Reference intervals for hematologic and biochemical constituents and protein electrophoretic fractions in captive common buzzards (Buteo buteo)

Background: Increasing interest in wildlife care leads to the need for new tools to evaluate animal health. Laboratory investigations require reference intervals against which to compare the results obtained. For common buzzards, only a few studies have been performed to establish hematologic and biochemical reference intervals. Objectives: The aim of this work was to develop reference values for routine hematologic and biochemical constituents and protein electrophoretic fractions and evaluate possible seasonal differences in values for healthy common buzzards. Methods: Heparinized blood samples were collected from 23 captive, clinically healthy common buzzards between February 2001 and June 2003. A CBC, routine biochemical analysis, and protein electrophoresis were performed. Data distribution was assessed and results from birds sampled in spring, summer, and winter were compared. Results from alternative methods for hemoglobin (Hgb; estimated as HCT ÷ 3 vs spectrophotometry), total protein (biuret vs refractometry), and albumin (bromcresol green vs electrophoresis) concentrations also were compared. Results: Reference intervals were calculated as 10-90th percentiles. In spring and summer, total WBC and heterophil counts, and urea, total protein, prealbumin, and β- and γ-globulins concentrations were significantly different from winter values. Results obtained by alternative methods for Hgb, total protein, and albumin concentrations were significantly different from those obtained by standard methods, although estimated and spectrophotometric Hgb values were significantly correlated. Conclusions: The reference values obtained in this study for hematologic and plasma biochemical constituents and their seasonal variation in healthy, captive common buzzards will be useful in the clinical evaluation of these birds in rehabilitation settings.