Anesthesia, Capture, and Handling of Cervidae
By: Clifford F. Shipley, DVM, DACT University of Illinois, College of Veterinary Medicine
Originally appeared in the Summer 2016 Issue of Whitetails of Louisiana
There are many different species of cervidae and their behavior, physiology, and biology are not the same. Therefore, this topic will be limited to whitetails, mule deer and wapiti that are the primary species being farmed today in the US. A brief history of remote anesthesia, considerations for anesthesia and capture and drugs, equipment and supplies necessary for successful capture and anesthesia will be discussed. For more training and in-depth detail, persons interested should take a full length training course in remote anesthesia and capture. Care should be taken when working with other cervid species to find the correct dose of selected anesthetics as they may vary wildly from species to species.
Plant and animal poisons have been used for thousands of years by various peoples to catch or kill game or people. Puff adder, cobra, scorpion, frog, and beetle venoms have all been used by various peoples as has curare. Blowpipes, darts, spears, and bows and arrows have all been used as delivery vehicles for these chemicals. In 1953 a Crossman air rifle was adapted to deliver Flaxedil to a whitetail deer by Hall. Palmer “Cap-Chur” equipment was developed in the late 1950‘s. Since then, crossbows, cartridge fired guns, spring fired guns, CO2 fired, and etc. have all been used to deliver drugs for the purpose of capturing or killing animals.
Considerations for remote injection are very important. One of the most important considerations is time. One should never get in a hurry. This can lead to mistakes with drugs on dosages and the situation that you are dealing with. One must judge the animal and attempt to guess its weight as closely as possible. Most drugs used in remote injection have a fairly wide safety margin, but it is best to try to get within 10-20% of the animal‘s weight If possible. There are weight tapes that may be useful in estimating weights and should be carried with you to “weigh" animals after capture to allow you to more accurately guess animals on the hoof as you gain experience. .
Other time considerations that may need to be taken into account are the facts that these procedures almost always take longer than anticipated. Start early in the day so that if procedures do take longer than anticipated, you do not run out of daylight. Also find out how long personnel may be able to stay around to help (carrying animals long distances is not fun) as well as making provisions for food, water, and bathroom if possible.
The temperament of the animal is very important in choosing your drugs and how you go about delivering the drugs to the animal. If it is very wild and you can only get within 50 yards, it may change what drug you use, dose, and delivery method. Conversely, if it is a bottle-fed animal that's extremely tame, hand or pole injection may work well and dosages may be reduced. Likewise, if the animal is worked up and is pacing or running the pen, it may well need special attention after capture due to hyperthermia. If it is too worked up, consideration should be given to delaying the event so that capture myopathy does not occur.
Ambient temperature is very important as well. Working animals in even moderate temperatures can be dangerous as they overheat very quickly if agitated. Cold weather can be just as dangerous as they do not thermoregulate well under anesthesia and may go hypothermic if not observed, covered or properly cared for. Putting an anesthetized animal in the sun on a hot day or on frozen ground is a recipe for disaster.
Preparedness is critical. Walk through or visualize the process. Go over all procedures and actions that you will take. Take control of the situation and tell everyone what their job is and what it is exactly that you will want them to do. Have an equipment checklist and go over it before leaving for the capture event. Making up “kits” that contain all supplies necessary for the procedure and having a list on that kit that makes it easy to find and restock, maintain and clean. Human emergencies should also be anticipated. Exposure to drugs and injuries during capture events can and do happen. Make sure that you know the local emergency procedures and location of hospitals or other emergency treatment areas. Animal emergencies from darting also happen frequently. Darts may cause damage or animals may become worked up and injure themselves by hitting fencing, fighting, attempting to elude capture. Know the drugs you will use and what complications that they may cause as you may have an adverse reaction to deal with.
Consideration for "why" to do remote anesthesia is very important. Is the procedure or treatment necessary? Is there a better way to accomplish the mission? Does the risk of anesthesia and/or remote Injection warrant it? If no working facilities are available or they are In poor condition or are inadequate for the procedure, it may be beneficial to do remote anesthesia. Sometimes it would endanger the animal more to move it to a handling facility or the facility is too far away to move the animal to. Is this the best option for the safety and welfare of the animal? Do the personnel have the training and background for the job and are they willing to take responsibility for the outcome? Taking all of the questions into account before undertaking the procedure should be standard operating procedure.
Anesthetic considerations for whitetails and mule deer should include some of the following: length of the procedure, pain associated with the procedure, is the animal tame, wild, in rut, excited, in pain, suffering from disease or condition that may affect the outcome if anesthetized, where will the procedure take place (they can drown in puddles and ponds, hurt themselves on fences, machinery, feeders, or wedge themselves in trees, etc.), how fast will the animal go down and how far away can they get?
There are a number of drugs on the market that will work well for injectable anesthesia in these animats. You should probably select two or three different protocols that will fit most situations and become familiar with the dose, how fast they go down, how they react to the drug(s), how they metabolize the drug(s), how long they will stay down, how to extend anesthetic time if necessary, reversal agents and dose. and what to do If human exposure occurs among others.
Very calm whitetails and mule deer may be anesthetized with xylazine alone at a dose of 2.5-3.0 mg/kg IM. This may be accomplished by hand injection, blow darting, and pole syringe or dart gun. If the animal is excited at all, this may not work. Fawns less than a year of age may require more xylazine, up to 60mgtkg IM (Bubenick 1982). This has not been the author's experience and he routinely uses the adult dose or less. Reversal at any time can be done with tolazine (tolazoline) 3 mg/kg IM or ½ dose IV and ½ IM; yohimbine 0.125 mg/kg IM or ½ dose IV or atipamezole 0.35 mg/kg IM or ½ IV and ½ IM.
For deer that are wilder or are going to be subjected to short, painful procedures, a xylazine plus ketamine combination works very well. Ketamine has a very wide safety margin and the dose can be adjusted up or down depending on the excitement of the animal and the length of the procedure. It's also useful to “top off” animals during the procedure or if the procedure takes longer than anticipated. This combination usually gives a working time of approximately 30 minutes. Dosages for this combination are xylazine 2.5-3.0 mg/kg + ketamine 3-6 mg/kg IM. Reversal can be done 30 minutes after the last dose of ketamine is given with any of the reversal agents mentioned above for the xylazine.
Xylazine 03-0.8 mg/kg + Telazol® 1.5-2.0 mg/kg M is another very effective combination for mildly excited deer. This combination gives approximately 60 minutes of working time and can be topped off with ketamine if necessary. Reversal with any of the agents listed for xylazine can be given 60-80 minutes past induction. They will still be mildly sedated due to the effects of Telazol|®. Induction times vary with excitability levels but are usually 5-8 minutes.
Other drugs and combinations for mildly excited deer are ketamine 7.5 mg/kg + xylazine 1.5 mg/kg IM; ketamine 2.0 mg/kg + medetomidine 0.07 mg/kg (reverse with atipamezole 0.35 mg/kg); etorphine 6 mg, reverse with 2 mg diprenorphine per mg etorphine given. For more excited deer, Telazol® 4.4 mg/kg + xylazine 2.2 mg/kg works very well and can be supplemented with 2.2 mg/ kg ketamine as needed every 10-15 minutes. Reverse the xylazine fraction at 60-80 minutes post induction or 30 minutes after the last dose of supplemental ketamine has been given. Telazol® 4.4 mg/kg may be used by itself and gives up to an hour of working time. Carfentanil 0.03 mg/kg + xylazine 0.7 mg/kg may also be used for extremely wild or excited deer. Reverse With 100 mg naltrexone per mg carfentanil and either tolazine or yohimbine for the xylazine fraction of the combination.
A tranquilizer that may be used in combination with xylazine is azaperone (0.1 mg/kg IM). This will not be reversed with the xylazine and the deer will remain tranquil post reversal. This is also one of the drugs in a new combination combining butorphanol and medetomidine. The dosage for this combination is butorphanol 0.41-0.62 mg/kg + azaperone 0.31-0.41 mg/kg + medetomidine 0.19-0.25 mg/kg. Recommended reversal dosage is 15 mg atipamezole for fawns and does and 25 mg for bucks, 50 mg naltrexone (fawns, does, and bucks) and tolazine 200 mg for fawns and does and 400 mg for bucks, all IM.
Wapiti (elk) and red deer dosages for xylazine are 1.0 mg/kg IM; xylazine 1.0 mg/kg + ketamine 1.0-2.0 mg/kg IM; xylazine 1.0 mg/kg + Telazol® 20 mg/kg IM; carfentanil 10 µg/kg + xylazine 0.1 mg/kg IM. Reversal agents are yohimbine 0.1-0.2 mg/kg IM or divide the dose and give ½ IM and ½ IV; tolazoline 2.0-4.0 mg/kg IM or divide the dose and give ½ IM and ½ IV; atipamezole 100 μg/kg IM or divide the dose and give ½ IM and ½ IV or ¼ IV and ¾ SQ; naltrexone 1mg/kg IV. (All dosages are from Anesthesia of North American Deer, Caulkett, N and Haigh. J. 2004.) Other drugs and dosages are ketamine 4 mg/kg + xylazine 2 mg/kg IM, reverse in 30-40 minutes With yohimbine 0.125 mg/kg IM or ½ IM and ½ IV; ketamine 2 mg/kg + medetomidine 0.07 mg/kg, reverse with atipamezole 0.35 mg/kg (0.1-0.15 mg/kg IV and the rest SQ); Telazol®3 mg/kg + xylazine 0.4 mg/kg IM, reverse with yohimbine as previous. Many authors feel that yohimbine works better in elk and red deer and tolazoline better in whitetails and mule deer.
Darting considerations for delivery at the drug should Include size of the animal, muscle mass, dart size and speed, length of needle, type of needle (barbed or side ported), animal movement, distance of delivery, fluid characteristics of the medicament and others. It is always best to dart into the large muscle groups at the rear leg, neck or front leg. The length of the needle is important to deliver anesthetic drugs deep IM so they may be absorbed and distributed properly. An injection into fat or fascia slows absorption and animals will not respond as anticipated. When delivering antibiotics or vaccines via darting equipment, dart length may not be as important, but side potting may be beneficial.
Patient monitoring during anesthesia is important. If possible, the patient should be kept in sternal recumbency to allow eructation and keep proper circulation to the lungs and heart. The temperature of the animal should be monitored to keep from getting too hot or too cold. If patient temperature goes above 103 degrees F or below 100 degrees F, interventions should be started to keep hyper- or hypo-thermia from setting in. Packing the animal with ice, giving alcohol baths, giving cold water enemas, and pouring cold water over the animal may all be tried to help regulate overheating. Heating pads, blankets, straw, or other material may be used to help keep the animal warm. Reversing anesthetics may be necessary to alleviate bloating, respiratory and cardiac depression. It is usually beneficial to cover the animal’s eyes to decrease stress and lessen the chance of arousal. It may also keep the eyes from being damaged during the capture and restraint process.
Capture myopathy is the most dangerous potential complication. The cause is intensive muscle activity and results in high lactic acid levels which destroy muscle in both the body and the heart. Death may be immediate, or they may die within 24 hours with another stress that releases K+ from damaged muscle. Ataxic-myoglobinuric Syndrome may appear hours to days after capture. Muscle Rupture Syndrome may appear up to 4 weeks later. Prevention is the key. Limit chase or stress episodes to two minutes or less. Don't be afraid to abort the mission. Dead animals don't heal well.
Make sure that recovery from anesthesia is in an appropriate area. Make sure all people and equipment are safe and away from the recovery area. Try to assure that the temperature is appropriate and reverse as soon as possible. Place the animal in sternal recumbency in a quiet area where n can be watched from a distance for problems during recovery. Try to observe till animal is ambulatory and out of danger from falling or other animals.
K. Amass and L. Nielsen, Chemical Immobilization of Animals, Safe-Capture International, Inc., Mt. Horeb, Wisconsin, 2000.
M. Fowler and R. Miller, Zoo and Wild Animal Medicine, 5th Edition, Saunders, St. Louis, Missouri, 2003, pages 637-639.
Originally appeared in the Summer 2016 Issue of Whitetails of Louisiana
There are many different species of cervidae and their behavior, physiology, and biology are not the same. Therefore, this topic will be limited to whitetails, mule deer and wapiti that are the primary species being farmed today in the US. A brief history of remote anesthesia, considerations for anesthesia and capture and drugs, equipment and supplies necessary for successful capture and anesthesia will be discussed. For more training and in-depth detail, persons interested should take a full length training course in remote anesthesia and capture. Care should be taken when working with other cervid species to find the correct dose of selected anesthetics as they may vary wildly from species to species.
Plant and animal poisons have been used for thousands of years by various peoples to catch or kill game or people. Puff adder, cobra, scorpion, frog, and beetle venoms have all been used by various peoples as has curare. Blowpipes, darts, spears, and bows and arrows have all been used as delivery vehicles for these chemicals. In 1953 a Crossman air rifle was adapted to deliver Flaxedil to a whitetail deer by Hall. Palmer “Cap-Chur” equipment was developed in the late 1950‘s. Since then, crossbows, cartridge fired guns, spring fired guns, CO2 fired, and etc. have all been used to deliver drugs for the purpose of capturing or killing animals.
Considerations for remote injection are very important. One of the most important considerations is time. One should never get in a hurry. This can lead to mistakes with drugs on dosages and the situation that you are dealing with. One must judge the animal and attempt to guess its weight as closely as possible. Most drugs used in remote injection have a fairly wide safety margin, but it is best to try to get within 10-20% of the animal‘s weight If possible. There are weight tapes that may be useful in estimating weights and should be carried with you to “weigh" animals after capture to allow you to more accurately guess animals on the hoof as you gain experience. .
Other time considerations that may need to be taken into account are the facts that these procedures almost always take longer than anticipated. Start early in the day so that if procedures do take longer than anticipated, you do not run out of daylight. Also find out how long personnel may be able to stay around to help (carrying animals long distances is not fun) as well as making provisions for food, water, and bathroom if possible.
The temperament of the animal is very important in choosing your drugs and how you go about delivering the drugs to the animal. If it is very wild and you can only get within 50 yards, it may change what drug you use, dose, and delivery method. Conversely, if it is a bottle-fed animal that's extremely tame, hand or pole injection may work well and dosages may be reduced. Likewise, if the animal is worked up and is pacing or running the pen, it may well need special attention after capture due to hyperthermia. If it is too worked up, consideration should be given to delaying the event so that capture myopathy does not occur.
Ambient temperature is very important as well. Working animals in even moderate temperatures can be dangerous as they overheat very quickly if agitated. Cold weather can be just as dangerous as they do not thermoregulate well under anesthesia and may go hypothermic if not observed, covered or properly cared for. Putting an anesthetized animal in the sun on a hot day or on frozen ground is a recipe for disaster.
Preparedness is critical. Walk through or visualize the process. Go over all procedures and actions that you will take. Take control of the situation and tell everyone what their job is and what it is exactly that you will want them to do. Have an equipment checklist and go over it before leaving for the capture event. Making up “kits” that contain all supplies necessary for the procedure and having a list on that kit that makes it easy to find and restock, maintain and clean. Human emergencies should also be anticipated. Exposure to drugs and injuries during capture events can and do happen. Make sure that you know the local emergency procedures and location of hospitals or other emergency treatment areas. Animal emergencies from darting also happen frequently. Darts may cause damage or animals may become worked up and injure themselves by hitting fencing, fighting, attempting to elude capture. Know the drugs you will use and what complications that they may cause as you may have an adverse reaction to deal with.
Consideration for "why" to do remote anesthesia is very important. Is the procedure or treatment necessary? Is there a better way to accomplish the mission? Does the risk of anesthesia and/or remote Injection warrant it? If no working facilities are available or they are In poor condition or are inadequate for the procedure, it may be beneficial to do remote anesthesia. Sometimes it would endanger the animal more to move it to a handling facility or the facility is too far away to move the animal to. Is this the best option for the safety and welfare of the animal? Do the personnel have the training and background for the job and are they willing to take responsibility for the outcome? Taking all of the questions into account before undertaking the procedure should be standard operating procedure.
Anesthetic considerations for whitetails and mule deer should include some of the following: length of the procedure, pain associated with the procedure, is the animal tame, wild, in rut, excited, in pain, suffering from disease or condition that may affect the outcome if anesthetized, where will the procedure take place (they can drown in puddles and ponds, hurt themselves on fences, machinery, feeders, or wedge themselves in trees, etc.), how fast will the animal go down and how far away can they get?
There are a number of drugs on the market that will work well for injectable anesthesia in these animats. You should probably select two or three different protocols that will fit most situations and become familiar with the dose, how fast they go down, how they react to the drug(s), how they metabolize the drug(s), how long they will stay down, how to extend anesthetic time if necessary, reversal agents and dose. and what to do If human exposure occurs among others.
Very calm whitetails and mule deer may be anesthetized with xylazine alone at a dose of 2.5-3.0 mg/kg IM. This may be accomplished by hand injection, blow darting, and pole syringe or dart gun. If the animal is excited at all, this may not work. Fawns less than a year of age may require more xylazine, up to 60mgtkg IM (Bubenick 1982). This has not been the author's experience and he routinely uses the adult dose or less. Reversal at any time can be done with tolazine (tolazoline) 3 mg/kg IM or ½ dose IV and ½ IM; yohimbine 0.125 mg/kg IM or ½ dose IV or atipamezole 0.35 mg/kg IM or ½ IV and ½ IM.
For deer that are wilder or are going to be subjected to short, painful procedures, a xylazine plus ketamine combination works very well. Ketamine has a very wide safety margin and the dose can be adjusted up or down depending on the excitement of the animal and the length of the procedure. It's also useful to “top off” animals during the procedure or if the procedure takes longer than anticipated. This combination usually gives a working time of approximately 30 minutes. Dosages for this combination are xylazine 2.5-3.0 mg/kg + ketamine 3-6 mg/kg IM. Reversal can be done 30 minutes after the last dose of ketamine is given with any of the reversal agents mentioned above for the xylazine.
Xylazine 03-0.8 mg/kg + Telazol® 1.5-2.0 mg/kg M is another very effective combination for mildly excited deer. This combination gives approximately 60 minutes of working time and can be topped off with ketamine if necessary. Reversal with any of the agents listed for xylazine can be given 60-80 minutes past induction. They will still be mildly sedated due to the effects of Telazol|®. Induction times vary with excitability levels but are usually 5-8 minutes.
Other drugs and combinations for mildly excited deer are ketamine 7.5 mg/kg + xylazine 1.5 mg/kg IM; ketamine 2.0 mg/kg + medetomidine 0.07 mg/kg (reverse with atipamezole 0.35 mg/kg); etorphine 6 mg, reverse with 2 mg diprenorphine per mg etorphine given. For more excited deer, Telazol® 4.4 mg/kg + xylazine 2.2 mg/kg works very well and can be supplemented with 2.2 mg/ kg ketamine as needed every 10-15 minutes. Reverse the xylazine fraction at 60-80 minutes post induction or 30 minutes after the last dose of supplemental ketamine has been given. Telazol® 4.4 mg/kg may be used by itself and gives up to an hour of working time. Carfentanil 0.03 mg/kg + xylazine 0.7 mg/kg may also be used for extremely wild or excited deer. Reverse With 100 mg naltrexone per mg carfentanil and either tolazine or yohimbine for the xylazine fraction of the combination.
A tranquilizer that may be used in combination with xylazine is azaperone (0.1 mg/kg IM). This will not be reversed with the xylazine and the deer will remain tranquil post reversal. This is also one of the drugs in a new combination combining butorphanol and medetomidine. The dosage for this combination is butorphanol 0.41-0.62 mg/kg + azaperone 0.31-0.41 mg/kg + medetomidine 0.19-0.25 mg/kg. Recommended reversal dosage is 15 mg atipamezole for fawns and does and 25 mg for bucks, 50 mg naltrexone (fawns, does, and bucks) and tolazine 200 mg for fawns and does and 400 mg for bucks, all IM.
Wapiti (elk) and red deer dosages for xylazine are 1.0 mg/kg IM; xylazine 1.0 mg/kg + ketamine 1.0-2.0 mg/kg IM; xylazine 1.0 mg/kg + Telazol® 20 mg/kg IM; carfentanil 10 µg/kg + xylazine 0.1 mg/kg IM. Reversal agents are yohimbine 0.1-0.2 mg/kg IM or divide the dose and give ½ IM and ½ IV; tolazoline 2.0-4.0 mg/kg IM or divide the dose and give ½ IM and ½ IV; atipamezole 100 μg/kg IM or divide the dose and give ½ IM and ½ IV or ¼ IV and ¾ SQ; naltrexone 1mg/kg IV. (All dosages are from Anesthesia of North American Deer, Caulkett, N and Haigh. J. 2004.) Other drugs and dosages are ketamine 4 mg/kg + xylazine 2 mg/kg IM, reverse in 30-40 minutes With yohimbine 0.125 mg/kg IM or ½ IM and ½ IV; ketamine 2 mg/kg + medetomidine 0.07 mg/kg, reverse with atipamezole 0.35 mg/kg (0.1-0.15 mg/kg IV and the rest SQ); Telazol®3 mg/kg + xylazine 0.4 mg/kg IM, reverse with yohimbine as previous. Many authors feel that yohimbine works better in elk and red deer and tolazoline better in whitetails and mule deer.
Darting considerations for delivery at the drug should Include size of the animal, muscle mass, dart size and speed, length of needle, type of needle (barbed or side ported), animal movement, distance of delivery, fluid characteristics of the medicament and others. It is always best to dart into the large muscle groups at the rear leg, neck or front leg. The length of the needle is important to deliver anesthetic drugs deep IM so they may be absorbed and distributed properly. An injection into fat or fascia slows absorption and animals will not respond as anticipated. When delivering antibiotics or vaccines via darting equipment, dart length may not be as important, but side potting may be beneficial.
Patient monitoring during anesthesia is important. If possible, the patient should be kept in sternal recumbency to allow eructation and keep proper circulation to the lungs and heart. The temperature of the animal should be monitored to keep from getting too hot or too cold. If patient temperature goes above 103 degrees F or below 100 degrees F, interventions should be started to keep hyper- or hypo-thermia from setting in. Packing the animal with ice, giving alcohol baths, giving cold water enemas, and pouring cold water over the animal may all be tried to help regulate overheating. Heating pads, blankets, straw, or other material may be used to help keep the animal warm. Reversing anesthetics may be necessary to alleviate bloating, respiratory and cardiac depression. It is usually beneficial to cover the animal’s eyes to decrease stress and lessen the chance of arousal. It may also keep the eyes from being damaged during the capture and restraint process.
Capture myopathy is the most dangerous potential complication. The cause is intensive muscle activity and results in high lactic acid levels which destroy muscle in both the body and the heart. Death may be immediate, or they may die within 24 hours with another stress that releases K+ from damaged muscle. Ataxic-myoglobinuric Syndrome may appear hours to days after capture. Muscle Rupture Syndrome may appear up to 4 weeks later. Prevention is the key. Limit chase or stress episodes to two minutes or less. Don't be afraid to abort the mission. Dead animals don't heal well.
Make sure that recovery from anesthesia is in an appropriate area. Make sure all people and equipment are safe and away from the recovery area. Try to assure that the temperature is appropriate and reverse as soon as possible. Place the animal in sternal recumbency in a quiet area where n can be watched from a distance for problems during recovery. Try to observe till animal is ambulatory and out of danger from falling or other animals.
SUGGESTED READINGS AND REFERENCES:
T. Kreeger, J. Arnemo and J. Raath, Handbook Wildlife Chemical Immobilization, International Edition, Wildlife Pharmaceuticals, Inc. Fort Collins, Colorado, 1999.K. Amass and L. Nielsen, Chemical Immobilization of Animals, Safe-Capture International, Inc., Mt. Horeb, Wisconsin, 2000.
M. Fowler and R. Miller, Zoo and Wild Animal Medicine, 5th Edition, Saunders, St. Louis, Missouri, 2003, pages 637-639.
