BackgroundIntra-articular local anesthetics are widely used for diagnostic analgesia in horses, but their effects on lameness and the synovial environment may differ between drugs.Aims/objectiveso compare clinical efficacy and synovial fluid biochemical response after intra-articular administration of mepivacaine and ropivacaine in horses.MethodsIn a prospective study, 24 middle carpal joints from 12 clinically healthy horses were evaluated for synovial fluid total protein and lactate dehydrogenase activity before and 24 h after administration of mepivacaine 3% (100 mg) or ropivacaine 1% (40 mg), each diluted with 0.9% saline to a final volume of 5 mL. The same doses were used in a second randomized crossover experiment involving eight horses with naturally occurring tarsal joint-related lameness, with clinical efficacy assessed by objective inertial-sensor gait analysis from baseline to 240 min.ResultsObjective lameness values changed over time (P < 0.001), with no treatment effect (P = 0.620) or treatment-by-time interaction (P = 0.409). Mean clinical improvement approached 70% for both treatments at 10 min. At 240 min, improvement was approximately 86% after ropivacaine and 46% after mepivacaine; however, this was descriptive because the treatment-by-time interaction was not significant. At 24 h, total protein was 2.16 g/dL after ropivacaine and 3.42 g/dL after mepivacaine (P < 0.001). Lactate dehydrogenase activity was lower after ropivacaine than mepivacaine (513 vs. 991 U/L; P = 0.012).ConclusionUnder the conditions studied, ropivacaine produced a clinical response comparable to mepivacaine while being associated with smaller acute changes in the evaluated synovial fluid biomarkers.

The Criollo horse is prized for its endurance, yet its specific biomechanical signatures remain under-researched. This study investigated diagonal dissociation and support patterns in eleven clinically sound Criollo horses to understand the influence of head and neck position (HNP), surface compliance, and morphometry. Using high-speed video (120 fps) and kinematic analysis, we found that diagonal dissociation occurred in 85.24% of hoof contacts, while HNP1 showed a higher frequency of positive (hindlimb-first) dissociation and HNP2 had a higher incidence of negative (forelimb-first) dissociation (p = 0.0398). On soft ground, both HNPs predominantly exhibited hindlimb-first dissociation (p = 0.0446). Soft ground is also associated with the appearance of tripedal support, whereas hard ground presented more synchronous (non-dissociated) diagonal limb support. Thoracic monopedal and tripedal supports are weakly correlated with forelimb measurements, whereas pelvic monopedal and tripedal supports correlate with global body dimensions. All associations were weak to moderate (R² ≤ 0.40). The prevalence of dissociated phases and the absence of a standard symmetrical trot suggest a distinct breed signature adapted for functional efficiency and stability required for its traditional working roles.