Hematologic and biochemical reference ranges for captive California condors (Gymnogyps californianus)

Basic blood biochemical parameters of wild common ravens (Corvuscorax)

Baseline haematological and biochemical blood parameters in healthy wild birds are key to managing wild populations and to saving critically ill individuals. This knowledge is crucial for the care, rehabilitation and the release of birds after treatment in wildlife rescue centres. Plasma levels provide valuable information for the evaluation of the physical condition of animals. The objective of this study was to obtain reference values of some basic biochemical blood parameters of wild common ravens (Corvuscorax). Between 2020 and 2023, we took blood samples from the wild population of common ravens in Bulgaria (n = 36). We determined the values of 18 parameters - alanine transaminase (ALT, U/I), albumin (g/l), alkaline phosphatase (ALP, U/I), amylase (U/I), aspartate transaminase (AST, U/I), calcium (mmol/l), chloride (mmol/l), cholesterol (mmol/l), creatine kinase (CK, U/I), creatinine (μmol/l), blood glucose (mmol/l), lactate dehydrogenase (LDH, U/I), magnesium (mmol/l), phosphorus (mmol/l), total bilirubin (μmol/l), total protein (g/l), triglycerides (TG, mmol/l) and uric acid (μmol/l). We made a comparative analysis including the regions in which the groups were sampled and the time of year. Most of the presented results were comparable to published values of other species from the Corvidae family and some were higher (ALP, amylase, AST, CK, total protein and uric acid levels). Most of these could be explained by the capture- and handling stress. This is the first report in official literary sources presenting some basic biochemical blood parameters of healthy wild common ravens in Bulgaria. The results may be of use to scientists, veterinarians and other researchers in rescue and rehabilitation centres and they can provide the basis for further studies with regards to animal welfare and health assessment of the species.

Revisiting glucose regulation in birds - A negative model of diabetes complications

Birds naturally have blood glucose concentrations that are nearly double levels measured for mammals of similar body size and studies have shown that birds are resistant to insulin-mediated glucose uptake into tissues. While a combination of high blood glucose and insulin resistance is associated with diabetes-related pathologies in mammals, birds do not develop such complications. Moreover, studies have shown that birds are resistant to oxidative stress and protein glycation and in fact, live longer than similar-sized mammals. This review seeks to explore how birds regulate blood glucose as well as various theories that might explain their apparent resistance to insulin-mediated glucose uptake and adaptations that enable them to thrive in a state of relative hyperglycemia.

The Influence of Biological Factors on Haematological Values in Wild Marsh Harrier (Circus aeruginosus) Nestlings

Simple Summary

Haematological examination can be used to address the health state of birds. The present study aimed to investigate how hatching order, brood size, and nest initiation date influence the haemoglobin level, red blood cell count, white blood cell count, and glucose level in the blood of raptor nestlings in which brood reduction occurs during nestling rearing. Blood samples were collected to assess the health status of wild marsh harrier nestlings in the agricultural landscape of eastern Poland. Statistical analyses revealed that hatching order, but not brood size or nest initiation date, had an impact on the haematological data of nestlings. Hatching order affected these data in that haemoglobin levels and red blood cell counts gradually decreased, whereas glucose levels and white blood cell counts increased, from the first- to the last-hatched nestlings. The poor condition of the youngest nestlings reflected in these indices may increase the likelihood of their perishing, and consequently, of brood reduction.

Abstract

Marsh harrier (Circus aeruginosus) is a species with obligatory cainism, in which hatching asynchrony creates a pronounced size hierarchy in nestlings. The size-related competitive advantage of older nestlings means that they tend to dominate the younger ones, and brood reduction occurs in most nests. The aim of the study was to reference values and carry out a haematological examination in order to evaluate the physiological status and health of nestlings with respect to hatching order, brood size, and nest initiation date. To do so, we examined 19 nests with a total of 58 nestlings from a free-living population of this species located in fishpond complexes in the agricultural landscape of eastern Poland. Repeated blood samples (118 in all) were collected from nestlings. The following parameters were measured using fresh full blood: red blood cell count (RBC), haemoglobin level (Hb), white blood cell count (WBC), and plasma glucose level (Glu). The data were analysed using generalized linear mixed models and linear mixed models ((G)LMM). The study revealed that hatching order, but not brood size or nest initiation date, affected the physical condition of marsh harrier nestlings. Hb levels and RBC counts gradually decreased, whereas Glu levels and WBC counts increased from the first- to the last-hatched nestlings. This result points to the generally poorer condition of the youngest nestlings compared with their older siblings. The poor physiological condition of the youngest nestlings may consequently increase the likelihood of their perishing, and hence, of brood reduction.

Venous hematology, biochemistry, and blood gas analysis of free-ranging Eastern Copperheads (Agkistrodon contortrix) and Eastern Ratsnakes (Pantherophis alleghaniensis)

Hematology, plasma biochemistry, and blood gas analysis were performed on venous samples obtained from free-ranging Eastern Copperheads (Agkistrodon contortrix) and Eastern Ratsnakes (Pantherophis alleghaniensis) in central North Carolina during a mark-recapture study conducted from April to October 2015 at the North Carolina Zoo. Blood samples were collected from 31 (15 male and 16 female) free-ranging copperheads and 34 (20 male and 14 female) free-ranging ratsnakes at the beginning and end of restraint. Restraint was performed for morphometric measurements, sex determination, and identification via placement of intracelomic passive integrated transponder (PIT) tags and marking of ventral scutes with a handheld electrocautery unit. Blood gas analytes were measured at the beginning of restraint and compared to analytes measured at the end to evaluate for changes secondary to handling. Total restraint time prior to the first blood sampling was 1.4 ± 0.4 mins (mean ± SD) and 1.0 ± 0.2 mins (mean ± SD) and restraint time prior to second blood sampling was 12.5 ± 2.4 mins (mean ± SD) and 13.5 ± 3.4 mins (mean ± SD) for copperheads and ratsnakes, respectively. Blood lactate concentrations at the beginning of restraint were similar for both species. Lactate concentrations increased significantly and pH decreased significantly for both species at the end of restraint when compared to the beginning of restraint. Furthermore, lactate concentrations at the end of restraint were significantly elevated in ratsnakes compared to copperheads. This study provides guidelines for interpretation of venous hematology, plasma biochemistry, and blood gas values for free-ranging copperheads and ratsnakes in central North Carolina and demonstrates the physiological response to venous blood gas analytes secondary to capture and restraint.

Protein electrophoresis in Andean condors (Vultur gryphus): Reference values and differences between wild and rehabilitating individuals

The study of wildlife health greatly contributes to understanding population dynamics and detecting conservation threats. The determination of the different fractions of plasma proteins (proteinogram) is an important laboratory tool to study wildlife health. The aim of this study was to characterize protein electrophoresis in wild Andean condors (Vultur gryphus) from north-western Patagonia and to evaluate differences according to age and sex classes. Once reference values of wild, apparently healthy individuals, were established, we compared these values to those of individuals received at the Buenos Aires Zoo in Argentina for rehabilitation due to various health problems. Reference proteinograms from wild Andean condors differed only in the α 1 and β 2-fractions between sex categories. Males showed higher concentrations of these protein fractions than females. We found clear differences between wild birds and rehabilitating individuals. Total proteins, globulins, α 1-globulins, total α-globulins, β 2-globulins, total β-globulins, and γ-globulins were significantly higher in rehabilitating than in wild individuals, whereas albumin, α 2, and β1-globulins were similar between these groups. The albumin/globulin ratio, as a general indicator of health, was significantly lower in rehabilitating than in wild individuals. The results indicate the effects on different protein fractions of pathologic processes occurring in individuals undergoing rehabilitation. Our results provide useful insights, contributing to improving diagnoses and prognoses in this species. This information may also be useful to assess the health status of Andean condors in studies of wild populations and for comparisons with other bird species.

Plasma biochemistry RIs and age effect in European Strigiformes

BACKGROUND

Blood biochemistry and hematology are essential in the laboratory diagnosis of disease. In Strigiformes, little information regarding reference values and influence of different preanalytic factors is available, while age is known to have an effect on some biochemistry analytes, especially in early life characterized by a rapid growth rate and increase in body mass.

OBJECTIVE

The objective of this study was to determine baseline data for 29 blood biochemistry variables in 5 species of Iberian Strigiformes assigned to different age classes.

METHODS

Healthy nocturnal birds living in wildlife health centers of Catalonia, Northeastern Spain were assigned to different age classes (chicks, juveniles, adults where possible and available) and their blood was collected and analyzed for different standard biochemistry variables. Species included Tawny owls, Little owls, Long-eared owls, Scop owls, and Barn owls.

RESULTS

A total of 276 clinically healthy animals were sampled, including between 179 chicks, 52 juveniles, and 45 adults. The RIs of cholesterol, albumin, and osmolality were the only variables that did not show interspecific variability. Common trends between age class groups were observed in 4 species. Phosphorus and calcium concentrations and ALP activities decreased with increasing age, while concentrations of sodium and γ-globulins tended to increase in the Strigidae family. Differences were concentrated in chicks and no differences were observed between juveniles and adults in any variable.

CONCLUSIONS

Our results demonstrate the importance of defining biochemical RIs specific for certain age classes.

Hematologic reference intervals and age effect in European Strigiformes

BACKGROUND

The clinical importance of hematologic testing in avian veterinary medicine is reflected in the increasing number of studies for the establishment of hematologic RIs of Strigiformes and other species. Age is an important physiologic factor in birds and the effect on hematology variable should be understood.

OBJECTIVES

The objective of this study was to determine baseline data of hematologic variables in 5 species of Iberian Strigiformes in different age classes.

METHODS

Nocturnal birds of prey were sampled at Wildlife Health Centers. Packed cell volume was determined by the microhematocrit centrifugation method, and RBC and WBC counts were determined using the direct hemocytometer count method with Natt and Herrick solution. Hemoglobin concentration was measured spectrophotometrically. The MCV, MCHC, and MHC were calculated using the standard formulas. The differential WBC count was performed by the routine microscopic evaluation of 200 cells on a blood smear manually stained with Wright stain. Thrombocyte blood count estimate was obtained from the blood film.

RESULTS

No differences were observed between juveniles and adults for any variable evaluated in Tawny owl, Little owl, Scops owl, Long-eared owl, and Barn owl. In addition, PCV, RBC, and HGB of chicks were statistically significantly lower than in juveniles and adults, and total WBC was significantly higher in Tawny owl, Little owl, Scops owl, and Long-eared owl.

CONCLUSIONS

Our findings provide evidence that laboratory data from chicks of Strigiformes are different compared to juveniles and adults; therefore, separate RIs were defined.

Hematologic and serum biochemical reference intervals of the Oriental white stork (Ciconia boyciana) and the application of an automatic hematologic analyzer

This study was conducted to establish accurate baseline values of clinical laboratory data with regard to age-related changes in the Oriental white stork (Ciconia boyciana). In addition, the availability of an automated hematological cell counter was evaluated. A total of 94 clinically normal storks, including 64 young storks (＜1 year old; 30 male and 34 female) and 30 adults (＞ 1 year old; 17 male and 13 female) were included. Hematological assays were performed using manual and automated cell counters and serum biochemistry profiles were examined using an automated analyzer. There were no significant differences in any parameters between male and female storks, while 16 parameters were significantly different between young and adult storks. Of these 16 parameters, total protein, albumin, aspartate aminotransferase, alanine aminotransferase, creatinine, triglyceride, total bilirubin, potassium, white blood cell count, packed cell volume, mean cell volume and hemoglobin levels were higher in adult storks than in young storks, while the latter showed higher glucose, uric acid and alkaline phosphatase levels, as well as a higher sodium/potassium ratio. The results presented herein will aid researchers who work for the conservation and rehabilitation of this endangered species.

Lead Toxicosis in a Southern Ground Hornbill Bucorvus leadbeateri in South Africa

The southern ground hornbill (Bucorvus leadbeateri) has been classified as globally vulnerable and, in South Africa, regionally endangered, with a negative population trend. Factors contributing to the population decline in South Africa are poisoning, electrocution, and illegal capture for trade, coupled with slow reproductive rates and extensive habitat requirements. Lead toxicosis is a previously undescribed threat for the population. An adult southern ground hornbill presented with acute lead toxicosis due to lead particles in the gizzard, which required intensive treatment. Two other hornbills were likely exposed. The source of the lead in these cases was likely a carcass of a porcupine that was killed with lead shot. This report highlights the importance of the use of lead-free ammunition within the habitat of the southern ground hornbill in South Africa.

HEMATOLOGY AND BIOCHEMISTRY IN CAPTIVE WHITE-NAPED CRANES (GRUS VIPIO)

In this retrospective study, 36 hematologic and biochemistry samples from white-naped crane (Grus vipio) were analyzed. All birds were housed at a single institution, and samples were obtained between 1990 and 2013. All cranes were healthy at the time of sample collection, and ages ranged from 1 mo to 33 yr old. Cranes below 18 mo old were considered juveniles. Comparisons were made between means for juveniles and adults and for males and females. Significant increases in adults (P < 0.05) were found in the following variables (differences shown in parentheses): packed cell volume (8.3%), mean cell volume (28 fl), monocyte percentage (3.2%), absolute monocyte count (200 × 10³/ml), total solids (1.0 g/dl), albumin (0.5 g/dl), and sodium (3 mM/L). Significant decreases in adults (P < 0.05) were found in phosphorus (1.7 mg/dl), creatine phosphokinase (1,146 U/L), alkaline phosphatase (451 U/L), lactate dehydrogenase (149 U/L), and glucose (25 mg/dl). Results from adult male and female cranes were also compared; calcium levels were higher in females (4.68 mg/dl, P < 0.05). Plasma electrophoresis and radioimmunoassay for bile acids were performed on 25 banked serum or plasma samples; results from juvenile and adult samples were also compared. Significant increases in adult birds were found in total protein (1.2 g/dl, P < 0.05) and in all absolute values for all protein types; however, no difference was found when protein fractions were compared. Bile acids were found to decrease in adults (19.9 μM/L, P < 0.05).

Reference intervals in avian and exotic hematology

Historically, reference intervals (RI) have come from many sources and been generated by several methods and sample sizes. As RI generation has matured in human laboratory medicine, important guidelines have been adopted in veterinary medicine. Although meeting the goals of these guidelines may be difficult, especially with avian and exotic species, sets of 20 to 40 samples can be used with proper statistical calculations, and other viable alternatives have been examined. The adoption and knowledge of these different methods are important to make a positive move forward in RI generation for special species.

Hematologic and plasma biochemical reference values of the horned guan, Oreophasis derbianus

The horned guan (Oreophasis derbianus) is an endangered species with small and seriously fragmented wild populations. Breeding efforts during the last decade have maintained a slowly increasing captive population with the potential to play an important role in the recovery of the species. Clinical hematology and biochemistries are powerful tools to diagnose and monitor diseases in captive birds. Therefore, establishing hematologic and plasma biochemistry reference values will improve the medical management of this species. This study determines the reference values for 9 hematologic and 15 plasma biochemical variables for 27 male and 12 female, apparently healthy, captive horned guans from three institutions. Differences related to age, sex, and husbandry were identified but were usually small and clinically insignificant. These results should improve veterinary care of captive individuals of this species and provide comparative data for other species of cracids.

Veterinary assessment for free-ranging Eurasian Black Vulture (Aegypius monachus) chicks in southeastern Mongolia

Working as a veterinarian in remote field locations can be physically and intellectually challenging. A collaborative multi-disciplinary approach is often required for successful data collection. Technologies and methodologies frequently need to be modified to work in these harsh field environments. This article will describe a collaboration in southeastern Mongolia collecting blood for sera analytes and physiologic data from Eurasian Black Vulture (Aegypius monachus) chicks during a tagging operation.

Hematologic and biochemical reference intervals for wild osprey nestlings (Pandion haliaetus)

A retrospective study of blood samples from 95 osprey (Pandion haliaetus) nestlings from Scotland and England, collected opportunistically over a 10-yr period, was performed to determine hematologic and plasma biochemistry reference intervals. The age of the sampled nestlings was estimated to be between 4 and 8 wk. Ninety-five percent reference intervals were determined for all hematologic and biochemical variables using parametric and nonparametric methods as appropriate. No blood parasites were detected. This is the first published study providing baseline reference data for osprey nestlings, and it is hoped the data will be of use to wildlife veterinarians and biologists in assessing the health of this species.

Hematocrit and plasma chemistry values in adult collared scops owls (Otus lettia) and crested serpent eagles (Spilornis cheela hoya)

In this study, we report hematocrit and plasma chemistry values for adult captive collared scops owls (Otus lettia) and crested serpent eagles (Spilornis cheela hoya). In particular, we address the gender-specific differences within these values. We measured hematocrit (HCT) and plasma chemistry values for uric acid (UA), plasma urea nitrogen (BUN), total protein (TP), albumin (ALB), glucose (GLU), cholesterol (CHO), triglyceride (TG), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), total bilirubin (TBIL), creatine (CRE), creatine phosphokinase (CPK), amylase (AMY), calcium (CA), ionic phosphorous (IP) and sodium (NA), potassium (K) and chloride ions (CL) in 37 adult captive collared scops owls and 39 adult captive crested serpent eagles. Significant differences between the sexes were found for UA, GLU and CPK in the collared scope owls. UA and GLU concentrations were significantly higher (P<0.01 and P<0.05) among males than females, while the CPK concentration was significantly lower (P<0.05) in males. There were no significant differences in of all of the measured parameters between male and female eagles. These finding suggested that HCT and plasma chemistry values of raptors vary individually according to species and sex. Our results provide the 1st available reference data for ranges of plasma values in adult captive collared scops owls and crested serpent eagles, making them a potentially useful complementary diagnostic tool for veterinary care of individuals for both species in captivity.

Hematologic parameters in raptor species in a rehabilitation setting before release

To be considered for release, raptors undergoing rehabilitation must have recovered from their initial injury in addition to being clinically healthy. For that purpose, a good understanding of reference hematologic values is important in determining release criteria for raptors in a rehabilitation setting. In this study, retrospective data were tabulated from clinically normal birds within 10 days of release from a rehabilitation facility. Hematologic values were compiled from 71 red-tailed hawks (Buteo jamaicensis), 54 Eastern screech owls (Megascops asio), 31 Cooper's hawks (Accipiter cooperii), 30 great-horned owls (Bubo virginianus), 28 barred owls (Strix varia), 16 bald eagles (Haliaeetus leucocephalus), and 12 broad-winged hawks (Buteo platypterus). Parameters collected included a white blood cell count and differential, hematocrit, and total protein concentration. Comparisons were made among species and among previously published reports of reference hematologic values in free-ranging birds or permanently captive birds. This is the first published report of reference values for Eastern screech owls, barred owls, and broad-winged hawks; and the first prerelease reference values for all species undergoing rehabilitation. These data can be used as a reference when developing release criteria for rehabilitated raptors.