Evaluation of the cooling efficacy of different equine leg cooling methods

Abstract

The use of cold therapy or cryotherapy is widespread in human and veterinary medicine and sports medicine and ranges from focal, localised treatment to whole body treatment. In equestrian sport, a variety of methods and commercial products exist for cooling the lower limbs. To date, there have been no studies comparing the relative efficacy of these different cooling methods. Due to the difficulty in standardising techniques for comparing cooling on live horses, a repeatable laboratory method for determining cooling efficacy was developed using a metal flask. The amount of heat removed from the flask by different traditional methods (corrected for the heat lost over 30 min for the flask without treatment) and a variety of commercial cooling products was calculated by measuring the decrease in temperature (in triplicate) within the flask from an initial external temperature of 40.2±0.4 °C and an internal temperature of 42.1±0.9 °C (mean ± standard deviation) over 30 min. The methods compared were: cold hosing (15 °C), standing in ice and water (0 °C), ice-cube packs, instant cold-packs, ice boots, evaporative (water) cooled boots, ice gel and clay. The greatest amount of heat removed in 30 min was 134±4 kJ for standing in ice & water (0 °C). The next highest rates of removal were 66.4±1.3, 57.1±6.1 and 56.9±1.3 kJ for cold hosing (15 °C), Ice Horse (-23 °C) and Cryochaps (-23 °C), respectively. The lowest amount of heat removed was for covered clay (8±1 kJ; initial clay temperature 15 °C). This approach allows different methods of cooling to be compared without the difficulties encountered in standardisation in live horses.