A xylazine infusion regimen to provide analgesia in sheep.

The efficacy of continuous low-dose xylazine infusion following an initial loading dose in providing analgesia in sheep was examined using an algesimetry method based on a leg lifting response to an electrical stimulus. Sheep received a 5 mg intramuscular injection of xylazine followed by continuous infusion of intravenous xylazine (2mg/h) for 90 min. This treatment resulted in significant increases in the level of current required to elicit a leg lifting response (287% of baseline) and steady state analgesia was maintained from 10 min after the start of the infusion until the end of the experimental period. This protocol appears to be a simple and effective regimen for providing steady state analgesia in sheep.