Individual stress responses of white rhinoceros (Ceratotherium simum) to transport: implication for a differential management

Physiological acclimation of elk during population restoration in the Missouri Ozarks, USA

Conservation translocations-the intentional movement of animals to restore populations-have increased over the past 30 years to halt and reverse species declines and losses. However, there are many challenges translocated animals face that should be considered for restoration programs to be successful. Understanding how long it takes for translocated animals to acclimate to these challenges and their new landscape is a critical component of post-release population management. Physiological measures such as hormone responses are increasingly used to assess animal responses and acclimation to disturbances including translocation. We determined the physiological acclimation period of elk (Cervus canadensis) translocated to the Missouri Ozarks, USA, as part of a restoration effort. From 2011 to 2013, we translocated 108 GPS-radio-collared elk from Kentucky, USA, to Missouri, USA, and collected faecal samples for glucocorticoid metabolite extraction to use as an indicator of physiological acclimation. We modelled the response of population-wide faecal glucocorticoid metabolites (fGCMs) across the initial 9 years of the restoration in response to days following release and additional site-specific covariates. Presence of white-tailed deer (Odocoileus virginianus) hunts and monthly precipitation levels were positively and negatively associated with fGCM levels, respectively. Concurrent with influences from site-specific conditions on the release landscape, fGCM levels declined following release. We identified a breakpoint in fGCM decline at ~42 days following translocation releases suggesting elk acclimated physiologically relatively quickly compared to other species. The fast physiological acclimation by Missouri elk suggests effective use of temporary post-release management efforts. Determining how quickly animals acclimate following translocations allows researchers to tailor post-release management plans to each species' needs, thus maximizing the success of future translocation efforts while minimizing costs.

Non-Invasive Assessment of the Seasonal Stress Response to Veterinary Procedures and Transportation of Zoo-Housed Lesser Anteater (Tamandua tetradactyla)

Management procedures affect behavioural and physiological stress responses of wild mammals under human care. According to the Reactive Scope Model, normal values are presumed to exist within predictive and reactive ranges. First, stress parameters of zoo-housed adult Tamandua tetradactyla were evaluated in winter and summer (29 days each), determining the level of behaviour and/or physiological parameters needed to respond to predictable environmental changes. Secondly, the effects of veterinary procedures and transportation were studied in both seasons. Non-invasive methods were applied, assessing behaviour through videos and adrenocortical activity by faecal glucocorticoid metabolites (FGMs). Lesser anteaters exhibited seasonality (summer > winter) in some behavioural parameters, such as nocturnal activities, as well as in the activity cycle (e.g., acrophase) and FGMs. A veterinary check elicited an increase in total activity (TA), natural behaviours and repetitive locomotion and affected the activity cycle, particularly in summer. Transport produced changes in TA, nocturnal and natural activity and some variables of the activity cycle, mostly during summer. Although the effects of routine management procedures were different from each other and presumably stressful, they elicited changes only at the behavioural level, which was greater during summer. The differences observed according to non-invasive methodologies highlight the importance of a multidisciplinary approach in this context and suggest that it is unlikely that individual welfare was affected.

Comparison of body temperature in donkeys using rectal digital, infrared, and mercury-in-glass thermometers during the hot-dry season in a tropical savannah

The study aimed at comparing variations in body temperature values recorded using rectal digital, infrared, and mercury-in-glass thermometers in donkeys during the hot-dry season, prevailing under tropical savannah conditions. Thirty donkeys that served as subjects were divided into three groups of adults, yearlings, and foals. Values of the body temperature of each donkey were recorded bihourly, starting from 06:00 h till 18:00 h, by digital (5-cm depth of insertion), mercury-in-glass (3 cm depth), and infrared thermometers. The values obtained by each type of the thermometer were compared with those recorded using a 15-cm digital probe (Model HI935007, Hanna Instruments, range -50.0 to 150.0°C; accuracy ± 0.2°C) which served as the gold standard. Dry-bulb temperature (34.00 ± 0.50°C), temperature-humidity index (79.65 ± 0.15), and wet-bulb globe temperature (28.00 ± 0.50) index peaked at 14:00 h. The mean body temperatures for rectal probe, digital, mercury-in-glass, and infrared thermometers were 38.35 ± 0.11°C, 37.24 ± 0.04°C, 36.76 ± 0.06°C, and 36.92 ± 0.07°C, respectively. In comparison to the rectal probe, the mean bias for digital (-1.11 ± 0.05°C), mercury-in-glass (-1.59 ± 0.07°C), and infrared thermometers (-1.38 ± 0.07°C) was large. The Passing-Bablok regression plot demonstrated significant deviation from linearity (p < 0.01) when digital, infrared, and mercury-in-glass thermometers were compared to the rectal probe. The area under the curve (AUC) for digital (AUC: 0.7005 ± 0.01 [95%: 0.6853 - 0.7310], infrared (AUC: 0.6711 ± 0.01 [95%: 0.6322 - 0.7100], and mercury-in-glass (AUC: 0.6321 ± 0.01 [95%: 0.6001 - 0.7873] thermometers showed poor accuracy with low sensitivity. In conclusion, the use of digital, mercury-in-glass, and infrared thermometers in recording body temperature in donkeys during the hot-dry season underestimated the values. Their use in measuring body temperature may result in wrong diagnosis, and compromise the control of hyperthermia and diseases associated with thermoregulatory impairments in donkeys.

CHALLENGES TO ANIMAL WELFARE DURING TRANSPORTATION OF WILD MAMMALS: A REVIEW (1990-2020)

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.

Effects of Chronic Stress on the Fecal Microbiome of Malayan Pangolins (Manis javanica) Rescued from the Illegal Wildlife Trade

Pangolins (scaly anteaters, Pholidota) are among those mammals that are most affected by the international, illegal wildlife trade. Recently, wildlife rescue centers in China became dedicated to rehabilitate confiscated pangolins and prepare them for reintroduction to the wild. Chronic stress is thought to be the main reason for a disturbed microbiota community and a higher mortality rate of pangolin in captivity. In this study, we compared the cortisol levels and the fecal microbiome of Malayan pangolin (Manis javanica) born and reared in captivity (PCB; n = 7) with those rescued from the wildlife trade (PCT; n = 16). Results show that the level of cortisol in PCT was significantly lower than that observed in PCB. There were also significant differences in the composition of the fecal microflora between the two groups, and the diversity of intestinal microbiota was higher in PCB than in PCT. At the phylum level, the bacteria with significant difference between the two groups included Firmicutes and Bacteroides. At the genus level, bacteria such as Bacteroides, Parabacterides, and Clostridium showed significant differences between the two groups. This study proves that chronic stress has a considerable effect on the diversity and composition of fecal microbiota in Malayan pangolin.

Negligible hormonal response following dehorning in free-ranging white rhinoceros (Ceratotherium simum)

The white rhinoceros (Ceratotherium simum) is experiencing unsustainable poaching losses fuelled by a demand for horn. Increasingly, private and state reserves are dehorning their rhinoceros populations in an attempt to reduce poaching pressure. Rhinoceroses use their horns in social interactions as well as during resource access and so its partial removal as part of reserve management practices may adversely influence these behaviours. Physiological stress can correlate with animal welfare, reproductive state and health and thus acts as a useful indicator of these parameters. To establish whether dehorning causes a physiological stress response, glucocorticoid and gonadal steroid profiles of free-ranging white rhinoceroses were determined through the collection and analysis of faecal steroid metabolites before and after dehorning. Faecal corticoid profiles were not influenced by the number of occasions a rhinoceros had been dehorned or by the number of days that had elapsed since dehorning. Furthermore, there was no apparent suppression in the concentrations of testosterone or progesterone metabolites in males and females, respectively, after exposure to multiple dehorning procedures. These findings should increase wildlife managers' confidence that dehorning does not negatively impact white rhinoceros physiology as measured hormonally.