A comparison of carfentanil/xylazine and Telazol/xylazine for immobilization of white-tailed deer

October 2001 to January 2002, captive free-ranging white-tailed deer (Odocoileus virginianus) were immobilized with a combination of carfentanil citrate and xylazine hydrochloride. From this study, we selected a dose of carfentanil/xylazine for the purpose of comparing immobilization parameters and physiologic effects with those of a combination of tiletamine and zolazepam (Telazol) and xylazine. Animals were initially given intramuscular injections of 10 mg xylazine and one of four doses of carfentanil (i.e., 0.5, 1.0, 1.5, and 2.0 mg). A carfentanil dose of 1.2 mg (x +/- SD = 23.5 +/- 3.2 microg/kg) and 10 mg xylazine (0.2 +/- 0.03 mg/kg) were selected, based on induction times and previously published reports, to compare with a combination of 230 mg of Telazol (4.5 +/- 0.6 mg/kg) and 120 mg xylazine (2.3 +/- 0.3 mg/kg). Time to first observable drug effects and to induction were significantly longer for deer treated with carfentanil/xylazine than with Telazol/xylazine (P < 0.01). Hyperthermia was common in deer immobilized with carfentanil/xylazine, but heart rate, respiration rate, and hemoglobin saturation were within acceptable levels. Degree of anesthesia of deer immobilized with Telazol/xylazine was superior to deer immobilized with carfentanil/xylazine. The combination of 120 mg of naltrexone hydrochloride and 6.5 mg of yohimbine hydrochloride provided rapid and complete reversal (1.9 +/- 1.1 min) of carfentanil/xylazine immobilization. Animals immobilized with Telazol/xylazine had long recovery times with occasional resedation after antagonism with 6.5 mg of yohimbine. The combination of carfentanil and xylazine at the doses tested did not provide reliable induction or immobilization of white-tailel (leer even though drug reversal was rapid and safe using naltrexone and yohimbine.     

Relative efficiency of succinylcholine, xylazine, and carfentanil/xylazine mixtures to immobilize free-ranging moose

We compared the efficiency of succinylcholine chloride, xylazine hydrochloride and carfentanil/xylazine mixtures in immobilizing 364 free-ranging moose (Alces alces) between 1987 and 1997 in Québec (Canada). With succinylcholine chloride (0.070, 0.062, 0.051 mg/kg of estimated body weight for calves, juveniles and adults), 63% of the 252 immobilization attempts led to complete immobilization and marking, whereas 7% of the darted animals died of respiratory paralysis during handling. The moose took an average of 13 min to lay down after darting (down time). Injection of xylazine (3.67-4.22 mg/kg) permitted sedation (the animal laid down but got up again when approached) or complete immobilization in 78% of the 40 darted adult moose, the mean down time being 8.7 min. No mortality was noted with this drug but 58% of the marked animals were only sedated. The use of RX821002A (0.058 mg/kg) as an antagonist, permitted a mean recovery time of 2.8 min after intravenous injection. With the carfentanil/xylazine mixtures (0.0071 and 0.181 mg/kg), 96% of the immobilization trials (n = 72) led to complete (88%) or partial (8%) immobilization, but 6% of the moose died several days after capture. The mean down time was 6.6 min, and injection of naltrexone (0.709 mg/kg) antagonized the effect of the immobilizing agent within 3.7 min. The respiratory rate was higher (P < 0.05) among moose immobilized with xylazine (35/min) than among those immobilized with carfentanil/xylazine mixtures (19/min) but this variation could be related to a longer pursuit time (z = 3.60; P < 0.01) and higher stress levels during handling. Rectal temperature also was higher with xylazine but the difference was small (39.7 vs. 39.3, P = 0.03) and did not differ significantly between the sexes (P > 0.05). Considering loss of materials and helicopter flight time due to non-successful marking trials, carfentanil/xylazine mixtures were the least expensive ($333 Cdn/animal).     

Immobilization of gray wolves (Canis lupus) with sufentanil citrate

Gray wolves (Canis lupus) were immobilized with 0.5 mg/kg xylazine plus 7.5 micrograms/kg of either sufentanil (n = 8), etorphine (n = 8), or carfentanil (n = 2). Drug doses used in this study were selected to provide consistency for comparison and are not recommended doses for effective immobilization of wolves. Induction times were similar among groups (11.9 +/- 1.0 min). Thirty min after induction, wolves were given either 0.5 mg/kg naloxone hydrochloride plus 0.15 mg/kg yohimbine hydrochloride or saline only intravenously. Arousal times for wolves given naloxone and yohimbine (1.2 +/- 0.1 min) were shorter than wolves given saline (35.5 +/- 6.4 min). Respiratory rates were similar among the three drug groups (6.9 +/- 1.0 breaths/min). One animal given sufentanil then saline was found dead 108 min after induction. Presumptive diagnosis was renarcotization and hypothermia. Results indicated that sufentanil is an effective opioid immobilizing agent for gray wolves.     

Prolonged and multiple immobilizations of the southern elephant seal using ketamine hydrochloride-xylazine hydrochloride or ketamine hydrochloride-diazepam combinations

Thirty seven southern elephant seals (Mirounga leonina) were singularly or repeatedly immobilized with combinations of ketamine hydrochloride (HCl) and xylazine HCl or ketamine HCl and diazepam. Atropine sulphate was included in the drug combinations. To permit experimental procedures the seals were immobilized for periods of 30-330 min. The mean induction dose of ketamine HCl was 8.71 +/- 0.25 mg/kg (mean +/- SE). The mean induction time was 16.02 +/- 2.62 min. For the elephant seals immobilized for periods in excess of 180 min, the mean dose of ketamine HCl used per hr was 3.31 +/- 0.13 mg/kg/hr and the mean dose of ketamine HCl used per hr postinduction was 1.31 +/- 0.15 mg/kg/hr. The mean dose of diazepam used was 0.09 +/- 0.01 mg/kg and the mean dose of xylazine HCl was 0.41 +/- 0.01 mg/kg. Elephant seals were weighed on 20 occasions (weight range: 897-1,932 kg) and the relationship between standard length and weight was found to be: Weight = 9.98 length - 2,317.63 (r2 = 0.724). Adverse reactions to seals immobilized only once or twice were not observed. Two seals immobilized on three occasions developed abscesses at the site of injection.     

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.     

Carfentanil and xylazine for immobilization of moose (Alces alces) on Isle Royale

Twenty-one moose were captured on Isle Royale between 28 May and 2 June 1984 at licks on the western end of the island. The animals were darted, at ranges of 10 to 35 m, with 3-cc dart syringes containing 3 or 4 mg of carfentanil and 100 or 175 mg of xylazine. Three animals were drugged with carfentanil alone. Immobilization time ranged from 2.5 to 6 min. There was no excitement phase evident in 18 of the animals and they rarely moved more than 30 m after darting. Reversal was begun at 30 to 90 min after darting using naloxone and diprenorphine given intramuscularly (i.m.) and intravenously (i.v.). Recovery time varied from 10 min to 3 hr with the longer times occurring at the higher doses of immobilizing drugs. Two animals died within 30 hr, one as the result of aspiration of rumen contents and the other was unable to get on its feet and was euthanized. Analysis of blood samples from the 18 moose immobilized with the drug combination yielded hemoglobin values of 13.1 +/- 0.3 g/dl, hematocrit: 37.6 +/- 0.7%, red blood cells: 5.46 +/- 0.1 million/microliter, leucocytes: 6.1 +/- 0.4 thousand/microliter, and serum urea nitrogen: 29.3 +/- 1.6 mg/dl. Our experience indicated that quiet, undisturbed moose can be immobilized with 3 mg carfentanil and 100 mg or less of xylazine.     

Efficacy of immobilizing free-ranging elk with Telazol and xylazine hydrochloride using transmitter-equipped darts

From January 1999 to April 2002, 14 free-ranging elk were darted with a mixture of Telazol reconstituted with xylazine hydrochloride (HCl) in a forested habitat in southwestern Oklahoma and north-central Arkansas. Elk were darted from ground blinds, tree stands, or a vehicle at distances of 14-46 m and were recovered 37-274 m from the dart site. Elk were located using radiotelemetry with 3-cc disposable Pneu-dart transmitter darts. Mean+/-SD dose of Telazol and xylazine HCl was 590+/-192 mg/ml and 276+/-153 mg/ml, respectively, and mean time to standing after injection of reversal agent was 27 min (range: 1-65 min). The combination of Telazol and xylazine HCl successfully immobilized free-ranging elk, and transmitter-equipped darts permitted successful location of sedated elk by two people in areas of dense forest cover. The dose required to sedate elk appeared to vary depending on physiology and behavior, but no drug-induced mortality occurred despite the wide variance in the doses administered. We recommend 500 mg Telazol reconstituted with 300 mg xylazine HCl as an initial dose for a >or=200 kg elk. If needed to achieve full sedation, up to 3 additional ml of the mixture may be administered without adverse effects.     

Xylazine hydrochloride-ketamine hydrochloride immobilization of wolves and its antagonism by tolazoline hydrochloride

Fourteen wolves (Canis lupus L.) were singularly or repeatedly immobilized with 30 mg xylazine hydrochloride (HCl) and 400 mg ketamine HCl. Mean induction time was 5.3 +/- 4.6 min (mean +/- SD). Administration of 8.0 mg/kg tolazoline HCl as an antagonist significantly reduced immobilization times from 148.0 +/- 52.7 to 47.9 +/- 8.9 min (F = 63.69, df = 1,17, P less than 0.05). The average times from injection to ambulation for 2.0, 4.0, and 8.0 mg/kg tolazoline HCl were 35.2 +/- 31.8, 18.5 +/- 11.7, and 10.2 +/- 9.1 min. Tolazoline HCl increased heart rates significantly (P less than 0.001) from 75 +/- 14 to 120 +/- 23 beats/min, reversing a xylazine HCl-induced bradycardia. Respiratory rates also increased significantly (P less than 0.01) after tolazoline HCl injection from 19 +/- 7 to 28 +/- 8 breaths/min. Immobilization resulted in an initial hypertension which was normalized after tolazoline HCl administration. One female wolf had a single sinoatrial block within 1 min of receiving tolazoline HCl. Tolazoline HCl appears to be an effective antagonist for xylazine HCl-ketamine HCl immobilization of wolves.     

Cardiovascular and behavioral responses of gray wolves to ketamine-xylazine immobilization and antagonism by yohimbine

Adult wolves (Canis lupus) were immobilized with 6.6 mg/kg ketamine hydrochloride (KET) and 2.2 mg/kg xylazine hydrochloride (XYL) administered intramuscularly. Induction time was 4.6 +/- 0.3 min (mean +/- SE). Immobilization resulted in significant bradycardia and hypertension (P less than 0.05). Twenty min after induction, the wolves were given 0.05-0.60 mg/kg yohimbine hydrochloride (YOH). Yohimbine given intravenously produced dose-related increases in heart rate (HR) with doses greater than 0.15 mg/kg resulting in extreme tachycardia (greater than 300 bpm). All doses of YOH caused a temporary decrease in mean arterial blood pressure (MABP) with some individual animals manifesting profound hypotension (less than 30 torr) at doses greater than 0.15 mg/kg. Increasing the dose of YOH above 0.15 mg/kg did not significantly decrease either arousal or ambulation times. Administering YOH at 40 or 60 min after induction resulted in decreased arousal and ambulation times. Stimulation by weighing and taking repeated blood samples during anesthesia did not shorten arousal times. We recommend that wolves immobilized with XYL-KET be antagonized with doses of YOH less than 0.15 mg/kg.     

Field immobilization of bighorn sheep with xylazine hydrochloride and antagonism with idazoxan

Xylazine hydrochloride was used to immobilize 124 Rocky Mountain bighorn sheep (Ovis canadensis canadensis) between 1983 and 1988. Doses of xylazine for free-ranging lambs ranged from 70 to 130 mg with amounts increasing with lamb age. Average doses for 11 free-ranging adult males and 21 adult females darted from the ground were (means +/- SE) 363 +/- 16 and 251 +/- 7 mg, respectively. Adult females captured in "Stevenson's " box traps (n = 7) could be immobilized with significantly (P less than 0.001) less xylazine (93 +/- 9 mg) than free-ranging females but had similar induction times. Long recovery times associated with xylazine immobilization were eliminated with the intravenous administration of idazoxan (RX 781094) at an approximate dosage of 0.1 mg/kg. Eighteen sheep given idazoxan appeared fully recovered within 3 min of injection (means +/- SE = 1.2 +/- 0.2 min). Four mortalities (three lambs, one yearling male) (3% of total) occurred before idazoxan was available for trial.     

Overwinter survival of carfentanil-immobilized male bison

A problem with studies that examine immobilization-related drug effects on large mammals is that no true control group exists because untreated (non-captured) animals in the same population have not been examined. We present data to show that overwinter survival in male bison (Bison bison) immobilized with carfentanil was the same as untreated bison. This unique experimental design allows us to conclude that the drug had no long-term effect on male bison overwinter survival.     

Immobilization with a single dose of ketamine hydrochloride and a combination of xylazine hydrochloride-ketamine hydrochloride and antagonism by yohimbine hydrochloride in the Japanese monkey (Macaca fuscata)

Forty-nine free-ranging Japanese monkeys (Macaca fuscata) were immobilized with 4.3–15.6 mg/kg (mean±S.D.=10.0±2.5 mg/kg) of ketamine hydrochloride (HCl), and 27 Japanese monkeys kept in enclosures were immobilized with a combination of 0.8–1.4 mg/kg (1.0±0.2 mg/kg) of xylazine HCl and 4.0–7.1 mg/kg (5.0±0.6 mg/kg) of ketamine HCl. In the xylazine HCl-ketamine HCl combination, good myorelaxation was induced. The mean induction times for the single dosage of ketamine HCl and the xylazine HCl-ketamine HCl combination were 2.8±1.5 min and 6.9±4.4 min, respectively. The mean immobilization times with the single dosage of ketamine HCl and the xylazine HCl-ketamine HCl combination were 39.3±16.5 min and 58.8±34.2 min, respectively. A half dose of ketamine HCl in combination with xylazine HCl could also immobilize Japanese monkeys successfully. Administrations of 0.5 mg/kg i.v. and 1.0 mg/kg i.m. of yohimbine HCl as an antagonist to xylazine HCl at 30 min after the induction reduced the immobilization time to 31.4±0.5 min and 49.0±22.1 min, respectively. Yohimbine HCl appears to be an effective antagonist to combination anesthesia by xylazine HCl-ketamine HCl in the Japanese monkey.     

Tiletamine-zolazepam-xylazine immobilization of fishers (Martes pennanti)

The effectiveness of tiletamine plus zolazepam (Telazol) and xylazine as an immobilizing combination for fishers (Martes pennanti) was evaluated. Ten fishers were intramuscularly injected using a 5:3 mixture of Telazol (2.9+/-0.6 mg/kg [mean+/-SD]) and xylazine (2.1+/-0.4 mg/kg) at Pictured Rocks National Lakeshore, Michigan (USA) during May to October, 2001-05. Mean induction time was 4.7+/-4.4 min; mean recovery time was 94.6+/-46.0 min. There was no relationship between the amount (mg/kg) of Telazol-xylazine injected and time to first effect of immobilants, dosage and time to induction, or between dosage and time to recovery. Mean heart rate remained constant through 20 min postinduction. Respiratory rate and body temperature declined through 10 and 20 min postinduction, respectively. No mortality occurred and no adverse effects were observed in individuals up to 19 mo later. It was concluded that a 5:3 mixture of Telazol-xylazine is a safe and effective immobilizing agent for fishers when conducting nonsurgical field procedures. Immobilizing fishers with 6-7 mg/kg of the combination (3.8-4.4 mg/kg Telazol and 2.3-2.6 mg/kg xylazine) should provide > or =30 min of handling time and allow full recovery in < 90 min.     

Evaluation of medetomidine/ketamine for short-term immobilization of variable flying foxes (Pteropus hypomelanus)

Four medetomidine/ketamine (M/K) doses (30 microg/kg/3 mg/kg; 40/4; 50/5; 60/6), administered by intramuscular injection, were evaluated for short-term immobilization of adult male variable flying foxes (Pteropus hypomelanus). The highest dose (60 microg/kg/6 mg/kg) produced a significantly faster induction (31 +/- 46 sec) than the lowest dose (30/3) (125 +/- 62 sec). The highest dose levels (50/5, 60/6) produced significantly longer immobilization times (52.5 +/- 25.7 min and 60.6 +/- 20.8 min, respectively) than did the lower doses (30/3, 40/4) (18.8 +/- 8.7 min and 31.0 +/- 14.3 min, respectively). The dose at which 50% of the bats were immobilized for > or = 30 min (ED(50)) was approximately 40 microg/kg/4 mg/kg. This dose produced a mean immobilization time of 31 +/- 14 min, bradypnea and bradycardia. In conclusion, a M/K dose of 50 microg/kg/5 mg/kg is recommended for greater than 30 min of relaxed immobilization in free-living variable flying foxes and is sufficient for safe collection of samples.     

Tiletamine-zolazepam-xylazine immobilization of American marten (Martes americana)

The effectiveness of tiletamine-zolazepam (Telazol) and xylazine as an immobilizing combination for American martens (Martes americana) was evaluated. Fifteen martens were intramuscularly injected on 19 occasions using a 3:2 mixture of tiletamine-zolazepam (3.2+/-0.6 mg/kg [mean +/- SD]) and xylazine (2.1+/-0.4 mg/kg) at Pictured Rocks National Lakeshore, Michigan (USA) during May to October 2002-2003. Mean induction time was 2.5+/-1.8 min; mean recovery time was 70.8+/-31.9 min. There was no relation between the amount (mg/kg) of tiletamine-zolazepam-xylazine injected and induction (r(2)=0.08, P=0.26). However, there was an inverse relation (r(2)=0.28, P<0.01) between dosage and time to first effect of immobilants. Time to recovery increased (r(2)=0.21, P=0.05) with increased dosage. Mean heart rate, respiratory rate, and body temperature declined through 10 min postinduction (P<0.05). No mortality occurred and no short-term adverse effects were observed in recaptured individuals. In conclusion, a 3:2 mixture of tiletamine-zolazepam/xylazine is a safe and effective immobilizing agent for martens when conducting non-surgical field procedures. Immobilizing martens with 4.2 mg/kg tiletamine-zolazepam and 2.8 mg/kg xylazine should provide < or =30 min of handling time and allow full recovery in about 70 min.     

Field immobilization of raccoons (Procyon lotor) with Telazol and xylazine

The effectiveness of tiletamine plus zolazepam (Telazol) and xylazine was evaluated as an immobilizing combination for raccoons (Procyon lotor). Fifteen raccoons were injected intramuscularly with a 3:2 mixture of Telazol (3.2+/-0.6 mg/kg [mean+/-SD]) and xylazine (2.1+/-0.4 mg/kg) at Pictured Rocks National Lakeshore, Michigan, USA, during May-October, 2001-03. Mean induction time was 4.8+/-3.8 min; mean recovery time was 128.5+/-48.4 min. No linear relationships were found between the amount (mg/kg) of Telazol-xylazine injected and induction (r2 = 0.06, P = 0.40) or recovery times (r2 = 0.01, P = 0.78). Mean heart rate, respiratory rate, and body temperature declined through 20 min after induction (P< 0.05). No mortality occurred and no short-term adverse effects were observed in recaptured individuals. I conclude that a 3:2 mixture of Telazol-xylazine is a safe and effective immobilizing agent for raccoons when conducting nonsurgical field procedures. Immobilizing raccoons with Telazol at 3 mg/kg and xylazine at 2 mg/kg should provide up to 60 min of handling time and usually allow full recovery in about 120 min.     

Determination and evaluation of an optimal dosage of carfentanil and xylazine for the immobilization of white-tailed deer (Odocoileus virginianus)

Using an iteration method, optimal hand-injected immobilization dosages of carfentanil/xylazine (CAR/XYL) were determined for 13 adult white-tailed deer (Odocoileus virginianus). Deer were temporarily restrained in a squeeze chute and were repeatedly immobilized one to four times at 2-5-wk intervals from December 2002 to March 2003. A fixed ratio of 1 mg CAR:10 mg XYL intramuscularly was used, increasing or decreasing the dosage until the optimal dosage (defined by an induction time < 3 min and PaCO(2)< 60 mmHg) was reached for each animal. Inductions were video-recorded and reviewed by observers blinded to drugs and dosages, who rated qualitative aspects of each induction. There were significant (P < 0.05) dosage-dependent decreases in induction time, time to first effect, PaO(2), SaO(2), and arterial pH, and significant dosage-dependent increases in PaCO(2) and quality ratings. The median optimal dosage (mOD) was 0.03 (range, 0.015-0.06) mg/kg CAR+0.3 (range, 0.15-0.6) mg/kg XYL. Induction times using the mOD were rapid (median 3.0 min [range, 1.8-10.0]), but quality ratings were considered undesirable for nine of 13 deer. Increased rectal body temperatures of 40.6+/-0.5 C (mean +/- SD) were noted in all deer and hyperthermia (T > 41 C) was noted in three. There was a positive correlation between body temperature and induction time (r=0.44). Heart rates significantly decreased from 5 to 15 min postinduction and remained decreased at the 20-min reading; there was occasional bradycardia. There was a significant increase in pH from 10 to 20 min postinduction, but metabolic acidemia (pH<7.3) persisted throughout the immobilization periods for all deer. Possible hypoxemia (SaO(2) and SpO(2)<90 mmHg but PaO(2)>60 mmHg) was present after induction, while hypercapnea (PaCO(2) > 60 mmHg) did not occur. Reversal times with naltrexone and yohimbine were rapid (mean 3.7+/-1.5 min) and uneventful, with no evidence of renarcotization. Although the median optimal dosage produced rapid inductions, no respiratory depression, complete reversal after antagonist administration, and no renarcotization, negative attributes included elevated body temperatures, acidemia, and undesirable induction qualities.     

Ciprofloxacin concentrations in serum, bone and bone marrow of rabbits

Ciprofloxacin concentrations were determined in serum, bone and bone marrow of rabbits. Four experimental groups of animals were examined: group A (n = 6) received a dosage of 60 mg/kg/day intramuscularly for 4 weeks, groups B (n = 6), C (n = 15) and D (n = 15) received dosages of 120 mg/kg/day subcutaneously for 2 days, 2 weeks, and 4 weeks, respectively. In the kinetic portion of the study, peak serum concentrations of ciprofloxacin measured at the 15 min sampling time were: 2.61 +/- 0.27 micrograms/ml in the 60 mg/kg/day group (group A) and 3.24 +/- 0.78 micrograms/ml in the 120 mg/kg/day group (group B). At necropsy, rabbits in group A had mean ciprofloxacin concentrations of 3.60 +/- 2.27 micrograms/ml in serum, 2.24 +/- 1.19 micrograms/g in marrow and 1.19 +/- 0.44 micrograms/g in bone. Rabbits in group B achieved mean levels of 4.02 +/- 1.23 micrograms/ml in serum, 2.48 +/- 0.79 micrograms/g in marrow, and 1.35 +/- 0.40 micrograms/g in bone. Rabbits in group C achieved mean levels of 5.65 +/- 2.16 micrograms/ml in serum, 3.74 +/- 1.33 micrograms/g in marrow and 1.92 +/- 0.94 micrograms/g in bone. Rabbits in group D achieved mean levels of 7.24 +/- 2.50 micrograms/ml in serum, 4.48 +/- 1.68 micrograms/g in marrow, and 1.93 +/- 0.54 micrograms/g in bone. Differences between mean values for the four experimental groups were not statistically significant.     

Antagonism of xylazine hydrochloride-ketamine hydrochloride immobilization in guineafowl (Numida meleagris) by yohimbine hydrochloride

The mean time to arousal (MTA), the mean time to sternal recumbency (MTSR) and the mean time to walking (MTW) were measured in 10 adult guineafowl (Numida meleagris) immobilized with a combination of xylazine hydrochloride (1 mg/kg) and ketamine hydrochloride (25 mg/kg). Yohimbine hydrochloride, given intravenously (1 mg/kg) at 40 min after the injection of the xylazine-ketamine, significantly shortened the MTA, the MTSR and the MTW compared to saline controls. Increasing the dosage of yohimbine to 2.5 mg/kg did not shorten recovery when compared to the lower dosage. No adverse effects were noted at either dosage of yohimbine. Yohimbine appeared to be a safe and effective antagonist of xylazine-ketamine immobilization in guineafowl and may prove useful in other avian species to produce more rapid recovery from xylazine-ketamine immobilization, xylazine sedation or xylazine overdosage.     

Anesthesia of boma-captured Lichtenstein's hartebeest (Sigmoceros lichtensteinii) with a combination of thiafentanil,medetomidine, and ketamine

A dose range was determined for anesthesia of recently boma-captured Lichtenstein's hartebeest (Sigmoceros lichtensteinii) (n = 13) with the synthetic opiate thiafentanil (THIA) (formerly called A3080) combined with medetomidine (MED) and ketamine (KET) in the Kasungu National Park, Malawi on 4 to 5 September 1999. The dose range of 11-29 micrograms/kg THIA (mean +/- SD = 21 +/- 4 micrograms/kg) combined with 5-10 mg/kg MED (8 +/- 1 micrograms/kg) plus 0.7-1.4 mg/kg KET (1.1 +/- 0.2 mg/kg) was found to be safe and effective for the field conditions associated with this study. The anesthesia produced by this drug combination was very predictable and characterized by a short induction time (3:34 +/- 1:20 min:sec), good muscle relaxation, and acceptable physiologic parameters for anesthesia periods ranging from 22:30-35:00 min:sec (31:14 +/- 2:50). Within the range of doses used in this study, times to onset of initial effects and recumbency were not dependent on THAI, MED, or KET doses. Anesthesia was rapidly and completely reversed by intravenous injections of naltrexone at 30 times the THAI dosage (0.69 +/- 0.19 mg/kg) and atipamezole at about four times the MED dosage (38 +/- 14 micrograms/kg). There was no residual effect from ketamine noted following reversal of THIA and MED and no mortality or morbidity was associated with this anesthetic regimen.