Browsing by Author "Villouta, G"

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    Adrenocorticotrophin-induced stress response in captive vicunas (Vicugna vicugna) in the Andes of Chile
    (UNIV FEDERATION ANIMAL WELFARE, 2003) Bonacic, C; Macdonald, DW; Villouta, G
    The vicuna is mainly used in two ways: wild captured, shorn and returned to the wild; or wild captured and maintained in captivity as part of a programme of sustainable use in the Andes of South America. Farming of wild vicunas has hitherto involved no assessment of their welfare. In this study we measured a set of basic blood parameters in order to characterise baseline values in captivity, and we then characterised adrenal cortical responsiveness using an ACTH challenge. The ACTH challenge is widely used for assessing neuroendocrine responses to stress and is now increasingly being applied to studies of wild animals' welfare. Five male vicunas were injected with exogenous ACTH and their responses compared with those of a control group injected with placebo. Behavioural and haematological changes were monitored. Injection of ACTH produced a 4.5-fold increase in cortisol concentration within 1 h. Total white blood cell count almost doubled in less than 5 h. The neutrophil:lymphocyte ratio also changed, with a decrease in lymphocytes and an increase in neutrophils, suggesting that the neutrophil:lymphocyte ratio was affected by the ACTH challenge. Packed cell volume increased from 40% to 44%. Observations of individual vicunas during sampling revealed no discernible behavioural differences between treated and control animals; however, animals that had higher initial baseline cortisol concentration made more attempts to escape, and vocalised more during handling, regardless of whether they were treated with ACTH or placebo. The results reveal the different blood parameter levels associated with stress in different species and highlight the hazard of interpreting stress levels in one species on the basis of measures calibrated in another. We provide calibrated reference values for future studies of stress in vicunas.
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    Haematological and clinical biochemistry findings in captive juvenile guanacos (Lama guanicoe Muller 1776) in central Chile
    (ELSEVIER SCIENCE BV, 2003) Zapata, B; Fuentes, V; Bonacic, C; Gonzalez, B; Villouta, G; Bas, F
    The purpose of this study was to describe haematological and blood biochemistry findings of farmed guanacos in central Chile, in order to establish reference values for this species in captivity. Haematological and clinical biochemical measurements were performed on blood and plasma respectively, from 40 clinically healthy guanacos (20 females and 20 castrated males), aged between 2 and 3 years. The effects of gender and seasons of the year were studied. Gender affected the number of lymphocytes and the ratio of neutrophils: lymphocytes (N/L), with castrated males having a lower number of lymphocytes and higher N/L ratio than females. Seasons of the year affected most variables, presenting greater packed cell volume (PCV), haemoglobin (Hb), total protein (TP) and albumin values in winter than the rest of the seasons. White blood cells (WBCs) were not affected by season. Glucose decreased significantly over the year and creatine kinase (CK) activity, like glucose, had a tendency to decrease over the year, which may be related to habituation to sampling and handling. Haematological and clinical biochemistry values given in this study can serve as reference values for juvenile farmed guanacos in central Chile. (C) 2002 Elsevier Science B.V. All rights reserved.