The Use of Infrared Thermography (IRT) as Stress Indicator in Horses Trained for Endurance: A Pilot Study

Abstract

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, gluteus and longissimus dorsi muscle (mm), 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 and serum cortisol. Eight horses were tested before and after training of different intensities (low, moderate, and high). The results partially supported our hypothesis; all the studied parameters increased after training (p < 0.05), eye temperature (ET) correlated positively with HR (p < 0.01), and crown temperature (CT) correlated positively with cortisol (p < 0.01). However, only HR and white blood cells increased with the intensity of the exercise (p = 0.0016 and p = 0.0142, respectively). Our findings suggest the evaluation of ET and CT may become a useful non-invasive tool to detect physiological stress during training and to evaluate how the horses cope with the training. Infrared thermography technique may also become a useful tool for the early identification of horses that are not fit to compete or to continue the competition. However, further studies should be conducted on a larger number of horses and during competitions to ascertain our preliminary findings.

Keywords: endurance; horse; thermography; training.

Figure 1

Paddock where the horses used for the experiment were kept daily and night.

Figure 2

Horse stable where the horses were led and fed before the training.

Figure 3

Walker where the horses were trained.

Figure 4

Area adjacent to the walker where the horses were cross tied and blood sampling, heart rate measurement, and infrared thermography technique (IRT) were performed.

Figure 5

Examples of an infrared image in the examined regions. The cross indicates the position of the maximum temperature within the examined areas used for analysis.