The Effect of Xylazine Premedication on the Dose and Quality of Anesthesia Induction with Alfaxalone in Goats

SIMPLE SUMMARY: Goats have been used as animal models in research and are increasingly kept as companion animals like dogs and cats. Therefore, keeping them to be always healthy and disease free is an important matter for the owners. Anesthesia is a prerequisite for veterinarians to treat animals suffering from medical and surgical disorders. However, information about the efficacy of anesthetic drugs is scant in this species. In this current study, the quality of induction, antinociceptive and cardio-respiratory effects of a newer anesthetic combination “xylazine–alfaxalone” were evaluated. It is well known that the small opening of the oral cavity and long soft palate make intubation in goats a very challenging procedure. The findings demonstrated that xylazine reduced the dose of alfaxalone required for successful intubation and uneventful induction. In addition, this anesthetic regimen produced better antinociception with stability in cardiac function indices, however oxygen supplementation is necessary, especially in compromised animals, to counteract xylazine-associated lowering of hemoglobin oxygen saturation. ABSTRACT: Goats have been used as animal models in research and are increasingly kept as companion animals. However, information about effective anesthetic drugs is scarce in this species. The objective of this study was to evaluate the effect of xylazine premedication on alfaxalone induction. Twelve clinically healthy goats weighing 18.5 ± 2 kg were randomly assigned to two groups. Induction was performed with alfaxalone alone intravenously (ALF group) or with xylazine premedication before alfaxalone administration (XYL-ALF group). The quality of induction was scored, induction doses of alfaxalone were determined, and cardiorespiratory parameters and nociceptive thresholds were measured before any treatment(s) (baseline) and at 5, 15, 25 and 35 min after alfaxalone administration. The mean dose of alfaxalone required for induction in the ALF group was greater than that in the XYL-ALF group (p < 0.001). There were no significant changes in diastolic arterial pressure (DAP), mean arterial pressure (MAP) or systolic arterial pressure (SAP) compared to baseline in either group, while hemoglobin oxygen saturation (SpO(2)) was lower from 5 to 25 min (p < 0.5) in the XYL-ALF group. The nociceptive threshold was significantly higher at 5 min in the XYL-ALF group than in the ALF group (p = 0.0417). Xylazine premedication reduced the required dose of alfaxalone for anesthetic induction and produced better antinociception than alfaxalone alone. In addition, the combination of xylazine and alfaxalone allowed for successful induction; however, oxygen supplementation is necessary to counteract xylazine-associated hypoxemia.