Relationship between serum cortisol levels and some physiological parameters following reining training session in horse

Eye Temperature Measured with Infrared Thermography to Assess Stress Responses to Road Transport in Horses

The aim of the present study was to investigate eye temperature modifications after road transport in athletic horses habituated to travel. Eight adult Italian saddle horses traveled 100 km and, two weeks later, 300 km. Eye temperature (ET), rectal temperature (RT) and serum cortisol concentration were assessed before (T1), after (T2) and 60 min (T3) after the road transport. ET was evaluated with infrared thermography (IRT) in three regions of interest: EL1 (medial canthus), EL2 (central cornea) and EL3 (lateral canthus). Two-way analysis of variance (ANOVA) for repeated measures showed statistically higher values at T2 and T3 for EL1 (p < 0.01), EL2 (p < 0.01) and EL3 (p < 0.01) following the 100 km journey. RT (p < 0.01) showed higher values at T2 and T3 after the 100 km journey and higher values at T2 (p < 0.01) following the 300 km journey. ET values were positively correlated with RT at T1, T2 and T3 following the 100 km journey and at T2 following the 300 km journey and positively correlated with serum cortisol concentration at T1, T2 and T3 following the 100 km journey and at T2 and T3 following the 300 km journey. Eye temperature monitoring with IRT allows quick and practical strategies to monitor an animal's physiological state and welfare during daily activities.

Effect of Exercise in a Vector-Protected Arena for Preventing African Horse Sickness Transmission on Physiological, Biochemical, and Behavioral Variables of Horses

During an African horse sickness (AHS) outbreak, horses were able to exercise daily in a net-covered arena, yet the physiological responses to exercise in a netted arena was unknown. In a cross-over study design, eight horses performed a 39-minute aerobic exercise in conventional (CA) and vector-protected arenas (VPA). Horses were slower in some gaits and covered less distance in the VPA arena (P < .01). Cortisol release, hematology, and heart rate variability (HRV) were also examined. An interaction between the riding arena and time was observed in hematocrit (P = .0013), hemoglobin (P = .0012), and red blood cell count (P = .0027) and HRV variables, including mean beat-to-beat (RR) intervals (P < .0001), mean heart rate (P < .0001), sympathetic nervous system (SNS) index (P = .0038) and parasympathetic nervous system (PNS) index (P < .0001). Cortisol concentrations increased during exercise and 30 minutes postexercise in both arenas. Hematocrit, hemoglobin, and red blood cell count increased immediately postexercise in horses in VPA while remaining high from immediate post-exercise to 60 minutes postexercise in horses in CA. HRV decreased during exercise and was not different between horses in both arenas, but a higher RR interval and PNS index, corresponding to lower heart rate and SNS index, were detected during 30 to 60 minutes postexercise in horses in the VPA compared to the CA. Riding horses in different arenas impacted hematological and HRV variables. The greater RR intervals and PNS index, coinciding with the lower SNS index and heart rate, indicated parasympathetic dominance post-exercise in horses in VPA compared to CA.

Cortisol Variations to Estimate the Physiological Stress Response in Horses at a Traditional Equestrian Event

In many countries, horses remain involved in traditional equestrian events such as those celebrated in Menorca (Balearic Islands, Spain) every year since at least the 14th century. The present study aimed to evaluate the variations in salivary cortisol concentrations to estimate the physiological stress response in horses at the Menorca patronal festivals. Two different editions (years 2016 and 2018) of the festivals in honor of the Virgin of Grace in Maó (Menorca, Spain) were studied. Nineteen and seventeen Pure Breed Menorca stallions were included in the study, respectively. The stallions were aged between seven and twelve years. During celebrations, samples were collected before the start of the festivals between 8-9 a.m. and during the festivals at 8-9 p.m. On the second day of celebrations, the samples were collected at 8-9 a.m. and 3-4 p.m. Finally, on the day after the festivals, one sample was collected at 8-9 p.m. Additionally, a control group was sampled at 8-9 a.m., 3-4 p.m., and 8-9 p.m. Salivary cortisol concentrations were assessed by using a commercial enzyme immunoassay kit specially validated to quantify salivary cortisol in horses. Salivary cortisol concentrations did not show significant differences between sampling hours in the control group (p > 0.05). All the samples collected during festivals were significantly higher than samples of the control group (p < 0.05). Within the twenty-four hours after the end of the celebrations, cortisol concentrations returned to baseline levels and did not differ significantly from the control group (p > 0.05). Hence, the present study describes that the participation of the horses in these particular acts generate an acute and transitory stress response. Overall, the current work provides a reasonable basis for future research on the stress physiology and well-being of horses participating in traditional celebrations or similar events.

Ergogenic effects of phosphatidylserine alone and combined with branched-chain amino acids in trained rats

Acute phosphatidylserine (PS) or branched-chain amino acids (BCAA) supplements alone may have an adrenocorticotropic hormone, cortisol suppressive effect and increase the testosterone/cortisol ratio, but the associated effect of these supplements during a period of high-intensity physical stress is not yet known. The study investigated the effects of chronic PS supplementation alone and combined with BCAA during high-intensity interval training (HIIT) on training volume tolerance, anabolic-catabolic balance and stress biomarkers in rats. Thirty-three rats were separated into: placebo (PLA, n=11), PS alone (n=11) and combined with BCAA (PSBCAA, n=11). Groups performed swimming sessions of HIIT (5 series × 1 min × 1 min recovery; external load equivalent to 13% of body mass) and nine recovery sessions of moderate-intensity training (30 min at 5% of body mass) alternately. One-way ANOVA was used to compare biochemical variables and two-way ANOVA was calculated to compare training volume. Training volume performed (TVP) was higher in first, fourth, fifth, sixth, and eighth HIIT sessions in the PS group in comparison to PLA (P<0.05). TVP was higher in the fourth session in PSBCAA compared to PLA. There were no differences in TVP during the sessions between PS and BCAA groups. Creatine kinase (CK) was lower in PSBCAA in comparison to PS alone (P=0.03) and PLA (P=0.04) after the experimental period. Testosterone concentration was enhanced in PSBCAA group compared to PLA (P=0.01); testosterone/corticosterone ratio was higher in PSBCAA compared to PS (P=0.05) and PLA (P=0.004) after protocol. PS combined with BCAA increases testosterone concentration and testosterone/corticosterone ratio, demonstrating an enhancement of anabolic state in trained rats.

Interleukin-1Ra (Il-1Ra) and serum cortisol level relationship in horse as dynamic adaptive response during physical exercise

The monitoring of endocrine and immunologic markers during exercise is of paramount importance to assess and/or maintain the physical well-being of athletes as well as to optimize the athletic performance. This study aimed to investigate the linkage between acute stress response and immune status in Thoroughbred horses competing in an official 1300-m race. From 10 horses blood was collected 1 week before the day of the race (1W-BEFORE), before (REST) and immediately after the race to assess the cortisol, Interleukin-1 receptor antagonist (IL-1Ra), total proteins, white blood cells (WBC), red blood cells (RBC), haemoglobin (Hb) and haematocrit (Hct) concentration. Higher levels of cortisol, Il-1Ra, WBC and erythrocytes indices after exercise was found than 1W-BEFORE and REST (P < 0.0001). Cortisol concentration was positively correlated with Il-1Ra, WBC, RBC, Hb and Hct. Overall, the findings suggest that submaximal exercise induces an acute stress response and an immune system reaction in athletic horse. Also, the correlation found between cortisol levels and Il-1Ra, WBC and erythrocytes indices open new scenario on the positive role of this hormone on the complex and dynamic physiological adaptation to exercise implemented by the organism to re-establish the homeostatic equilibrium, and, interestingly, to maintain an adequate anti-inflammatory environment after exercise.

Changes in Body Surface Temperature Associated with High-Speed Treadmill Exercise in Beagle Dogs Measured by Infrared Thermography

Simple Summary

Heat exchange between the body surface and the external environment plays an important role in the regulation of body temperature in animals. Previous studies on the effect of exercise on the distribution of body surface temperature in dogs have been conducted on a variety of breeds and did not employ specific defined regions of interest. The aim of our research was to assess the influence of high-speed treadmill exercise on body surface temperature using infrared thermography in selected body regions of healthy Beagle dogs, taking into account gait and recovery time. The study was based exclusively on the Beagle breed, which presents short, uniform, and straight hair, conducting heat more readily from the skin. Statistical analysis indicated the highest temperature at the upper forearm and thigh, and the lowest on the croup, back, and neck. The peak surface temperature values in all examined areas were observed after the canter and the post-gallop walk, and the lowest were observed 2 h after exercise. Our study confirms that the body surface temperature of Beagle dogs is influenced by high-speed physical exercise on a treadmill as a result of muscle activity and changes in blood flow. The proximal forelimb and hindlimb were the most influenced by exercise.

Abstract

Evaluation of body surface temperature change in response to exercise is important for monitoring physiological status. The aim of the study was to assess the influence of high-speed treadmill exercise on body surface temperature using infrared thermography (IRT) in selected body regions of healthy Beagle dogs, taking into account gait and recovery time. Thermographic images of the dogs were taken before exercise (BE), after walk (AW), after trot (AT), after canter (AC), just after second walk (JAE), 5 min after exercise (5 AE), 15 min after exercise (15 AE), 30 min after exercise (30 AE), 45 min after exercise (45 AE), and 120 min after exercise (120 AE). Body surface temperature was measured at the neck, shoulder, upper forearm, back, chest, croup, and thigh. Statistical analysis indicated the highest temperature at the upper forearm, shoulder, and thigh, and the lowest on the croup, back, and neck. The peak values of surface temperature in all ROIs were at AC and JAE and the lowest at 120 AE. The study demonstrated that body surface temperature was influenced by high-speed physical exercise on a treadmill and IRT was a viable imaging modality that provided temperature data from specific body regions. The proximal forelimb and hindlimb were the most influenced by exercise.

Changes Associated with the Peri-Ovulatory Period, Age and Pregnancy in ACTH, Cortisol, Glucose and Insulin Concentrations in Mares

Simple Summary

The reproductive cycle of mares is associated with many hormonal changes, but the effects of this cycle and pregnancy on adrenocorticotropic hormone and insulin concentrations are poorly described, which could limit our ability to diagnose pituitary pars intermedia dysfunction and insulin dysregulation. In this study, healthy mares are followed through their reproductive cycle during the physiologic breeding season, and adrenocorticotropic hormone, cortisol, glucose and insulin concentrations are measured to determine the effects of age, pregnancy and the reproductive cycle on analyte concentrations. No significant effect of age, the reproductive cycle or pregnancy is detected on the cortisol, glucose or insulin concentrations; however, adrenocorticotropic hormone concentrations are significantly increased throughout the peri-ovulatory period and during pregnancy. Therefore, knowledge of a mare’s reproductive cycle might be beneficial when interpreting adrenocorticotropic hormone concentrations.

Abstract

Although there are many hormonal changes associated with reproduction, the effects of ovulation and early pregnancy on adrenocorticotropic hormone (ACTH) and insulin concentrations are poorly described. We hypothesise that both ovulation and early pregnancy will alter ACTH and insulin concentrations in healthy mares. Eighteen mares showing no clinical signs suggestive of, or laboratory findings consistent with, pituitary pars intermedia dysfunction PPID and insulin dysregulation (ID) are enrolled. ACTH, cortisol, insulin and glucose concentrations are measured over their peri-ovulatory period, as determined via ultrasounds and progesterone concentrations. The mares are grouped by age and gestation status, and a two-way repeated-measures ANOVA is used to determine the effects of age and early pregnancy, along with the peri-ovulatory period, on analyte concentrations. No significant effect of age, ovulation or early pregnancy is detected on the mares’ cortisol, insulin or glucose concentrations; however, there is a significant effect of early pregnancy and ovulation on ACTH concentrations (p = 0.04 and p = 0.04 respectively). ACTH concentrations change around ovulation and with early pregnancy. Therefore, knowledge of a mare’s reproductive status might be beneficial when interpreting ACTH concentrations.

The effect of repeated barrel racing on blood biomarkers and physiological parameters in Quarter Horses

The objective of this study was to evaluate barrel horses undergoing a field test with one repetition. Quarter-Horses were used (14 males and females; average age: 6.5 years old), and they ran two times for 5 min in the same field. Six different periods were evaluated: rest (T-0), immediately after the first (T-1) and second races (T-2), and after 15 (T-15), 30 (T-30) and 240 min (T-240) of recovery. Heart rate (HR), speed, distance and duration were measured using a HR monitor with GPS during the races. Blood was collected to determinate glucose, lactate, total proteins (TP), albumin, globulin, urea, creatinine, uric acid (UA), triglycerides, cholesterol, non-esterified fatty acids (NEFA), gammaglutamyltransferase (GGT), creatine kinase (CK), and cortisol concentrations, as well as to perform a haemogram. The results were analysed using ANOVA and Tukey’s tests using a P-value of 5%, and they showed a maximum HR>200 bpm after both races. The largest %HR>>170 bpm occurred in the second race (P<0.05). Glucose and lactate concentrations were elevated at T-2 (P<0.05). TP, creatinine, UA and triglycerides concentrations remained elevated at T-1, T-2 and T-30 (P<0.05). TP and creatinine concentrations returned to basal concentrations at T-30 (P>0.05), and UA and triglycerides returned to base concentrations at T-240 (P>0.05). NEFA, cholesterol, GGT and CK concentrations did not change (P>0.05). Cortisol concentrations were higher at T-2 (P<0.05) but at T-240 were similar to T-0 (P>0.05). Red blood cell concentrations and haematocrits had higher values after the second race (P<0.05). These results showed that barrel horses had intense exercise and that two races with a short rest interval between them produced similar metabolic and physiologic adaptations between races, showing that the proposed protocol may be a useful tool for field characterisation of horses’ training and may contribute to the implementation of adequate training and nutritional programs.

Comparison between specific and nonspecific tests for evaluating the physical fitness of show jumping horses

Show jumping is a century-old Olympic sport performed worldwide. However, despite the prominence of this sport, there is currently no satisfactory evaluation of the physical fitness of its horses. Our study compared two standardised exercise tests (specific and nonspecific for show jumpers) to determine the importance of a show jumping specific evaluation test. Sixteen horses were divided into two performance groups (high and low performance), and all horses performed standardised exercise tests without jumps (SET1) and with jumps (SET2). Heart rate, blood lactate, glucose, blood gas, haematological parameters, and plasma ions were measured before and after the tests, and performance indices were calculated. Both exercise tests (SET1 and SET2) resulted in changes in nearly all measured variables that were expected, based on other studies, for the duration and nature of the exercise performed. Differences between the two performance groups were observed for lactate and glucose, as well as some blood gas variables and performance indicators. These differences might have been the result of better cardiovascular and metabolic adaptation of the high performance group to the show jumping exercises. For the SET1, differences between groups were mainly noted for variables related to aerobic capacity, which suggests that this measurement is important for the evaluation of equine performance in show jumping. The SET2 was capable of detecting different horse performance levels that could not be detected by the SET1, which indicates that a specific test for show jumping (that includes jumping movements) could provide important information for the evaluation of show jumpers. Based on our findings, we recommend that the SET2 be included in future protocols for evaluating jumping horses.