The California condor (Gymnogyps californianus) was at the point of extinction with only 22 individuals in the wild two decades ago.8 Condors were taken into captivity for captive propagation and subsequent reintroduction with the last wild condor being captured in 1987. Today there are approximately 200 condors: 130 condors in captivity and 70 successfully reintroduced in the wild (J. Zuba, personal communication). In order to provide proper medical care for this endangered species, veterinarians need accurate hematologic and biochemical reference ranges on which to base medical evaluations and treatments.
Blood samples from 61 captive California condors housed at the San Diego Wild Animal Park were evaluated by sex and age to determine serum biochemical and hematologic reference ranges. Chloride, cholesterol, and total plasma protein concentrations were higher in males than in females (n=23 males, 21 females; p<0.05). The condors were grouped by age for analysis as follows: group 1 included birds 30 days of age or less; group 2 included birds from 30 days to 6 months of age; group 3 included birds from 6 months to 5 years of age; group 4 included all birds older than 5 years.
Results and Discussion
When comparing biochemical values by age, significant differences in glucose, potassium, phosphorus, calcium, albumin, globulin, cholesterol, and bile acid concentrations, as well as aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase, and creatine phosphokinase activities were identified. When comparing hematologic values by age, differences in white blood cell count, hemoglobin, hematocrit, total plasma protein concentration, heterophils, lymphocytes, and eosinophils were identified. A steady increase in glucose and a decrease in alkaline phosphatase and lactate dehydrogenase activities, as well as cholesterol, bile acid, calcium, and phosphorus concentrations were correlated with age. Condors from age group 1 and age group 2 were identified as unique compared to other age groups. Due to these differences, two reference ranges (condors under 6 months of age and condors over 6 months of age) have been established by calculating a 90% confidence interval. Reference ranges obtained from other published avian data including those for Psittaciformes, ratites, Galliformes, Anseriformes, and raptors were similar to the condors in this study.1-7,9,10
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