VN March 2023

Vetnuus | Maart 2023 6 ABSTRACT : Aerial translocation of captured black rhinoceroses (Diceros bicornis) has been accomplished by suspending them by their feet. We expected this posture would compromise respiratory gas exchange more than would lateral recumbency. Because white rhinoceroses (Ceratotherium simum) immobilized with etorphine alone are hypermetabolic, with a high rate of carbon dioxide production (VCO 2 ); we expected immobilized black rhinoceroses would also have a high VCO 2 . Twelve (nine male, three female; median age 8 yr old [range: 4–25]; median weight 1,137 kg [range: 804–1,234] body weight) wild black rhinoceroses were immobilized by aerial darting with etorphine and azaperone. The animals were in lateral recumbency or suspended by their feet from a crane for approximately 10 min before data were collected. Each rhinoceros received both treatments sequentially, in random order. Six were in lateral recumbency first, and six were suspended first. All animals were substantially hypoxemic and hypercapnic in both postures. When suspended by the feet, mean arterial oxygen pressure (P a O 2 ) was 42 mm Hg, 4 mm Hg greater than in lateral recumbency (P=0.030), and arterial carbon dioxide pressure (P a CO 2 ) was 52 mm Hg, 3 mm Hg less than in lateral recumbency (P=0.016). Tidal volume and minute ventilation were similar between postures. The mean VCO 2 was 2 mL/kg/min in both postures and was similar to, or marginally greater than, VCO 2 predicted allometrically. Suspension by the feet for 10 min did not impair pulmonary function more than did lateral recumbency and apparently augmented gas exchange to a small degree relative to lateral recumbency. The biological importance in these animals of numerically small increments in P a O 2 and decrements in P a CO 2 with suspension by the feet is unknown. Black rhinoceroses immobilized with etorphine and azaperone were not as hypermetabolic as were white rhinoceroses immobilized with etorphine. INTRODUCTION Poaching is a serious threat to the wild black rhinoceros (Diceros bicornis) in southern Africa. In addition, agricultural encroachment has reduced their range and isolated small herds, which promotes genetic homogeneity (Muya et al. 2011; Moodley et al. 2017). To minimize these adverse effects, governments, with support from nongovernmental organizations, actively manage the black rhinoceros population across southern Africa. Capture and subsequent translocation are a crucial part of such active management (Linklater et al. 2012). Unfortunately, the rugged terrain in whichmany black rhinoceroses live canmake translocation by truck impractical or impossible. To circumvent ground transportation, in July 2010 the Namibian Ministry of Environment, Forestry and Tourism adopted the practice of airlifting immobilized black rhinoceroses by suspending them from their feet under a helicopter for periods of up to 30 min (Fig. 1). The physiological effects on the rhinoceros of such transport have not been described. Established protocols for capture of wild black rhinoceroses use potent opioids such as etorphine. THE PULMONARY ANDMETABOLIC EFFECTS OF SUSPENSION BYTHE FEET COMPARED WITH LATERAL RECUMBENCY IN IMMOBILIZED BLACK RHINOCEROSES (DICEROS BICORNIS) CAPTURED BY AERIAL DARTING DOI: 10.7589/2019-08-202 Journal of Wildlife Diseases, 57(2), 2021, pp. 357–367 Wildlife Disease Association 2021 An excerpt of the article published in the Journal of Wildlife diseases For Full article please follow the link Figure 1 Helicopter-assisted aerial slinging of a black rhinoceros (Diceros bicornis) by its feet duringtranslocation operations in Namibia.