Reference intervals, longitudinal analyses, and index of individuality of commonly measured laboratory variables in captive bald eagles (haliaeetus leucocephalus)

The objectives of this study were to determine reference intervals, perform longitudinal analyses, and determine the index of individuality (IoI) of 8 hematologic, and 13 biochemical and electrophoretic variables for a group of captive bald eagles (Haliaeetus leucocephalus). Reference intervals were determined from blood samples collected during annual wellness examinations for 41 eagles (23 male and 18 female) with ages ranging between 6 and 43 years (18.7 ± 7.4, mean ± SD) at the time of sample collection. Longitudinal analyses and IoI were determined for measured hematologic, biochemical, and protein electrophoretic variables, both individually and as a group, for a subset of 16 eagles (10 male and 6 female) during a 12-year period. This smaller group of eagles ranged in age between 2 and 20 years at the start of the study period, and between 14 and 32 years (21.9 ± 5.0, mean ± SD) at the end of the study period. Significant increases with age within the group of 16 eagles were observed only for red blood cells, percent heterophils, total protein, and β-globulin protein fraction, while albumin:globulin decreased significantly with age. A low IoI (≥1.4) was determined for all hematologic and biochemical variables except γ globulins, which had high IoI (≤0.6) for 3 individuals within the subset of 16.