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Author (up) Ostner, J.; Heistermann, M.; Schülke, O. url  doi
openurl 
  Title Dominance, aggression and physiological stress in wild male Assamese macaques (Macaca assamensis) Type Journal Article
  Year 2008 Publication Hormones and Behavior Abbreviated Journal  
  Volume 54 Issue 5 Pages 613-619  
  Keywords Social stress; Dominance; Aggression; Fecal glucocorticoid excretion; Male bonds; Assamese macaques  
  Abstract In group-living animals relative rank positions are often associated with differences in glucocorticoid output. During phases of social stability, when dominance positions are clear and unchallenged, subordinates often face higher costs in terms of social stress than dominant individuals. In this study we test this prediction and examine additional potential correlates of stress, such as reproductive season, age and amount of aggression received in wild, seasonally breeding Assamese macaques (Macaca assamensis). During a mating and a non-mating season we collected 394 h of focal observational data and 440 fecal samples of six adult and six large subadult males living in a multimale-multifemale group in their natural habitat in northeastern Thailand. The mating season was characterized by a general increase in aggressive behavior and glucocorticoid excretion across all males compared to the non-mating season. Among adult males, mating season glucocorticoid levels were significantly negatively related with dominance rank and positively with the amount of aggression received. Both relationships were non-significant among large subadult males. Thus, our results suggest that in adult Assamese macaques a high dominance position is not associated with high costs. Low costs of dominance might be induced by strong social bonds among top-ranking males, which exchange frequent affiliative interactions and serve as allies in coalitionary aggression against potentially rank-challenging subordinate males.  
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  ISSN 0018-506x ISBN Medium  
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  Call Number Equine Behaviour @ team @ Serial 4694  
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Author (up) Overli, O.; Korzan, W.J.; Hoglund, E.; Winberg, S.; Bollig, H.; Watt, M.; Forster, G.L.; Barton, B.A.; OVerli, E.; Renner, K.J.; Summers, C.H. doi  openurl
  Title Stress coping style predicts aggression and social dominance in rainbow trout Type Journal Article
  Year 2004 Publication Hormones and Behavior Abbreviated Journal Horm Behav  
  Volume 45 Issue 4 Pages 235-241  
  Keywords Adaptation, Psychological/physiology; Aggression/*physiology; Animals; *Dominance-Subordination; Female; *Hierarchy, Social; Hydrocortisone/blood; Individuality; Male; Matched-Pair Analysis; Oncorhynchus mykiss/*physiology; Stress/*physiopathology  
  Abstract Social stress is frequently used as a model for studying the neuroendocrine mechanisms underlying stress-induced behavioral inhibition, depression, and fear conditioning. It has previously been shown that social subordination may result in increased glucocorticoid release and changes in brain signaling systems. However, it is still an open question which neuroendocrine and behavioral differences are causes, and which are consequences of social status. Using juvenile rainbow trout of similar size and with no apparent differences in social history, we demonstrate that the ability to win fights for social dominance can be predicted from the duration of a behavioral response to stress, in this case appetite inhibition after transfer to a new environment. Moreover, stress responsiveness in terms of confinement-induced changes in plasma cortisol was negatively correlated to aggressive behavior. Fish that exhibited lower cortisol responses to a standardized confinement test were markedly more aggressive when being placed in a dominant social position later in the study. These findings support the view that distinct behavioral-physiological stress coping styles are present in teleost fish, and these coping characteristics influence both social rank and levels of aggression.  
  Address Biology Department and Neuroscience Group, University of South Dakota, Vermillion, SD 57069, USA. oyvind.overli@bio.uio.no  
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  Notes PMID:15053939 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4192  
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Author (up) Reimers, M.; Schwarzenberger, F.; Preuschoft, S. doi  openurl
  Title Rehabilitation of research chimpanzees: stress and coping after long-term isolation Type Journal Article
  Year 2007 Publication Hormones and Behavior Abbreviated Journal Horm Behav  
  Volume 51 Issue 3 Pages 428-435  
  Keywords Adaptation, Psychological/*physiology; Animals; *Animals, Laboratory; Exploratory Behavior; Hydrocortisone/analysis/metabolism; Male; Models, Biological; *Pan troglodytes; Social Dominance; Social Environment; *Social Isolation/psychology; Stress/*rehabilitation/veterinary; Time  
  Abstract We report on the permanent retirement of chimpanzees from biomedical research and on resocialization after long-term social isolation. Our aim was to investigate to what extent behavioral and endocrine measures of stress in deprived laboratory chimpanzees can be improved by a more species-typical social life style. Personality in terms of novelty responses, social dominance after resocialization and hormonal stress susceptibility were affected by the onset of maternal separation of infant chimpanzees and duration of deprivation. Chimpanzees, who were separated from their mothers at a younger age and kept in isolation for more years appeared to be more timid personalities, less socially active, less dominant and more susceptible to stress, as compared to chimpanzees with a less severe deprivation history. However, permanent retirement from biomedical research in combination with therapeutic resocialization maximizing chimpanzees' situation control resulted in reduced fecal cortisol metabolite levels. Our results indicate that chimpanzees can recover from severe social deprivation, and may experience resocialization as less stressful than solitary housing.  
  Address Department of Natural Sciences, Institute of Biochemistry, University of Veterinary Medicine, Veterinarplatz 1, 1210 Vienna, Austria. reimers@wild-vet.at  
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  Notes PMID:17292368 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4188  
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Author (up) Romero, L.M.; Dickens, M.J.; Cyr, N.E. url  doi
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  Title The reactive scope model — A new model integrating homeostasis, allostasis, and stress Type Journal Article
  Year 2009 Publication Hormones and Behavior Abbreviated Journal Horm. Behav.  
  Volume 55 Issue 3 Pages 375-389  
  Keywords Stress; Allostasis; Glucocorticoids; Fight-or-flight; Homeostasis  
  Abstract Allostasis, the concept of maintaining stability through change, has been proposed as a term and a model to replace the ambiguous term of stress, the concept of adequately or inadequately coping with threatening or unpredictable environmental stimuli. However, both the term allostasis and its underlying model have generated criticism. Here we propose the Reactive Scope Model, an alternate graphical model that builds on the strengths of allostasis and traditional concepts of stress yet addresses many of the criticisms. The basic model proposes divergent effects in four ranges for the concentrations or levels of various physiological mediators involved in responding to stress. (1) Predictive Homeostasis is the range encompassing circadian and seasonal variation — the concentrations/levels needed to respond to predictable environmental changes. (2) Reactive Homeostasis is the range of the mediator needed to respond to unpredictable or threatening environmental changes. Together, Predictive and Reactive Homeostasis comprise the normal reactive scope of the mediator for that individual. Concentrations/levels above the Reactive Homeostasis range is (3) Homeostatic Overload, and concentrations/levels below the Predictive Homeostasis range is (4) Homeostatic Failure. These two ranges represent concentrations/levels with pathological effects and are not compatible with long-term (Homeostatic Overload) or short-term (Homeostatic Failure) health. Wear and tear is the concept that there is a cost to maintaining physiological systems in the Reactive Homeostasis range, so that over time these systems gradually lose their ability to counteract threatening and unpredictable stimuli. Wear and tear can be modeled by a decrease in the threshold between Reactive Homeostasis and Homeostatic Overload, i.e. a decrease in reactive scope. This basic model can then be modified by altering the threshold between Reactive Homeostasis and Homeostatic Overload to help understand how an individual's response to environmental stressors can differ depending upon factors such as prior stressors, dominance status, and early life experience. We illustrate the benefits of the Reactive Scope Model and contrast it with the traditional model and with allostasis in the context of chronic malnutrition, changes in social status, and changes in stress responses due to early life experiences. The Reactive Scope Model, as an extension of allostasis, should be useful to both biomedical researchers studying laboratory animals and humans, as well as ecologists studying stress in free-living animals.  
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  Call Number Equine Behaviour @ team @ Serial 5583  
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Author (up) Schmidt, A.; Aurich, J.; Möstl, E.; Müller, J.; Aurich, C. url  doi
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  Title Changes in cortisol release and heart rate and heart rate variability during the initial training of 3-year-old sport horses Type Journal Article
  Year 2010 Publication Hormones and Behavior Abbreviated Journal Horm Behav  
  Volume 58 Issue 4 Pages 628-636  
  Keywords Horse; Initial training; Cortisol; Heart rate variability  
  Abstract Based on cortisol release, a variety of situations to which domestic horses are exposed have been classified as stressors but studies on the stress during equestrian training are limited. In the present study, Warmblood stallions (n = 9) and mares (n = 7) were followed through a 9 respective 12-week initial training program in order to determine potentially stressful training steps. Salivary cortisol concentrations, beat-to-beat (RR) interval and heart rate variability (HRV) were determined. The HRV variables standard deviation of the RR interval (SDRR), RMSSD (root mean square of successive RR differences) and the geometric means standard deviation 1 (SD1) and 2 (SD2) were calculated. Nearly each training unit was associated with an increase in salivary cortisol concentrations (p < 0.01). Cortisol release varied between training units and occasionally was more pronounced in mares than in stallions (p < 0.05). The RR interval decreased slightly in response to lunging before mounting of the rider. A pronounced decrease occurred when the rider was mounting, but before the horse showed physical activity (p < 0.001). The HRV variables SDRR, RMSSD and SD1 decreased in response to training and lowest values were reached during mounting of a rider (p < 0.001). Thereafter RR interval and HRV variables increased again. In contrast, SD2 increased with the beginning of lunging (p < 0.05) and no changes in response to mounting were detectable. In conclusion, initial training is a stressor for horses. The most pronounced reaction occurred in response to mounting by a rider, a situation resembling a potentially lethal threat under natural conditions.  
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  Call Number Equine Behaviour @ team @ Serial 5223  
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Author (up) Schmidt, A.; Möstl, E.; Wehnert, C.; Aurich, J.; Müller, J.; Aurich, C. url  doi
openurl 
  Title Cortisol release and heart rate variability in horses during road transport Type Journal Article
  Year 2010 Publication Hormones and Behavior Abbreviated Journal Horm. Behav.  
  Volume 57 Issue 2 Pages 209-215  
  Keywords Horse; Transport; Cortisol; Heart rate variability  
  Abstract Based on plasma cortisol concentrations it is widely accepted that transport is stressful to horses. So far, cortisol release during transport has not been evaluated in depth by non-invasive techniques such as analysis of salivary cortisol and faecal cortisol metabolites. Transport also causes changes in heart rate and heart rate variability (HRV). In this study, salivary cortisol, faecal cortisol metabolites, heart rate and HRV in horses transported by road for short (one and 3.5 h) and medium duration (8 h) were determined. With the onset of transport, salivary cortisol increased immediately but highest concentrations were measured towards the end of transport (4.1 ± 1.6, 4.5 ± 2.6, 6.5 ± 1.8 ng/ml in horses transported for one, 3.5 and 8 h, respectively). Faecal cortisol metabolite concentrations did not change during transport, but 1 day after transport for 3.5 and 8 h had increased significantly (p < 0.01), reflecting intestinal passage time. Compared to salivary cortisol, changes in faecal cortisol metabolites were less pronounced. Heart rate increased and beat-to-beat (RR) interval decreased (p < 0.05) with the onset of transport. Standard deviation of heart rate increased while root mean square of successive RR differences (RMSSD) decreased in horses transported for 3.5 (from 74 ± 5 to 45 ± 6 ms) and 8 h (from 89.7 ± 7 to 59 ± 7 ms), indicating a reduction in vagal tone. In conclusion, transport of horses over short and medium distances leads to increased cortisol release and changes in heart rate and HRV indicative of stress. The degree of these changes is related to the duration of transport. Salivary cortisol is a sensitive parameter to detect transient changes in cortisol release.  
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  Call Number Equine Behaviour @ team @ Serial 5387  
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Author (up) Sharon, L.; Crowell-Davis, S.L. doi  openurl
  Title Sexual behavior of mares Type Journal Article
  Year 2007 Publication Hormones and Behavior Abbreviated Journal Horm Behav  
  Volume 52 Issue 1 Pages 12-17  
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  Abstract The mare is seasonally polyestrus, having an anovulatory period during the short light days of late fall and early winter, and beginning to ovulate as the days become longer during the winter. The complete estrus cycle is typically about 3 weeks, with 5 to 7 days of estrus and approximately 2 weeks of diestrus. When a mare lives within the natural social structure of the horse, i.e. a family band with several adult mares and one or more stallions, estrus is characterized by repeatedly approaching the stallion, frequent urination, deviating the tail away from the perineum, and standing still with the hind limbs spread apart. Diestrus is characterized by avoidance of an approaching stallion, and aggression toward the stallion, such as squealing, striking, and kicking, if he persists in attempting to court the diestrus mare. However, mares and stallions with long-term social relationships will often rest together, graze together and groom each other, all without sexual interactions. Hormonally, estrous behavior in the mare is initiated by estradiol that is secreted by the follicle, while estrous behavior is suppressed by progesterone, secreted by the corpus luteum. Mares are unusual among the ungulates in that they periodically exhibit estrous behavior during the anovulatory period. This is probably due to the release of estrogenic steroids secreted by the adrenal cortex. The display of sexual behavior by the mare throughout the year is thought to facilitate maintenance of the horse's social structure, in which the male remains with a group of females year round, in contrast with most ungulates in which the females and males only come together during the mating season.  
  Address Department of Anatomy and Radiology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA  
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  Notes PMID:17488645 Approved no  
  Call Number refbase @ user @ Serial 1969  
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Author (up) Touma, C.; Palme, R.; Sachser, N. openurl 
  Title Analyzing corticosterone metabolites in fecal samples of mice: a noninvasive technique to monitor stress hormones Type Journal Article
  Year 2004 Publication Hormones and Behavior Abbreviated Journal Horm Behav  
  Volume 45 Issue 1 Pages 10-22  
  Keywords Adrenal Cortex/drug effects; Adrenal Cortex Function Tests; Adrenocorticotropic Hormone/pharmacology; Analysis of Variance; Animals; Circadian Rhythm; Corticosterone/*analysis/metabolism; Dexamethasone/pharmacology; Feces/*chemistry; Female; Immunoenzyme Techniques/*methods; Male; Mice; Mice, Inbred C57BL; Models, Animal; Reproducibility of Results; Stress, Psychological/*metabolism  
  Abstract In small animals like mice, the monitoring of endocrine functions over time is constrained seriously by the adverse effects of blood sampling. Therefore, noninvasive techniques to monitor, for example, stress hormones in these animals are highly demanded in laboratory as well as in field research. The aim of our study was to evaluate the biological relevance of a recently developed technique to monitor stress hormone metabolites in fecal samples of laboratory mice. In total, six experiments were performed using six male and six female mice each. Two adrenocorticotropic hormone (ACTH) challenge tests, two dexamethasone (Dex) suppression tests and two control experiments [investigating effects of the injection procedure itself and the diurnal variation (DV) of glucocorticoids (GCs), respectively] were conducted. The experiments clearly demonstrated that pharmacological stimulation and suppression of adrenocortical activity was reflected accurately by means of corticosterone metabolite (CM) measurements in the feces of males and females. Furthermore, the technique proved sensitive enough to detect dosage-dependent effects of the ACTH/Dex treatment and facilitated to reveal profound effects of the injection procedure itself. Even the naturally occurring DV of GCs could be monitored reliably. Thus, our results confirm that measurement of fecal CM with the recently established 5alpha-pregnane-3beta,11beta,21-triol-20-one enzyme immunoassay is a very powerful tool to monitor adrenocortical activity in laboratory mice. Since mice represent the vast majority of all rodents used for research worldwide and the number of transgenic and knockout mice utilized as animal models is still increasing, this noninvasive technique can open new perspectives in biomedical and behavioral science.  
  Address Department of Behavioural Biology, University of Muenster, D-48149 Muenster, Germany. touma@uni-muenster.de  
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  Notes PMID:14733887 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4084  
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