Distal limb immersion in ice and water is the most effective means of cooling the equine hoof lamellae under clinically relevant conditions.

Abstract

OBJECTIVE: To determine the relationship between hoof surface (HS), hoof wall (HW), and lamellar tissue (LAM) temperature during distal limb cooling and evaluate 4 cooling methods in ambulatory horses over extended periods using HW to estimate LAM temperature. METHODS: 8 healthy, university-owned horses were enrolled. Temperature was measured over 4 hours at LAM, HS, and HW for 4 cooling methods: ice sleeve (SLEEVE), ice pack system (ICEPACK), low-volume ice water immersion (LV-IMMERSION), and high-volume ice water immersion (HV-IMMERSION). The relationship between HW, HS, and LAM was mathematically modeled, generating a method-specific correction factor to predict LAM based on HW. Hoof wall temperature was then measured over 8 hours with horses free in a stall (LAM was estimated using HW). Mixed-effects linear regression was used to compare cooling methods. RESULTS: HV-IMMERSION and LV-IMMERSION significantly decreased LAM temperature over 4 hours (P < .001), whereas ICEPACK and SLEEVE did not. Lamellar tissue temperature estimated using HW showed good concordance (&#x3c1;c = 0.93 [0.93 to 0.94]; P < .001) and correlation (r = 0.93; P < .001) with measured LAM temperature. In horses free in the stall for 8 hours, the estimated LAM temperature decreased significantly with HV-IMMERSION (-20.4 &#xb0;C [-22.9 to -17.8]) and LV-IMMERSION (-14.9 &#xb0;C [-17.7 to -12.1]) compared to control (32.7 &#xb0;C [32.2 to 33.2]; P < .001) but did not decrease with ICEPACK (-2.7 &#xb0;C [-5.6 to -0.3]; P < .08) or SLEEVE (-1.8 &#xb0;C [-5.6 to -2.0]; P < .4). CONCLUSIONS: HV-IMMERSION and LV-IMMERSION were superior to ICEPACK and SLEEVE for lamellar cooling. CLINICAL RELEVANCE: Immersion of the distal limb in ice and water is most effective for cooling the digital lamellae under clinically relevant conditions.