Journal Articles
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Item Use of butorphanol and diprenorphine to counter respiratory impairment in the immobilised white rhinoceros (Ceratotherium simum)(African Online Scientific Information Systems (Pty) Ltd t/a AOSIS, 2018-10-18) Meyer LCR; Fuller A; Hofmeyr M; Buss P; Miller M; Haw AOpioid-induced immobilisation results in severe respiratory impairment in the white rhinoceros. It has therefore been attempted in the field to reverse this impairment with the use of opioid agonist-antagonists, such as nalorphine, nalbuphine, butorphanol and diprenorphine; however, the efficacy of some of these treatments has yet to be determined. The efficacy of butorphanol, either alone or in combination with diprenorphine both with and without oxygen insufflation, in alleviating opioid-induced respiratory impairment was evaluated. The study was performed in two parts: a boma trial and a field trial. Rhinoceroses were immobilised specifically for the study, according to a strict protocol to minimise confounding variables. A two-way analysis of variance was used to compare the physiological responses of the rhinoceroses to the different treatments and their effects over time. The intravenous administration of butorphanol (at 3.3 mg per mg etorphine) plus diprenorphine (at 0.4 mg per mg etorphine) did not offer any advantage over butorphanol (at 15 mg per mg etorphine) alone with regard to improving PaO2, PaCO2 and respiratory rates in etorphine-immobilised white rhinoceroses. Both butorphanol + diprenorphine + oxygen and butorphanol + oxygen, at the doses used, significantly improved the etorphine-induced hypoxaemia in both boma- and field-immobilised white rhinoceroses. Clinically acceptable oxygenation in field-immobilised white rhinoceroses can be achieved by using either treatment regimen, provided that it is combined with oxygen insufflation.Item Muscle tremors observed in white rhinoceroses immobilised with either etorphine-azaperone or etorphine-midazolam: An initial study(AOSIS, 2021-06-28) Nasr M; Meyer LCR; Buss P; Fàbregas MC; Gleed RD; Boesch JM; Pohlin FEtorphine-azaperone is the most commonly used drug combination for chemical immobilisation of free-ranging white rhinoceroses, but causes several profound physiological disturbances, including muscle tremors. The addition of benzodiazepine sedatives, such as midazolam, has been proposed to reduce the muscular rigidity and tremors in immobilised rhinoceroses. Twenty-three free-ranging, sub-adult white rhinoceros bulls were darted and captured using a combination of etorphine plus either azaperone or midazolam. Skeletal muscle tremors were visually evaluated and scored by an experienced veterinarian, and tremor scores and distance run were compared between groups using the Wilcoxon rank sum test. No statistical differences were observed in tremor scores (p = 0.435) or distance run (p = 0.711) between the two groups, and no correlation between these variables was detected (r = -0.628; p = 0.807). Etorphine-midazolam was as effective as etorphine-azaperone at immobilising rhinoceroses, with animals running similar distances. Although the addition of midazolam to the etorphine did not reduce tremor scores compared to azaperone, it might have other beneficial immobilising effects in rhinoceroses, and further investigation is necessary to elucidate possible methods of reducing muscle tremoring during chemical immobilisation of rhinoceroses.Item Ketamine-butorphanol-medetomidine for the immobilisation of free-living hyenas (Crocuta crocuta)(Journal of the South African Veterinary Association, 2024-03-01) Roug A; Meyer L; Netshitavhadulu L; Leiberich M; Buss PFree-ranging spotted hyenas (Crocuta crocuta) are immobilised for a variety of purposes, including wildlife-human conflict mitigation, research, and veterinary treatment. Combinations of tiletamine-zolazepam (Zoletil) and medetomidine are commonly used for immobilisation of hyenas, however, recovery times are long. In this descriptive study, a total of 20 adult or subadult free-ranging hyenas were immobilised near Skukuza in the Kruger National Park using ketamine, butorphanol, and medetomidine. The goal of the study was to evaluate a suitable dose and measure cardiorespiratory effects of this combination. The quality of induction and recovery were scored using an established scoring system from 1 (excellent) to (poor). Twelve of the 20 hyenas were given an induction score of 1 (excellent), five an induction score of 2 (good), and three an induction score of 3 (fair). Of the animals with induction score = 1, the mean drug dose was 1.17 mg/kg ketamine, 0.25 mg/kg butorphanol and 0.03 mg/kg medetomidine, and the mean induction time and time to handling 6:25 minutes and 9:46 minutes respectively. The mean recovery time (from reversal to standing) was 10:16 min, which is shorter than what has been reported for tiletamine-zolazepam-based combinations in hyenas. Most hyenas were bradycardic (< 40 beats per minute) and the mean PaO2 69.5 mmHg. Three hyenas, one with induction score = 2, and two with induction scores = 3 spontaneously recovered at 33, 44 and 56 minutes post approach respectively. Regardless of induction time, all hyenas reached a level of surgical anaesthesia while immobilised. Overall, ketamine-butorphanol-medetomidine (KBM) was effective in immobilising hyenas but induction times varied, and animals were bradycardic during immobilisation.