ANESTHETIC EFFECTS OF TILETAMINE-ZOLAZEPAM, ALONE OR IN COMBINATION WITH BUTORPHANOL, IN GOATS

Objective-To evaluate anesthetic effects of tiletamine-zolazepam (TZ), alone or in combination with butorphanol, in goats undergoing laparot omy for embryo collection. Design-Randomized clinical trial with cross over design. Animals-9 adult female goats. Procedure-Goats were anesth etized twice: once with TZ (5.5 mg/kg [2.5 mg/lb] of body weight, IV) and once with tiletamine-zolazepam and butorphanol (0.1 mg/kg [0.045 m g/lb], IV). Additional doses of TZ (0.5 to 1.0 mg/kg [0.23 to 0.45 mg/ lb], IV) were administered as needed to maintain a surgical anesthetic plane. Time to sternal recumbency was recorded, and quality of induct ion was scored. Arterial pressures, heart rate, respiratory rate, and rectal temperature were recorded every 5 minutes; arterial blood sampl es were collected every 30 minutes. Oxygen was insufflated if estimate d saturation of hemoglobin in peripheral arterial blood with oxygen wa s < 90%; intermittent positive-pressure ventilation was performed if g oats became apneic. Muscle relaxation, quality of anesthesia, and eye signs were scored every 15 minutes during anesthesia. Anesthesia time was recorded, and quality of recovery and degree of postoperative anal gesia were scored. Plasma cortisol concentration was measured before i nduction, immediately after extubation, and 2 hours after extubation. Results-Induction was rapid and smooth. Five goats regurgitated, 3 req uired supplemental oxygen, and 1 required intermittent positive-pressu re ventilation, but none of the goats became hypotensive. Muscle relax ation and quality of anesthesia were adequate. Goats recovered from an esthesia without complications. We did not detect any significant diff erences between anesthetic regimens for any of the variables measured, except bicarbonate concentration and base excess. Clinical Implicatio ns-TZ at a dose of 5.5 mg/kg was satisfactory for anesthetic induction in goats; additional doses can be given to extend anesthesia time, bu t addition of butorphanol at a dose of 0.1 mg/kg to this regimen does not seem to provide any measurable benefit. An oxygen source and a mea ns of assisting ventilation should be available.