Thermoregulation during Field Exercise in Horses Using Skin Temperature Monitoring

Abstract

Hyperthermia and exertional heat illness (EHI) are performance and welfare issues for all exercising horses. Monitoring the thermoregulatory response allows for early recognition of metabolic heat accumulation during exercise and the possibility of taking prompt and effective preventative measures to avoid a further increase in core body temperature (Tc) leading to hyperthermia. Skin temperature (Tsk) monitoring is most used as a non-invasive tool to assess the thermoregulatory response pre- and post-exercise, particularly employing infrared thermographic equipment. However, only a few studies have used thermography to monitor skin temperature continuously during exercise. This commentary provides an overview of studies investigating surface skin temperature mainly by infrared thermography (IRT) during exercise. The scientific evidence, including methodologies, applications, and challenges associated with (continuous) skin temperature monitoring in horses during field exercise, is discussed. The commentary highlights that, while monitoring Tsk is straightforward, continuous Tsk alone does not always reliably estimate Tc evolvement during field exercise. In addition, inter-individual differences in thermoregulation need to be recognized and accounted for to optimize individual wellbeing. With the ongoing development and application of advanced wearable monitoring technology, there may be future advances in equipment and modeling for timely intervention with horses at hyperthermic risk to improve their welfare. However, at this point, infrared thermographic assessment of Tsk should always be used in conjunction with other clinical assessments and veterinary examinations for a reliable monitoring of the welfare of the horse.

Comparison of infrared thermography of the blowhole mucosa with rectal temperatures in killer whales (Orcinus orca)

“…Use of infrared thermography in wildlife and marine mammal medicine is well established and in managed-care animals is used to evaluate wounds, musculoskeletal injury, skin conditions, or diseases of the oral cavity (Sweeney and Ridgway, 1975;Walsh and Gaynor, 2001;McCafferty, 2007;Cilulko et al, 2013;Melero et al, 2015). These types of conditions are particularly amenable to infrared imaging, as inflammatory processes cause vasodilation and a subsequent increase in surface temperature, or in the case of cetaceans, injury may cause detectable breaches of the temperature-insulating blubber layer (Barbieri et al, 2010;Rekant et al, 2016;Mota-Rojas et al, 2022;Verdegaal et al, 2024).…”

Functional infrared thermography imaging can be used to assess the effectiveness of Maxicam Gel® in pre-emptively treating transient synovitis and lameness in horses

“…Heat is one of the key signs of inflammation, as the increased blood supply caused by inflammation leads to an increase in local temperature ( 16 ). IRT has been used in various studies involving horses, such as detection of jugular venipuncture for anti-doping control in equestrian events ( 17 ), monitoring of musculoskeletal adaptation to training ( 18 ), evaluation of the welfare in athlete horses ( 19 ), monitoring the effects of training ( 20 , 21 ), assessment of thermoregulation during exercise ( 22 ), validation for the use of eye temperature as an indicator of well-being ( 23 ), detection of pregnancy in mares ( 24 ), evaluation of the oral administration of meloxicam or flunixin meglumine in an inflammatory response induced by the administration of systemic LPS ( 25 ), evaluation of thermoregulation using two methods of post-exercise cooling ( 26 ), evaluation of biocompatibility of polymers ( 27 , 28 ), among others.…”

Table_1.DOCX

“…Heat is one of the key signs of inflammation, as the increased blood supply caused by inflammation leads to an increase in local temperature (16). IRT has been used in various studies involving horses, such as detection of jugular venipuncture for anti-doping control in equestrian events (17), monitoring of musculoskeletal adaptation to training (18), evaluation of the welfare in athlete horses (19), monitoring the effects of training (20, 21), assessment of thermoregulation during exercise (22), validation for the use of eye temperature as an indicator of well-being (23), detection of pregnancy in mares (24), evaluation of the oral administration of meloxicam or flunixin meglumine in an inflammatory response induced by the administration of systemic LPS (25), evaluation of thermoregulation using two methods of post-exercise cooling (26), evaluation of biocompatibility of polymers (27,28), among others.…”