Sedation with xylazine and lumbosacral epidural administration of lidocaine and xylazine for umbilical surgery in calves.

摘要

Six newborn male dairy calves were sedated with xylazine (0.1 mg/kg body weight, i.m.), and 5 min later a 2% solution of lidocaine (0.18 to 0.24 ml/kg) and xylazine (0.05 mg/kg) were administered into the lumbosacral epidural space. Calves were positioned in dorsal recumbency, and the umbilical structures were resected. Local infusion of lidocaine, cranial to the umbilicus, was required in 5 of 6 calves to provide adequate analgesia. Xylazine sedation was reversed with tolazoline (1 mg/kg, i.v.). Calves maintained adequate cardiac output and oxygen delivery throughout the procedure but were hypotensive. Reversal of xylazine-induced sedation with tolazoline caused transient sinus bradycardia and sinus arrest, accompanied by severe systemic arterialhypotension. All calves regained a suckle reflex within 10 min and were able to stand within 90 min. Intramuscular administration of xylazine for sedation and epidural administration of lidocaine and xylazine for analgesia failed to provide satisfactoryanalgesia for umbilical resection without supplemental local infiltration of lidocaine. It is suggested that the anaesthetic protocol is most useful when respiratory compromise or cost are concerned and the surgical procedure can be completed in <1 h. It is added that caution should be exercised when tolazoline is administered intravenously to reverse xylazine-induced sedation in calves.