Eye Surface Temperature as a Potential Indicator of Physical Fitness in Ranch Horses

Unconventional Animal Species Participation in Animal-Assisted Interventions and Methods for Measuring Their Experienced Stress

The participation of animals during complementary therapy for humans is a developing area. Dogs and horses are the most frequent partner species in animal-assisted services, but several unconventional species have also been involved, although there is a lack of information about the stress they experience caused by AAS. We conducted a comprehensive literature search, analyzing 135 articles with the purpose of investigating the effects of AAS on unconventional species such as guinea pigs, rabbits, farm animals, alpacas, donkeys, reptiles, aquarium fishes, and dolphins. We found that the relevant articles emphasize investigating the impact of animal-assisted interventions on humans, and they generally report positive outcomes. Limited data is available concerning the potential consequences the interventions may have on the animals. Therefore, it is our conclusion that more extensive studies should be conducted to get adequate information on stress experienced by animals during AAS, such as the measurement of biochemical parameters such as cortisol. Hence, meeting animal welfare considerations in addition to human interests could serve as a basis for the recommended methodology for therapies.

The Postural and Body Surface Temperature Response of Leisure Horses to Lunging with Selected Lunging Aids

Incorporating lunging into a horse's daily routine aims to enhance fitness, physical condition, and specific skills or exercises when using lunging aids (LAs). To assess the effectiveness of lunging, non-contact technologies like geometric morphometrics and infrared thermography can be employed. This study seeks to evaluate lunging efficiency based on the horse's posture and surface temperature when lunging with different head and neck positions. The study aims to determine if changes in a horse's posture correspond to increased metabolic activity, as indicated by body surface temperature. Thirteen horses included in the study were lunged with chambon (CH), rubber band (RB), and triangle side reins (TRs) as well as with a freely moving head (FMH). Images were taken in visible light and infrared. Principal Component Analysis (PCA) was used to analyze horse posture changes and a Pixel-Counting Protocol (PCP) was used to quantify surface temperature patterns. The horses' posture exhibited contrasting changes, reflected by a changing centroid shape (p < 0.0001) but not size (p > 0.05) when lunged with RB and TRs, but not CH. Different (p < 0.0001) surface temperature patterns were observed during lunging. FMH lunging resulted in lower temperatures over a larger surface, CH induced moderate temperatures on a smaller area, RB caused moderate to high temperatures across a broader surface, and TRs led to higher temperatures over a smaller region. The studied lunging cases returned different (p < 0.0001) surface temperature patterns. Lunging with FMH returned lower temperatures over a larger surface, CH moderate temperatures on a smaller area, RB moderate to high temperatures across a broader surface, and TRs higher temperatures over a smaller region. The proposed methods can be applied to evaluate the efficiency of lunging in horses.

Use of Infrared Thermography to Assess Body Temperature as a Physiological Stress Indicator in Horses during Ridden and Lunging Sessions

Equitation is a cause of physiological stress in the equine athlete, and personality is a factor generally associated with the different responses of equines to stressors. This study explored ocular temperature, measured via infrared thermography, associated with personality and stress in horses submitted to dressage exercising in riding lessons, ridden training and lunging. Infrared thermograms of 16 horses were taken before and after sessions using an FLIR F4 camera (FLIR Systems AB, Sweden) to determine maximum eye surface IRT temperature (IRTmax), and total training time was registered (T). A novel-stimulus test was conducted for personality assessment, and the ridden behavior was scored (mRBS). The results showed that T was statistically different (p ˂ 0.001) between modalities, but no differences were found in any IRTmax tests. Statistical correlations were found between mRBS and personality groups, sex and age (all p < 0.001). Additionally—and with caution, given the sample—no association was found between mRBS and post-workout IRT readings and modality, or between pre-workout IRT readings and personality groups. We conclude that trained horses show little stress when working in a familiar environment and when the workout plan is submaximal. The personality test was adequate and positively correlated with ridden behavior.

Correlation between Ocular and Rectal Temperature with Intra Ocular Pressure in Horse during Exercise

Simple Summary

The athletic horse has been found to be sensitive to numerous metabolic and physiological changes during physical exercise, making it a stressor which may go on to affect thermal and homeostatic well-being. In the present study we aimed to evaluate some ocular physiological variables (ocular temperature and intraocular pressure) and how they may be correlated to the rectal temperature, which better describes the thermoregulatory system. This study was conducted on 14 healthy horses from the same horse training center. Ocular temperature, intraocular pressure and rectal temperature were evaluated under different experimental conditions (am and pm hours) and before and after a show jumping exercise protocol. Ocular and rectal temperature increased after the exercise as a result of muscle metabolism activation, increasing blood flow in several regions of the body to improve oxygen supply and heat dissipation. On the contrary, intraocular pressure significantly decreased after exercise, probably due to peripheral vasodilatation. Our results showed a correlation between increased body temperatures and IOP variations during exercise. It would be interesting to consider these variables as indicators to determine physiological status of horses during physical exercise.

Abstract

The aim of the present study was to investigate the response to physical exercise of some ocular physiological variables (ocular temperature and intraocular pressure) in horses performing a jumping course in the morning (a.m.) or in the afternoon hours (p.m.), before and after the exercise, in correlation with the rectal temperature. Data collection was carried out on 14 clinical healthy Italian saddle horses. All horses were trained from 9:00 to 10:00 a.m. and from 19:00 to 20:00 p.m. according to a specific training program. Ocular temperature (OT), rectal temperature (RT) and intraocular pressure (IOP) were determined. Statistical analysis showed no differences between the results for the left and the right eyes. The application of two-way repeated-measures analysis of variance (ANOVA) showed a statistically significant effect of time (before vs. after) on IOP (p = 0.0001). RT and OT were statistically influenced by time of day and by experimental conditions (a.m. vs. p.m.) (p = 0.0001). Bland–Altman (B-A) testing showed an agreement between the values of RT and OT. Our results showed a correlation between increased body temperatures and IOP variations during exercise, so they can probably be considered indicators of athletic horses’ physical fitness during exercise.

Salivary cortisol and eye temperature changes during endurance competitions

Background

The purpose of this study was to investigate the usefulness of salivary cortisol (SC) and eye temperature measured by infrared thermography (IRT^ET) as biomarkers to manage competitions more effectively and monitor horse welfare in endurance competitions. Based on previous studies, it was hypothesised that pre-exercise baseline SC and IRT^ET would be higher in younger or less experienced horses, and that post-exercise variation from baseline would be higher in the top finishers.

Results

Salivary cortisol measured in 61 competing at qualifier 40 km and 80 km rides showed an abrupt variation (93–256% rise) of the baseline SC levels [median ± interquartile range (IQR) = 0.27 ng/dl ± 0.36] obtained at the Pre-Inspection (PI) into Vet Gate (VG)1 independently of the covered distance, but modest or even lower in the subsequent Vet Gates, e.g. VG2 or VG3. The IRT^ET measured concomitantly in 16 horses showed significant (p < 0.05) higher levels at the PI in less experienced horses participating in the 40 km ride (median ± IQR = 35.7 °C ± 1.4) than their counterparts in the 80 km ride (median ± IQR = 35.0 °C ± 1.5), but not SC. Baseline SC levels at the PI of horses classifying in the Top5 in the 40 km ride category were significantly (p < 0.05) higher median ± IQR = 0.90 ng/ml ±0.61) when compared to horses positioned from 10th position on (median ± IQR = 0.16 ng/ml ±0.40). A lower IRT^ET in the PI was correlated with better placement (p < 0.05) and those in the Top5 (median ± IQR = 33.9 °C ± 0.0) had a significantly (p < 0.5) higher variation (+ 10.65%) into the last VG.

Conclusion

Pre-exercise baseline IRT^ET levels, but not SC, were higher in less experienced horses in the 40 compared to their counterparts in the 80 km ride competitions. SC and IRT^ET showed different indications according to the competition. In the40 km ride competition, higher baseline pre-exercise SC levels seemed to be linked to a better classification outcome. In contrast, in the 80 km ride horses, the higher IRT^ET variation from pre-exercise into final Vet Gate was the parameter associated with a better performance. A more controlled environment and a larger sample are needed to confirm these results and monitor horse welfare in competitions.

Validation of Eye Temperature Assessed Using Infrared Thermography as an Indicator of Welfare in Horses

This study aimed to validate eye temperature (ET) assessed using infrared thermography (IRT) as an indicator of welfare in horses. Moreover, this study aimed to determine the most accurate position for ET measured using IRT and to validate this approach as a gold-standard measurement method. As the quantitative data obtained by IRT have strongly influenced the ET results depending on the specific location of the measurement area, an accurate definition of the regions of interest (ROI) was established. A total of 176 horses (Thoroughbred, Warmblood, and Halla horses) were used at the racing course of the Korea Racing Authority and public horse-riding clubs in South Korea. The present study also compared temperatures among three ROIs of the eye—lacrimal sac, medial canthus, and lateral canthus—at rest. Correlations between ET, rectal temperature (RT), heart rate (HR), and respiratory rate (RR) were assessed. There were no significant correlations between HR, RR or RT; however, among the three ROIs, the temperature of the medial canthus was positively correlated with RT (p < 0.05). Furthermore, the size of ROI was negatively correlated with accuracy of temperature measurement. These results indicate that the most suitable area for ET measurement using IRT in horses is the medial canthus, and it is recommended to use the average temperature of the smallest ROIs (2 × 2 pixels) for temperature analysis. Therefore, this study offers a validated protocol in which ET measured using IRT in the horses is useful as an indicator of welfare.