophytes,
phyto-estrogens and other compounds in pasture are under intensive investigation.
Fusarium mycotoxins remain a candidate with many pasture samples proving
positive for zearalenone, an estrogenic mycotoxin that has been shown to
cause reproductive problems, cardiac and eye problems in horses and other
species. With the notable exception of Moldy Corn Poisoning (equine
leukoencephalomalacia), little is known with respect to the toxicological
effects of mycotoxins in horses.
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A considerable difficulty encountered during the early stages of the investigation
was that reliable and rapid assays to identify a variety of suspect agents
were not available. The coordinating group has established panels
of rapid and sensitive assays for zearalenone and 3 other mycotoxins as
well as for ergot alkaloids in pasture and urine, which will provide a
much faster turnaround for sample analysis.
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Daily pasture samples are being taken on selected farms to identify and
monitor the levels of several highly suspect environmental toxins.
Pasture samples taken and stored prior to May 5 are considered critical
to the investigation. Samples of hay baled before May 5 are highly
desirable for analysis and should be submitted to Dr. T. Tobin’s laboratory
at the Department of Veterinary Science. Hay samples are best ‘core
sampled’ with which your county agent can assist. In the absence
of a corer, take a flake from the middle of the bale and submit for analysis.
Alternatively, call Dr. S. Jackson, 859-873-9218.
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Over 100 pasture samples have been taken of which 70% are being processed,
and all of which will be subject to further analysis. In addition,
urine samples from affected mares as well as blood samples have been taken
and are being analyzed.
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Examination of tent caterpillars has revealed high levels of zearalenone.
The significance of this finding is not clear. Caterpillars and their
excrement have tested negative for cyanide.
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This syndrome is unparalleled in its intensity and severity. The
horse industry of Kentucky together with private equine consultants, state
and federal agencies and the scientific community, locally, nationally
and internationally, has come together in a tremendous unified effort to
solve this problem.
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Further information will be provided as it becomes available.
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