Effects of distal limb ice bag cryotherapy in horses - a thermographic evaluation

This experimental study evaluated the cooling effect of ice bag cryotherapy on the hoof surface temperature in horses. In 6 horses one forelimb was cooled for 90 minutes using an ice water bag system applied between the carpus and the hooves, while the contralateral hoof served as control. Surface temperature of the hooves was determined using thermography before, during cooling and for 90 minutes following the end of cooling. Coronary and mid wall temperature was evaluated during the time course and compared with the contralateral hoof temperature. At 60 and 90 min cooling had a significant, but very small cooling effect of 1.4 degrees C at the coronary band, while at mid wall no significant temperature change was found. The cooling effect of three tightly fitting ice water bags around fetlock and cannon bone was only small. As this method acted by cooling the distal limb with the supplying arterial blood rather than the hoof itself, the hoof surface temperature probably underestimated the laminar temperature in an unknown extent. Ice bags do have the advantage, that they can be used also in horses, which should be allowed to lie down, like horses suffering from severe laminitis. However, these cooling effects are far from cooling effects of ice water immersion in rubber boots and possibly not effective for therapeutic purposes in laminitic horses.