A comparison of two combinations of xylazine-ketamine administered intramuscularly to alpacas and of reversal with tolazoline.
OBJECTIVE
To evaluate the anesthetic and cardiorespiratory effects of two doses of intramuscular (IM) xylazine/ketamine in alpacas, and to determine if tolazoline would reduce the anesthetic recovery time.


METHODS
Prospective randomized crossover study.


METHODS
Six castrated male alpacas.


METHODS
Each alpaca received a low dose (LD) (0.8 mg kg(-1) xylazine and 8 mg kg(-1) ketamine IM) and high dose (HD) (1.2 mg kg(-1) xylazine and 12 mg kg(-1) ketamine IM) with a minimum of one week between trials. Time to sedation, duration of lateral recumbency and analgesia, pulse rate, respiratory rate, hemoglobin oxygen saturation, arterial blood pressure, blood-gases, and the electrocardiogram were monitored and recorded during anesthesia. With each treatment three alpacas were randomly selected to receive tolazoline (2 mg kg(-1) IM) 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 > or =30 minutes of anesthesia in five of six alpacas. The LD provided > or =30 minutes of anesthesia in three of six alpacas. Respiratory depression and hypoxemia occurred with the HD treatment during the first 10 minutes of lateral recumbency: two animals were severely hypoxemic and received nasal oxygen for 5 minutes. Heart rate decreased, but there were no significant changes in arterial blood pressure. Tolazoline significantly shortened the duration of recumbency with the HD.


CONCLUSIONS
The HD provided more consistent clinical effects in alpacas than the LD. Intramuscular tolazoline shortened the duration of lateral recumbency in alpacas anesthetized with the HD combination.


CONCLUSIONS
Both doses of the combination were effective in providing restraint in alpacas and the duration of restraint was dose dependent. Supplemental oxygen should be available if using the HD and IM administration of tolazoline will shorten the recovery time.
Prado
Tulio M
TM
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK, USA. tprado@utk.edu
DuBois
William R
WR
Ko
Jeff C H
JC
Mandsager
Ronald E
RE
Morgan
Gregor L
GL
D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000778:Anesthetics, Dissociative / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D002161:Camelids, New World; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D007273:Injections, Intramuscular; D007649:Ketamine / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008297:Male; D014043:Tolazoline / Q000494:pharmacology*; D014991:Xylazine / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D000778:Anesthetics, Dissociative; D014991:Xylazine; D007649:Ketamine; D014043:Tolazoline