A comparison of three combinations of injectable anesthetics in miniature donkeys.

Objective: To compare three combinations of injectable anesthetics in miniature donkeys for quality of induction, recovery, muscle relaxation, cardiopulmonary changes during anesthesia and duration of recumbency. Design  Prospective, randomized experimental study.

Animals: Six miniature donkeys (< 90 cm in height at the withers) weighing 92-127 kg were used.

Materials and Methods: The drug combinations were: xylazine-butorphanol-ketamine (XBK), xylazine-butorphanol-tiletamine-zolazepam (XBT) and xylazine-propofol (XP). Each miniature donkey was anesthetized with each combination at 1-week intervals in random order. Heart and respiratory rates, indirect blood pressure and temperature were measured before and at 5-minute intervals during recumbency. Arterial blood samples were drawn for blood-gas analysis before and at 5, 15 and 30 minutes of anesthesia when samples could be collected. Recumbency time to sternal and time to standing were recorded and a subjective evaluation of induction, muscle relaxation and recovery were made.

Results: Mean recumbency time ± SD was 14.7 ± 9.4, 33.8 ± 6.3 and 14.6 ± 1.9 minutes with XBK, XBT and XP, respectively. Mean time to standing ± SD was 28.4 ± 11.3, 43.7 ± 7.2 and 26.3 ± 2.9 minutes with XBK, XBT and XP, respectively. Heart and respiratory rates and blood pressures varied from baseline but were always within normal ranges. Hemoglobin saturation, pH and PaO 2 tended to be lower with these doses of XBT and XP.

Conclusions and Clinical Relevance: Overall quality of anesthesia was poor with XBK. At the doses used this combination did not provide sufficient anesthesia compared with the combinations of XBT and XP, which appeared to provide acceptable anesthesia of short duration in miniature donkeys.

(Copyright © 2002 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)