MDC has some answers from initial examinations but is awaiting additional test results.
JEFFERSON CITY, Mo. –
The Missouri Department of
Conservation (MDC) is awaiting additional laboratory test results to
help determine the causes of recent elk deaths, including six cow elk.
One yearling bull elk was also recently found dead along
with three calves, two of which were born to cow elk that died. All
deaths occurred in mid-to-late July and involved elk relocated earlier
this year from Kentucky to Missouri’s elk restoration zone in Carter,
Shannon and Reynolds counties.
According to MDC
Resource Scientist Lonnie Hansen, preliminary test results from several
veterinary pathology laboratories have not pointed to one specific cause
of death for all animals. A combination of
stress from relocation, extreme heat and drought conditions appear to
be contributing factors.
Hansen and other MDC
staff are working with state veterinarians from the Missouri Department
of Agriculture and experts from the University of Missouri Veterinary
Services to learn more. Staff are also consulting
wildlife veterinarians and other experts from around the country.
In addition, three
newborn calves from elk brought to Missouri in 2012 died in June shortly
after birth. One elk cow and her calf from the 2011 restoration group
died while birthing in early June.
Hansen says that all
restored elk underwent a series of health tests after capture in
Kentucky and received clean bills of health before being relocated to
MDC’s Peck Ranch Conservation Area in May.
Necropsies of the
dead elk included testing for bovine tuberculosis and other diseases,
which were also among health tests conducted in Kentucky. MDC staff also
reviewed health records of the dead elk for
clues. Other than pneumonia found in the bull elk, no disease-related
causes have surfaced. Preliminary results from necropsies on the animals
and initial lab tests did not detect epizootic hemorrhagic diseases
(EHD) or bluetongue, which are more prevalent
in deer during dry weather. Elk typically do not get sick from EHD or
bluetongue.
Hansen adds that poaching was not involved.
“What we could be
seeing is stress that is catching up to some of the 2012 elk a month
after being released, compounded with abnormal and extreme heat and
drought conditions,” he says. “Stress in wildlife
can temporarily affect their immune systems and make them more
susceptible to these extreme weather conditions. Wildlife can be
susceptible to pneumonia as a result of stress and dry, dusty conditions
during drought.”
He adds that, overall, the 2011 herd appears to be doing well despite the heat and drought, including calves born this spring.
One of the dead cow
elk from the 2012 group was found stuck in a muddy pond. After being
pulled free by MDC staff, it died the next day. Hansen says that heat
exhaustion likely contributed to its death.
He adds that the
combination of relocation and calving in extreme heat and drought may
have contributed to the cow-elk deaths. It appears that malnutrition or
other stress-related factors contributed the deaths
of the three calves.
Other potential
causes being evaluated include naturally occurring toxins in water or
food that can be concentrated to lethal levels during drought.
Water samples from
several ponds on Peck Ranch used by elk tested negative for blue-green
algae toxins. These toxins have caused livestock deaths in surrounding
states.
MDC staff checked
food plots for blister beetles, which are prevalent throughout the
Ozarks, especially during drought. The beetles have a toxin that is
lethal to horses and other livestock that ingest them.
No blister beetles were found in food plots near where dead elk were
found, or during necropsies.
Johnson grass grows
in the restoration zone and was found near four of the dead cow elk.
During drought conditions, Johnson grass can concentrate nitrates and
prussic acid, a chemical that can cause death
within hours. Samples of Johnson grass are being analyzed by University
of Missouri Veterinary Medicine staff. Test results are pending.
Johnson grass is an invasive species that has become common in the
region. During normal years, it is not toxic and is
used as hay.
Wheat with
potentially toxic black-tip fungus was found in many of the food plots
at Peck Ranch. The wheat has been mowed so elk cannot consume infected
kernels. Samples are being tested and results are pending.
Hansen adds that the approximately 80 remaining elk
are staying close to or on Peck
Ranch and The Nature Conservancy release site, which indicates adequate
food and water in these areas of the 346-square-mile restoration zone.
He says that several other Midwestern states are also reporting heat- and drought-related livestock and wildlife deaths.
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