Effects of acepromazine and xylazine on subjective and objective assessments of forelimb lameness

Background To facilitate lameness evaluation, sedatives such as xylazine and acepromazine are regularly used in the clinical setting, despite concerns that they may confound lameness assessment. Objectives The objective of this study was to determine the effect of low doses of acepromazine and xylazine on subjective and objective lameness assessment. Study design Randomised, blinded, crossover study. Methods Six horses with experimentally induced solar pain were evaluated over a 1‐hour period after treatment with intravenous xylazine (0.1 or 0.2 mg/kg), intravenous acepromazine (0.02 or 0.04 mg/kg), intravenous saline (1 mL) or local analgesia (4 mL 2% mepivacaine administered subcutaneously). Lameness was assessed objectively with inertial sensors and subjectively on a scale from 0 to 5. Lameness assessments were compared with logistic regression analysis to account for the repeated measures and cross‐over study design (P