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Bosch, O. J., Nair, H. P., Ahern, T. H., Neumann, I. D., & Young, L. J. (2008). The CRF System Mediates Increased Passive Stress-Coping Behavior Following the Loss of a Bonded Partner in a Monogamous Rodent. Neuropsychopharmacology, 34(6), 1406–1415.
Abstract: Social relationships significantly influence physiology and behavior, including the hypothalamo–pituitary–adrenal axis, anxiety, and mental
health. Disruption of social bonds through separation or death often results in profound grieving, depression, and physical illness. As the
monogamous prairie vole forms enduring, selective pair bonds with the mating partner, they provide an animal model to study the
physiological consequences of pair bonding and, thus, the loss of the bonded partner. Male prairie voles were paired with a novel female
or male sibling. After 5 days, half of the males of each group were separated from the partner. Elevated plus-maze, forced swim, and tail
suspension tests were used to assess anxiety-like and passive stress-coping behaviors indicative of depressive-like behavior. Following 4
days of separation from the female but not the male partner, experimental males displayed increased passive stress-coping. This effect
was abolished by long-term intracerebroventricular infusion of a nonselective corticotropin-releasing factor (CRF) receptor antagonist
without disrupting the bond itself. Both CRF type 1 and 2 receptors were involved in the emergence of passive stress-coping behavior.
Furthermore, pairing with a female was associated with elevated CRF mRNA in the bed nucleus of the stria terminalis, and partner loss
elicited a pronounced increase in circulating corticosteroid and adrenal weight. We speculate that the CRF system may mediate an
aversive affect following separation from the female partner, which may facilitate proximity seeking between the pair-bonded individuals.
Hence, the prairie vole model may provide insights into brain mechanisms involved in the psychopathological consequences of partner
loss.
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Houpt, K. A., Eggleston, A., Kunkle, K., & Houpt, T. R. (2000). Effect of water restriction on equine behaviour and physiology. Equine Vet J, 32(4), 341–344.
Abstract: Six pregnant mares were used to determine what level of water restriction causes physiological and/or behavioural changes indicative of stress. Nonlegume hay was fed ad libitum. During the first week of restriction, 5 l water/100 kg bwt was available, during the second week 4 l/100 kg bwt and, during the third week, 3 l/100 kg bwt. Ad libitum water intake was 6.9 l/100 kg bwt; at 3 l/100 kg bwt water intake was 42% of this. Daily hay intake fell significantly with increasing water restriction from 12.9 +/- 0.75 kg to 8.3 +/- 0.54 kg; bodyweight fell significantly for a total loss of 48.5 +/- 8.3 kg in 3 weeks. Daily blood samples were analysed; osmolality rose significantly with increasing water restriction from 282 +/- 0.7 mosmols/kg to 293.3 +/- 0.8 mosmols/kg bwt, but plasma protein and PCV did not change significantly. Cortisol concentrations fell from 8.1 ng/ml to 6.4 ng/ml over the 3 week period. Aldosterone fell from 211.3 +/- 74.2 pg/ml to 92.5 +/- 27.5 pg/ml at the end of the first week. The behaviour of 4 of the 6 mares was recorded 24 h/day for the duration of the study. The only significant difference was in time spent eating, which decreased with increasing water restriction from 46 +/- 3% to 30 +/- 3%. It is concluded that water restriction to 4 l/100 kg bwt dehydrates pregnant mares and may diminish their welfare, but is not life- or pregnancy-threatening.
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Kedzierski, W., Wilk, I., & Janczarek, I. (2014). Physiological response to the first saddling and first mounting of horses: comparison of two sympathetic training methods. Animal Science Papers and Reports, 32(3), 219–228.
Abstract: There is not much research done on the influence of sympathetic training on the emotional reaction
of horses. The aim of the present study was to evaluate the emotional response and the stress level
in horses to two sympathetic training methods: (1) with the use of the “round pen technique” (RP),
and (2) in which the RP was not applied (SH). Twenty two half-bred Anglo-Arab horses (2.5
years ±3 months of age) were subject to an initial training. Eleven horses were randomly included
to the RP method and the other 11 horses for the SH method. Heart rate (HR) and saliva cortisol
concentration were measured as indicators of horse emotional arousal and stress level, respectively.
The HR values were analysed: at rest, during the habituation period, just after the first saddling
and tightening of the girth, during the first time a human leaned over the horse’s back, and during
the mounting of the horse. Saliva samples were taken before and 15 min after each training session
studied. After saddling, the HR occurred significantly higher when the RP technique was used. The
significant increase in saliva cortisol concentration was observed only after the first mounting of
the horse. Generally, the use of the RP technique did not involve more important physiological
reactions in the trained horses than did the SH method.
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Overli, O., Sorensen, C., Pulman, K. G. T., Pottinger, T. G., Korzan, W., Summers, C. H., et al. (2007). Evolutionary background for stress-coping styles: relationships between physiological, behavioral, and cognitive traits in non-mammalian vertebrates. Neurosci Biobehav Rev, 31(3), 396–412.
Abstract: Reactions to stress vary between individuals, and physiological and behavioral responses tend to be associated in distinct suites of correlated traits, often termed stress-coping styles. In mammals, individuals exhibiting divergent stress-coping styles also appear to exhibit intrinsic differences in cognitive processing. A connection between physiology, behavior, and cognition was also recently demonstrated in strains of rainbow trout (Oncorhynchus mykiss) selected for consistently high or low cortisol responses to stress. The low-responsive (LR) strain display longer retention of a conditioned response, and tend to show proactive behaviors such as enhanced aggression, social dominance, and rapid resumption of feed intake after stress. Differences in brain monoamine neurochemistry have also been reported in these lines. In comparative studies, experiments with the lizard Anolis carolinensis reveal connections between monoaminergic activity in limbic structures, proactive behavior in novel environments, and the establishment of social status via agonistic behavior. Together these observations suggest that within-species diversity of physiological, behavioral and cognitive correlates of stress responsiveness is maintained by natural selection throughout the vertebrate sub-phylum.
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Clayton, H. M., Lanovaz, J. L., Schamhardt, H. C., & van Wessum, R. (1999). The effects of a rider's mass on ground reaction forces and fetlock kinematics at the trot. Equine Vet J Suppl, 30, 218–221.
Abstract: Ground reaction force (GRF) measurements are often normalised to body mass to facilitate inter-individual comparisons. The objective of this study was to explore the effect of a rider on the GRFs and fetlock joint kinematics of trotting horses. The subjects were 5 dressage-trained horses and 3 experienced dressage riders. Ground reaction force measurements and sagittal view videotapes were recorded as the horses trotted at the same velocity in hand (3.49 +/- 0.52 m/s) and with a rider (3.49 +/- 0.46 m/s). Data were time-normalised to stance duration. Ground reaction force measurements were expressed in absolute terms and normalised to the system mass (horse or horse plus rider). All the horses showed changes in the same direction when comparing the ridden condition with the in-hand condition. There was an increase in the absolute peak vertical GRFs of the fore- and hindlimbs with a rider. However, the mass-normalised peak vertical GRFs were lower for the ridden condition, with the peak occurring later in the forelimbs and earlier in the hindlimbs compared with the inhand condition. Maximal fetlock angle and its time of occurrence were similar for the 2 conditions, but the fore fetlock joint was more extended during the later part of the stance phase in ridden horses. The presence of a rider appeared to affect the GRFs and fetlock joint kinematics differently in the fore- and hindlimbs, and the ridden horse did not seem to be equivalent to a proportionately larger horse. This should be considered when normalising for body mass in studies comparing horses in hand and ridden horses.
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Candura, S. M., Verni, P., Minelli, C. M., Rosso, G. L., Cappelli, M. I., Strambi, S., et al. (2006). [Occupational risks among public safety and security forces]. G Ital Med Lav Ergon, 28(1), 53–62.
Abstract: The present paper tries to identify the occupational risk factors (physical, chemical, biological, psychological), variable depending on jobs and tasks, to which the heterogeneous public safety/security workers are exposed. The fight against criminality and public order maintenance imply (sometimes fatal) traumatic risks, and expose to psychophysical and sensorial tiring, unfavourable macro- and microclimatic conditions, the risk of baropathy (air navigation, underwater activities), noise (generated by firearms and several other sources), vibrations and shakings (automatic weapons, transport vehicles), the risk of electric injury, ionizing (X and gamma rays) and non-inonizing (ultraviolet rays, microwaves and radiofrequencies, electromagnetic fields) radiations. Chemical hazards include carbon monoxide and other combustion products (fires, urban traffic), substances released in chemical accidents, tear gases, lead (firing grounds, metal works, environmental pollution), solvents, lubrificants and cutting oils (mechanic repair and maintenance), laboratory materials and reagents, irritant and/or sensitizing agents contained in gloves. The main biological risks are tetanus, blood-borne diseases (viral hepatitis, AIDS), aerogenous diseases (e.g., tuberculosis, Legionnaire's disease, epidemic cerebrospinal meningitis), dog- or horse-transmitted zoonosis. Finally, emotional, psychosomatic and behavioural stress-related disorders (e.g., burn-out syndrome, post-traumatic stress disorder) are typically frequent. The presence of numerous and diversified hazards among public safety/security forces imposes the adoption of occupational medicine measures, including risk assessment, health education, technical and environmental prevention, personal protective devices, sanitary surveillance and biological monitoring, clinical interventions (diagnosis, therapy and rehabilitation of occupational accidents and illnesses), prompt medico-legal evaluation of occupational-related compensation claims.
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Fazio, E., & Ferlazzo, A. (2003). Evaluation of Stress During Transport. Veterinary Research Communications, 27, 519–524.
Abstract: Domestic animals are transported for a variety of reasons including breeding, biomedical purposes, slaughter and, in the case of sporting horses, for competitions, pleasure activities or ceremonial proceedings. Studies to determine the amount of stress on farm animals during transport often have highly variable results and are difficult to interpret. The reaction of animals to stressors depends on the duration and intensity of the stressors, the animal's previous experience, its physiological status and the immediate environmental restraints. Behavioural, haematological, haematochemical, physiological and neuro-hormonal (ß-endorphin, ACTH, cortisol, iodothyronines) variables are discussed on the basis of handling, loading and transport procedures of animals.
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Carroll, G. L., Matthews, N. S., Hartsfield, S. M., Slater, M. R., Champney, T. H., & Erickson, S. W. (1997). The effect of detomidine and its antagonism with tolazoline on stress-related hormones, metabolites, physiologic responses, and behavior in awake ponies. Vet Surg, 26(1), 69–77.
Abstract: Six ponies were used to investigate the effect of tolazoline antagonism of detomidine on physiological responses, behavior, epinephrine, norepinephrine, cortisol, glucose, and free fatty acids in awake ponies. Each pony had a catheter inserted into a jugular vein 1 hour before beginning the study. Awake ponies were administered detomidine (0.04 mg/kg intravenously [i.v.]) followed 20 minutes later by either tolazoline (4.0 mg/kg i.v.) or saline. Blood samples were drawn from the catheter 5 minutes before detomidine administration (baseline), 5 minutes after detomidine administration, 20 minutes before detomidine administration which was immediately before the administration of tolazoline or saline (time [T] = 0), and at 5, 30, and 60 minutes after injections of tolazoline or saline (T = 5, 30, and 60 minutes, respectively). Compared with heart rate at T = 0, tolazoline antagonism increased heart rate 45% at 5 minutes. There was no difference in heart rate between treatments at 30 minutes. Blood pressure remained stable after tolazoline, while it decreased over time after saline. Compared with concentrations at T = 0, tolazoline antagonism of detomidine in awake ponies resulted in a 55% increase in cortisol at 30 minutes and a 52% increase in glucose at 5 minutes. The change in free fatty acids was different for tolazoline and saline over time. Free fatty acids decreased after detomidine administration. Free fatty acids did not change after saline administration. After tolazoline administration, free fatty acids increased transiently. Tolazoline tended to decrease sedation and analgesia at 15 and 60 minutes postantagonism. Antagonism of detomidine-induced physiological and behavioral effects with tolazoline in awake ponies that were not experiencing pain appears to precipitate a stress response as measured by cortisol, glucose, and free fatty acids. If antagonism of an alpha-agonist is contemplated, the potential effect on hormones and metabolites should be considered.
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Reyna-Garfias, H., Miliar, A., Jarillo-Luna, A., Rivera-Aguilar, V., Pacheco-Yepez, J., Baeza, I., et al. (2010). Repeated restraint stress increases IgA concentration in rat small intestine. Brain, Behavior, and Immunity, 24(1), 110–118.
Abstract: The most abundant intestinal immunoglobulin and first line of specific immunological defense against environmental antigens is secretory immunoglobulin A. To better understand the effect of repeated stress on the secretion of intestinal IgA, the effects of restraint stress on IgA concentration and mRNA expression of the gene for the alpha-chain of IgA was assessed in both the duodenum and ileum of the rats. Restraint stress induced an increase in intestinal IgA, which was blocked by an adrenalectomy, suggesting a role of catecholamines and glucocorticoids. Whereas the blocking of glucocorticoid receptors by RU-486 did not affect the increased IgA concentration, it did reduce IgA alpha-chain mRNA expression in both segments, indicating a possible mediation on the part of glucocorticoids in IgA secretion by individual cells. Treatment with corticosterone significantly increased both the IgA concentration and IgA alpha-chain mRNA expression in ileum but not in duodenum, suggesting that glucocorticoids may act directly on IgA-antibody forming cells to increase IgA secretion in the former segment. A probable role by catecholamines was evidenced by the reduction in IgA concentration and IgA alpha-chain mRNA expression in both segments after a chemical sympathectomy with 6-hydroxydopamine (6-OHDA). Additionally, norepinephrine significantly reduced IgA alpha-chain mRNA levels but increased pIgR mRNA expression and IgA concentration in both intestinal segments. We propose that the increased intestinal IgA levels caused by repeated restraint stress is likely due to the effects of catecholamines on the transport of plgA across the epithelium.
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Carlstead, K., & Brown, J. L. (2005). Relationships between patterns of Fecal corticoid excretion and behavior, reproduction, and environmental factors in captive black (Diceros bicornis) and white (Ceratotherium simum) rhinoceros. Zoo Biol., 24(3), 215–232.
Abstract: Mortality is high in zoo-housed black rhinoceros (Diceros bicornis), and the reproductive rates of captive white rhinoceros (Ceratotherium simum) are unsustainably low. To determine the possible role of stress in the causation of these problems, we analyzed weekly fecal samples collected for 1 year from black (10 males and 16 females) and white (six males and 13 females) rhinoceroses at 16 zoos for corticoid metabolite concentrations. Fecal corticoid profiles were examined in relation to behavior as rated by keepers in a questionnaire, luteal phase ovarian cycles of females (Brown et al., 2001), and socioenvironmental factors. We compared individual fecal corticoid profiles by examining hormone means and variability (i.e., standard deviation (SD) and coefficient of variation (CV)). For the black rhinos, higher mean corticoid concentrations were found at zoos where rhinos were maintained in enclosures that were exposed to the public around a greater portion of the perimeter. Higher variability in corticoid excretion was correlated with higher rates of fighting between breeding partners and higher institutional mortality rates. Black rhino pairs that were kept separated exhibited lower corticoid variability and less fighting activity when they were introduced during female estrous periods compared to pairs that were kept together every day. For white rhinos, significantly lower mean corticoids were found for individuals that rated higher on “friendliness to keeper.” Higher corticoid variability was found in noncycling as compared to cycling white rhino females. Noncycling females exhibited higher rates of stereotypic pacing and lower frequencies of olfactory behaviors. Interindividual differences in mean corticoids in both species appeared to be related to responsiveness to humans, whereas corticoid variability was related to intraspecific social relationships. More importantly, high corticoid variability appeared to be an indicator of chronic or “bad” stress, because of its association with potentially deleterious consequences in each species (i.e., fighting and mortality (black rhino), and reproductive acyclicity (white rhino)). Our results provide evidence that social stressors may cause chronic stress in black and white rhinos, and that this contributes to the captive-population sustainability problems observed in each species. Zoo Biol 0:1–18, 2005. © 2005 Wiley-Liss, Inc.
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