Topic:Cortisol
Cortisol is a steroid hormone produced by the adrenal glands in horses, playing a significant role in the regulation of metabolism, immune response, and stress management. As a glucocorticoid, cortisol influences various physiological processes, including glucose metabolism, inflammation modulation, and the maintenance of homeostasis during stress. Its levels in horses can vary due to factors such as exercise, environmental changes, and psychological stressors. Cortisol is often measured to assess stress responses and overall well-being in equine health management. This page compiles peer-reviewed research studies and scholarly articles that explore the production, regulation, and implications of cortisol in equine physiology and health.
Cortisol and adrenocorticotropic hormone concentrations in horses with systemic inflammatory response syndrome. Plasma adrenocorticotropic hormone (ACTH) and serum cortisol concentrations increase with illness-associated stress. Dynamics of plasma ACTH and serum cortisol concentrations in adult horses with systemic illness are undocumented. Objective: To determine whether ACTH and cortisol concentrations and the ACTH/cortisol ratio vary with survival, the presence of systemic inflammatory response syndrome (SIRS), or ischemic gastrointestinal lesions at admission, or throughout hospitalization. Methods: One hundred fifty-one adult horses. Methods: Prospective study measuring serum cortisol and plasma AC...
Plasma concentrations of steroid precursors, steroids, neuroactive steroids, and neurosteroids in healthy neonatal foals from birth to 7 days of age. Transient hypothalamic-pituitary-adrenal axis dysfunction occurs in critically ill foals with sepsis and neonatal maladjustment syndrome (NMS). Cortisol is the most commonly measured steroid. However, a complex interaction of various steroid compounds might play a role in pathophysiology of this disorder. Objective: To identify steroid compounds present at high concentrations at birth that rapidly and steadily decrease within the first 7 days of life in healthy foals and that might be supportive diagnosis of NMS and other neonatal disorders. Methods: Ten healthy neonatal Quarter Horse foals ...
Natural Horse Boarding Vs Traditional Stable: A Comparison of Hormonal, Hematological and Immunological Parameters. In the equestrian world, two different types of management can be distinguished: traditional management and natural boarding. The aim of this research was to compare hormonal, hematological and immunological parameters of 47 horses kept in these two different managements. Blood and horsehair of the horses were sampled to determine DHEA (dehydroepiandrosterone) and cortisol concentration through RIA. Moreover, blood count was conducted, and flow cytometry was employed to phenotype lymphocyte subpopulations. Results showed that, in horsehair, DHEA concentration was significantly higher in natura...
Stimulation of Bladder Acupoints by Cloprostenol for Treating Back Soreness in Athletic Horses. Twenty-five Thoroughbred jumper geldings suffered back soreness with poor performance, and 5 control horses were assessed by archived computer data, clinical examination, and laboratory analyses of complete blood picture, serum enzymes, and cortisol level, before and after cloprostenol-pharmacopuncture. The 25 diseased horses before therapy showed significant increases in aspartate aminotransferase and creatine phosphokinase with clinical pains scored mild in 15 horses, moderate in 9 horses, and severe in one horse, without changes in the hormonal and hematological data. After therapy, they re...
Influence of season and pituitary pars intermedia dysfunction on hair cortisol concentration in horses. Hair cortisol has been demonstrated to reflect hypothalamic-pituitary-adrenal axis activity (including Cushing's disease and stress) in several species. We hypothesized that hair cortisol concentrations are increased in horses with pituitary pars intermedia dysfunction (PPID) compared with healthy adult horses and that this difference is magnified in the fall, when circulating adrenocorticotropin (ACTH) is generally the highest. Cortisol from hair collected using clippers with a #40 blade from the neck was compared between PPID horses and control horses over several months in the fall (August-...
Controlled delay of the expulsive phase of foaling affects sympathoadrenal activity and acid base balance of foals in the immediate postnatal phase. Stress at foaling has been demonstrated to delay birth. In this study, we followed the hypothesis that even a short delay of foaling increases catecholamine and cortisol release in foals, induces acidosis and impairs neonatal adaptation. Foaling was prolonged for 5 min by transferring mares to an unfamiliar environment at rupture of the allantochorion (group delay, n = 6) while control mares (n = 5) were left undisturbed. In their foals, times from birth to first standing and first suckling, heart rate, heart rate variability (HRV) and salivary cortisol concentration were analysed. B...
Plasma Apelin Concentration in Exercised Horses: Preliminary Study. Physical effort is one of the key aspects of keeping horses in good condition. The condition of the animal is reflected by multiple blood parameters. The newly discovered cytokine-apelin can pose one of them, however, so far, has not been studied in the horse population. Apelin is produced by adipocytes and myocytes and plays an important role in the energy metabolism of the body through the influence, for example, on the process of adipogenesis and lipolysis. The aim of this study was to investigate if physical effort of various intensity affects the plasma concentration of apelin in horses. ...
Effect of delayed plasma centrifugation on equine adrenocorticotropic hormone concentration. Plasma adrenocorticotropic hormone (ACTH) concentration is used in the diagnosis of pituitary pars intermedia dysfunction (PPID) in horses. We enrolled 10 horses, 5 PPID-positive and 5 PPID-negative, in our study, September 20-22, 2016. On day 0, 5 mL of whole blood was collected into each of 6 EDTA tubes and immediately placed in a refrigerator at 7°C. One tube was centrifuged within 15 min of collection, followed by centrifugation of one tube from each horse at 4, 8, 12, 24, and 36 h following collection. At each time, centrifuged plasma was pipetted into 1.5-mL polypropylene tubes and stor...
Prospective randomized investigation of topical anesthesia during unilateral laparoscopic ovariectomy in horses. To compare pain-related responses in mares receiving topical or injected anesthesia of the ovarian pedicle prior to standing unilateral laparoscopic ovariectomy. Methods: Prospective randomized, blinded, placebo-controlled study. Methods: Fifteen healthy research mares. Methods: Mares were restrained in stocks and administered sedation. A right or left paralumbar ovariectomy was performed by using a laparoscopic portal and two instrument portals. Mares were divided into two treatment groups, and equal volumes of mepivacaine anesthesia were administered either topically (n = 8) or by injection ...
Hair cortisol concentration is inversely related to the severity of equine squamous gastric disease. Equine squamous gastric disease (ESGD) is common in horses and many factors, including stress, may play a role in lesion development. Hair cortisol concentration (HCC) provides a measure of medium to long-term stress and therefore, the relationship between HCC and ESGD was examined in this study. Hair samples were collected from 25 horses and gastroscopy was performed to determine the presence and severity of ESGD. Hair cortisol concentrations were lower in horses with ESGD (P = 0.014), and negatively correlated with lesion severity. Mares had lower HCC than geldings (P = 0.031), and a...
Multiple adrenocortical steroid response to administration of exogenous adrenocorticotropic hormone to hospitalized foals. The hypothalamic-pituitary-adrenal axis regulates the response to sepsis-associated stress. Relative adrenal insufficiency or adrenocorticotropic hormone (ACTH):cortisol imbalance, defined as a poor cortisol response to administration of ACTH, is common and associated with death in hospitalized foals. However, information on other adrenal steroid response to ACTH stimulation in sick foals is minimal. Objective: To investigate the response of multiple adrenocortical steroids to administration of ACTH in foals. Methods: Hospitalized (n = 34) and healthy (n = 13) foals. Methods: In this prospecti...
Stress effects on the regulation of parturition in different domestic animal species. This review summarizes current knowledge on stress-like responses in parturient animals and their role for the onset and fine-tuning of parturition. The antepartum maternal cortisol increase is part of the endocrine changes that initiate parturition but a further increase in cortisol release during labor indicates a stress response. During the last minutes of delivery, sinus arrhythmias occur in 80% of foaling mares and 60% of calving cows. Expulsion of the neonate is thus characterized by parasympathetic dominance. In late-pregnant cows transported by road, cortisol concentrations increased b...
Effect of different doses of inhaled ciclesonide on lung function, clinical signs related to airflow limitation and serum cortisol levels in horses with experimentally induced mild to severe airway obstruction. Inhaled corticosteroids are effective for the treatment of equine asthma but they induce cortisol suppression with potential side effects. Objective: To study the efficacy of ciclesonide, an inhaled corticosteroid with an improved safety profile, on lung function, clinical signs related to airway obstruction, and serum cortisol levels in asthmatic horses exposed to a mouldy hay challenge. Methods: Cross-over placebo controlled, blinded, randomised experiment. Methods: Sixteen horses were enrolled in three subsequent dose-titration studies (8 horses/study) to investigate the effects of inhaled ...
Effects of Overcheck Use on Stress Parameters and Welfare Implications in Driving Horses. Three sequential studies were performed to evaluate the effects of tying horses while wearing overchecks (strap from the bridle to backpad). In an observational study, horses (n = 305) wore high (HC), low (LC), or no overchecks (NC) with frequencies of 29.2%, 51.8% and 19.0% respectively. Study 1 (Latin square, n = 6) consisted of a 90-min tie test (90TT) with treatments (HC, LC, NC) x periods (1-3). Horses wearing HC had higher plasma cortisol (P < 0.01) when compared to LC and NC. Muscle soreness (MSS) and tightness (MTS) were evaluated pre and 24 hr post 90TT and were higher (P <...
Oral Administration of Meloxicam Suppresses Low-Dose Endotoxin Challenge-Induced Pain in Thoroughbred Horses. Nonsteroidal anti-inflammatory drugs such as flunixin meglumine have been used to treat signs of systemic inflammatory conditions, but it is also known to have the side effect to small intestine mucosa. It may be considered to be due to inhibition of both cyclooxygenase (COX)-1 and COX-2. On the other hand, meloxicam is widely used in equine clinical practice and an effective nonsteroidal anti-inflammatory drug with the preferential inhibitory effect on COX-2. However, it has not yet been evaluated in equine systemic inflammation. The aim of this study was to evaluate the effect of meloxicam a...
The Use of Infrared Thermography (IRT) as Stress Indicator in Horses Trained for Endurance: A Pilot Study. The aim of this pilot study was to document the effects of endurance training at different intensities on heart rate (HR), blood count, serum cortisol, and maximal temperatures of different body locations, namely eye, crown, pastern pasterns, and muscle (, measured by infrared thermography technique (IRT) in horses trained for endurance. Possible associations among the studied parameters were also investigated. Our hypothesis was that temperature, measured by IRT after endurance training of different intensities would vary depending on the intensity and would be positively correlated with HR...
Determination of Salivary Cortisol in Donkey Stallions. Salivary cortisol provides information about free plasma cortisol concentration, and salivary sampling is a noninvasive well-tolerated procedure. The aim of this study was to validate a commercial enzyme immunoassay for the determination of salivary cortisol in donkeys. Saliva samples were collected in four donkey stallions on 13 nonconsecutive days at 8:30 AM to avoid circadian variation. Animals were already accustomed to be handled. Saliva was collected using a swab inserted at the angle of the lips, placed onto the tongue for 1 minute and returned into a polypropylene tube. Tubes were cen...
External stress increases sympathoadrenal activity and prolongs the expulsive phase of foaling in pony mares. Mares usually give birth when they perceive their environment as safe and therefore disturbance at foaling may inhibit labor. In this study, foaling mares were transferred to an unfamiliar environment at rupture of the allantochorion (stress, n = 6) or were left undisturbed (control, n = 5). The progress of foaling, heart rate, heart rate variability (HRV) and plasma catecholamine, oxytocin and cortisol concentration were determined. In stressed mares, time from rupture of the allantochorion to appearance of the fetal feet (5.3 ± 1.1 vs. 1.6 ± 0.4 min) and total length of f...
Thyroid Hormone and Thyrotropin Concentrations and Responses to Thyrotropin-Stimulating Hormone in Horses with PPID Compared with Age-Matched Normal Horses. Glucocorticoids are known to exert inhibitory action on the hypothalamic-pituitary-thyroid axis. With recent evidence that free plasma cortisol and urinary excretion of cortisol metabolites may be increased in horses with pituitary pars intermedia dysfunction (PPID), it is important to further examine thyroid function in horses with PPID. To test the hypothesis that serum thyrotropin (TSH) concentrations are decreased in horses with PPID, baseline serum thyroid hormone and TSH concentrations, and responses to TSH-releasing hormone (TRH), were compared between 12 horses diagnosed as having PPID...
Modelling of oscillatory cortisol response in horses using a Bayesian population approach for evaluation of dexamethasone suppression test protocols. Cortisol is a steroid hormone relevant to immune function in horses and other species and shows a circadian rhythm. The glucocorticoid dexamethasone suppresses cortisol in horses. Pituitary pars intermedia dysfunction (PPID) is a disease in which the cortisol suppression mechanism through dexamethasone is challenged. Overnight dexamethasone suppression test (DST) protocols are used to test the functioning of this mechanism and to establish a diagnosis for PPID. However, existing DST protocols have been recognized to perform poorly in previous experimental studies, often indicating presence of ...
Replication Pilot Trial of Therapeutic Horseback Riding and Cortisol Collection With Children on the Autism Spectrum. We aimed to determine whether results of our prior randomized control trial [RCT; NCT02301195, (1)] of Therapeutic Horseback Riding (THR) for children and adolescents with autism spectrum disorder (ASD) could be at a different riding center and if treatment effects also included differences in the expression of associations between problem behavior and the activity of the hypothalamic-pituitary-adrenal (HPA) axis. Participants with ASD ( = 16) ages 6-16 years were randomized by nonverbal intelligence quotient to either a 10-week THR group ( = 8) or no horse interaction barn activity (BA) cont...
Evaluation of dynamic testing for pituitary pars intermedia dysfunction diagnosis in donkeys. Endocrine disorders are common in donkeys. Pituitary pars intermedia dysfunction (PPID) is thought to be a frequent disturbance in donkeys due to their longevity. However, information on PPID dynamic testing in donkeys is lacking. Objective: The objective of this study was to evaluate the previously described guidelines for PPID diagnosis in horses in donkeys with suspicion of PPID. Methods: Prospective experimental study. Methods: Eighty donkeys were evaluated for PPID suspicion based on clinical signs and baseline adrenocorticotropic hormone (ACTH) concentrations. Six mix-breed donkeys (one ...
Effect of racing on blood variables in Standardbred horses. Blood is collected for hematologic and biochemical analyses when racehorses perform poorly. However, racing affects most analyte levels; therefore, the timing of blood sampling can affect analyte levels and interpretations. Objective: This study aimed to determine if the blood variable levels returned to pre-racing levels 2 and 3 days post-racing. Methods: Blood was sampled from 17 healthy racehorses pre- and post-racing. The variables measured from plasma were albumin, cholesterol, creatinine, calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na), potassium (K), creatine phosphokinase (C...
Dysregulation of Cortisol Metabolism in Equine Pituitary Pars Intermedia Dysfunction. Equine Cushing disease [pituitary pars intermedia dysfunction (PPID)] is a common condition of older horses, but its pathophysiology is complex and poorly understood. In contrast to pituitary-dependent hyperadrenocorticism in other species, PPID is characterized by elevated plasma ACTH but not elevated plasma cortisol. In this study, we address this paradox and the hypothesis that PPID is a syndrome of ACTH excess in which there is dysregulation of peripheral glucocorticoid metabolism and binding. In 14 horses with PPID compared with 15 healthy controls, we show that in plasma, cortisol levels...
Facial expression and oxytocin as possible markers of positive emotions in horses. Behavioural and physiological markers of discrete positive emotions remain little investigated in animals. To characterise new markers in horses, we used tactile stimulations to induce emotional situation of contrasting valence. In the Gentle grooming group (G, N = 13) horses were gently groomed during 11 sessions on the body areas they appreciated the most. Horses in the Standard grooming group (S, N = 14) were groomed using a fixed procedure, reported to induce avoidance reactions in some horses. At session 11, G horses expressed significantly more contact-seeking behaviours than S h...
Microbiome and Blood Analyte Differences Point to Community and Metabolic Signatures in Lean and Obese Horses. Due to modern management practices and the availability of energy dense feeds, obesity is a serious and increasingly common health problem for horses. Equine obesity is linked to insulin resistance and exacerbation of inflammatory issues such as osteoarthritis and laminitis. While the gut microbiome is thought to play a part in metabolic status in horses, bacterial communities associated with obesity have yet to be described. Here we report differences in metabolic factors in the blood of obese, normal and lean horses correlated with differences in gut microbiome composition. We report that ob...
Anticipatory response before competition in Standardbred racehorses. It is generally accepted that besides cortisol concentrations, parameters of heart rate variability (HRV) are appropriate indicators of stress in horses. The aim of this study was to determine anticipatory stress in eight Standardbred stallions participating in harness race. Cortisol and HRV responses to a mild exercise performed in training circumstances were compared to a maximal effort exercise performed in real trotting race conditions. Parameters of HRV reflecting vagal (root mean square of the successive differences, RMSSD) and sympathetic nervous system activity (ratio of the low and hi...
Progressive habituation to separation alleviates the negative effects of weaning in the mother and foal. Early and definitive separation between offspring and their mothers has negative consequences on behavioral and physiological responses. This study compared sudden and definitive weaning (Sudd group, N = 16) and weaning involving progressive habituation to separation using a fence line during the month preceding definitive separation (Prog group, N = 18). The impact of these two methods was assessed in both foals and their mothers through behavioral and biological parameters, including salivary cortisol, telomere length and blood transcriptomes. On the day of definitive separation, Pro...
Cortisol, progesterone, 17αOHprogesterone, and pregnenolone in foals born from mare’s hormone-treated for experimentally induced ascending placentitis. This study aimed to evaluate steroid hormones in foals born from mares treated for ascending placentitis with different combinations of trimethoprim-sulfamethoxazole (TMS), flunixin meglumine (FM), long-acting altrenogest (ALT) and estradiol cypionate (ECP) for ten consecutive days, starting two days after experimental induction of placentitis with Streptococcus zooepidemicus. Fourty-six pregnant mares and respective foals were assigned as healthy group (Control, n = 8) or treated groups as follows: TMS+FM (n = 8), TMS+FM+ALT (n = 8), TMS+FM+ALT+ECP (n = 6), TMS+FM+ECP (n = 6) and no...
Influence of caudal epidural analgesia on cortisol concentrations and pain-related behavioral responses in mares during and after ovariectomy via colpotomy. To determine the influence of epidural detomidine and morphine on serum corticosteroid concentrations and pain-related behavioral responses in mares during and after ovariectomy via colpotomy. Methods: Blinded prospective study. Methods: Nine university-owned mares. Methods: Five of 9 horses received caudal epidural detomidine hydrochloride (0.01 mg/kg) and morphine sulfate (0.1 mg/kg) prior to surgery. All horses received local anesthetic around the ovarian pedicle, 0.02 mg/kg butorphanol IV at the start of the procedure and after first ovary removal, were sedated as required throughout the p...