Immobilization of sika deer with medetomidine and ketamine, and antagonism by atipamezole

Forty wild sika deer (Cervus nippon) were immobilized with medetomidine and ketamine and reversed by atipamezole in summer and fall captures from September 1994 to October 1995. For large yearling and older deer, mean +/- SD doses of 57.0+/-15.6 microg/kg medetomidine and 1.64+/-0.49 mg/kg (male) or 4.02+/-1.16 mg/kg (female) of ketamine were administered by intramuscular injection. For calves and small yearlings, 69.3+/-7.0 microg/kg medetomidine and 2.69+/-0.44 mg/kg ketamine were administered. While immobilized, deer were easy to handle, and muscles were well relaxed. After intramuscular administration of atipamezole (about 5 times the dose of medetomidine), deer recovered rapidly and smoothly.     

Immobilization of California sea lions using medetomidine plus ketamine with and without isoflurane and reversal with atipamezole

The use of medetomidine and ketamine, alone and in combination with isoflurane, with atipamezole reversal was evaluated for immobilizing 51 California sea lions (Zalophus californianus) for a variety of medical procedures at a rehabilitation center in northern California (USA) between May 1997 and August 1998. Animals were given 140 microg/kg medetomidine with 2.5 mg/kg ketamine intramuscularly. Mean (+/-SD) time to maximal effect was 8+/-5 min. At the end of the procedure, animals were given 200 microg/kg atipamezole intramuscularly. Immobilization and recovery times were, respectively, 25+/-12 and 9+/-7 min for 35 animals maintained with medetomidine and ketamine alone and 58+/-30 and 9+/-9 min for 16 animals intubated and maintained with isoflurane. No mortalities occurred as a result of the immobilizations. Disadvantages of the medetomidine and ketamine combination included a moderate variation in time to maximal effect and plane of sedation, a large injection volume and high cost. However, this combination offers safe and reversible immobilization that can be easily administered by the intramuscular route and that produces a plane of anesthesia that is sufficient to carry out most routine diagnostic procedures.     

Effects of repeated anaesthesia with ketamine/medetomidine and of pre-anaesthetic administration of buprenorphine in rats

Two groups of rats were anaesthetized at weekly intervals for 6 weeks with either ketamine/medetomidine alone (60 mg/0.4 mg/kg i.p.) or ketamine/medetomidine (45 mg/0.3 mg/kg i.p.) one hour following buprenorphine (0.05 mg/kg s.c.). Animals that received buprenorphine had longer periods of surgical anaesthesia (P = 0.04) and a greater depression of both mean pedal withdrawal score (P < 0.01) and mean respiratory rate (P = 0.014). Mean total duration of anaesthesia was also greater in the buprenorphine group on day 1. Sleep times reduced with successive doses of anaesthetic in the buprenorphine group (P = 0.024). Two animals in the buprenorphine group died. Repeated anaesthesia with ketamine/medetomidine alone was not associated with anaesthetic mortality. These results indicate that although buprenorphine has a clear anaesthetic-sparing effect, its use with ketamine/medetomidine may be associated with an increased risk of anaesthetic-related mortality.     

The influence of pre-anaesthetic administration of buprenorphine on the anaesthetic effects of ketamine/medetomidine and pentobarbitone in rats and the consequences of repeated anaesthesia

Rats received pentobarbitone (60, 48 and 36 mg/kg i.p.) or ketamine/medetomidine (75/100, 60/80 and 45/60 mg/microg/kg i.p.) alone, or one hour following buprenorphine (0.5 mg/kg s.c.). Animals were anaesthetized once per week for 6 weeks with one of three anaesthetic doses according to a randomized block design. In the pentobarbitone group, animals which received buprenorphine had longer sleep times (236 +/- 22 cf. 204 +/- 21 min) and longer durations of surgical anaesthesia (83 +/- 14 cf. 27 +/- 8 min) (P<0.01), these effects being potentiated with increasing anaesthetic doses (P<0.01). A greater degree of respiratory depression was found in animals that received buprenorphine (P<0.01) although this was judged clinically acceptable in all cases. Unexpectedly high mortality and a high incidence of anaesthetic complications (nine of 16 animals) in the ketamine/medetomidine group made statistical analysis of these data impossible. We conclude that for pentobarbitone, pre-anaesthetic administration of buprenorphine reduces the dose of anaesthetic required to produce surgical anaesthesia, in addition to the presumed benefits of pre-emptive analgesia. In view of the high mortality encountered, we advise caution when considering pre-anaesthetic use of opioids in combination with ketamine/medetomidine in rats.     

Effective immobilizing doses of medetomidine-ketamine in free-ranging, wild Norwegian reindeer (Rangifer tarandus tarandus)

Combinations of medetomidine and ketamine were evaluated in free-ranging, wild Norwegian reindeer (Rangifer tarandus tarandus) as part of a reintroduction program in southwestern Norway in November 1995 and November 1996. The drugs were administered by dart from a helicopter. The mean (SD) effective immobilizing doses for 29 adults (8 males, 21 females) were 0.21 (0.04) mg medetomidine/kg and 1.0 (0.2) mg ketamine/ kg based on estimated body mass. There was no significant difference in mean induction times between males and females. However, animals with optimal hits (shoulder or thigh muscles; n=16) had a significantly shorter (P<0.05) mean induction time than did animals with suboptimal hits (abdomen or flank; n=13), 5.6 (2.2) min and 11.1 (4.7) min, respectively. Inductions were calm, and immobilized animals were maintained in sternal recumbency. Clinical side effects included hypoxemia and hyperthermia in most animals. For reversal, all animals received 5 mg atipamezole per mg medetomidine, half intravenously and half intramuscularly, and the mean (SD) time to standing was 3.7 (3.6) min.     

Comparison of intravenous medetomidine and medetomidine/ketamine for immobilization of free-ranging variable flying foxes (Pteropus hypomelanus)

Medetomidine (0.03 mg/kg) and medetomidine/ketamine (0.05/5.0 and 0.025/2.5 mg/kg), administered by intravenous injection, were evaluated for short-term immobilization of wild-caught variable flying foxes (Pteropus hypomelanus). Medetomidine alone produced incomplete chemical restraint and a stressful, prolonged induction. Both ketamine/medetomidine doses produced a smooth induction and complete immobilization. The combined medetomidine/ketamine dose of 0.025/2.5 mg/kg produced a rapid induction (232±224 sec) with minimal struggling and vocalization, a complete and effective immobilization period, and tended to lead to a faster and better quality recovery than medetomidine alone or a higher dose of medetomidine and ketamine (0.05/5.0 mg/kg), thus reducing holding time and permitting an earlier release of the bat back into the wild.     

Experience with a naphthylmedetomidine – ketamine – hyaluronidase combination in inducing immobilization in anthropoid apes

Background The aim of the study was to compare the effect of naphthylmedetomidine to medetomidine on the behavior of orangutans and chimpanzees. Methods The immobilization was performed as part of a medical examination in five chimpanzees and three orangutans. Following pre‐medication with midazolam (0.70–1.20 mg/kg p.o.), naphthylmedetomidine (50–70 μg/kg), or medetomidine (20–30 μg/kg) was given with ketamine (3 mg/kg) and hyaluronidase (150 M.U.) into musculus deltoideus. Results We observed the distinct anti‐aggressive effect of naphthylmedetomidine. The immobilization with naphthylmedetomidine was shallower and the influence on cardiac frequency less substantial compared to medetomidine. The overall sedative effect of naphthylmedetomidine lasted for less time, and its effect was incompletely antagonized with atipamezole in comparison to medetomidine. Conclusions Naphthylmedetomidine could replace medetomidine for inducing immobilization and sedation. A combination of naphthylmedetomidine–ketamine is suitable for relocating animals to other cages or for painless medical examinations.     

Immobilization of Chacoan peccaries (Catagonus wagneri) using medetomidine, Telazol, and ketamine

A combination of medetomidine, Telazol, and ketamine hydrochloride was used to immobilize captive Chacoan peccaries (Catagonus wagneri) for translocation within Paraguay during August-October 2002. Animals were darted in enclosed areas of varying size. The average dose used was 32.5+/-7.2 microg/kg of medetomidine, 0.63+/-0.2 mg/kg of Telazol, and 3.9+/-0.65 mg/kg of ketamine. First effects were noted at 4.3+/-2.1 min, and ability to handle the animals was achieved by 12.6+/-3.7 min. Heart and respiratory rates declined and oxygen saturation increased during anesthesia. Muscle relaxation was good. Atipamezole was used to antagonize the medetomidine, although recoveries were still slow. This drug combination provided adequate immobilization of Chacoan peccaries; however, this protocol would not be considered to be reversible, and confinement during recovery is recommended.     

Anesthesia of wild red howler monkeys (Alouatta seniculus) with medetomidine/ketamine and reversal by atipamezole

Wild red howler monkeys (Alouatta seniculus) were translocated during the flooding of the forest at a hydroelectric dam site in French Guiana. For a variety of minor clinical procedures, 96 monkeys were anesthetized with various intramuscular injections of combinations of medetomidine and ketamine. The howler population was composed of healthy animals (42 males and 54 females) of various ages. Medetomidine (150 μg/kg) associated with ketamine (4 mg/kg) gave the best results and was used on 63 animals. The injection rapidly resulted in complete immobilization with good to excellent myorelaxation. The induction stage was quiet, with absence of both corneal and pedal withdrawal reflexes in 57 animals after 2.9 ± 1.4 min. Six animals required an additional injection. Rectal temperature and respiratory and heart rates decreased during anesthesia, whereas relative oxyhemoglobin saturation increased. One death occurred during anesthesia. One abortion and one death also occurred the day following anesthesia but were more probably a result of capture stress. Atipamezole given i.m. at a dose of five times the medetomidine dose 38.4 ± 8.0 min after the anesthetic injection led to standing recovery in 7.1 ± 4.5 min. Spontaneous recovery occurred in 17 animals before the atipamezole injection after an average of 30.6 ± 9.6 min. Total recovery time was shorter in young animals. Medetomidine/ketamine induced good myorelaxation and provided considerably shortened immobilization duration, which are two notable advantages for field studies. We recommend this association for short procedures including minor surgery in red howler monkeys. Am. J. Primatol. 45:399–410, 1998. © 1998 Wiley-Liss, Inc.     

The effect of the novel partial alpha2-adrenoceptor agonist naphthylmedetomidine on the basic cardiorespiratory parameters and behavior in rhesus monkeys

Background  The aim of this study was to compare cardiorespiratory and behavioral profile of a new alpha 2-adrenoceptor ligand naphthylmedetomidine with medetomidine in rhesus monkeys.
Methods  Naphthylmedetomidine or medetomidine (50 μg/kg) together with ketamine (3 mg/kg) and hyaluronidase (150 IU/kg) i.m was administered to 35 rhesus monkeys. Behavioral changes were then observed together with blood pressure, heart rate and oxygen saturation of hemoglobin.
Results  The onset of sedation, ataxia, and reduction of aggression was similar in both treatment groups. Immobilization was observed only in medetomidine treated animals, while in naphthylmedetomidine treated animals loss of aggressiveness was observed but the animals never completely lost mobility. Naphthylmedetomidine showed less prominent effects on cardiorespiratory functions compared with medetomidine.
Conclusions  Our results suggest that naphthylmedetomidine can be used to induce sedation in primates and other small animals while avoiding the serious side effects observed after administration of the currently used full α₂-AR agonists.     

The efficacy of orally dosed ketamine and ketamine/medetomidine compared with intramuscular ketamine in rhesus macaques (Macaca mulatta) and the effects of dosing route on haematological stress markers

BACKGROUND: This study compared the efficacy of two orally-dosed (PO) anaesthetic regimens for chemical immobilization in rhesus macaques (Macaca mulatta), versus the standard protocol of intramuscular (TM) ketamine. In addition, the effects of dosing route on haematological stress markers were evaluated. METHODS: Testing was conducted on 18 chronically housed animals. Animals were trained to accept oral dosing and then randomly assigned to one of three drug regimens: (1) ketamine IM, (2) ketamine PO, (3) Ketamine/medetomidine PO. Sedation levels for each regimen were evaluated. RESULTS: Oral dosing alone was not sufficient to achieve a plane of sedation that allowed for safe handling. Serum cortisol and glucose levels were unchanged across groups, although differences were observed in the leukogram profiles. CONCLUSION: The oral dosages used in this study fell short in providing adequate sedation for safe handling for routine veterinary procedures. Leukogram profiles indicated that orally dosed animals experienced a higher level of stress.     

Comparison of Neurologic Responses to the Use of Medetomidine as a Sole Agent or Preanesthetic in Laboratory Beagles

Different dose regimens of medetomidine (a potent α2-adrenergic agonist), adding up to a combined dose of 80 µg/kg, were administered to laboratory beagles to determine physiologic responses including neurologic. The study was intended to determine EEG responses where sufficient sedative and analgesic effects are reached with medetomidine and in contrast its effects when used with ketamine or halothane. Cardiopulmonary responses were very similar in each dose regimen, showing the characteristic properties of single doses of 80 µg/kg of medetomidine. Effective sedative and analgesic duration seemed to be a function of when the largest dose was administered. Adequate additional sedative and analgesic could be gained from injections at doses of half of the initial one. The potent sedative and analgesic effects of medetomidine confirmed by neurologic evaluation supports its potential use as a premedication to general anesthesia in dogs. In this study, 2 different doses of medetomidine were also tested as premedication to both ketamine HCl and halothane anesthesia. Neorologic responses were determined at the same time cardiopulmonary parameters, anesthetic quality, and dose requirements were recorded. Medetomidine was found to have favorable qualities in conjunction with these anesthetics. Cardiopulmonary parameters remained satisfactory in both groups as preanesthetic medication prior to halothane, but no additional benefits could be seen from doses of 40 µg/kg medetomidine compared to 20 µg/kg, except a significant 30% reduction in halothane requirement. The positive chronotropic and inotropic properties of ketamine restored the medeto-midine-induced bradycardia and produced a short anesthetic period of 15 to 30 min depending on the dose of medetomidine. The quality of anesthesia was better when 40 µg/kg medetomidine was used, but recorvery was quicker with 20 µg/kg medetomidine. Medetomidine significantly reduced cerebral activity as demonstrated by recordings of total amplitude and frequency evaluation of the EEG with compressed spectral analysis. This analytical method was effective in confirming clinical signs of sedation, analgesia, and anesthesia in canine subjects.     

外科教学中犬的复合麻醉效果观察

目的比较氯胺酮、地西泮和丙泊酚复合麻醉在外科教学中对犬的麻醉效果。方法成年健康杂种犬42条,诱导麻醉相同,均肌注氯胺酮（10 mg/kg）和氟哌利多（0.5 mg/kg）混合液。静脉维持采用不用的方法,分为三组,分别是静脉滴注氯胺酮地西泮混合液（n=12）、静脉推注氯胺酮地西泮混合液（n=12）和静脉滴注丙泊酚利多卡因混合液（n=18）。结果三组麻醉效果显示,静脉滴注丙泊酚利多卡因混合液效果最好,优83.3%,良16.7%,死亡率0%。结论在外科教学中,对犬采用丙泊酚复合麻醉是一种较为理想的麻醉方法。     

Field immobilization of feral 'Judas' donkeys (Equus asinus) by remote injection of medetomidine and ketamine and antagonism with atipamezole

The Judas technique is a method used for landscape control of feral donkeys (Equus asinus) in northern Australia. Central to the success of any Judas program is the safe, efficient, and humane attachment of the telemetry device. For feral donkeys, this involves the use of field immobilization. We examine the replacement of the current chemical capture agent, succinylcholine, with contemporary immobilization agents to achieve positive animal welfare outcomes. A combination of medetomidine and ketamine delivered by remote injection from a helicopter was used to capture 14 free-ranging feral donkeys for the fitting of telemetry collars in Western Australia in November 2010. Dose rates of 0.14 mg/kg medetomidine and 4.1 mg/kg ketamine were appropriate to immobilize animals in 9 min (± SD = 3). Mean recovery time (total time in recumbency) was 21 min (± 14). All animals recovered uneventfully after being administered atipamezole, a specific antagonist of medetomidine, intramuscularly at 0.35 mg/kg. Physiologic parameters were recorded during recumbency, with environment-related hyperthermia being the only abnormality recognized. No significant complications were encountered, and this drug combination represents an efficient approach to capturing wild donkeys. This new method allows a rapid, safe, cost-effective approach to the immobilization of feral donkeys for use as Judas animals. This drug combination will replace the relatively inhumane succinylcholine for the field immobilization of feral donkeys.     

Transplacental transfer of medetomidine and ketamine in pregnant ewes

The extent of placental transfer of medetomidine and ketamine is unknown in pregnant ewes. Date-mated singleton (n = 8) and twin (n = 8) pregnant merino cross ewes were anaesthetized for Caesarean delivery of preterm lamb fetuses. A combination of medetomidine (20 μg/kg) and ketamine (10 mg/kg) was administered by intravenous injection and surgery performed immediately thereafter. Blood samples were collected from the ewe at one, five and 10 min after intravenous injection and from the umbilical vein of the fetus at delivery. Non-pregnant ewes were also anaesthetized (n = 8). There was no difference in the plasma concentration of medetomidine or ketamine when comparing singleton and twin ewes or pregnant and non-pregnant ewes for the short duration of the study. Fetal plasma concentrations of each drug were comparable to the maternal concentrations at the same time. We conclude that both drugs cross the placenta readily and provide anaesthesia and analgesia for the fetus when it is delivered.     

Pentobarbital versus medetomidine-ketamine-fentanyl anaesthesia: effects on haemodynamics and the incidence of ischaemia-induced ventricular fibrillation in swine

The present study was performed to compare haemodynamic variables at baseline and the incidence of ventricular fibrillation during the early phase of ischaemia in swine during pentobarbital or medetomidine-ketamine-fentanyl anaesthesia. Twenty-two swine (mean +/- SD: 29+/- 3 kg) were anaesthetized with sodium pentobarbital (induction with 36 mg/kg intraperitoneally, and maintenance with 5-20 mg/kg/h intravenously [i.v.]) and 6 swine (27+/- 3 kg) were anaesthetized with ketamine and fentanyl (premedicated with medetomidine 0.1 mg/kg and ketamine 10 mg/kg intramuscularly, induction with ketamine 20 mg/kg and fentanyl 0.025 mg/kg i.v., and maintenance with ketamine 20 mg/kg/h and fentanyl 0.025 mg/kg/h i.v.). After a stabilization period of 30 min, the left anterior descending coronary artery (LAD) was occluded for 10 min. Haemodynamic data and occurrence of ventricular fibrillation were recorded. The ischaemic area was measured by fluorescing microspheres. Swine anaesthetized with medetomidine-ketamine-fentanyl had significantly lower heart rate, myocardial contractility, peak left ventricular pressure, arterial blood pressure, aortic blood flow, myocardial blood flow and cardiac index at baseline, than swine anaesthetized with pentobarbital. Whereas none of the swine anaesthetized with pentobarbital fibrillated during the LAD occlusion, ventricular fibrillation occurred in 83% of the animals anaesthetized with medetomidine-ketamine-fentanyl (P< 0.001). No significant difference was found in size of ischaemic area between the two groups. Thus, we show a depression in haemodynamic variables at baseline and a higher incidence of ventricular fibrillation during the early phase of ischaemia in swine anaesthetized with medetomidine-ketamine-fentanyl compared to swine anaesthetized with pentobarbital.     

Optimal medetomidine dose when combined with ketamine and tiletamine-zolazepam to immobilize white-tailed deer

Chemical immobilization is often needed for safe and effective capture and handling of wildlife. We evaluated medetomidine (125, 150, 175, or 200 μg/kg; for synergistic effects and relaxation) mixed with ketamine (1.5 mg/kg; for relatively shorter recovery) and tiletamine-zolazepam (1.0 mg/kg; for rapid induction) in 22 female white-tailed deer (Odocoileus virginianus) at the University of Georgia Whitehall Deer Research Facility in Athens, Georgia, USA, on 14-15 and 21 May 2009. Deer were weighed before treatment, hand-injected intramuscularly (IM) while restrained in a squeeze chute, and released into a pen for monitoring. We measured rectal temperature, respiration rate, heart rate, hemoglobin saturation (using pulse oximetry), and arterial blood gases at 0, 10, and 20 min postimmobilization. We found no differences in induction time with different doses of medetomidine. Deer became laterally recumbent for all treatments combined at a median of 4.2 (2.6-21.3) min and were approachable by a median of 4.8 (3.5-21.8) min. Twelve of the 22 deer had rectal temperatures >40 C at time 0 and were treated with a cold-water enema. Hemoglobin saturation, estimated using pulse oximetry, was 79.5, 82.0, and 82.3% at times 0, 10, and 20, respectively. We injected atipamezole (0.35 mg/kg, IM) for reversal. Recovery occurred sooner and was more consistent for 125 and 150 μg/kg medetomidine whereby deer stood with minimal sedation to moderate ataxia within 60-90 min after atipamezole administration. We recommend using 150 μg of medetomidine with ketamine (1.5 mg/kg) and tiletamine-zolazepam (1.0 mg/kg) to provide effective and safe chemical immobilization of white-tailed deer.     

Immobilization of Himalayan tahr with a xylazine-ketamine mixture and reversal with atipamezole under field conditions

Twenty-nine free-ranging Himalayan tahr (Hemitragus jemlahicus) were darted in the Sagarmatha National Park (Nepal) using different combinations of xylazine and ketamine. Animals in Group 1 (n = 4) received a mean xylazine-ketamine dose of 2.77 +/- 0.99 mg/kg xylazine plus 3.32 +/- 0.19 mg/kg ketamine in males and 2.39 +/- 0.10 mg/kg xylazine plus 4.29 +/- 0.17 mg/kg ketamine in females. Animals in Group 2 (n = 25) received a mean xylazine-ketamine dose of 1.70 +/- 0.41 mg/kg xylazine plus 3.06 +/- 0.74 mg/kg ketamine in males and 1.82 +/- 0.29 mg/kg xylazine plus 3.29 +/- 0.52 mg/kg ketamine in females. No anesthetic-related mortality was recorded. Anesthesia was reversed by a standard dose of 11 mg/animal of atipamezole administered by intramuscular injection. Although all anesthetic dosages immobilized free-ranging tahr successfully, a quick and smooth recovery was obtained (11.1 +/- 5.6 min) only with the dosages of Group 2.     

Field immobilization and euthanasia of American opossum

Seventeen recently trapped opossum, Didelphis virginiana, (median weight 2.45 kg; range = 1.6-5.0 kg; quartiles = 1.8-3.3 kg) were immobilized with either telazol (15 or 30 mg/kg) or a mixture of medetomidine (100 micrograms/kg), butorphanol (0.2 mg/kg), and ketamine HCl (10 mg/kg) based on estimated weights. Anesthetized animals were subjected to cardiac puncture for blood withdrawal and toe pinch. Euthanasia was accomplished by intracardiac administration of 1 ml of concentrated pentobarbital sodium/phenytoin solution. Weights were underestimated for 14 of 17 animals, but were within 0.5 kg of the actual weight. Both drug combinations provided rapid and calm immobilization. Median time to recumbency for the medetomidine-butorphanol-ketamine group (n = 5) was 6 min (range = 4-10 min; quartiles = 6 and 8 min). The median time to recumbency was not statistically different for the low (n = 6) and high dose (n = 6) telazol groups, 3 and 3.5 min respectively (quartiles 3; 3.5 and 4; 5.5 min). The stronger heart beat with telazol immobilization facilitated cardiac puncture. All five animals administered the medetomidine-butorphanol-ketamine mixture and three of six animals given the low telazol dose reacted to cardiac puncture. Only one of six animals given the estimated 30 mg/kg dose of telazol reacted slightly to cardiac puncture. We conclude that 30 mg/kg telazol provides sufficient immobilization and analgesia to allow accurate cardiac puncture of the opossum if the procedure is performed within 5 to 10 min of recumbency. Intracardiac administration of concentrated pentobarbital sodium/phenytoin solution followed by bilateral thoracotomy provides appropriate euthanasia suitable for field situations.     

Immobilization of free-ranging European mink (Mustela lutreola) an polecat (Mustela putorius) with medetomidine-ketamine and reversal by atipamezole

From March 1996 to August 1999, 24 free-ranging European mink (Mustela lutreola) and 25 free-ranging polecats (Mustela putorius) were immobilized for clinical procedures and to place radio transmitters. Data were recorded during 14 and 12 trials, respectively. Animals received intramuscularly 10 mg/kg ketamine (KET) combined with 0.20 mg/kg medetomidine (MED), antagonized by 1.00 mg/kg atipamezole (ATI). Anesthesia times were similar between species. Induction was smooth and rapid (0.7-3.9 min); the degree of anesthesia and muscle relaxation was satisfactory in most animals. Two individuals showed signs of spontaneous recovery before injection of ATI. In other individuals, ATI was injected 28.1-54.0 min after the MED-KET injection and rapidly reversed the effects of the MED. Rectal temperature and heart and respiratory rates decreased significantly 5-25 min post MED-KET injection in both species. Rectal temperature successfully remained stable by placing animals on a warmed plastic table (37 C) during anesthesia. According to these results, this anesthetic protocol produces a safe and rapid immobilization in free-ranging European mink and polecats and is recommended for surgical procedures such as radio transmitter implantation. However caution is required as hypothermia can be severe. Body temperature must be monitored and means provided to maintain stability.