Objectives Digital cryotherapy is commonly used for laminitis prophylaxis and treatment. Currently validated methods for distal limb cryotherapy involve wet application or compression technology. There is a need for a practical, affordable, dry cryotherapy method that effectively cools the digit. The objective of this study was to evaluate the hoof wall surface temperatures (HWSTs) achieved with a novel dry cryotherapy technology. Design Repeated-measures in vivo experimental study. Setting Experimental intervention at a single site. Participants 6 systemically healthy horses (3 mares, 3 geldings). Interventions Cryotherapy was applied to six horses for eight hours with a commercially available rubber and rubber and welded fabricice boot, which extended proximally to include the foot and pastern. Reusable malleable cold therapy packs were secured against the foot and pastern with the three built-in hook-and-loop fastener panels. Primary and secondary outcome measures HWST and pastern surface temperature of the cryotherapy-treated limb, HWST of the control limb and ambient temperature were recorded every five minutes throughout the study period. Results Results were analysed with mixed-effects multivariable regression analysis. The HWST (median 11.1°C, interquartile range 8.6°C–14.7°C) in the cryotherapy-treated limb was significantly decreased compared with the control limb (median 29.7°C, interquartile range 28.9°C–30.4°C) (P≤0.001). Cryotherapy limb HWST reached a minimum of 6.75°C (median) with an interquartile range of 4.1°C–9.3°C. Minimum HWST was achieved 68 minutes after cryotherapy pack application. Conclusions Dry application of cryotherapy significantly reduced HWST and reached minimums below the therapeutic target of 10°C. This cryotherapy method might offer an effective alternative for digital cooling.

No current treatments available halt osteoarthritis progression in horses or humans. Intra-articular injection of mitochondria is a novel treatment that has the potential to improve cell metabolism and decrease inflammation, but safety of this treatment has yet to be established in the horse. Autologous blood-derived mitochondria isolated using a commercially available kit were injected into the left carpus joint of 3 horses which were monitored for 28 days. Horses received physical examinations, video recorded gait evaluations, joint diameter measurement, synovial fluid collection, and blood collection on day 0 (baseline prior to mitotherapy, day of mitochondria injection), 1, 3, 7, 14, and 28. Systemic inflammation was assessed via complete blood count, fibrinogen, and plasma serum amyloid A (SAA). Local inflammation was assessed via synovial fluid cytology and physical examination parameters. Physical exam parameters remained stable and no joint swelling was observed after mitotherapy. No change was noted in video recorded gait evaluations as determined by a blinded evaluator. Complete blood counts revealed no significant increase in white blood cells. SAA only increased mildly in 1 horse. Fibrinogen became slightly elevated above reference range in 2 horses at day 7, but later normalized. Mild increases in synovial fluid nucleated cell counts and total protein occurred on day 1 and 3, but resolved within 7 days without intervention. Autologous mitochondria injection into the equine intercarpal joint was well tolerated with no signs of inflammation. This safety information allows for future studies evaluating mitotherapy efficacy.

Objective: To determine the safety and pharmacokinetics of a single dose of the oral ectoparasiticide fluralaner at 10 and 25 mg/kg in healthy horses. Methods: 12 clinically healthy university-owned horses, 9 to 17 years of age, were administered a single oral dose of fluralaner at 10 or 25 mg/kg. Physical examinations, neurological examinations, plasma samples, hematology and biochemistry panels, and skin biopsies were collected throughout the 84-day trial period. Fluralaner concentrations were measured in plasma and skin by liquid chromatography-tandem mass spectrometry, and pharmacokinetics were evaluated in plasma using a noncompartmental analysis. Results: After oral administration at 10 or 25 mg/kg, fluralaner was detected in all horses. Fluralaner was detectable in plasma for a mean of 42 ± 16.6 or 30.3 ± 3.61 days at the 10- and 25-mg/kg doses, respectively. Pharmacokinetic results for 10- and 25-mg/kg doses, respectively, were a terminal half-life of 6.03 ± 3.87 or 3.02 ± 0.25 days, maximum concentration of 162.1 ± 21.6 or 403.3 ± 129.5 ng/mL, and time to maximal concentration of 0.42 ± 0.14 or 0.64 ± 0.29 days. Skin concentrations in horses administered 25 mg/kg peaked 1 day postadministration at a median of 2.30 μg/g (IQR, 1.31 to 8.23 μg/g) and remained detectable to day 84. No adverse effects of fluralaner were detected. Conclusions: Fluralaner is absorbed orally at 10 and 25 mg/kg in healthy horses and appears to be safe and well tolerated. Clinical Relevance: Fluralaner's persistence in skin and plasma after oral administration has potential as a treatment for select ectoparasites in the horse, although further study is needed to determine the appropriate dose and dose interval.