Anecdotal accounts of inebriated elephants are widespread across elephant-inhabited regions, yet the molecular and mechanistic basis underlying these observations remains incompletely understood. Alcohol metabolism in mammals is primarily mediated by alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). We investigated elephant ADH and ALDH at the genomic, transcriptional, and enzymatic levels, comparing them with humans, hamsters, and rats. Elephant liver predominantly expressed three ADH1 genes, as in humans and hamsters that voluntarily consume ethanol, a feature otherwise reported mainly in primates. We measured hepatic ADH and cytosolic ALDH activities in elephants, despite challenges in sample collection. Elephant ADH exhibited high ethanol affinity, allowing enzymatic activity at low substrate concentrations, likely related to large body size. ADH catalytic efficiency was comparable to other species, and cytosolic ALDH showed relatively high efficiency. These results suggest that elephants are less likely to possess exceptionally low hepatic ethanol-metabolizing capacity, although the lack of data on mitochondrial ALDH2 activity should be taken into consideration. Elephants also exhibited unique features, including the absence of ADH4 gene expression, duplication of ALDH1A1, and pseudogenization of ALDH1B1, which appear to have arisen in association with diet and potential functional redundancy among paralogs. In addition to their ecological and evolutionary significance, these findings may contribute to the interpretation of drug metabolism and support evidence-based pharmacological management in elephants, given the role of ADH and ALDH in pharmaceutical metabolism. Together, this study provides a molecular and enzymatic basis for understanding ethanol metabolism in elephants.

Regular welfare assessments are essential for identifying and addressing the physical, behavioral, and emotional needs of shelter dogs, thereby ensuring their well-being and improving chances for adoption or long-term stability within the shelter environment. This study compared biomarkers of physiological stress [fecal glucocorticoid metabolites (fGCM)], metabolic status [serum malondialdehyde (MDA), glucose, triglycerides, low- (LDL) and high- (HDL) density lipoproteins], and fecal microbiota composition over a 1-month period in healthy and spinal-injured disabled dogs housed in a large dog rescue shelter in Thailand for over 1 year. No significant differences in fGCM concentrations were observed between groups, indicating comparable levels of physiological stress in healthy and disabled dogs under long-term shelter conditions. In contrast, disabled dogs exhibited significant metabolic and oxidative alterations, including elevated MDA and glucose, along with lower triglyceride and HDL concentrations. Microbial analyses revealed comparable alpha diversity but differences in beta diversity between groups. Notably, disabled dogs exhibited a reduced Firmicutes-to-Bacteroidetes (F/B) ratio and decreased relative abundances of beneficial taxa such as Peptostreptococcaceae. These findings suggest that, despite comparable hormonal stress indicators, disabled dogs may experience subclinical physiological shifts that warrant more nuanced welfare monitoring. A multifactorial assessment incorporating metabolic and microbial parameters is recommended to ensure comprehensive welfare evaluation for physically impaired shelter dogs.

Non-invasive biomarkers of immune function are increasingly important for assessing health, welfare and disease risk in zoo and wild mammals, particularly because they support repeated monitoring while minimizing handling-related disturbance. Secretory immunoglobulin A (IgA), a key component of mucosal immunity, can be quantified from faecal samples and provides a practical measure of gut-associated immune activity without invasive sampling. We conducted a systematic literature review of 21 peer-reviewed studies that quantified faecal IgA across diverse mammalian taxa and ecological contexts. Across species, faecal IgA was technically measurable and biologically responsive, but its interpretation was strongly context dependent. Reported patterns reflected interactions among pathogen exposure, physiological stress, nutritional state, life-history stage and management conditions. In captive settings, faecal IgA frequently varied with individual heterogeneity and management factors and showed inconsistent alignment with endocrine stress markers. In free-ranging populations, faecal IgA more commonly tracked parasite burden, reproductive investment, seasonal variation and host-microbiome dynamics. However, most ecological and welfare-associated patterns were derived from observational designs, which limit causal inference. Additionally, methodological heterogeneity in assay validation, sample processing and preservation limited direct quantitative comparison among studies. Overall, faecal IgA does not function as a unidimensional indicator of stress or welfare, but rather as a context-sensitive marker of mucosal immune allocation. We integrate these findings into a conceptual framework linking external pressures, mucosal immune dynamics, complementary biomarkers and health-related outcomes to guide interpretation across zoo and wild settings. When embedded within longitudinal and multi-marker approaches supported by species-specific validation, faecal IgA has potential to contribute meaningfully to non-invasive health assessment in conservation physiology.

Variations in space allocation and husbandry practices can significantly affect the health and welfare of long-term shelter dogs. This study compared adrenal, metabolic, and microbiological health indicators among dogs from three shelters in Thailand: Shelter A - low-density (20.3 m²/dog), adequate enclosure size (101.9 m²), and an enrichment program; Shelter B - medium-density (3.9 m²), large enclosures (150 m²); and Shelter C - high density (3.0 m²), one communal space (800 m²), and no enrichment. Fecal glucocorticoid metabolite (fGCM) concentrations, oxidative stress (malondialdehyde, MDA), metabolic parameters (glucose, insulin, fructosamine, lipid profiles), and fecal microbiota composition and diversity were measured and analyzed in relation to management factors. Dogs in Shelter A exhibited the lowest fGCM concentrations (207.41 ± 4.55 ng/g), normal metabolic profiles, and richer, more even fecal microbiota. In contrast, dogs in Shelter C, a temple-based facility with more crowding and limited space, exhibited higher fGCM (278.71 ± 10.44 ng/g) and fructosamine concentrations, reduced alpha diversity, and a highly skewed Firmicutes-to-Bacteroidota ratio, suggesting possible adrenal cortical and microbial dysbiosis. Shelter B presented intermediate values across most parameters and management inputs. These findings show that management practices, including space allocation and enrichment, can influence stress physiology, metabolic health, and fecal microbiota composition in long-term sheltered dogs.

The international travel ban initiated in March 2020 due to the COVID-19 pandemic greatly affected how captive elephants were managed in Thailand. A lack of tourists and associated income meant elephants were chained longer with reduced food provisions, had fewer mahouts, and limited exercise like riding, which likely affected health and welfare. Fifty-eight elephants from six tourist camps were assigned a body condition score (BCS) and blood samples were collected monthly for 2 years during the travel ban to measure: (1) muscle enzymes [creatine kinase (CK), aspartate aminotransferase (AST)]; (2) liver enzymes [aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT)]; (3) lipids [total cholesterol (TC), triglycerides (TG), low (LDL) and high (HDL) density lipoproteins]; and metabolic function [glucose, insulin, fructosamine]. Serum CK concentrations were lower at the end of the study, possibly due to no tourist activities like riding. Changes in liver function included increased AST and ALP, also possibly due to physical inactivity. Feeding less bananas and sugar cane was associated with fewer elephants in the obese category and lower TG concentrations. However, increases in glucose, insulin and fructosamine were observed as local people returned to feed elephants after lifting travel restrictions. In sum, changes in several health biomarkers were observed in association with restricted activities and food resources. Camps need better plans to meet the health and welfare needs of elephants during any future disruptions to the tourism industry, although reduced feeding of sweet treats appeared to have positive effects on body condition and metabolic function.

Stallion mules have been used as working equids in several countries. Aggressiveness under the influence of testosterone results in the necessity for surgical castration before work training. The gonadotropin-releasing hormone (GnRH) vaccine may be an alternative method for immunocastration in mules. The objective of this study was to evaluate the effect of the GnRH vaccine on anti-GnRH antibody concentration, serum testosterone concentration, clinical adverse effects, and behavioral changes in response to receiving selected physical manipulations from humans. Twenty-five mules were separated into three groups: Control-intact, Control-castrated, and Treatment. The Treatment group was further divided according to condition (intact or unilateral cryptorchid) and age. The Treatment group received 195 µg of the GnRH vaccine intramuscularly at weeks 0, 4, and 8. The anti-GnRH antibody concentrations increased at weeks 6 and 10, and then they gradually decreased to baseline at week 24. The Treatment-intact-young group had the highest concentration of anti-GnRH antibody. The serum testosterone concentrations in the Treatment group were lower than before vaccination from weeks 6 to 14. Subcutaneous edema adjacent to the injection site was detected in the Treatment-intact group after booster vaccination. In conclusion, the mules responded to the GnRH vaccine, which could temporarily suppress testosterone for up to 14 weeks.

IntroductionOxidative stress refers to an imbalance between oxidant and antioxidant activity and accumulation of reactive oxygen species, which can have detrimental effects on animal health. Annual fluctuations in oxidative stress status can occur, increasing disease susceptibility during certain time periods. However, a full understanding of factors related to oxidative stress in Asian elephants and how to mitigate the negative consequences is lacking.MethodsThis study measured six serum oxidative stress markers [reactive oxygen species (ROS), malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), albumin, glutathione peroxidase (GPx), and catalase] and two stress markers [serum cortisol and fecal glucocorticoid metabolites (fGCM)] in 23 captive Asian elephants in Thailand over a 12 months period to examine relationships with age and season.ResultsSeasonal variations were observed, with several markers exhibiting significantly higher concentrations in the summer (ROS, MDA, 8-OHdG, albumin) and lower values during the rainy/winter seasons (MDA, 8-OHdG, albumin, catalase). By contrast, GPx was the only marker to be highest during the rainy season. For the stress markers, higher fGCM concentrations were noted during the rainy season, which contrasts with earlier studies showing more activity in the winter (tourist season). Positive correlations were found between the temperature-humidity index and ROS, GPx, and fGCM, while a negative correlation was observed with serum albumin. Elephant endotheliotropic herpesvirus (EEHV) shedding events were associated with higher concentrations of ROS and MDA. A moderate negative correlation was observed between 8-OHdG and the PCR threshold cycle of EEHV shedding (Ct), indicating DNA damage may be involved in EEHV shedding in elephants.DiscussionResults revealed significant age and seasonal effects on several oxidative stress markers, indicating those factors should be considered in study design and data interpretation. There also may be physiological adaptations in oxidative stress conditions in relation to environmental changes that could impact health outcomes.

Oxidative stress is a pathological condition that can have adverse effects on animal health, although little research has been conducted on wildlife species. In this study, blood was collected from captive Asian elephants for the assessment of five serum oxidative status markers (reactive oxygen species (ROS) concentrations; malondialdehyde, MDA; albumin; glutathione peroxidase, GPx; and catalase) in healthy (n = 137) and sick (n = 20) animals. Health problems consisted of weakness, puncture wounds, gastrointestinal distress, eye and musculoskeletal problems, and elephant endotheliotropic herpesvirus hemorrhagic disease (EEHV-HD). Fecal samples were also collected to assess glucocorticoid metabolites (fGCMs) as a measure of stress. All data were analyzed in relation to age, sex, sampling season, and their interactions using generalized linear models, and a correlation matrix was constructed. ROS and serum albumin concentrations exhibited the highest concentrations in aged elephants (>45 years). No sex differences were found for any biomarker. Interactions were observed for age groups and seasons for ROS and catalase, while GPx displayed a significant interaction between sex and season. In pairwise comparisons, significant increases in ROS and catalase were observed in summer, with higher ROS concentrations observed only in the adult female group. Lower catalase activity was exhibited in juvenile males, subadult males, adult females, and aged females compared to subadult and adult elephants (males and females) in winter and the rainy season. There was a positive association between catalase activity and fGCMs (r = 0.23, p < 0.05), and a number of red blood cell parameters were positively associated with several of these biomarkers, suggesting high oxidative and antioxidative activity covary in red cells (p < 0.05). According to health status, elephants with EEHV-HD showed the most significant changes in oxidative stress markers, with MDA, GPx, and catalase being higher and albumin being lower than in healthy elephants. This study provides an analysis of understudied health biomarkers in Asian elephants, which can be used as additional tools for assessing the health condition of this species and suggests age and season may be important factors in data interpretation.

To evaluate the effect of P. mirifica supplementation on ovarian activity in crossbred Thai native does, a study was carried out for three consecutive estrus cycle periods: 1) D0-D21(pre-treatment), 2) D21-D42 (treatment) and 3) D42-D63 (post-treatment); D0, D21 and D42 were the days of expected estrus. P. mirifica was orally fed at 1000 mg/kg BW/d for 21 days in supplemented groups. Twenty-one does were equally divided into three groups: 1) CON – control, no supplementation and 2) supplemented groups included 2.1) FEC – start feeding at early-cycle (D21-D42), and 2.2) FMC – start feeding at mid-cycle (D32-D53). Estrus behavior was determined by observation, ovarian activity was monitored by transrectal ultrasonography and fecal progesterone concentration (FPC) was analyzed by EIA. The results showed that CON had lower (P<0.05) receptive behavior and shorter (P<0.05) estrous duration than those of FEC and FMC at treatment and post-treatment periods. FEC had a lesser number of developed follicles (P<0.05) and a greater number of undeveloped follicles than others at treatment period. FMC had a higher (P<0.05) number of undeveloped follicles at post-treatment period. Moreover, FEC and FMC had a higher (P<0.05) number of anovulatory follicles than that of CON, while only FMC had a lower (P<0.05) number of CLs along with a greater (P<0.05) number of early CL regression at the post-treatment period. FPC of FEC and FMC was lower than that of CON during administration. In conclusion, the P. mirifica dosage used in this study enhanced estrus behavior but suppressed ovarian activity in the consequent cycle when fed either at early or mid-cycle. Feeding over ovulation might have more adverse effects concerning CL function.

The aim of this study was to examine relationships among serum progestagens, cortisol, and prolactin in pregnant and normal cycling Asian elephants living in tourist camps in northern Thailand. Samples were collected twice a month for 22 months from nine elephants. Of those, four were pregnant (24.3 ± 2.9 years of age; range 21–28 years) and five (20.2 ± 9.6 years; range 8–34 years) exhibited normal ovarian cycles based on serum progestagen analyses. Gestation was divided into three periods: 1st (week 1–31), 2nd (week 32–62), and 3rd (week 63 to parturition), while the estrous cycle was divided into the follicular and luteal phases. Serum progestagens were higher during the luteal phase of the cycle (p < 0.003), whereas cortisol and prolactin were similar. In pregnant elephants, there were no differences in serum progestagens or cortisol concentrations across the three gestational periods, whereas prolactin concentrations increased significantly during the 2nd and 3rd periods (p < 0.0001). By contrast, prolactin concentrations in nonpregnant elephants were consistently low throughout the ovarian cycle. In one cycling female, prolactin concentrations were similar to pregnant elephants, perhaps because she was an allomother to two calves. Another cycling female exhibited consistently elevated cortisol concentrations, 5 to 10 times higher than the other elephants. There were no correlations between serum progestagens, cortisol, and prolactin throughout gestation; however, serum progestagens and cortisol were positively related in cycling elephants (r = 0.386, p < 0.001). From our results, there were a number of individual differences in reproductive hormonal patterns, so it is important to develop personalized monitoring programs for each elephant to enhance breeding success and create sustaining captive populations of elephants in Asia.

Elephant endotheliotropic herpesvirus hemorrhagic disease (EEHV-HD) is a virulent disease that causes severe hemorrhage and sudden death in Asian elephant calves. A change in hematology profiles is one indicator of infection before clinical signs appear; however, to be effective, individual baselines and age-matched reference values are needed. Stress has been speculated to be a factor in clinical EEHV cases, but relationships have not been demonstrated empirically. This study evaluated blood hematology and several stress response markers—salivary cortisol, fecal glucocorticoid metabolites (FGM), salivary Immunoglobulin A (SIgA), and fecal IgA (FIgA) in samples collected for 1 year from three healthy calves with no EEHV history (non-EEHV), and six that had previously been infected, developed clinical signs and survived (prior-EEHV). Hematology values between non-EEHV and prior-EEHV elephants were not different and within published reference ranges. Concentrations of salivary cortisol, FGM, SIgA, and FIgA also were variable and showed seasonal differences, but no relationships to prior EEHV status. One of the prior EEHV calves became re-infected, developed hemorrhagic disease (HD), and died during the study period. That calf exhibited lymphocytopenia, monocytopenia, and thrombocytopenia. Additionally, all stress biomarker concentrations were lower in the 12 days before viremia was observed. Thus, as in other studies, changes in hematology occur with EEHV infection, while preliminary data in one calf suggests that stress-response measures might also be informative and should be studied further.

This study aimed to compare the follicular dynamics in goats during naturally infected with foot-and-mouth disease virus (FMD) subjected to induced ovulations, and after disease recovery, crossbred Thai native does were synchronized with CIDR for 14 days, and then PGF2α and PMSG were administered on the day following CIDR removal. The ovarian activity was determined by transrectal ultrasonography. Clinical signs (fever, anorexia, lameness, and foot lesion) were observed on day 12 post-estrus (day 0, day of expected estrus). The study was carried out for 2 periods: FMD outbreak (day 0–day 21) and FMD recovery (day 63–day 84). Infected does were classified into two groups: (I) does without (n = 5) and (II) does with clinical signs (n = 5). The results showed that during FMD outbreak, the number of follicles/waves and number of follicles > 5 mm in ovulatory follicle wave of group II were lower than those of group I and those of its own group after FMD recovery (P<0.05). Higher in follicular regression rate were found in group II compared to group I in the does with 3 follicular waves during FMD outbreak (P<0.05). Moreover, during FMD outbreak, the does had lower number of follicles > 5 mm and longer day of emergence and day of largest follicles in ovulatory follicle wave than of those after FMD recovery. This observation demonstrated that FMD impaired folliculogenesis in goats, and the ovarian activity could be restored about 1 month after disease recovery.

Asian elephants have been an important part of wildlife ecotourism in Thailand for over two decades. Elephants in tourist camps are exposed to a variety of management styles and daily activities that can potentially affect health and welfare. This study investigated relationships between a novel welfare biomarker, immunoglobulin A (IgA), and daily camp activities, and compared results to glucocorticoid (GC) measures. Often no-riding camps are portrayed as providing better welfare than camps that offer riding. Therefore, we predicted that elephants at no-riding camps would have lower GC and higher IgA concentrations, and a low GC/IgA ratio. Forty-four female elephants from six elephant camps were divided into three groups based on riding activities: saddle-riding, bareback-riding, and no-riding. Fecal and salivary samples were collected monthly for 1 year along with evaluations of body condition, foot health, and wounding. Camp environment and management varied among camps, although the major difference was in riding activities. Concentrations of GCs and IgA varied among the working groups, but not always consistently between sample matrices. Overall fecal glucocorticoid metabolite concentrations were lowest in the saddle-riding group. Only in one bareback-riding camp did the elephants exhibit a potentially positive welfare response with a low GC/IgA ratio over time. Other results varied between the two biomarkers, with considerable variability across camps, suggesting there is more to good welfare than whether elephants participate in riding or not. Several other human-induced stressors, like chaining, ankus use, and limited social opportunities are likely to be impacting well-being and should be considered to ensure management practices meet physical and psychological welfare needs.

Salivary immunoglobulin A (sIgA) has been proposed as a potential indicator of welfare for various species, including Asian elephants, and may be related to adrenal cortisol responses. This study aimed to distinguish circadian rhythm effects on sIgA in male and female Asian elephants and compare patterns to those of salivary cortisol, information that could potentially have welfare implications. Subjects were captive elephants at an elephant camp in Chiang Mai province, Thailand (n = 5 males, 5 females). Salivette® kits were used to collect saliva from each elephant every 4 h from 06:00 to 22:00 h for 3 consecutive days (n = 15 samples/elephant). Enzyme immunoassays were used to quantify concentrations of IgA and cortisol in unextracted saliva. Circadian rhythm patterns were determined using a generalized least-squares method. Both sIgA and cortisol followed a circadian rhythm, although the patterns differed. sIgA displayed a daily quartic trend, whereas cortisol concentrations demonstrated a decreasing linear trend in concentrations throughout the day. There was no clear relationship between patterns of sIgA and salivary cortisol, implying that mechanisms of control and secretion differ. Results demonstrate for the first time that circadian rhythms affect sIgA, and concentrations follow a daily quartic pattern in Asian elephants, so standardizing time of collection is necessary.

Establishing links between ecological variation, physiological markers of stress and demography is crucial for understanding how and why changes in environmental conditions affect population dynamics, and may also play a key role for conservation efforts of endangered species. However, detailed longitudinal studies of long-lived species are rarely available. We test how two markers of stress and body condition vary through the year and are associated with climatic conditions and large-scale mortality and fertility variation in the world's largest semi-captive population of Asian elephants employed in the timber industry in Myanmar. Glucocorticoid metabolites (used as a proxy for stress levels in 75 elephants) and body weight (used as a proxy for condition in 116 elephants) were monitored monthly across a typical monsoon cycle and compared with birth and death patterns of the entire elephant population over half a century (n = 2350). Our results show seasonal variation in both markers of stress and condition. In addition, this variation is correlated with population-level demographic variables. Weight is inversely correlated with population mortality rates 1 month later, and glucocorticoid metabolites are negatively associated with birth rates. Weight shows a highly positive correlation with rainfall 1 month earlier. Determining the factors associated with demography may be key to species conservation by providing information about the correlates of mortality and fertility patterns. The unsustainability of the studied captive population has meant that wild elephants have been captured and tamed for work. By elucidating the correlates of demography in captive elephants, our results offer management solutions that could reduce the pressure on the wild elephant population in Myanmar.