Friederike Pohlin

Background: Etorphine, a highly potent opioid, disrupts multiple steps of the oxygen cascade, including alveolar ventilation, pulmonary gas exchange, systemic oxygen transport, and tissue-level oxygen utilisation, resulting in hypoxaemia and cellular hypoxia during immobilisation of wild ungulates. To evaluate potential mitigating agents, a randomised, prospective, controlled crossover design was used in etorphine-immobilised sheep (0.05 mg·kg ⁻¹ , intramuscularly, n = 6). After etorphine administration, animals received either the serotonergic agonist BIMU-8 (1.5 mg·kg ⁻¹ ), the alpha-2 adrenoceptor antagonist vatinoxan (0.15 mg·kg ⁻¹ ), or sterile water (control) intravenously with a four-week washout period. Immobilisation was reversed with naltrexone 19 min after treatment administration. Sequential steps of the oxygen cascade were assessed using thoracic electrical impedance-derived variables (respiratory rate (RR _EIT ) and tidal impedance variation (TIV)) for ventilation, blood gas analysis and venous admixture for pulmonary gas exchange, oxygen delivery (DO ₂ ) for oxygen transport, and oxygen extraction ratio (ER) for tissue oxygen utilisation. Measurements were obtained at baseline, after etorphine administration, at five-minute intervals following treatment, and after naltrexone. Data was analysed using linear mixed-effects models. Results: Etorphine induced respiratory depression, characterised by reduced RR _EIT ( p < 0.001) and TIV ( p = 0.01), and impaired gas exchange, indicated by increased venous admixture ( p < 0.001) compared with baseline, causing hypercapnia and hypoxaemia in all treatments. Neither BIMU-8 nor vatinoxan improved these variables compared with the control. Consequently, progressive decreases in arterial partial pressure of oxygen (F _3,90 = 104.82, p < 0.001) were observed across treatments during immobilisation, resulting in persistently reduced DO ₂ (F _3,84 = 51.55, p < 0.001) and increased ER (F _3,90 = 8.09, p < 0.001) at similar levels in all treatments. All variables normalised after naltrexone administration. Conclusions: Etorphine profoundly impaired multiple sequential steps of the oxygen cascade in sheep, resulting in hypoxaemia, reduced DO ₂ , and compensatory increases in ER. BIMU-8 and vatinoxan did not effectively mitigate these disturbances at any level of the cascade compared with the control. Future research is needed to develop targeted strategies that address the key mechanisms underlying the disruptions in the oxygen cascade during etorphine immobilisation.

The garden dormouse (Eliomys quercinus) is commonly used as model species for studies on hibernation, which may involve surgery. Similar to laboratory rodents, inhalational anesthesia, which does not provide analgesia, is often performed for surgical procedures. We retrospectively compared cardiorespiratory effects between ketamine-butorphanol-medetomidine (KBMed), ketamine-butorphanol-midazolam (KBMid) and butorphanol-medetomidine-midazolam (BMM) administered SC in 48 garden dormice undergoing laparotomy for bio-logger implantation plus tissue (liver, brown fat) biopsy surgery (n = 48/48 [28 females, 20 males] ∼5 wk old) and bio-logger explantation surgery (n = 42/48 [24 females, 18 males], ∼1 yr old). Doses were ketamine (40 mg/kg), medetomidine (0.2 mg/kg), midazolam (1 mg/kg), and butorphanol (0.2 mg/kg). Anesthesia was supplemented with isoflurane (1.29 ± 0.53%) in 100% oxygen via facemask; meloxicam and lactated Ringer's solution were administered SC; and a splash block using lidocaine was performed. Sedation score and recovery time were recorded. The pedal withdrawal reflex, pulse rate, RR, SpO2, and temperature were monitored throughout the laparotomy. The effects of group and time were tested using linear mixed-effect models, with individuals as random factor. Sedation score was the deepest with KBMed. Pulse rate, RR, and temperature remained within physiological ranges for KBMid, but were decreased with KBMed and BMM (P < 0.001). SpO2 remained >96% in all groups. Recovery time was shortest with KBMid (20.8 ± 18.1 min); KBMed and BMM required reversal with atipamezole after 60 min, otherwise recovery time would have been prolonged. All combinations allowed for appropriate intraoperative analgesia, cardiorespiratory stability, and adequate postoperative wound healing.

Translocation and dehorning are common and important practices for rhinoceros management and conservation. It is not known if dehorning causes a stress response or negatively affects rhinoceroses during transport. Twenty-three subadult wild Southern white rhinoceros (Ceratotherium simum simum) bulls were immobilized and translocated >280 km for population management reasons. Ten animals were dehorned at capture, and 13 animals were transported without dehorning. For transport, five dehorned and six nondehorned rhinoceroses were sedated with azaperone (62.38±9.54 µg/kg) and five dehorned and seven nondehorned rhinoceroses with midazolam (64.61±9.28 µg/kg). Blood samples were collected at capture, start of transport, and after 6 h of transport. Measurements included 10 physiologic variables: hematocrit, total serum protein, creatine kinase (CK), aspartate aminotransferase, gamma-glutamyl transferase (GGT), creatinine, urea, cholesterol, β -hydroxybutyrate, and glucose; and four stress response variables: cortisol, epinephrine, neutrophil-to-lymphocyte ratio, and leukocyte coping capacity. Using a linear mixed model, CK and GGT were higher in dehorned compared with nondehorned rhinoceroses. There were no significant differences in the other variables between the two groups. The likely cause of these differences is that dehorned animals spent more time in the crate before the start of transport than nondehorned rhinoceroses (3:11±0:54 h vs. 1:12 ±0:56 h, P<0.001). These results indicate that dehorning does not negatively alter the white rhinoceros' physiologic and stress responses during translocation, supporting its use for antipoaching measures.

Translocations of Rhinocerotidae are commonly performed for conservation purposes but expose the animals to a variety of stressors (e.g. prolonged fasting, confinement, novel environment, etc.). Stress may change the composition of gut microbiota, which can impact animal health and welfare. White rhinoceroses in particular can develop anorexia, diarrhea and enterocolitis after translocation. The aim of this study was to investigate the associations of age, sex and translocation on the rhinoceros’ fecal bacterial microbiota composition. fecal samples were collected from rhinoceroses at capture (n = 16) and after a >30-hour road transport (n = 7). DNA was isolated from these samples and submitted for 16S rRNA V3-V4 phylotyping. Alpha diversity indices of the rhinoceros’ fecal microbiota composition of different age, sex and before and after transport were compared using non-parametric statistical tests and beta diversity indices using Permutational Multivariate Analysis Of Variance (PERMANOVA). Resulting P-values were alpha-corrected (Padj.). Alpha and beta diversity did not differ between rhinoceroses of different age and sex. However, there was a significant difference in beta diversity between fecal samples collected from adult animals at capture and after transport. The most abundant bacterial phyla in samples collected at capture were Firmicutes and Bacteroidetes (85.76%), represented by Lachnospiraceae, Ruminococcaceae and Prevotellaceae families. The phyla Proteobacteria (Padj. = 0.009) and Actinobacteria (Padj. = 0.012), amongst others, increased in relative abundance from capture to after transport encompassing potentially pathogenic bacterial families such as Enterobacteriaceae (Padj. = 0.018) and Pseudomonadaceae (Padj. = 0.022). Important commensals such as Spirochaetes (Padj. = 0.009), Fibrobacteres (Padj. = 0.018) and Lachnospiraceae (Padj. = 0.021) decreased in relative abundance. These results indicate that the stressors associated with capture and transport cause an imbalanced fecal microbiota composition in white rhinoceroses that may lead to potentially infectious intestinal disorders. This imbalance may result from recrudescence of normally innocuous pathogens, increased shedding of pathogens or increased vulnerability to new pathogens.

Translocation is a valuable conservation tool, but poses significant risks for the transported rhinoceroses. Interventions reducing these risks are required to ensure positive welfare during transportation. The aim of this study was to evaluate the effect of journey duration and feeding during the transport of white rhinoceroses (Ceratotherium simum simum). A total of 32 animals were transported by road during two events, five days apart. Fifteen rhinoceroses in the first transport event (37.0 +/- 2.4 hr duration) were not fed, while 17 rhinoceroses in the second event (32.2 +/- 1.5 hr duration) were offered lucerne. Blood samples were collected at capture and after transport for the evaluation of changes in serum clinical chemistry analytes. The Wilcoxon rank-sum test was used to compare differences between the groups. In all rhinoceroses, transport resulted in changes in serum electrolyte, metabolite and enzyme concentrations, indicating a loss in total body water, nutritional shifts, stress and fatigue. Fed rhinoceroses, transported over a shorter time, displayed greater changes in osmolality (p < 0.006), serum sodium and chloride concentrations (p = 0.005 and = 0.001, respectively) indicating a greater degree of total body water loss than non-fed rhinoceroses. Feeding and a shorter transport duration reduced, but did not prevent, nutritional challenges. A greater increase in the muscle enzymes CK and AST (p = 0.027 and = 0.001, respectively), indicated greater fatigue in non-fed rhinoceroses transported over a longer time. Further work to distinguish the effects of feeding and journey duration is required to better understand the role feeding may play in mitigating welfare challenges during rhinoceros translocation.

Background: Hematocrit (HCT) determination is an integral part of health and disease assessments in captive and wild white rhinoceroses. Several affordable automated hematology analyzers have been developed for in‐clinic and field use and have the advantage of being able to measure a large number of additional measurands. However, the accuracy of these analyzers for rhinoceros HCT measurements has not yet been investigated.Objectives: We aimed to compare the HCT results generated by the EPOC portable analyzer system and the Abaxis VetScan HM5 with the gold standard of a manual packed cell volume (PCV) measured using the microhematocrit method.Methods: Hematocrits were measured with the EPOC and the Abaxis VetScan HM5 (bovine setting) and compared with the PCVs of 69 white rhinoceros whole blood samples. Results were compared using Bland–Altman difference plots and Passing‐Bablok regression analysis. A total allowable analytical error of 10% was set as the performance goal.Results: A significant positive bias, with a mean of 7.7% for the EPOC and 17.9% for the Abaxis, was found compared with the manual PCV method.Conclusions: The allowable error goal of 10% was not exceeded with the EPOC analyzer. Although not analytically equivalent to the gold standard, the EPOC results could therefore be used as approximations in critical situations where manual measurements cannot be performed. The Abaxis exceeded this allowable error and overestimated HCTs in rhinoceroses. Therefore, method‐specific reference intervals should be used.

Wild mammal transport is an important component of conservation translocation as well as the economic wildlife trade. This article reviews the physiological responses to transport that have been measured in wild mammalian species, factors associated with these responses, and interventions that have been applied to mitigate these responses. By organizing the literature review along the “five domains model” of animal welfare, namely, the physical-functional domains (nutrition, environment, health, behavior) and the mental domain (mental state), it can be demonstrated that wild mammal transport is associated with challenges to ensuring positive animal welfare in all five domains. Transported wild mammals can experience dehydration, catabolism, fatigue, immunosuppression, behavioral changes, and stress. Factors influencing these physiological responses to transport have only been researched in a few studies encompassing species, journey length, ambient temperature, vehicle motion, stocking density, orientation, habituation, vehicle speed allowance, and road type. The administration of tranquilizers has been shown to mitigate negative physiological responses to transport. There is a need to further investigate species and situation-specific physiological responses to transport and factors associated with these responses in order to identify challenges to ensuring animal welfare and improving translocation success.

Capture and transport are essential procedures for the management and conservation of southern white rhinoceroses (Ceratotherium simum simum), but are associated with stress-induced morbidity and mortality. To improve conservation efforts, it is crucial to understand the pathophysiology of rhinoceros stress responses and investigate drug combinations that could reduce these responses. In this study we measured rhinoceros stress responses to capture and transport by quantifying hematological and immunological changes together with adrenal hormone concentrations. We investigated whether the potent anxiolytic drug midazolam was able to mitigate these responses compared to azaperone, which is more commonly used during rhinoceros transport. Twenty three wild white rhinoceros bulls were transported for 6 h (280 km) within the Kruger National Park for reasons unrelated to this study. Rhinoceroses were immobilized with either etorphine-azaperone (group A, n = 11) or etorphine-midazolam (group M, n = 12) intramuscularly by darting from a helicopter. Azaperone (group A) or midazolam (group M) were re-administered intramuscularly every 2 h during transport. Serial blood samples were collected at capture (TC), the start of transport (T0) and after 6 h of transport (T6). Changes in hematological and immunological variables over time and between groups were compared using general mixed models. Increases in plasma epinephrine and serum cortisol concentrations indicated that rhinoceroses mounted a stress response to capture and transport. Packed cell volume decreased from TC to T6 indicating that stress hemoconcentration occurred at TC. Neutrophils progressively increased and lymphocytes and eosinophils progressively decreased from T0 to T6, resulting in an increase in neutrophil to lymphocyte ratio; a characteristic leukocyte response to circulating glucocorticoids. A reduction in serum iron concentrations may suggest the mounting of an acute phase response. Rhinoceroses experienced a decrease in unsaturated fatty acids and an increase in lipid peroxidation products at capture and toward the end of transport indicating oxidative stress. Midazolam, at the dose used in this study, was not able to mitigate adrenal responses to stress and appeared to directly influence leukocyte responses.

A two‐year‐old spayed female great dane crossbreed dog and a three‐year‐old spayed female Yorkshire terrier were presented for surgical correction of hydrocephalus and syringohydromyelia. Obstruction of cerebrospinal fluid flow and associated increase in cerebrospinal fluid volume commonly result in an elevated intracranial pressure. During anaesthesia, maintaining an optimal balance between intracranial pressure and cerebral perfusion is crucial to avoid neuronal damage. Volatile anaesthetics are the most commonly used drugs for maintaining anaesthesia in veterinary practice but have the potential to cause an increase in intracranial pressure through vasodilation. This case series describes inhalational maintenance of neuroanaesthesia for ventriculoperitoneal shunt surgery with isoflurane. Interventions applied to manipulate the anaesthetic drug’s effects on intracranial pressure to maintain optimal cerebral perfusion are described.

Acidemia represents a major life-threatening factor during rhinoceros capture. The acid-base status during rhinoceros transport is unknown. The purpose of this study was to describe changes in acid-base status during rhinoceros capture and transport and compare these changes between rhinoceroses sedated with azaperone or midazolam. Twenty-three wild white rhinoceros bulls were road-transported 280 km for reasons unrelated to this study. Rhinoceroses were captured with etorphine-azaperone (Group A) or etorphine-midazolam (Group M). During transport, azaperone (Group A) or midazolam (Group M) was re-administered every 2 h and venous blood collected. Changes in blood pH and associated variables were compared over time and between groups using a general linear mixed model. Rhinoceroses of both groups experienced a respiratory and metabolic acidosis during capture (pH 7.109 ± 0.099 and 7.196 ± 0.111 for Group A and Group M, respectively) that was quickly compensated for by the start of transport (pH 7.441 ± 0.035 and 7.430 ± 0.057) and remained stable throughout the journey. Rhinoceroses from Group M showed a smaller decrease in pH and associated variables at capture than rhinoceroses from Group A (p = 0.012). The use of midazolam instead of azaperone could therefore improve the success of rhinoceros capture and thus, contribute to the outcome of important conservation translocations.