Hematologic parameters in raptor species in a rehabilitation setting before release

Sub-lethal impacts of lead poisoning on blood biochemistry, immune function and delta-aminolevulinic acid dehydratase (δ-ALAD) activity in Cape (Gyps coprotheres) and white-backed (G. africanus) Vulture chicks

Although the prevalence of lead poisoning in southern Africa's Gyps vultures is now well-established, its finer physiological effects on these endangered species remain poorly characterised. We evaluated the sub-lethal impact of acute lead exposure on Cape and White-backed Vulture chicks from two breeding colonies in South Africa, by analysing its possible effects on key blood biochemistry parameters, immune function, packed cell volume and δ-aminolevulinic acid dehydratase (δ-ALAD) activity. All 37 White-backed Vulture nestlings sampled displayed elevated lead levels (>10 μg/dL), and seven had blood [Pb] >100 μg/dL. Eight of 28 Cape Vulture nestlings sampled had blood [Pb] exceeding background exposure, with one showing blood [Pb] >100 μg/dL. Delta-aminolevulinic acid dehydratase (δ-ALAD) activity was significantly and negatively related to blood [Pb] in nestlings from both species, with 50% inhibition of the enzyme predicted to occur at blood [Pb] = 52.8 μg/dL (White-backed Vulture) and 18.8 μg/dL (Cape Vulture). Although no significant relationship was found between % packed cell volume (PCV) and blood [Pb], the relatively lower mean PCV of 32.9% in White-backed Vulture chicks, combined with normal serum protein values, is likely indicative of depression or haemolytic anaemia. The leukogram was consistent in both species, although the presence of immature heterophils suggested an inflammatory response in White-backed Vulture chicks with blood [Pb] >100 μg/dL. Values for cholesterol, triglycerides, total serum protein, albumin, globulin, albumin/globulin ratio, alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) were consistent with values previously reported. Calcium and phosphorus concentrations suggested no adverse effects on bone metabolism. A significant decrease in urea: uric acid (U:UA) ratio at blood [Pb] >100 μg/dL in White-backed Vulture chicks, brought about by a decrease in urea production, raises the possibility of hepatic abnormality. These results suggest that δ-ALAD activity may serve as a sensitive biomarker of lead toxicity in both species, while highlighting the need to better understand the significant variability in sensitivity that is observed, even between closely related members of the same genus.

Determination of Haematological Reference Values for Tucúquere (Bubo magellanicus) Habiting in Central Chile

Tucuquere (Bubo magellanicus) is an owl inhabiting Chile, which is classified as a species of agricultural interest, but its current conservation status is not well defined. The determination of previously unknown haematological ranges via laboratory techniques for species analysis is of great importance in the search for diagnoses in clinical veterinary work. Thirty-three samples from healthy tucuquere were obtained from zoos and rehabilitation centres in central Chile and analysed using standard laboratory techniques to obtain reference values that were determined according to the standard recommendations for animal species. The mean, standard deviation, maximum, and minimum reference limits were calculated at 95% and 97.5% error. These results differ from those of other studies, especially in terms of the white blood cells because most of the values were lower than those described for the species. These results could be explained by the habitat and location from which the samples were taken, and they corroborate the need to obtain reference values for different geographical areas. This study provides useful haematological values for use in conservation medicine and zoos and highlights the importance of carrying out these studies in different geographical areas for species of ecological interest.

Hematological and serum biochemical parameters of the captive long‐legged buzzard ( Buteo rufinus ) in Iran

Background

Although normal haematological and serum biochemical values for both pet and wild birds have been published, little information is available on the haematological and serum biochemical values in long‐legged buzzards (Buteo rufinus).

Objectives

This is the first study that aimed to define reference values of haematological, biochemical parameters, and protein electrophoretic fractions of long‐legged buzzards in Iran.

Methods

Blood samples were collected from 30 clinically healthy adult long‐legged buzzards of both sexes. Hematological, biochemical parameters, and protein electrophoretic fractions were measured. The mean and standard deviations were calculated.

Results

Mean values for red blood cells, packed cell volume, haemoglobin, and white blood cells were 2.72 ± 0.60 ×10⁶/μl, 39.10 ± 3.70%, 13.45 ± 1.30 g/dl, and 3.92 ± 1.39 ×10³/μl, respectively. Mean values for biochemistry parameters were total protein 4.46 ± 1.27 g/dl, albumin 1.78 ± 0.55 g/dl, creatinine 0.54 ± 0.22 mg/dl, uric acid 7.81 ± 2.89 mg/dl, calcium 9.63 ± 2.22 mg/dl, phosphorus 4.31 ± 1.00 mg/dl, glucose 398.87 ± 96.90 mg/dl, blood urea nitrogen 10.46 ± 3.85 mg/dl, alkaline phosphatase 127.01 ± 1.46 IU/L, aspartate aminotransferase 262.22 ± 116.30 IU/L, and alanine aminotransferase 56.63 ± 27.85 IU/L. Mean values for serum protein fractions included pre‐albumin, albumin, α‐1 globulin, α‐2 globulin, β‐ globulin, and ϒ‐globulin was 0.20 ± 0.09, 2.35 ± 0.67, 0.28 ± 0.13, 0.32 ± 0.07, 0.62 ± 0.24, and 0.68 ± 0.53 g/dl, respectively.

Conclusion

The reference data presented in this study can be used as health assessment values for veterinary laboratories and clinicians when developing release criteria for rehabilitated long‐legged buzzards.

Adenoviral infection in 5 red-tailed hawks and a broad-winged hawk

Adenoviral infections among raptors are best described in falcons and are characterized most commonly by necrotizing hepatitis and splenitis; only one case has been reported in a hawk. Five red-tailed hawks (Buteo jamaicensis) and a broad-winged hawk (Buteo platypterus) had an adenoviral infection based on history, histopathology, negative-stain electron microscopy, and PCR. All birds had acute onset of illness resulting in death; 3 had evidence of a concurrent bacterial infection. Microscopically, all 6 birds had solitary, pale eosinophilic-to-amphophilic, intranuclear inclusion bodies within presumed hematopoietic cells in bone marrow and macrophages in spleen. Five of the 6 birds had similar inclusions within hepatocytes and Kupffer cells. All but one bird had severe bone marrow necrosis. There was moderate splenic necrosis (3 of 6) and mild-to-marked hepatic necrosis (4 of 6). Negative-stain electron microscopy demonstrated adenoviral particles in bone marrow (5 of 6), liver (1 of 5), and/or spleen (1 of 5). PCR was positive for adenovirus in bone marrow (3 of 5), liver (1 of 3), spleen (4 of 6), and/or intestinal contents (2 of 3). Viral DNA polymerase gene sequences clustered within the Siadenovirus genus. There was 99% nucleotide identity to one another and 90% nucleotide identity with the closest related adenovirus (Harris hawk, EU715130). Our case series expands on the limited knowledge of adenoviral infections in hawks. The splenic and hepatic necrosis, and particularly the hitherto unreported bone marrow necrosis, suggest that adenoviral infection is clinically relevant and potentially fatal in hawks.

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.

Prognostic Indicators of Avian Survival

The objective of this study was to evaluate whether blood glucose, packed cell volume, and total protein are effective diagnostic tests to predict short-term (48 h following admittance to a veterinary hospital) prognosis for wild birds with traumatic injuries. The cohort study conducted for this investigation took place at the Jivdaya Charitable Trust in Ahmedabad, India, over a 7-d period, at the time of the International Kite Flying Festival of Uttarayan. A small blood sample was collected from every avian patient prior to surgical treatment and immediately analyzed. Patient outcome was reviewed and recorded at the end of a 48-h period following admittance to the veterinary hospital. Statistical analysis revealed no significant correlations between blood glucose levels (P = .24), packed cell volume (P = .80), or total protein levels (P = .47) outside the reference intervals and short-term outcome of the patients. There is a lack of evidence regarding the use of these diagnostic tests to ascertain short-term prognosis in avian species. While research has been conducted on avian wound healing, studies fail to identify any correlation between duration of injury and patient outcome. Despite a lack of statistically significant results from this study, the findings should not be dismissed and could be used as a basis for future studies on this subject.

Distraction Osteogenesis in Two Wild Raptors

Distraction osteogenesis was used in 2 wild raptor patients for the repair of tibiotarsal fractures. The first case was a hatching year female peregrine falcon (Falco peregrinus) admitted with an open oblique right distal tibiotarsal fracture. The fracture was surgically managed with the external skeletal fixator intramedullary pin tie-in technique (ESF-IM pin tie-in). Appropriate healing of the fracture site occurred with the ESF-IM pin tie-in. However, there was significant pelvic limb shortening of the affected leg, and the bird consequently developed pododermatitis on the contralateral foot. The second case was an adult female great horned owl (Bubo virginianus) that was admitted with a closed, partially healed, overriding right tibiotarsal fracture. Because of the advanced stage of this fracture, which presented with a fibrous callus, and the already apparent pelvic limb shortening, the ESF-IM pin tie-in was not used. Both patients were fitted with a circular external skeletal fixator (CESF), and distraction osteogenesis was performed until the length of the pelvic limb was deemed anatomically adequate. It is critical that rehabilitated raptors be released without any physical conditions that may reduce their ability to survive and reproduce in the wild. Pelvic limb shortening can potentially predispose a raptor patient to pododermatitis, even with fatal consequences, in both captive and wild environments. The orthopedic technique used here proved useful to repair the limb shortening in both raptor cases, and each bird fully recovered and was released.

Multifocal respiratory and vertebral mycobacteriosis in a red-tailed hawk (Buteo jamaicensis)

An adult, female, free-ranging red-tailed hawk (Buteo jamaicensis) was presented to a rehabilitation facility for an inability to stand. On examination, it displayed bilateral exaggeration of the pelvic limb reflexes with extensor muscle rigidity, intact superficial pain response, and positive withdrawal reflexes. A complete blood count identified moderate leukocytosis characterized by moderate heterophilia. No abnormalities were appreciable on radiographic evaluation. After initial improvement, it regressed and was euthanized 27 days after presentation. Necropsy and histologic investigation identified reduction in the diameter of the vertebral canal and spinal cord at cervical segments 8-9 with coalescing granulomas and intralesional acid-fast bacilli within the intertrabecular space, left side of the clavicular air sac, and cranial left lung. Bacterial culture and genetic sequencing from respiratory lesions identified Mycobacterium avium avium. Real time-polymerase chain reaction of paraffin-fixed spinal tissue tested positive for M. avium complex. Mycobacteriosis should be considered when peripheral neurologic deficits are present in raptors.

Laboratory blood analysis in Strigiformes-Part I: hematologic reference intervals and agreement between manual blood cell counting techniques

BACKGROUND

While hematologic reference intervals (RI) are available for multiple raptorial species of the order Accipitriformes and Falconiformes, there is a lack of valuable hematologic information in Strigiformes that can be used for diagnostic and health monitoring purposes.

OBJECTIVES

The objective was to report RI in Strigiformes for hematologic variables and to assess agreement between manual cell counting techniques.

METHODS

A multi-center prospective study was designed to assess hematologic RI and blood cell morphology in owl species. Samples were collected from individuals representing 13 Strigiformes species, including Great Horned Owl, Snowy Owl, Eurasian Eagle Owl, Barred Owl, Great Gray Owl, Ural Owl, Northern Saw-Whet Owls, Northern Hawk Owl, Spectacled Owl, Barn Owl, Eastern Screech Owl, Long-Eared Owl, and Short-Eared Owl. Red blood cell count was determined manually using a hemocytometer. White blood cell count was determined using 3 manual counting techniques: (1) phloxine B technique, (2) Natt and Herrick technique, and (3) estimation from the smear. Differential counts and blood cell morphology were determined on smears. Reference intervals were determined and agreement between methods was calculated.

RESULTS

Important species-specific differences were observed in blood cell counts and granulocyte morphology. Differences in WBC count between species did not appear to be predictable based on phylogenetic relationships. Overall, most boreal owl species exhibited a lower WBC count than other species. Important disagreements were found between different manual WBC counting techniques.

CONCLUSIONS

Disagreements observed between manual counting techniques suggest that technique-specific RI should be used in Strigiformes.

Prognostic indicators associated with early mortality of wild raptors admitted to a wildlife rehabilitation centre in Spain

BACKGROUND

Assessment of the prognostic indicators of wildlife casualties is critical in wildlife rehabilitation practice, to optimize the use of economical resources, and to protect animal welfare. Few studies have been conducted in this field.

OBJECTIVE

To identify the prognostic indicators associated with raptor mortality during the first week of hospitalization.

ANIMALS AND METHODS

Complete medical records of 1722 wild raptor cases admitted to a wildlife rehabilitation centre from 1995 to 2007 were used. Regression models were created to determine mortality-related factors for different variables (order, sex, body condition (BC), clinical signs, and available haematological and biochemical parameters).

RESULTS

In the bivariate analysis, the presence of nervous (OR = 11.9, 95%CI:5.1-27.6) or musculoskeletal (OR = 12.1, 95%CI:5.8-25.3) signs, a poor BC (OR = 32.9, 95%CI:19-81.2), and low values of packed cell volume (PCV), haemoglobin or total solids (TS), were all associated with early mortality. After adjusting variables in the multivariate model, BC was excluded due to co-linearity with other variables, and alteration of the nervous system was the only significant risk factor (OR = 4.0; 95%CI:1.9-8.8). In species specific analysis, poor prognosis was related to neurological signs in Athene noctua, poor BC in Strix aluco, trauma in Acciptiter nisus and Tyto alba, low PCV in Buteo buteo and Falco tinnunculus and low TS in Falco tinnunculus.

CONCLUSIONS

Raptors with a poor BC, low values of PCV and those presenting with neurological signs, had the highest risk of dying in the first days of admittance. Thus, either medical care or humane euthanasia for poor prognosis should be performed to address animal welfare.

Final disposition and quality auditing of the rehabilitation process in wild raptors admitted to a Wildlife Rehabilitation Centre in Catalonia, Spain, during a twelve year period (1995-2007)

Background

Variability in reporting and classification methods in previous published data of the final dispositions in the rehabilitation of wild raptors makes use of this data limited in trying to audit the quality of the rehabilitation process. Crude as well as stratified disposition rates are needed if quality auditing of the rehabilitation process is to be adequately performed.

Methodology

Final dispositions of 6221 hospitalized wild raptors admitted at a wildlife rehabilitation centre (WRC) of Catalonia during 1995–2007 were analyzed. These dispositions were calculated as the euthanasia (Er), unassisted mortality (Mr), release (Rr) and captivity rates (Cr)., time to death (Td) for dead and euthanized raptors, and length of stay for released (Tr) raptors was estimated. Stratified analyses by main causes of admission and clinical signs were performed.

Results

The disposition for the total population were: Er  = 30.6%, Mr = 19.1%, Rr  = 47.2%, and Cr  = 3%. By main causes of admission, Er was higher in the trauma category (34.2%), whereas Mr was found similar between trauma (37.4%) and non-trauma categories (34.8%). The highest Rr was observed for the orphaned group (77.9%). Furthermore, Cr was low in all the categories (<4%). By clinical signs, the highest Er was found in animals suffering musculoskeletal (37.9%) or skin (32.3%) lesions; Mr was high in infectious/parasitic diseases (66.7%) and in case of neurological symptoms (64.5%). The euthanized birds had a median Td  = 1 day (P₁₀ = 0-P₉₀ = 59) for both trauma and non-trauma categories, and Td  = 36 days for the orphaned young group (P₁₀ = 0; P₉₀ = 596). The median Td in the unassisted dead birds was 2 days for all the categories (P₁₀ = 0-P₉₀ = 31). Finally, the median Tr in the centre was variable among categories.

Conclusions/Significance

Reporting of final dispositions in wildlife rehabilitation should include the crude and stratified rates (Er, Mr, Rr, and Cr), by causes and clinical presentation, as well as Td and Tr, to allow meaningful auditing of the rehabilitation process quality.