Effect of sedation on fore- and hindlimb lameness evaluation using body-mounted inertial sensors.

This study explores the effects of sedation on the evaluation of lameness in horses, primarily the front and hind legs, using body-mounted inertial sensors. The main objective was to determine whether sedation with a dose of xylazine would influence the severity of lameness as measured by these sensors.

Research Background and Objectives

• The study addressed an integral challenge in equine healthcare – the evaluation of lameness. Sedation is often required in uncooperative horses to facilitate diagnostic analgesia. But the study focused on whether sedation, which has effects such as ataxia (lack of voluntary coordination of muscle movements) and analgesia (inability to feel pain), would interfere with the evaluation of lameness.
• Considering the above challenge, the research specifically aimed to evaluate whether a low-dose sedation with xylazine, a drug commonly used to sedate horses, impacts the accuracy of lameness assessments which are measured using body-mounted inertial sensors.

Research Methods

• The experiment involved forty-four horses that were randomly divided into two groups. Subsequently, lameness in these horses was measured using body-mounted inertial sensors both before and after injecting xylazine (0.3 mg/kg bwt) or saline.
• The impact of sedation on the severity of lameness was assessed at 5, 20, and 60 minutes following the treatment. Both forelimb and hindlimb lameness were evaluated with measurements of the differences in head height and pelvic height maximums and minimums for right and left strides.
• To evaluate changes over time, the numbers of horses whose lameness remained the same, improved, or worsened were compared across groups at each time interval.

Research Findings

• The results showed that there were no significant differences in the head or pelvic movement asymmetry between the groups treated with xylazine and saline. However, some horses with forelimb lameness in the xylazine group showed a substantial decrease in head movement asymmetry – indicative of a decrease in forelimb lameness – 60 minutes after sedation.
• Based on these findings, the study concluded that low-dose sedation with xylazine can be used without the worry of masking potential lameness in the hindlimb during evaluation. However, caution must be exercised in cases involving some horses showing mild severity forelimb lameness.