VN March 2023

Vetnuus | Maart 2023 8 TABLE 1. Descriptors for 12 immobilizedwild black rhinoceros (Diceros bicornis) in Namibia during investigations comparing the pulmonary physiology of lateral position with aerial suspension by the feet. Each rhinoceros received both treatments sequentially, in random order. Data are collated by whichever treatment was assigned first; either lateral recumbency or suspension by the feet. Age and weight are expressed as median(minimum–maximum). a NA = not applicable. b n =5 (one adult not aged by dentition). For responses where treatment order had a significant effect, the data were subdivided by treatment order and the significance of differences between valuesobtained in lateral recumbencyfirst and thoseobtained in lateral recumbency secondweremeasuredusinga two-tailed, unpaired t-test (GraphPad Prism6, La Jolla, California, USA); the significance of differences between values in suspension first and in suspension secondweremeasured likewise.The significance of differences betweenVCO 2 andValloCO 2 weremeasuredwith the above two-tailed, unpaired t-test. Data that underwent statistical analysis are reported as mean (SD); unless otherwise stated, data that did not undergo statistical analysis are reported as median (range: minimum–maximum). RESULTS The median weight of nine male and three female rhinoceroses was 1,137 kg (range: 804– 1,234) and the animals were a median age of 8 yr old (range: 4–25; Table 1). The median doses of etorphine, azaperone, and hyaluronidase used for darting were 4.6 lg/kg (range: 4.2–5.4) , 53 lg/kg (range: 49–75), and 2.2 IU/ kg (range: 2.0–3.1), respectively. The animals became laterally recumbent 4.4 min (range: 1.2–6.7) after being darted. The median ambient temperature was 27.8 C (range: 21.4–27.8) and the median atmospheric pressure was 629 mm Hg (range: 627–632). The median rectal temperature of the rhinoceroses in lateral recumbency was 37.6 C (range: 36.6–38.7) and 37.7 C (range: 36.8–38.7) when they were suspended by their feet (Table 2). Measurements were completedwithin 55min (range: 44–71) of the animal becoming recumbent. All animals recovered uneventfully. TABLE 2. Median (minimum–maximum) rectal temperature and mean (SD) arterial blood gas tensions and acid-base values from 12 immobilized wild black rhinoceroses (Diceros bicornis) in Namibia during investigations comparing the pulmonary physiology of lateral position with aerial suspension by the feet. Animals were in lateral recumbency or suspended by the feet for approximately 10 min before data collection. Each rhinoceros received both treatments sequentially, in random order. The alpha value for comparisons was 0.05. a a P a O 2 = arterial oxygen pressure; S a O 2 = saturation of arterial hemoglobin with oxygen; P a CO 2 = arterial carbon dioxide pressure; NE = not evaluated. * = significantly different. Leading Article Lateral recumbency first (n=6) Suspended by the feet first (n=6) n or median Range a n or median Range a Female(n) 2 NA 1 NA Male (n) 4 NA 5 NA Subadult (n) 2 NA 1 NA Adult (n) 4 NA 5 NA Median age (yr) 9 4-25 8 b 5-20 Median weight (kg) 1,077 804-1,172 1,138 940 – 1,234 Measurements Lateral recumbency (n=12+) Suspended by the feet (n = 12) Median or mean SD or range Median or mean SD or range P Median rectal temperature (C; range) 37.6 36.6–38.7 37.7 36.8–38.7 NE Mean P a O 2 (mm Hg) 38 5.6 42 3.7 0.030* Mean S a O 2 (%) 63 9.9 71 6.7 0.025* pH a 7.32 0.03 7.34 0.03 0.011* P a CO 2 (mm Hg) 55 5.4 52 4.3 0.016* Base excess of extracellular fluid (mmol/L) 2.3 1.72 2.1 2.23 0.536 Lactate (mmol/L) 2.1 1.08 2.0 0.97 0.425