Stress in horses refers to the physiological and behavioral responses of equines to various stressors, including environmental changes, social dynamics, and physical exertion. These responses can manifest through alterations in heart rate, cortisol levels, and behavior, among other indicators. Stress can affect a horse's overall health, performance, and welfare, making it a significant area of study in equine research. This topic encompasses research on identifying stressors, measuring stress responses, and understanding the implications of stress on equine health and behavior. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, effects, and management of stress in horses.
Ebisuda Y, Kitaoka Y, Takahashi Y, Sugiyama F, Yoshida T, Mukai K.Heat acclimation enhances thermoregulation and cardiovascular function. While daily training protocols are typically recommended for humans, optimal training protocols for Thoroughbred horses remain unclear. Here, we compared the effects of two heat acclimation protocols, consecutive and intermittent, in Thoroughbred horses. In a randomized crossover study, eight trained Thoroughbred horses completed either a consecutive (CONS: 9 consecutive days) or an intermittent (INT: 3 days/week for 3 weeks) heat acclimation protocol, comprising 30 min of exercise in hot conditions (WBGT 30°C). Increment...
Yu S, Yue X, Yang Q, Xu P, Yuan H, Tang W, Luan Y, Wang Q.Intestinal microbial homeostasis and metabolic balance play a crucial role in maintaining normal physiological function in horses. Exogenous stress involving abrupt turns and jumps during show jumping significantly impacts intestinal microbial homeostasis and metabolic balance in these animals. Results: By comparing rectal (faecal) samples from 10 Warmblood horses collected before and immediately after a show jumping competition on the same day, we observed substantial alterations in intestinal microbial homeostasis and metabolic balance post-exercise. Microbial evenness significantly increase...
Bethel M.EPM remains particularly rampant in racing populations due to transport stress, young age, and congregate housing conditions. For compounding pharmacists, understanding that we're managing chronic parasite suppression - not achieving cure - fundamentally changes our approach to formulation strategy, stability assessment, and client counseling. The two formulations presented separately represent years of refinement, demonstrating compounding's essential role when commercial products fall short.
Telhede EH, Bräutigam Ewe M, Jormfeldt H.Mental health, encompassing self-esteem, confidence, physical activity, and social interaction, is essential for the well-being of children and adolescents and supports executive functions crucial for school performance. Mental ill health among young people is increasing in Sweden, with rising rates of self-reported problems, psychiatric diagnoses, and prescriptions of psychotropic medication. The aim of this study was to explore the experiences of equine-assisted interventions (EAI) among children and adolescents with anxiety-related mental ill health in southern Sweden. A qualitative design ...
Çortu A, Çınar H.Rectal examination is routine in equine reproduction but may trigger acute stress affecting welfare and safety. Intraocular pressure (IOP) responds rapidly to autonomic changes and may capture short-lived stress responses. Objective: To evaluate whether rectal examination acutely affects IOP and behavioral responses in mares, and whether reactions differ by reproductive status. Methods: Twenty Rahvan mares (10 pregnant, 30-40 days' gestation; 10 non-pregnant; 4-7 years) underwent transrectal examination without sedation. IOP was measured bilaterally at six time points: 2 min pre-exam (T1), dur...
Dundjerovic I, Sneddon LU.Animal welfare concerns both the physical and mental wellbeing of animals so the assessment of animals kept in captivity, for example zoos, is important and necessary both legally and ethically. Good welfare is especially vital when breeding endangered species as stress impairs reproductive investment. As zoos often have high numbers of visitors, it is important to know if humans and the associated noise might influence the animals' welfare. The aim of this study was to investigate whether the presence of visitors and activities offered to the visitors caused a stress response in horses housed...
Valera M, Encina A, Sánchez-Guerrero MJ, Rodríguez-Sainz de Los Terreros A, Bartolomé E.Behavioral and emotional reactivity assessment in sport horses is essential for optimizing their management and sports performance, particularly in equestrian disciplines such as Dressage. This study investigates, in Pura Raza Española (PRE) horses, the association between facial hair whorl (FHW) patterns, behavioral traits, and physiological stress responses using ocular temperature (OT) assessed with infrared thermography as, an objective, non-invasive physiological stress indicator. Unassigned: A total of 98 male PRE horses, aged 4-6 years old and all gray coated, were evaluated during the...
McDonald C, Cullen S, O'Connor S, Warrington G, Pugh J, McGoldrick A, Nolan C, Losty C.The thoroughbred horse breeding industry contributes significantly to the Irish economy. However, staff shortages threaten the economic sustainability of the industry, as well as the welfare of both horses and workers. Previous research on the staffing crisis faced by the broader horseracing industry has highlighted mental health concerns as a factor. Furthermore, the influence of workplace context on mental health has been widely recognised in organisational psychology. The aim of this study was to assess prevalence rates of Common Mental Disorders (CMDs) in Irish thoroughbred horse breeding ...
Fialová S, Kuřitková D, Sobotková E.This pilot study investigated stress-related behaviors in 238 dressage horse-rider combinations competing at national levels from Elementary (A) to Grand Prix (GP). Noseband tightness was assessed on-site using the FEI noseband measuring device (FNMD), and all but two horses complied with FEI regulations. Video-based analysis quantified conflict behaviors including mouth opening, tail swishing, and changes in head-neck position. Because noseband tightness showed minimal variation, no meaningful association with behavioral expression could be determined. In contrast, competition level had a cle...
Jung Y, Yoon M.Oxytocin (OXT) plays a crucial role in regulating the serotonin (5-HT) system and behavior. Although previous studies have reported significant relationships among OXT, 5-HT, and behavioral responses, the effects of OXT on 5-HT concentrations and behavioral traits in horses remain poorly understood. This study aimed to investigate the effects of intravenous OXT administration on plasma 5-HT concentrations and trainability in horses. A crossover design was employed using eight horses, each receiving either a 10-IU intravenous dose of OXT or normal saline. Blood samples were collected at baselin...
Gerow SL, Clegg SR, Cooke AS.In the UK, fireworks are common during several celebratory events throughout the year. Previous evidence has shown the adverse effects of fireworks on domestic companion animals. However, there has been little focus on equids. An online survey was developed to understand the impact of fireworks on horses and donkeys, how owners attempt to mitigate these impacts, and the owners' views on fireworks. A total of 1,234 horse owners and 232 donkey owners responded. The majority (77%) advocated tighter regulations surrounding the use of fireworks, including reduction in the maximum noise produced, an...
Copelin C, Merkies K.Equestrian sport's social license to operate has come under scrutiny due to concerns surrounding the well-being of ridden horses. Inappropriate equipment use, such as harsh bits or overtight nosebands, can negatively influence well-being by generating inescapable pressure or pain on the sensitive structures of the horse's head and limiting natural behaviours. Restrictive equipment may also be used to generate exaggerated, stressful and uncomfortable head and neck positions such as hyperflexion. Saddles must be properly fitted to both horse and rider to ensure appropriate distribution of kinema...
Boger B, Naraian M, Hernandez E, Eaton A, Rockburn R, Tillman I, Payne S, Yob C, Panek C, Manfredi JM.Resistance bands used while horses are exercised with their handlers have shown benefits, but it is unknown if whole-body resistance bands used independently have therapeutic benefits. This study hypothesized that horses with varying gait asymmetries would experience improvements in lameness, muscular function, range of motion, posture, and cortisol following short-term use of a whole-body resistance band wrap (RBW). In this study, nine lame adult horses were evaluated with and without the RBW. The assessment included: objective gait analysis, acoustic myography, postural analysis, gait kinema...
Zalewski M, Kołodyńska G, Piątek A, Mucha A, Misztela W, Andrzejewski W.Stress urinary incontinence (SUI) is usually associated with aging and parity, but repetitive intra-abdominal pressure during physical activity can also trigger its onset in young women. Horseback riding, despite potential benefits for pelvic floor strengthening, may also contribute to pelvic floor strain and urinary symptoms. The study included 100 Polish women aged 21-54 engaged in horse riding, both recreational (85%) and professional (15%). Participants were divided into three age groups and screened for urinary incontinence symptoms. Quality of life was assessed with validated questionnai...
Journal of biomechanicsJanuary 16, 2026
Volume 197 113169 doi: 10.1016/j.jbiomech.2026.113169
Collins AE, Wayne JS, Ferrando CA, De Vita R.This experimental study characterizes the elastic behavior of male and female equine genital tissues using uniaxial tensile testing, with strain measurements obtained via digital image correlation. Dog-bone-shaped tissue specimens were excised from mares and geldings (n=23 from female specimens and n=42 from male specimens) with all specimens aligned along the circumferential direction (CD) of the vagina, penis, and scrotum. The results include load-displacement data, stress-strain data, and tangent moduli for the penile sheath, vaginal canal, and scrotum, with strain measured in both the CD a...
Jardat P, Destrez A, Damon F, Tanguy-Guillo N, Lainé AL, Parias C, Reigner F, Ferreira VHB, Calandreau L, Lansade L.Olfaction is the most widespread sensory modality animals use to communicate, yet much remains to be discovered about its role. While most studies focused on intraspecific interactions and reproduction, new evidence suggests chemosignals may influence interspecific interactions and emotional communication. This study explores this possibility, investigating the potential role of olfactory signals in human-horse interactions. Cotton pads carrying human odours from fear and joy contexts, or unused pads (control odour) were applied to 43 horses' nostrils during fear tests (suddenness and novelty ...
Jafari H, Abebe BK, Cong L, Ahmed Z, Zhaofei W, Sun M, Muhatai G, Chuzhao L, Dang R.The domestication and selective breeding of horses have profoundly influenced the emergence of adaptive traits and stress resistance mechanisms, shaping modern equine populations. This comprehensive review examines the genomic foundations of these traits, emphasizing recent advancements in high-throughput sequencing technologies and bioinformatics. These tools have elucidated the genetic underpinnings of key characteristics such as endurance, speed, metabolic efficiency, and disease resistance. Importantly, the review identifies and connects gene variants associated with thermoregulation, immu...
Mendoza Flores JE, Terrazas A, Lara Sagahon AV, Aleman M.Parasympathetic tone activity (PTA) and its association with behavior in conscious versus anesthesia in horses are unknown. Objective: To study PTA, heart rate (HR), minimum alveolar concentration (MAC), and mean arterial pressure (MAP) during castration under anesthesia. To study PTA, HR, Horse Grimace Scale (HGS), locomotor activity (LA), and behavior in conscious horses before and after castration. Methods: Pilot study including seven healthy adult horses. After habituation (days 1, 2, and 3), PTAm, HR, HGS, LA, and behavior were investigated during pre-surgery (days 4-, 5-, and one-hour pr...
In horses, heat exposure modulates the hypothalamic-pituitary-adrenal axis, autonomic nervous system, and hypothalamic-pituitary-thyroid axis to maintain body temperature and prevent excessive heat accumulation. However, during strenuous exercise under hot and humid conditions, heat production may exceed dissipation, leading to heat stress, anhidrosis, heat stroke, or brain damage. Unassigned: Incremental field standardized exercise tests (fSETs) provide a reliable approach to assess training and fitness levels. Six Arabian horses from Italia Endurance Stable and Academy were monitored during ...
Brumpton HL, Kargas N.Therapeutic horse riding (THR) is a non-traditional intervention that may support mental well-being in individuals with autism spectrum conditions. Despite growing interest, most research has focused on children and has tended to privilege practitioner or caregiver perspectives, leaving autistic adults underrepresented. This qualitative study explores the psychological benefits and systemic barriers associated with THR among Autistic adults, drawing on perspectives from both clients and practitioners. Semi-structured interviews were conducted with six Autistic clients and four practitioners, a...
Choi Y, Jung Y, Wickens CL, Yoon M.Horses are social animals, with early life experiences playing a crucial role in their physiological and behavioral development. This study explored the influence of herd dynamics and foundational training on behavioral and hormonal changes in weaned foals. We examined 13 six-month-old Quarter Horse foals over a three-month training period, performing behavioral observations, temperament assessments, and hormone analyses at the start, midpoint, and end of the training. The results indicated that affiliative behaviors decreased significantly, while agonistic behaviors first increased and then d...
Amaje J, Upton S, Garba UM, Jolayemi KO.Hay nets and slow feeders are designed to mimic natural grazing by prolonging forage intake, thereby supporting digestive health and reducing stress-related behaviours. Their design and use, however, can influence effectiveness and may introduce risks. Objective: This semi-systematic review evaluated the use of hay nets and slow feeders in feeding horses, focusing on their impact on feeding time, behaviour, forage management and health management. Methods: A semi-systematic search across PubMed, ScienceDirect, Google Scholar, and Scopus identified 26 full-text studies published between 2009 an...
Jastrzębska E, Dobbek D, Pawłowska A.Back pain in horses is a frequent musculoskeletal issue that affects performance and welfare. Magnetotherapy has been proposed as a complementary, non-invasive treatment to reduce pain and support soft tissue recovery, but studies in horses remain limited. This pilot study aimed to evaluate the effects of low-frequency pulsed magnetic field therapy on horses with hypersensitivity to palpation along the longissimus dorsi muscle. Four recreational horses participated in a 10-session magnetotherapy program, with changes assessed using palpation, neck flexibility tests, heart rate measurements and...
Crossland WL, Aviles-Rosa EO, Perry EB, Crowell C, Webberson E, Brown J, Fassbender J.Our objective was to evaluate the effect of transdermal melatonin on physiological stress biomarkers in horses, with some subjected to transport stress. Sixteen horses were assigned to a 2 × 2 factorial design assessing treatment (melatonin vs. no melatonin) and transport status (transported vs. non-transported), creating four groups: Control (CON), Transport only (TRS), Melatonin only (MEL), and Melatonin plus Transport (MELTRS). Horses in melatonin groups received 24 mg/day transdermally for 21 days and transported groups underwent a 3-hour trailer ride on day 21. Day 21 blood samples were ...
Busechian S, Di Salvo A, Orvieto S, Rueca F, Villella C, Sollevanti G, Pieramati C, Nisi I, Della Rocca G.Equine Gastric Ulcer Syndrome (EGUS) is a worldwide disease described in different categories of animals. A causal relationship between exercise and EGUS has been suggested, attributed to stress as well as physiological changes in the position of abdominal organs, especially during trot and gallop. EGUS can influence athletic fitness, as has been described in various papers on racehorses. The aim of this work was to determine if gastric ulcer healing is associated with changes in selected fitness parameters (i.e., speed, heart rate during exercise and recovery, stride length and frequency) in ...
Bonhomme MM, Boisdenghien L, Couroucé A, Votion DM.Public scrutiny of racehorse welfare is increasing. The preparatory training phase preceding the racing season is potentially a critical period for physical and mental development. Structured welfare assessment protocols have recently been developed, but their use in field conditions remains limited. Objective: (1) To evaluate the field applicability of a racehorse-specific welfare assessment protocol in a professional French jump racing yard; and (2) to explore whether it can detect relevant physical and behavioural changes in young horses during season preparation. Methods: Longitudinal obse...
Hiblu MA, Ahmed MO.This case report documents the first identified Brucella infection in a 6-year-old male Thoroughbred horse in Libya. The horse exhibited muscle and joint pain, inflammation over the shoulders with a pulpy texture (fistulous withers), stress, fatigue, and potential systemic infection. Its diagnosis was confirmed through serological testing, with agglutination titers of 1/80 for B. melitensis and 1/160 for B. abortus, and a blood culture revealing Gram-negative coccobacilli. After 3 weeks of combination therapy with rifampicin and doxycycline, the inflammation resolved, systemic signs disappeare...
Tripon MA, Manolăchescu D, Papuc I, Daradics Z, Crecan CM.Emotional contagion between horses and humans is a key aspect of their interaction, influencing welfare, training, and therapy, yet current methods for measuring this phenomenon lack standardization and consistency. Objective: The aim of this study was to verify what methods are used to assess emotional contagion in horse-human interactions, and what outcomes have been reported. Methods: A systematic search of Google Scholar, Web of Science, Scopus, PubMed, and Science Direct was conducted up to March 2024. Peer-reviewed studies assessing emotional transfer through behavioral and/or physiologi...
Briefer-Freymond S, Dalla Costa E, Jolivald A, Bruckmaier RM, Atallah E, Giorgia Riva M, Ijichi C.Personality affects both experience and expression of pain and the welfare impact of castration on horses is poorly understood. Therefore, the current study observed 19 horses to determine: the welfare impact of standard castration on horses; whether individuals consistently vary in their behavioural and emotional responses to pain; the influence of personality on behavioural and physiological responses to pain; whether Horse Grimace Scale (HGS) indicates how individuals feel about painful experiences. Eye temperature (IRT), salivary cortisol, HGS and a pain ethogram were measured at intervals...
von Borell E, Langbein J, Després G, Hansen S, Leterrier C, Marchant J, Marchant-Forde R, Minero M, Mohr E, Prunier A, Valance D, Veissier I.Measurement of heart rate variability (HRV) is a non-invasive technique that can be used to investigate the functioning of the autonomic nervous system, especially the balance between sympathetic and vagal activity. It has been proven to be very useful in humans for both research and clinical studies concerned with cardiovascular diseases, diabetic autonomic dysfunction, hypertension and psychiatric and psychological disorders. Over the past decade, HRV has been used increasingly in animal research to analyse changes in sympathovagal balance related to diseases, psychological and environmental...
Seyfarth RM, Cheney DL.Convergent evidence from many species reveals the evolutionary origins of human friendship. In horses, elephants, hyenas, dolphins, monkeys, and chimpanzees, some individuals form friendships that last for years. Bonds occur among females, among males, or between males and females. Genetic relatedness affects friendships. In species where males disperse, friendships are more likely among females. If females disperse, friendships are more likely among males. Not all friendships, however, depend on kinship; many are formed between unrelated individuals. Friendships often involve cooperative inte...
Garber A, Hastie P, Murray JA.Gastrointestinal microbiota play a crucial role in nutrient digestion, maintaining animal health and welfare. Various factors may affect microbial balance often leading to disturbances that may result in debilitating conditions such as colic and laminitis. The invention of next-generation sequencing technologies and bioinformatics has provided valuable information on the effects of factors influencing equine gut microbiota. Among those factors are nutrition and management (e.g., diet, supplements, exercise), medical substances (e.g., antimicrobials, anthelmintics, anesthetics), animal-related ...
Fureix C, Jego P, Henry S, Lansade L, Hausberger M.Recent reviews question current animal models of depression and emphasise the need for ethological models of mood disorders based on animals living under natural conditions. Domestic horses encounter chronic stress, including potential stress at work, which can induce behavioural disorders (e.g. "apathy"). Our pioneering study evaluated the potential of domestic horses in their usual environment to become an ethological model of depression by testing this models' face validity (i.e. behavioural similarity with descriptions of human depressive states). Results: We observed the spontaneous behav...
Visser EK, van Reenen CG, van der Werf JT, Schilder MB, Knaap JH, Barneveld A, Blokhuis HJ.Forty-one Dutch Warmblood immature horses were used in a study to quantify temperamental traits on the basis of heart rate (HR) and heart rate variability (HRV) measures. Half of the horses received additional training from the age of 5 months onwards; the other half did not. Horses were tested at 9, 10, 21 and 22 months of age in a novel object and a handling test. During the tests, mean HR and two heart variability indices, e.g. standard deviation of beat-to-beat intervals (SDRR) and root mean square of successive beat-to-beat differences (rMSSD), were calculated and expressed as response va...
Frank N, Tadros EM.Abnormalities of insulin metabolism include hyperinsulinaemia and insulin resistance, and these problems are collectively referred to as insulin dysregulation in this review. Insulin dysregulation is a key component of equine metabolic syndrome: a collection of endocrine and metabolic abnormalities associated with the development of laminitis in horses, ponies and donkeys. Insulin dysregulation can also accompany prematurity and systemic illness in foals. Causes of insulin resistance are discussed, including pathological conditions of obesity, systemic inflammation and pituitary pars intermedi...
Cappelli K, Felicetti M, Capomaccio S, Spinsanti G, Silvestrelli M, Supplizi AV.Adequate stress response is a critical factor during athlete horses' training and is central to our capacity to obtain better performances while safeguarding animal welfare. In order to investigate the molecular mechanisms underlying this process, several studies have been conducted that take advantage of microarray and quantitative real-time PCR (qRT-PCR) technologies to analyse the expression of candidate genes involved in the cellular stress response. Appropriate application of qRT-PCR, however, requires the use of reference genes whose level of expression is not affected by the test, by ge...
Lesimple C.Animal welfare is defined as a chronic state reflecting an individual's subjective perception of its situation. Because it is possible to be in a good welfare state and nevertheless experience acute fear or pain, and conversely, short-term positive emotions can be experienced during impaired welfare states, welfare as a chronic state has to be clearly distinguished from temporary states related to emotions, pain or stress. The evaluation of non-verbal individuals' welfare state, particularly in interspecific situations, is a real challenge that necessarily implies animal-based measures and req...
Dudhia J, Scott CM, Draper ER, Heinegård D, Pitsillides AA, Smith RK.Age-associated and degenerative loss of functional integrity in soft tissues develops from effects of cumulative and subtle changes in their extracellular matrix (ECM). The highly ordered tendon ECM provides the tissue with its tensile strength during loading. As age and exercise collide in the high incidence of tendinopathies, we hypothesized that aged tendons fail due to cumulative damage resulting from a combination of diminished matrix repair and fragmentation of ECM proteins induced by prolonged cyclical loading, and that this is an active cell-mediated process. We developed an equine ten...
Schmidt A, Möstl E, Wehnert C, Aurich J, Müller J, Aurich C.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...
Koolhaas JM, Van Reenen CG.This paper will argue that understanding animal welfare and the individual vulnerability to stress-related disease requires a fundamental understanding of functional individual variation as it occurs in nature as well as the underlying neurobiology and neuroendocrinology. Ecological studies in feral populations of mice, fish, and birds start to recognize the functional significance of phenotypes that individually differ in their behavioral and neuroendocrine response to environmental challenge. Recent studies indicate that the individual variation within a species may buffer the species for st...
Mach N, Foury A, Kittelmann S, Reigner F, Moroldo M, Ballester M, Esquerré D, Rivière J, Sallé G, Gérard P, Moisan MP, Lansade L.Weaning has been described as one of the most stressful events in the life of horses. Given the importance of the interaction between the gut-brain axis and gut microbiota under stress, we evaluated (i) the effect of two different weaning methods on the composition of gut microbiota across time and (ii) how the shifts of gut microbiota composition after weaning affect the host. A total of 34 foals were randomly subjected to a progressive (P) or an abrupt (A) weaning method. In the P method, mares were separated from foals at progressively increasing intervals every day, starting from five min ...
Yarnell K, Hall C, Royle C, Walker SL.The predominant housing system used for domestic horses is individual stabling; however, housing that limits social interaction and requires the horse to live in semi-isolation has been reported to be a concern for equine welfare. The aim of the current study was to compare behavioural and physiological responses of domestic horses in different types of housing design that provided varying levels of social contact. Horses (n = 16) were divided equally into four groups and exposed to each of four housing treatments for a period of five days per treatment in a randomized block design. The four h...
Peeters M, Sulon J, Beckers JF, Ledoux D, Vandenheede M.In horses, serum cortisol concentration is considered to provide an indirect measurement of stress. However, it includes both free and bound fractions. The sampling method is also invasive and often stressful. This is not the case for salivary cortisol, which is collected using a more welfare-friendly method and represents a part of the free cortisol fraction, which is the biologically active form. Objective: To compare salivary and serum cortisol assays in horses, in a wide range of concentrations, using an adrenocorticotropic hormone (ACTH) stimulation test, in order to validate salivary cor...
Fenner K, Yoon S, White P, Starling M, McGreevy P.Restrictive nosebands are common in equestrian sport. This is concerning, as recent evidence suggests that very tight nosebands can cause a physiological stress response, and may compromise welfare. The objective of the current study was to investigate relationships that noseband tightness has with oral behavior and with physiological changes that indicate a stress response, such as increases in eye temperature (measured with infrared thermography) and heart rate and decreases in heart rate variability (HRV). Horses (n = 12) wearing a double bridle and crank noseband, as is common in dressage ...
Ayala I, Martos NF, Silvan G, Gutierrez-Panizo C, Clavel JG, Illera JC.No detailed comparative data are available on the hormonal parameters of horses suffering from a number of diseases. The aim of our study was to measure concentrations of cortisol, adrenocorticotropic hormone (ACTH), serotonin, adrenaline and noradrenaline in horses with various diseases and following surgery, to assess the response of the HPA axis and adrenal medulla. Blood samples were obtained from six groups of horses comprising a total of 119 animals as follows: laminitis, acute abdominal syndrome (AAS), castration surgery, acute diseases, chronic diseases and healthy controls. Serum horm...
Fazio E, Ferlazzo A.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, physi...
Rekant SI, Lyons MA, Pacheco JM, Arzt J, Rodriguez LL.Abnormal body temperature is a major indicator of disease; infrared thermography (IRT) can assess changes in body surface temperature quickly and remotely. This technology can be applied to a myriad of diseases of various etiologies across a wide range of host species in veterinary medicine. It is used to monitor the physiologic status of individual animals, such as measuring feed efficiency or diagnosing pregnancy. Infrared thermography has applications in the assessment of animal welfare, and has been used to detect soring in horses and monitor stress responses. This review addresses the var...
Schmidt A, Aurich J, Möstl E, Müller J, Aurich C.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 di...
Schoster A, Mosing M, Jalali M, Staempfli HR, Weese JS.The intestinal microbiota is important for health and disease. Factors that disturb the equine intestinal microbiota need further investigation. Objective: To determine the effects of transport, fasting and anaesthesia on the faecal microbiota of healthy adult horses using next-generation sequencing. Methods: Experimental trial. Methods: Faecal samples were taken from 8 horses at baseline, after transport, 12 h of fasting and 24, 48 and 72 h after a 6 h anaesthesia. Next generation sequencing of the V4 region of the 16S rRNA gene was used to assess the microbial composition of faeces. Alpha...
von Lewinski M, Biau S, Erber R, Ille N, Aurich J, Faure JM, Möstl E, Aurich C.Although some information exists on the stress response of horses in equestrian sports, the horse-rider team is much less well understood. In this study, salivary cortisol concentrations, heart rate (HR) and heart rate variability (HRV), SDRR (standard deviation of beat-to-beat interval) and RMSSD (root mean square of successive beat-to-beat intervals) were analysed in horses and their riders (n=6 each) at a public performance and an identical rehearsal that was not open to the public. Cortisol concentrations increased in both horses and riders (P<0.001) but did not differ between performan...
Irvine CH, Alexander SL.In horses, a circadian rhythm in plasma cortisol concentrations has been reported in some but not all studies. When a rhythm occurred, horses were accustomed to a management routine, comprising stabling, feeding and sometimes exercise, which may entrain a circadian pattern. In this work, we monitored plasma cortisol by collecting jugular blood through indwelling cannulae from four groups: 1): 10 untrained, unperturbed mares grazing excess pasture, bled hourly for 26 hr; 2) 4 mares housed in a barn for 48 hr before sampling every 15 min for 20-24 hr; 3) 5 mares placed in an outdoor yard for sam...
Aurich J, Wulf M, Ille N, Erber R, von Lewinski M, Palme R, Aurich C.Analysis of salivary cortisol is increasingly used to assess stress responses in horses. Because spontaneous or experimentally induced increases in cortisol concentrations are often relatively small for stress studies, proper controls are needed. This requires an understanding of the factors affecting salivary cortisol over longer times. In this study, we have analyzed salivary cortisol concentration for 6 mo in horses (n = 94) differing in age, sex, reproductive state, and housing. Salivary cortisol followed a diurnal rhythm with the highest concentrations in the morning and a decrease throug...
Biewener AA.Measurements of the cross-sectional geometry and length of bones from animals of different sizes suggest that peak locomotory stresses might be as much as nine times greater in the limb bones of a 300 kg horse than those of a 0.10 kg chipmunk. To determine if the bones of larger animals are stronger than those of small animals, the bending strength of whole bone specimens from the limbs of small mammals and bipedal birds was measured and compared with published data for large mammalian cortical bone (horses and bovids). No significant difference (P greater than 0.2) was found in the failure st...
Bohák Z, Szabó F, Beckers JF, Melo de Sousa N, Kutasi O, Nagy K, Szenci O.Daily fluctuations of cortisol concentration in the blood or saliva have been repeatedly reported. However, several contradictions in the existing literature appear on this subject. The present study was performed to definitively establish options for testing adrenocortical function. To the best of our knowledge, this is the first study to evaluate parallel circadian rhythms in salivary and serum cortisol concentrations during a 24-h period. Twenty horses were examined under the same conditions. Blood and saliva samples were taken every 2 h for 24 h to determine the daily changes in cortisol c...
Schmidt A, Biau S, Möstl E, Becker-Birck M, Morillon B, Aurich J, Faure JM, Aurich C.It is widely accepted that transport is stressful for horses, but only a few studies are available involving horses that are transported regularly and are accustomed to transport. We determined salivary cortisol immunoreactivity (IR), fecal cortisol metabolites, beat-to-beat (RR) interval, and heart rate variability (HRV) in transport-experienced horses (N=7) in response to a 2-d outbound road transport over 1370 km and 2-d return transport 8 d later. Salivary cortisol IR was low until 60 min before transport but had increased (P<0.05) 30 min before loading. Transport caused a further marked i...
Rietmann TR, Staﾬher M, Bernasconi P, Auer JA, Weishaupt MA.The objective of this study was to compare the stress response of horses suffering from laminitis after short- and long-term treatment with the intent to evaluate power spectral analysis of heart rate variability (HRV) for pain monitoring. Data were collected from 19 horses with acute or chronic exacerbating laminitis without known primary disease before and after treatment with non-steroidal anti-inflammatory drugs (NSAID). Recordings were carried out the day after admission to the equine hospital. Measurements were repeated on day 7 of the treatment. The recorded parameters included a clinic...
Pawluski J, Jego P, Henry S, Bruchet A, Palme R, Coste C, Hausberger M.The hypothalamic-pituitary-adrenal (HPA) axis response to chronic stress is far from straight forward, particularly with regards to animal welfare. There are reports of no effect as well as both decreases and increases in cortisol after chronic stressors. Therefore, the first aim of the present study was to determine how measures of compromised welfare, such as chronic pain and haematological anomalies, related to cortisol levels in domestic horses (Equus caballus). Domestic horses are an informative model to investigate the impact of chronic stress (due to environment, pain, work, housing con...
Keeling LJ, Jonare L, Lanneborn L.The heart rates (HR) of horses and the people leading them (10 horses, 20 people), and riding them (17 horses, 17 people), were recorded in an indoor arena. The horses were Swedish leisure horses of mixed ages, sex and breed. All except two of the people were female and all were of mixed age and riding experience. Each horse-human pair walked or rode between points A and B (30m) four times on each test occasion. However, just before the fourth pass, participants were told that an umbrella would be opened as they rode, or led, the horse past the assistant. The umbrella was not opened, so this p...
Reilly GC, Currey JD.During locomotion, the anterior cortex of the equine radius is loaded predominantly in tension, the posterior predominantly in compression. The anterior cortex is relatively strong in tension, the posterior in compression. We investigated the pattern of failure of specimens from the two cortices using laser scanning confocal microscopy. All specimens were loaded in four-point bending to increasingly higher loads. We quantified the amount of diffuse microcracking on the tensile side of these specimens by observing the amount of light emitted under laser illumination. The amount of light emitted...
