Physiological monitoring of welfare for conservation of Arabian oryx, Oryx leucoryx
Al Jahdhami, Mansoor
Thesis or dissertation
University of Exeter
The endangered Arabian oryx, Oryx leucoryx faces a wide range of issues that potentially have adverse effects on their welfare while they are free-ranging in their natural habitat, housed in captivity for conservation breeding or when they are translocated from the wild to captivity or vice versa. Furthermore, the global increase in the number of captive Arabian oryx (currently more than 95 % of the world population of about 8000 individuals), gives rise to particular concern for their welfare and health within captive conditions. Thorough assessment of the welfare of animals involves physiological and behavioural measures. Methods for assessment of welfare in Arabian oryx have not been established and the present studies aim at establishing physiological tools for assessment of welfare. Therefore, the present studies developed and applied new methods for non-invasive assessment of welfare in the Arabian oryx (using faecal samples), and established reference values for a range of haematological, biochemical and clinical parameters. The potential disturbances in these parameters were investigated after immobilisation and tranquillisation and post- transportation. Two enzyme immuno-assays (EIA I and II) for faecal glucocorticoid metabolites (FGM) were validated by stimulation and suppression of the hypothalamic-pituitary-adrenal axis through injection of synthetic adrenocorticotropic hormone (ACTH) and dexamethasone, respectively. These studies established a lag-time of 14 ± 1 h between secretion of glucocorticoids into the blood stream and excretion of the measured FGM. Faecal incubation at 30°C for 3 days showed that EIA I measured more stable faecal glucocorticoid metabolites than EIA II, and has greater potential for application in field conditions. This method was found to be invaluable for measuring stress and hence assessment of welfare status, and its use is recommended in planning welfare improvements. Measurement of FGM successfully detected the stress of road transportation (630 km for 8-10 h), showing an increase 2 days after transport, followed by recovery to basal FGM levels after re-housing for up to 11 days. Releasing oryx to the wild, in Oman, and tracking for 11 days, after transportation 50-70 km from the captive site (Arabian Oryx Sanctuary, Jaaluni), caused an increase in FGM to the highest levels seen in these studies, and suggests a high level of stress was experienced after release of oryx. Published reference values for haematological, biochemical, hormonal and clinical parameters for Arabian oryx are limited, with little information for non-immobilised and non-tranquillised oryx or consideration of possible age and sex differences. Therefore, reference values and inter-percentile ranges (2.5 and 97.5 percentiles) were established for 32 parameters, in separate groups of male and female adult oryx, without using immobilising or tranquillising chemicals during capture. The haematological parameters investigated were white blood cell count and differentiation (%) of cell types (neutrophils, lymphocytes, monocytes, eosinophils, basophils), number of platelets, red blood cell count, haemoglobin concentration and haematocrit, erythrocyte cell volume, erythrocyte haemoglobin content and concentration, serum osmolality and ions (sodium, potassium, chloride, calcium, magnesium and phosphorus). Biochemical parameters investigated were serum urea, glucose, total protein, albumin and plasma lactate concentrations. Clinical parameters investigated were body temperature, heart and respiratory rates. Hormonal parameters measured were cortisol, free-thyroxine, free-triiodothyronine and insulin concentrations. Near basal values for serum cortisol were measured in Arabian oryx sampled within 2 min, while values were significantly higher in oryx sampled within 5-10 min. The reference values established in these studies are considered valuable tools for diagnosis of disease and physiological alterations in male and female Arabian oryx. To investigate the possible effects of the common practice of immobilisation and tranquillisation on physiological and biochemical status, two restraint chemicals (xylazine and perphenazine enanthate) were evaluated. Xylazine (an immobilising agent) caused changes in many clinical, hormonal, haematological and biochemical parameters; respiratory rate decreased by 74 %, heart rate decreased by 58 %, causing a decrease in red blood cell count, haemoglobin concentration and haematocrit, serum albumin and total protein concentration. Xylazine also induced a decrease in serum insulin, which probably caused the observed increase in serum glucose. Perphenazine enanthate (a long-acting tranquilliser) was found to have no adverse effects on most parameters, which generally remained in the reference ranges. However, a reduction in blood haematocrit and related parameters (red blood cell count and plasma haemoglobin concentration) occurred, 1-3 days after injection. The tranquilliser also plays a role in reducing stress and significantly reduced serum cortisol 2-3 days after injection in oryx held in captivity compared to oryx that received a saline (control) injection. FGM increased significantly one day after injection of perphenazine enanthate and saline, suggesting the animals were initially stressed by the handling and venipuncture, taking into consideration the lag-time from cortisol secretion to appearance of FGM. The baseline concentration of serum cortisol was used in assessing the stress caused by handling before and after transporting Arabian oryx for 630 km (8-10 h) and the acute effects of handling and injections. Increased serum cortisol was always associated with leukocytosis, neutrophilia and lymphopenia. Serum cortisol of non-transported oryx was reduced by the tranquilliser perphenazine enanthate, but transportation of tranquillised Arabian oryx during hot ambient temperature (maximum 42 °C) resulted in fatigue and prevented reaching a clear conclusion of the role of the tranquilliser in reducing transport stress. Non-tranquillised oryx transported at a maximum of 26-30 °C showed a similar level of stress as implied by the level of faecal glucocorticoid metabolites, but without fatigue. However, the tranquilliser induced calmness in Arabian oryx for up to 7 days, which facilitated capture and handling. Therefore, perphenazine enanthate has a potential to be used in the management practices, such as movement and transport of Arabian oryx. This thesis discusses the current and future welfare issues that face Arabian oryx in captivity, upon release and in the wild. Additional methods are proposed for thorough assessment and improvement of welfare to complement the methods established by the present studies.
PhD in Biological Sciences