Evaluation of hoof wall surface temperature as an index of digital vascular perfusion during the prodromal and acute phases of carbohydrate-induced laminitis in horses

Objective-To evaluate the use of hoof wall surface temperature (HWST) as an indirect indicator of digital perfusion and to describe HWST patterns duri ng the prodromal and acute phases of carbohydrate-induced laminitis in hors es. Animals-30 adult horses without fool abnormalities. Procedures-Three experiments were performed. In the first, HWST was measure d in 2 groups of horses acclimatized to hot (n = 6), or cold (6) environmen ts and exposed to cold (15 C) ambient temperature. In the second experiment , HWST were measured in both forefeet of 6 horses before and after applicat ion of a tourniquet to 1 forefoot to induce vascular occlusion. In the thir d experiment, HWST were recorded in 12 horses before and during the prodrom al and acute phases of carbohydrate-induced laminitis. Results-Mean HWST of hot-acclimatized cold-challenged horses was significan tly less than that of cold-acclimatized cold-challenged horses at all times . Transient episodes of high HWST were observed during prolonged cold-induc ed vasoconstriction. Hoof wall surface temperature significantly decreased during arterial occlusion and increased during reperfusion. Digital hypothe rmia was observed during the prodromal phase of carbohydrate-induced lamini tis. Conclusions and Clinical Relevance-Determination of HWST is a valid techniq ue to evaluate digital perfusion under appropriate controlled conditions in horses. Digital hypothermia detected during the prodromal phase of laminit is is consistent with decreased digital vascular perfusion or metabolic act ivity. If administered to horses during the prodromal phase, agents that en hance digital perfusion may prevent development of laminitis.