A comparison of two intramuscular doses of xylazine-ketamine combination and tolazoline reversal in llamas

Abstract

Objective To evaluate the anesthetic and cardiorespiratory e¡ects of two doses of intramuscular xylazine/ketamine in llamas, and to determine if an intramuscular injection of tolazoline would shorten the anesthesia recovery time.Study design Prospective randomized study. Animals Six castrated male llamas.Methods Each llama received a low dose (LD) (0.4 mg kg À1 xylazine and 4 mg kg À1 ketamine) and high dose (HD) (0.8 mg kg À1 xylazine and 8 mg kg À1 ketamine). Time to sedation, duration of lateral recumbency and analgesia, pulse, respiratory rate, hemoglobin oxygen saturation, arterial blood pressure, blood gases, and the electrocardiogram were monitored and recorded during anesthesia.Three llamas in each treatment were randomized to receive intramuscular tolazoline (2 mg kg À1 ) after 30 minutes of lateral recumbency.Results Onset of sedation, lateral recumbency, and analgesia was rapid with both treatments. The HD was able to provide at least 30 minutes of anesthesia in all six llamas. The LD provided only 30 minutes of anesthesia in two out of six llamas. Respiratory depression and hypoxemia were seen in the HD treatment during the ¢rst 10 minutes of lateral recumbency. Two llamas were severely hypoxemic during this period and were given nasal oxygen for ¢ve minutes. Heart rate decreased, but there were no sig-ni¢cant changes in blood pressure. Tolazoline signi¢cantly shortened the duration of recumbency in the HD treatment.Conclusions The HD provided more consistent clinical e¡ects in llamas than did the LD. Intramuscular tolazoline shortens the duration of lateral recumbency in llamas anesthetized with this combination.Clinical relevance Both doses appear to be very e¡ective in providing restraint in llamas. The LD may be used for procedures requiring a short period of anesthesia or restraint. The HD could be used when a longer duration of anesthesia is desired. Supplemental oxygen should be available if using the HD. Tolazoline (IM) shortened the recovery time with this combination in llamas.