Abstract:
Vulture (Accipitridae) poisonings are a
concern in South Africa, with hundreds of birds
dying annually. Although some of these poisonings
are accidental, there has been an increase in
the number of intentional baiting of poached
rhinoceros (Rhinocerotidae) and elephant (Elephantidae)
carcasses to kill vultures that alert
officials to poaching sites by circling overhead.
The primary chemicals implicated are the organophosphorous
and carbamate compounds. Although
most poisoning events can be identified
by dead vultures surrounding the scavenged
carcass, weak birds are occasionally found and
brought to rehabilitation centers for treatment.
The treating veterinarian needs to make an
informed decision on the cause of illness or
poisoning prior to treatment. We established the
reference interval for serum and plasma cholinesterase
activity in the Cape Griffon Vulture
(Gyps coprotheres) as 591.58–1,528.26 U/L,
providing a clinical assay for determining potential
exposure to cholinesterase-depressing pesticides.
Both manual and automated samplers were used with the butyrylthiocholine method. Species
reference intervals for both serum and plasma
cholinesterase showed good correlation and manual
and automated measurements yielded similar
results.
