Relationships among fecal lungworm loads, fecal glucocorticoid metabolites, and lamb recruitment in free-ranging Rocky Mountain bighorn sheep

Most wild Rocky Mountain big-horn sheep (Ovis canadensis canadensis) in northern latitudes are infected with lungworms. Indirect effects of lungworms on bighorn sheep are unknown, but high pulmonary burdens might increase stress (i.e., elevated glucocorticoid levels), and chronic stress could in turn decrease fitness. We hypothesized that high lungworm burdens in Rocky Mountain bighorn ewes increase stress, thereby increasing lamb mortality. To test our hypothesis, one subherd of bighorn sheep in Custer State Park, South Dakota was provided a free-choice loose mineral mix containing the anthelmintic fenbendazole every six weeks from March 1999 to August 2000 to eliminate lungworms; another subherd served as the control. Daily, individually marked ewes were located telemetrically from the ground and uniquely marked animals were observed until they defecated. After the herd moved from the area, fecal samples were collected and stored at -23 C. A consistent number of samples per season per herd (x-=16.56+/-3.99 samples) were collected. Fecal larval lungworm levels (LPG) in the treatment subherd were lower than levels in the control subherd; however, there was no difference in fecal glucocorticoid metabolite (FGM) levels between the two subherds. Fecal glucocorticoid metabolite levels varied by season in both subherds, with levels in winter lower than during the other three seasons. Lamb:ewe ratios were not different between the control and treatment subherds at the end of summer 1999. In contrast, the treatment group had a lower lamb:ewe ratio at the end of summer 2000 despite having lower LPG. However, this result was attributed to lower ewe production, not lower lamb survival. The LPG levels were not correlated with FGM concentrations; instead, FGM levels might reflect normal seasonal patterns. Other factors, including contagious ecthyma, were more important for determining lamb mortality than LPG and FGM levels during our study. We suggest further experimental work over a longer duration to address these relationships.     

Occurrence, diagnosis, and strain typing of Mycobacterium avium subspecies paratuberculosis infection in Rocky Mountain bighorn sheep (Ovis canadensis canadensis) in southwestern Alberta

The role that wildlife may play in the transmission of Mycobacterium avium subspecies paratuberculosis (Map), the causative agent of Johne's disease (JD), and the potential consequences of infection in these populations are being given increasing consideration. A yearling male Rocky Mountain bighorn sheep (Ovis canadensis canadensis) from southwestern Alberta, Canada, was found infected with Map in August 2009. Clinical signs of emaciation and diarrhea and histologic findings of diffuse granulomatous enteritis of the distal ileum, lymphadenitis of the mesenteric lymph nodes, and lymphangitis of the ileum were similar to previously described cases of JD in bighorn sheep. Infection with Map was confirmed by bacterial isolation through fecal culture, acid-fast staining, and polymerase chain reaction (PCR) of IS900. The Map1506 gene was sequenced, and the isolate was identified as a Cattle (Type II) strain. In a follow-up herd-level survey, three of 44 fecal samples (7%) from individual bighorn sheep from the same herd as the index case were PCR-positive and identified as Type II Map strains. Twenty-five samples from a distant bighorn population were negative. Additional strain typing of the isolates from the index case and the positive fecal samples was done by sequencing three discriminatory short sequence repeat (SSR) regions. All four SSR profiles differed from one another, suggesting multiple introductions or a long-existing circulation of Map within this bighorn population. Detailed molecular analyses are essential for understanding and managing diseases at the wildlife-livestock interface.     

Ecology of gastropod and bighorn sheep hosts of lungworm on isolated, semiarid mountain ranges in Utah, USA

Isolated, nonmigratory populations of bighorn sheep (Ovis canadensis) may experience high exposure to lungworms (Protostrongylus spp.) through a build-up of fecal material. However, semiarid climates may hinder lungworm transmission by limiting terrestrial gastropods, the intermediate hosts. We assessed potential for lungworm transmission, documented occurrence of transmission, and identified habitat types where transmission was likely to occur on ranges of two recently introduced populations of bighorn sheep in northern Utah. Gastropods were collected weekly on Antelope Island and the Newfoundland Mountains, May-August 2001-02, from each of the four major habitat types (riparian, rock, desert shrub, and grass). Distribution of 113 bighorn sheep groups was observed, and 421 fecal pellet groups were collected to estimate lungworm levels. A total of 1,595 gastropods representing five genera were collected from both ranges. Vallonia made up 85% of all gastropods collected. Of 980 gastropods collected on Antelope Island in 2002, only Vallonia were found infected with protostrongylid-type larvae (10 of 980=1%). Lungworm prevalence in bighorn fecal samples was 97% on Antelope Island and 90% on the Newfoundland Mountains. Lungworm prevalence in lambs indicated lungworm transmission was occurring on Antelope Island. Lungworm transmission was likely occurring in riparian habitat due to abundant gastropods, presence of infected gastropods, and reliance by bighorn sheep on few water sources. Differences in spatial distribution between ram and nursery groups may partly explain higher fecal larvae counts in nursery than in ram groups. We suggest lungworm levels in bighorn sheep on semiarid ranges may increase in dry years as bighorn sheep concentrate use on fewer perennial water sources.     

Comparison of three fecal steroid metabolites for pregnancy detection used with single sampling in bighorn sheep (Ovis canadensis)

We conpared three fecal steroid metabolite assays for their usefulness in detecting pregnalcy among free-ranging Rocky Mountain bighorn sheep (Ovis canadensis canadensis) from Bighorn Canyon National Recreation Area, Wyoming and Montana (USA) and captive bighorn ewes at ZooMontana in Billings, Montana. Fecal samples were collected from 11 free-ranging, radio-collared bighorn ewes in late January-May 2001 and from 20 free-ranging, radio-collared ewes in late March to mid-May 2002. Free-ranging ewes were monitored the following spring to determine whether or not they lambed. In addition, two captive ewes were studied at ZooMontana. With three exceptions, free-ranging bighorn ewes that produced lambs had nonspecific progesterone metabolite (iPdG) levels of >1800 ng/g feces and iPdG levels >7000 ng/gm feces when samples were collected between early March and mid-May. Samples collected earlier in the year were inconclusive. One false negative was suspected to be the result of sample collection error. Of the captive ewes, nonspecific pregnanediol-3alpha-glucuronide (PdG) and iPdG followed a predictable curve over the course of the 180-day pregnancies. We conclude that estrone conjugates are not useful in diagnosing pregnancy; however, fecal steroid analysis of PdG and iPdG can be used to accurately determine pregnancy and reproductive function in bighorn sheep. This holds great potential as a noninvasive technique for understanding the role of reproductive disease in wild bighom sheep.     

Muellerius capillaris (Mueller, 1889) (Nematoda: Protostrongylidae): an unusual finding in Rocky Mountain bighorn sheep (Ovis canadensis canadensis Shaw) in South Dakota

Lungs and fecal samples from nine hunter-killed Rocky Mountain bighorn sheep were examined for lungworms. All samples contained adults and/or larvae of Muellerius capillaris (Mueller, 1889). Protostrongylus spp., the lungworms commonly reported from bighorn sheep, were not present in any samples. Larvae of M. capillaris bear a spine on the dorsal side of the posterior end and are shorter than dorsal-spined larvae of other lungworms recorded from North American ungulates. Larvae similar in shape but longer than those of Muellerius were found in free-ranging bighorn sheep in Alberta and British Columbia. In addition, dorsal-spined larvae have been found in bighorn sheep in Montana, North Dakota, and Washington. The identity of the dorsal-spined larvae is known only from sheep in South Dakota. Thus, caution must be taken when diagnosing lungworm infections in Rocky Mountain bighorn sheep.     

Detection probability and Pasteurellaceae surveillance in bighorn sheep

We investigated the influence of detection probability (i.e., the probability of detecting the disease or organism of interest) on the repeatability of results reported from bacterial culture tests used to demonstrate the presence of species in the Pasteurellaceae family that infect bighorn sheep (Ovis canadensis). We also estimated occupancy probabilities (i.e., the probability an individual bighorn in a herd is infected) for each cultured biovariant and examined the effects of detection probability on the number of samples needed to detect the Pasteurellaceae biovariants from within an individual sheep as well as from within a herd. We collected 5-15 samples from free-ranging bighorns in Colorado, using oropharyngeal swabs or swabs of lungs, and submitted these swabs either immediately or after 2 days for bacterial culture. We saw significant variability in results for repeated samples from each of the sheep, and detection probabilities were ≤ 0.71 for all Pasteurellaceae biovariants cultured. The delayed (≥ 2 days) sample submission reduced both the microbial diversity detected and the detection probability for the biovariants characterized when compared to samples submitted immediately. Oropharyngeal sampling had higher detection probabilities of the individual biovariants than did lung swabs, and there was a difference in the biovariants detected between oropharyngeal and lung sampling. Depending on the biovariant of interest, estimates of occupancy probabilities ranged from 0.37-0.89, and we estimated that three to >30 swab samples were necessary to obtain a 95% confidence of detecting the cultured biovariants if they were present in an individual sheep. We estimated that the optimal sample sizes to detect the observed biovariants within a sheep herd with a 95% confidence ranged from sampling two bighorns twice to sampling 40 individuals once. Detection probability impacts the results reported from bacterial cultures for Pasteurellaceae in bighorn sheep, and confounding effects of the detection process should be addressed to improve the rigor of surveillance.     

Effects of helicopter net-gunning on survival of bighorn sheep

Wildlife capture, and the data collection associated with it, has led to major advancements in ecology that are integral to decision making pertaining to wildlife conservation. Capturing wildlife, however, can cause lethal and non-lethal risks to animals. Understanding the factors that contribute to the level of risk involved in wildlife capture is therefore important for the development and implementation of the safest and most effective methodologies. We used data from 736 animal captures of 389 individuals for 2 subspecies of female bighorn sheep (Rocky Mountain bighorn [Ovis canadensis canadensis], Sierra Nevada bighorn sheep [O. c. sierrae]) in Wyoming and California, USA, in 2002–2020 to evaluate the degree and extent of time that capture via helicopter net-gunning affects survival. We compared pre- and post-capture survival during a 10-week window centered on a capture event, and post-capture survival between captured animals and animals that were monitored but not captured during the 10-week window. Additionally, we evaluated the effects of handling techniques (number of times captured, season of capture event, handling time, chase time, and body temp) and biological factors (age and nutritional condition) on probability of capture mortality. Mean daily survival was 0.9992 during a 5-week pre-capture window, dropped to 0.9864 on the day of capture, and rebounded within 3 days of capture to pre-capture levels and that of sheep that were not captured. Overall, direct mortality resulting from capture was 1.36%, with 0.54% mortality occurring within the 3 days following a capture event for an overall 1.90% capture-related mortality. The only handling and biological metrics that influenced the probability of capture mortality were rectal temperature and nutritional condition; high initial rectal temperatures and poor body condition were associated with increased risk of mortality in the days following capture. Overall, helicopter net-gunning imposed low and short-term risk to survival of female bighorn sheep. To reduce bias in survival estimates, we recommend using a 3-day censorship window for post-capture mortalities as opposed to the common practice of a 2–5-week censor window. Helicopter net-gunning, including annual or seasonal recaptures, remains an effective and comparatively safe technique for capture and associated data collection of bighorn sheep.     

Blubber cortisol qualitatively reflects circulating cortisol concentrations in bottlenose dolphins

Stress hormones, released into circulation as a consequence of disturbance, are classically assayed from blood samples but may also be detected in a variety of matrices. Blubber and fecal samples can be remotely collected from free‐ranging cetaceans without the confounding hormone elevations associated with chase, capture, and handling required to collect blood samples. The relationship between cortisol concentrations in circulation with that of blubber and feces, however, is unknown. To assess these associations, we elevated cortisol by orally administering hydrocortisone for five days in five bottlenose dolphins. Voluntary blood and fecal samples were collected daily; blubber biopsies were collected on day one, just prior to hydrocortisone administration, and days three and five of hydrocortisone administration. We evaluated subsequent changes in several circulating stress hormones as well as cortisol and glucocorticoid metabolites in blubber and feces, respectively. There was a significant association between cortisol levels in serum and in blubber (F_1,12.7 = 14.3, P < 0.01, mR² = 0.57) despite substantial variability in blubber cortisol levels. Counterintuitively, fecal cortisol metabolite levels were inversely related to serum cortisol. The relationship between serum and blubber cortisol levels suggests blubber samples from remote sampling may be useful to detect stress loads in this species.     

Effects of capture on biological parameters in free-ranging bighorn sheep (Ovis canadensis): evaluation of drop-net, drive-net, chemical immobilization and the net-gun

Blood samples and physiological data were collected from 634 bighorn sheep captured between 1980 and 1986 in the western United States. Bighorn sheep were evaluated for physiological parameters (temperature, pulse and respiration), selected biochemical parameters (cortisol, creatine phosphokinase (CPK), serum glutamic oxaloacetic transaminase (SGOT), lactic dehydrogenase (LDH), alkaline phosphotase (AP), potassium, sodium, chloride, creatinine, blood urea nitrogen (BUN), selenium, glucose, total protein, plasma pH and plasma PCO2), and selected hematological parameters (packed cell volume (PCV), hemoglobin (HB), red blood cell count (RBC), and white blood cell count (WBC]. These parameters were compared among bighorn sheep captured by four different methods: drop-net (n = 158), drive-net (n = 249), chemical immobilization (n = 90) and the net-gun (n = 137). Biological parameters affected by stress, including temperature, respiration, cortisol, CPK, SGOT, potassium, glucose and WBC revealed significant differences among capture methods (P less than 0.05). Some blood parameter differences, including temperature, respiration, cortisol, glucose and WBC could be explained partially by the distribution of age and sex within capture method groups. Drop-net and net-gun methods of capture appeared to produce the least amount of alteration to biological parameters related to capture stress or compromise and capture mortality. Drive-net was similar to the former methods while chemical immobilization caused the greatest changes in the above physiological, biochemical and hematological parameters.     

Bighorn sheep, a new host record for Parelaphostrongylus odocoilei (Nematoda: Protostrongylidae)

Larval nematodes with a dorsal spine on the tail were recovered from fecal samples of California bighorn sheep (Ovis canadensis californiana) in northeastern Washington State, USA. The identity of these dorsal-spined larvae (DSL) was established by single-strand conformation polymorphism (SSCP) analyses of a partial fragment of the first internal transcribed spacer of the ribosomal DNA. The SSCP profiles of individual DSL from bighorn sheep were compared with those of DSL of five protostrongylid species (Parelaphostrongylus andersoni, P odocoilei, P. tenuis, Elaphostrongylus rangiferi, and Muellerius capillaris) but were identical to only those of P. odocoilei. This study represents the first confirmed identification of P. odocoilei in bighorn sheep.     

Plasma catecholamines and their physiologic thresholds during the first ten days of life in sheep

We studied serial plasma catecholamine levels in healthy newborn sheep over the first ten days of life. The results show that plasma norepinephrine values in newborn sheep are 3-4 fold higher, and plasma epinephrine values are two-fold higher than values in term fetal sheep. These elevations are sustained over the first 10 days of life. Cardiovascular (heart rate and blood pressure) and metabolic parameters (glucose and free fatty acids) are also significantly elevated above fetal levels. We performed graded catecholamine infusions in newborn animals and adult ewes to determine the minimum plasma catecholamine concentrations necessary for discernible physiologic effects. In response to step-wise increases in epinephrine or norepinephrine infusion rates, there were immediate increases in blood pressure and other physiologic responses. This pattern was seen in both newborn and adult animals, and differed from previous observations in fetal sheep where log-linear, dose response curves characteristic of a threshold response were seen. These results suggest that during the first two weeks of life plasma catecholamine levels are elevated above the threshold value for physiologic responses. These sustained elevations in circulating catecholamines are important in the maintenance of physiologic homeostasis.     

No response of plasma substance P, but delayed increase of interleukin-1 receptor antagonist to acute psychosocial stress

Psychosocial stress has been shown to induce inflammatory reactions, followed by the release of immunosuppressive glucocorticoids. This may be mediated by catecholamines or other stress reactive substances such as neuropeptides or cytokines. We here set out to explore the effects of acute psychosocial stress on plasma levels of substance P (SP), a possible mediator of stress-induced inflammatory reactions, and interleukin-1 receptor antagonist (IL-1ra). Twelve healthy male subjects (mean age 27 yrs.) were subjected to the psychosocial stress test "Trier Social Stress Test" (TSST) and a resting control condition. Blood and saliva samples were taken before, as well as 1, 20, 45, and 90 min after TSST or rest, respectively. Salivary cortisol and plasma SP and IL-1ra were measured using immunoassays, salivary alpha-amylase (sAA) was measured by an enzyme kinetic method, and plasma epinephrine (E) and norepinephrine (NE) were measured by HPLC. The TSST induced immediate increases of E, NE, and sAA, and a delayed increase of free cortisol. Plasma IL-1ra showed an even further delayed peak at 90 min after stress. Plasma levels of SP did not respond to stress. No significant associations between changes of stress hormones and IL-1ra or SP were found. We conclude that substance P, epinephrine, and norepinephrine are probably not involved in mediating peripheral inflammation following psychosocial stress, at least with respect to IL-1ra. Further studies have to reveal the mechanisms involved in the stress-induced up regulation of IL-1ra.     

Effect of phenothiazine derivative on adrenal cortex response of sheep to repeated emotional stress]

The study was aimed at the evaluation of propiopromazine (Combelen, Bayer), a derivative of phenothiazine, as an agent lowering in sheep the response to stress. The stress of emotional origin was induced in sheep by the isolation from herd lasting 1 hour. The isolation experiments were repeated 6 times on the same group of sheep, first three isolations (1-3) in daily intervals and next three (4-6) in weekly intervals. Propiopromazine was administered before each isolation experiment. The reaction of sheep to the isolation stress was weaker after propiopromazine administration. This was suggested by smaller increase in blood serum cortisol and glucose levels when compared to sheep subjected to isolation but not receiving the drug. Such effect was especially conspicuous during the course of the first isolation experiment; during the next experiments the difference concerning the reaction to stress between the sheep isolated from the herd receiving and not receiving the drug was gradually diminishing. It was shown in addition that propiopromazine administration to the sheep not subjected to stress caused an increase in cortisol level by 125 per cent and that in glucose level by 35 per cent. These results suggest that propiopromazine administration protects the organism against the effects of emotional stress only partially. Moreover, the effect of its administration gradually weakens with repeating of the stress inducing experiment, and propiopromazine itself may act as a stress inducing factor. It seems therefore that the use of propiopromazine and similar compounds as anti-stress agents may be questionable.     

Influence of rainfall on lungworm infections in bighorn sheep.

From 1959 through 1968, lungs from 124 Rocky Mountain bighorn sheep (Ovis c. canadensis) from the Sun River herd in western Montana were examined for lungworm infections. All lungs were infected with Protostrongylus stilesi and 104 (84%) contained concurrent infections of P. stilesi and P. rushi. Significant correlations were observed between levels of lungworm infection and total rainfall during April, May, and June of each year. An explanation of this in terms of terrestrial snail (intermediate host) populations and a suggestion for the possible use of these data in developing a predictive model for forecasting lungworm levels for use in in bighorn sheep management are given.     

Blood gas and catecholamine levels in capture stressed desert bighorn sheep.

Forty-seven bighorn sheep (Ovis canadensis nelsoni) were captured within a 3-day period in December, 1989 as part of a California Department of Fish and Game effort to repopulate historic ranges in California. They were captured on the Mojave Desert in the Kelso Mountains near Old Dad Peak, San Bernardino County, California. Venous blood gases measured at the site of capture demonstrated a severe metabolic acidosis (base deficit, 23 mEq/liter), with no evidence of respiratory acidosis. There were moderately elevated plasma epinephrine (1.25 ng/ml), norepinephrine (2.60 ng/ml), and dopamine (114 pg/ml) levels. These data appear to reflect animals that have been moderately stressed. These acid-base-catecholamine values differ from values in resting domestic sheep, and are similar to those reported in greyhounds after brief strenuous exercise.     

Endogenous monoamine oxidase inhibitory activity and HPA activation in the pig

Previously we have shown that an increase in endogenous monoamine oxidase A inhibitory activity (MAO-AI), measured in human saliva, both precedes and predicts psychological stress-induced activation of the hypothalamic pituitary adrenal (HPA) axis, as determined by the cortisol response. We now report the relationship between endogenous MAO-AI and the cortisol response in the plasma of prepubertal pigs (n=5 or 6) under two experimental paradigms of HPA activation. In the first condition, pigs were physically restrained (snaring) for 15 minutes. Blood samples were taken from indwelling catheters at intervals before and after snaring (a sampling period of about 1 hour), and at the same time intervals on a separate day to provide baseline measures. Both cortisol concentration and percentage MAO-AI were determined in each plasma sample. There was a pronounced cortisol response on the snaring day (cortisol peaked 30 minutes after the start of the snaring). There was also a significant MAO-AI response to snaring which peaked 15 minutes after the start of the stress challenge. In the second experimental paradigm, bacterial endotoxin (LPS: 20microg/pig) was used to induce HPA activation and plasma cortisol and MAO-AI were determined. This time, however, the cortisol response was not preceded by any change in MAO-AI. We conclude that generation of MAO-AI, which is associated with HPA activation induced by psychological stress, is not a component of the pathways involved in immunological stimulation of the HPA axis.     

Effects of neonatal handling on sympathoadrenal activity and body composition in adult male rats

Neonatal handling permanently alters the hypothalamic-pituitary-adrenal (HPA) response to stress. Because the sympathetic nervous system (SNS) and adrenal medulla also participate in stress responses, the impact of daily handling between birth and weaning on SNS and adrenal medullary function was examined in adult rats using techniques of [(3)H]norepinephrine ([(3)H]NE) turnover and urinary catecholamine excretion. Handled animals exhibited a 23% reduction in [(3)H]NE turnover in heart and a 53% decrease in spleen. [(3)H]NE turnover in brown adipose tissue, stomach, and kidney did not differ between handled and nonhandled animals. In contrast, urinary epinephrine (Epi) excretion was significantly greater in handled rats in response to a 3-day fast than in nonhandled animals. Although body weight, weight gain in response to dietary enrichment with sucrose or lard, or body fat content did not differ in handled and nonhandled animals, handled rats displayed heavier abdominal fat depots than nonhandled animals, implying a difference in body fat distribution. Neonatal handling thus leads to decreased sympathetic activity within specific subdivisions of the SNS and, by contrast, to increased adrenal medullary responsiveness.     

Baseline and stress-induced glucocorticoids during reproduction in the variable flying fox, Pteropus hypomelanus (Chiroptera: Pteropodidae)

Baseline and stress-responsive glucocorticoid (GC) levels were assessed during early pregnancy, late pregnancy, and lactation in female variable flying foxes (Pteropus hypomelanus) and in males over the same time period. Animals were maintained in a breeding colony in captivity. High levels of both cortisol and corticosterone were detected, with total plasma GC levels being among the highest documented in vertebrates (up to 3000 ng/ml in individual animals, with cortisol being the primary GC, accounting for approximately 78% of total GCs), and significantly greater in males than in females. Plasma levels of cortisol and corticosterone showed nearly identical profiles within each sex, with the exception of females in late pregnancy, in which corticosterone, but not cortisol, increased significantly. Baseline levels of plasma cortisol were highest in September (when pups were between 1 and 2 months of age) in both sexes, which may be related to the approaching onset of the mating period. There was a continuum in the magnitude of the response to stress (handling and sampling) over time in females, with the greatest stress response in early pregnancy, a dampened response during late pregnancy, and no significant stress response during lactation. Surprisingly, males failed to exhibit elevated GCs after this stress, but did have significant stress-induced hyperglycemia and suppression of plasma testosterone levels. This may be due to their high (perhaps maximal) baseline levels, which suggests that being in a breeding group was chronically stressful for males.     

Bombesin-induced HPA and sympathetic activation requires CRH receptors

Central administration of bombesin (BN) (into the ventricular system) increased circulating levels of ACTH, corticosterone, epinephrine, norepinephrine and glucose, indicating that this peptide activates the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system. We then assessed the potential contribution of corticotropin-releasing hormone (CRH) system, in the mediation of these BN effects. Blockade of CRH receptors with alphah-CRF (10 microg) attenuated or blocked the BN-induced rise in plasma ACTH, epinephrine, norepinephrine, glucose and corticosterone levels. These findings support the notion that BN-induced HPA axis and sympathetic activation are mediated, at least in part, via activation of CRH neurons.     

Behavioral and physiological responses of forest musk deer (<Emphasis Type="Italic">Moschus berezovskii</Emphasis>) to experimental fawn manipulation

High stress response is an important factor impeding the breeding of wild animals in captivity. Experimental fawn manipulation is considered a suitable approach to reduce the negative effects of behavioral and physiological stress. The forest musk deer (Moschus berezovskii) is classified as “endangered” by the IUCN Red List due to over-exploitation for musk production. Musk is highly valued for its cosmetic and alleged pharmaceutical properties and has stimulated the enthusiasm of captive musk deer breeding in recent years. This study attempts to reduce behavioral and physiological stress responses in juvenile musk deer using experimental fawn manipulation. Habituation started 5 days after birth and lasted until weaning age (90 days). We determined the behavioral stress response at the age of 30, 60, 90, 150, and 360 days by measuring acceptance or rejection of three treatment intensities (i.e., stroking, embracement) and quantified behavioral responses (urination, approaching the investigator). At the same time, physiological stress parameters were established, measuring the fecal glucocorticosteroid metabolite (FGM) concentration. Our results indicate that fawn manipulation initially reduced the behavioral stress, but after termination of treatments, stress symptoms reoccurred. We detected no difference in the FGM concentrations between treatment and control groups, suggesting that the experimental fawn manipulation did not decrease the physiological stress response. This implies that behavioral stress reduction cannot be sustained if the physiological stress remains unaltered. We argue that the socio-positive reactions of musk deer fawns to humans could be phenotypic and that the physiological stress response rather reflects their intrinsic characteristics than a successful manipulation.