Abstract:
Despite the devastating collapse of three vulture populations on the Asian
subcontinent as a result of their exposure to diclofenac, there is little available information on
the normal physiology of many vulture species, including the African White-backed Vulture (Gyps
africanus). Such information is needed to fully understand mechanisms for toxicity and to identify
and prevent future health problems. The aim of this study was to establish baseline parameters for
hematologic and selected serum chemistry parameters for this model species for further studies
into the toxicity of diclofenac. Captive nonreleasable and wild AfricanWhite-backed Vultures were
used to determine reference values. For hematology, erythrocyte counts, hemoglobin
concentration, hematocrit, packed cell volume, mean corpuscular volume, mean corpuscular
hemoglobin concentration, and total and differential leukocyte counts were measured. Chemical
analytes measured included sodium, potassium, calcium, albumin, and globulin concentrations,
aspartate aminotransferase, creatine kinase, and alanine aminotransferase activities. Uric acid and
urea concentrations and the urea:uric acid ratio also were evaluated. Values are presented as
means, standard deviations, and reference intervals. The serum chemistry parameters selected
may provide a starting point for the evaluation of changes in renal and hepatic function; these
organ systems are most severely affected by diclofenac. Results were also compared with values
reported for G. africanus nestlings, and from these results it is evident that the clinical pathologic
parameters are age related. This indicates that the use of nestling values for the evaluation of
clinical pathologic findings in adults may be unreliable and could lead to incorrect assumptions.
