Cooling by dousing with cold water does not alter the pathophysiological biochemical changes induced by capture in blesbok (Damaliscus pygargus phillipsi)

Abstract

Wild animals are commonly captured for conservation, research, and wildlife management purposes. However, capture is associated with a high risk of morbidity or mortality. Capture-induced hyperthermia is a commonly encountered complication believed to contribute significantly to morbidity and mortality. Active cooling of hyperthermic animals by dousing with water is believed to treat capture-induced pathophysiological effects, but remains untested. This study aimed to determine the pathophysiological effects of capture, and whether cooling by dousing with cold water effectively reduces these effects in blesbok (Damaliscus pygargus phillipsi). Thirty-eight blesbok were randomly allocated into three groups: a control group that was not chased (Ct, n=12), chased not cooled (CNC, n=14), and chased plus cooled group (C+C, n=12). The CNC and C+C groups were chased for 15 min prior to chemical immobilization on day 0. Animals in the C+C group were cooled with 10 L of cold water (4 C) for 10 min during immobilization. All animals were immobilized on days 0, 3, 16, and 30. During each immobilization, rectal and muscle temperatures were recorded, and arterial and venous blood samples collected. Blesbok in the CNC and C+C groups presented with capture-induced pathophysiological changes characterized by hyperthermia, hyperlactatemia, increased markers of liver, skeletal, and cardiac muscle damage, hypoxemia, and hypocapnia. Cooling effectively returned body temperatures to normothermic levels, but neither the magnitude nor the duration of the pathophysiological changes differed between the CNC and C+C groups. Therefore, at least in blesbok, capture-induced hyperthermia appears not to be the primary cause of the pathophysiological changes, but is more likely a clinical sign of the hypermetabolism resulting from capture-induced physical and psychological stress. Although cooling is still recommended to prevent the compounding cytotoxic effects of persistent hyperthermia, it is unlikely to prevent stress- and hypoxia-induced damage caused by the capture procedure.