Presentation on theme: "WILDLIFE CHEMICAL IMMOBILIZATION 1 Terry J. Kreeger Supervisor, Veterinary Services Branch Wyoming Game and Fish Department 2362 Highway 34 Wheatland,"— Presentation transcript:
WILDLIFE CHEMICAL IMMOBILIZATION 1 Terry J. Kreeger Supervisor, Veterinary Services Branch Wyoming Game and Fish Department 2362 Highway 34 Wheatland, WY Presentation prepared by N. J. Silvy
Introduction Chemical immobilization is the use of drugs to capture or restrain animals. The term “immobilization” describes the actions of such drugs which can range from tranquilization to paralysis to general anesthesia.
Considerations-Questions ► What is the species, age, sex, and physical condition of the animals being captured? ► What need to be done with or to the animals while they are restrained? ► Is physical restraint or chemical immobilization the better option? ► Is adequate assistance available? ► Is the proper equipment available? ► What is the local geography and landcover like? ► What is the local weather on the capture days?
Characteristics of Ideal Immobilizing Drug ► Wide safety margin for a given dosage ► Compatible with other drugs and solutions ► No adverse tissue reaction if administered intramuscularly ► Short induction time ► Should be reversible (with an antagonist or antidote) ► Chemically stable ► Concentrated to allow small volume dosage (~2–3ml) ► Low cost ► Not a controlled substance
Legal Considerations ► Conditions for the use of drugs (pharmaceuticals) are established by the Food and Drug Administration (FDA). Only 4 drugs have been specifically approved by the FDA for use on certain wild animals: carfentanil for use on cervids; xylazine for use on elk and fallow, mule, sika, and white-tailed deer; yohimbine for use on cervids (deer and elk); and ketamine for use on primates. ► However, the Animal Medicinal Drug Use Clarification Act of 1994 essentially allowed approved animal and human drugs to be used “extra label” under certain conditions. In general, those conditions are the drug: (1) approved by the FDA; (2) used by, or on the lawful written or oral order of, a licensed veterinarian; and (3) used within the context of a valid veterinarian/client/patient relationship.
Additional Legal Considerations ► Additionally, if the animal could be consumed by a human, the veterinarian should: (1) establish a substantially extended withdrawal time (the time from the date that a drug was administered to when the animal can safely be consumed by humans); (2) be able to identify the treated animals; and (3) assure that assigned timeframes for withdrawal are met and no illegal residues occur.
Controlled Substances A controlled substance means a drug that is identified in 1 of 5 schedules established by the Drug Enforcement Administration (DEA). Special regulations govern the recording and storage of these drugs. Act requires an individual to have a special DEA registration number in order to possess controlled substances. Biologists have obtained a DEA registration number and have been able to procure drugs through veterinary product distributors. However, even though they are in possession of these drugs, they cannot use them on animals without veterinary supervision. Non- veterinarians can legally administer drugs if a valid veterinarian/client/patient relationship is established. The veterinarian does not have to be on site during the actual immobilization event, but he or she should be involved in the planning process.
Drug Schedules Schedule I: This is reserved for experimental and abused drugs such as heroin, marijuana, and lysergic acid diethylamide (LSD). No capture drugs are Schedule I. Schedule II (IIN): This includes most of the opioids used for animal immobilization, such as etorphine, fentanyl, sufentanil, and carfentanil and the opioid antagonist, diprenorphine. Schedule III (IIIN): This contains ketamine and tiletamine/zolazepam. Schedule IV: Includes benzodiazepine tranquilizers, such as diazepam and midazolam, and butorphanol. Schedule V: This covers small, limited quantities of narcotic drugs included in preparations with non-narcotic active medicinal ingredients. No capture drugs are Schedule V.
Types of Drugs Used: Tranquilizers Usually will not cause immobilization by themselves Increase effectiveness of other agents Nearly always used in combination with other agents Examples ► Phenothiazine derivatives (readily available ) Promazine (Sparine®) Acetylpromazine (PromAce®) Chlorpromazine (Thorazine®) ► Droperidol (Innovar-vet® ) ► Haloperidol
Types of Drugs Used: Sedatives Can induce immobilization by themselves (depending on species) Can be used in combination with other agents Produces hypnotic-like state Manipulation of sedated animal may produce arousal Examples ► Diazepam (Valium®) ► Xylazine (Rompun®) Wide safety margin but may not effect immobilization Reversible with yohimbine (Antagonil®) Readily available
Types of Drugs Used: Neuromuscular Paralytic Agents Narrow safety margin Under dosage produces no effect Over dosage produces apnea (stops breathing) Not reversible Fairly readily available Examples ► Nicotine sulfate (extraordinarily narrow margin of safety) ► Succinylcholine chloride (Sucostrin®, Anectine®) ►
Types of Drugs Used: Dissociative Anesthetics Ketamine hydrochloride (Ketaset®, Vetalar®) ► Wide margin of safety ► Used with a wide variety of animals ► Often used with xylazine or acetylpromazine ► Produces catatonia-like immobilization ► Reversible with tolazoline (Priscoline®) ► Readily available ► May need large volumes for some species Tiletamine and zolazepam (Telazol®) ► Zolazepam is a tranquilizer, so no others needed ► Wide margin of safety ► Used with a wide variety of animals ► Federal permit required; Schedule III controlled substance; must be under the authority of licensed veterinarian Phencyclidine hydrochloride (Sernylan®) ► Wide margin of safety ► Was the agent of choice for large carnivores (e.g., Ursus spp.) ► Can be combined with tranquilizers ► Not readily available; Schedule II controlled substance; must be under the authority of licensed veterinarian ► Compound also known as PCP or "angel-dust" ► Human abuse potential
Types of Drugs Used: Narcotic Anesthetics Not readily available, controlled substances Significant risk to humans Used on a wide variety of animals, especially ungulates Can be used with other agents Reversible with naloxone (Naline®) or specific antagonists Examples ► Etorphine (M-99®) Readily reversible with diprenorphine (M- 50/50®) May require larger volumes in mega- herbivores Often used with xylazine Available with acepromazine as Large and Small Animal Immobilon® Schedule II controlled substance; must be under the authority of licensed veterinarian Fentanyl Often combined with droperidol (Innovar-Vet®) Readily reversible with naloxone Schedule II controlled substance; must be under the authority of licensed veterinarian ► Carfentanil citrate (Wildnil®) Works well on the largest animals Readily reversible with naloxone Schedule II controlled substance; must be under the authority of licensed veterinarian Extremely dangerous for humans if accidentally exposed
Dose Calculations ► Several factors influence dose needed Animal species Mass Age Sex Psychological state Condition ► Calculation Estimate animal mass Doses listed in mg of drug per kg body mass in reference books Syringes loaded as ml drug, so mg/ml required
Formula for Calculating Volume ► The formula is: ► Volume of Drug Administered = Body Weight x Dosage ► Drug Concentration ► ► For example, consider immobilizing an animal that weighs 80 kg (176 lb) with drug “X”. The recommended dosage of drug X for this animal is 5 mg/kg. The concentration of drug X is 100 mg/ml. First, calculate the total mg needed for this animal by multiplying the animal’s weight (80 kg) by the recommended drug dosage (5 mg/kg): ► ► Milligrams of drug X needed = 80 kg x 5 mg/kg = 400 mg ► ► Then calculate the volume of drug solution to withdraw from the bottle by dividing the total mg (400 mg) by its concentration (100 mg/ml):
► Hand-held syringe ► Push pole or pole syringe (easily made) ► Blow gun Limited size of dart Limited delivery volume Limited range, but accurate with practice Reduced danger of impact trauma as compared to air- and combustion-powered guns Can be readily manufactured by user Delivery Systems: Non-gun
Delivery Systems: Capture Guns Air-powered gun Pistol or rifle Variable power on demand (manual bleed-off, etc.) Can handle larger darts than blow gun Longer range than blow gun Can be accurate with practice Impact trauma not severe if proper technique used, but still potentially dangerous Combustion-powered gun Pistol or rifle Variable powder charges available Can handle large darts (6–10 inches) Poor range with largest darts; extended range with smaller darts Accurate ;can be equipped with telescopic sights Higher potential for impact trauma than previous delivery systems
Dart Placement The preferred areas for intramuscular injection are the large muscles of the hindquarters or the shoulder. In elk and many other ungulates, the area in the rump where the light hair meets the darker hair is a good aiming point.
Common Drugs and Their Antagonists Drug classificationDrug nameAntagonist ______________________________________________________________________________ ParalyticSuccinycholineNone Tranquilizer/SedativeAcepromazineNone Tranquilizer/SedativeDiazepamFlumazenil Tranquilizer/SedativeMidazolamFlumazenil Tranquilizer/SedativeAzaperoneNone Tranquilizer/SedativeXylazineYohimbine, tolazoline, atipamezole Tranquilizer/SedativeMedetomidineAtipamezole CyclohexaneKetamineNone CyclohexaneTiletamine (in Telazol ® )None OpioidCarfentanilNaltrexone, naloxone OpioidThiafentanilNaltrexone, naloxone OpioidSufentanilNaltrexone, naloxone OpioidButorphanolNaltrexone, naloxone OpioidEtorphineNaltrexone, naloxone, diprenorphine
Moose immobilized with only opioids (carfentanil, thiafentanil, etorphine) invariably remain sternal with head up. The addition of a tranquilizer increases the probability of pneumonia because moose have a tendency to roll over and aspirate rumen contents.
Resources (web sites) for Supplies Animal Care Equipment and Services, Inc. (Dart guns, darts, blow pipes, other animal capture equipment) Dan-Inject (Dart guns, darts, blow pipes) Palmer Chemical & Equipment Co., Inc. (Dart guns, darts) Pneu Dart, Inc. (Dart guns, darts, blow pipes) Telinject USA, Inc. (Dart guns, darts, blow pipes) Wildlife Pharmaceuticals, Inc. (North American supplier of capture drugs)
Recommended Dosages for Ungulates SpeciesImmobilizing dosage Antagonist _______________________________________________________________________________________________ Bison mg/kg carfentanil plus 0.07 mg/kg xylazine 0.5 mg/kg plus 1 mg/kg tolazoline Caribou 2.5 mg/kg ketamine plus 0.25 mg/kg medetomidine 1.25 mg/kg atipamezole Deer, mule4.4 mg/kg Telazol ® plus 2.2 mg/kg xylazine 2 mg/kg tolazoline Deer, white-tailed4.4 mg/kg Telazol ® plus 2.2 mg/kg xylazine 2 mg/kg tolazoline Moose0.01 mg/kg carfentanil 1 mg/kg naltrexone Mountain goat0.035 mg/kg carfentanil 3.5 mg/kg naltrexone Pronghorn0.05 mg/kg carfentanil plus 1 mg/kg xylazine 5 mg/kg naltrexone plus 2 mg/kg tolazoline Bighorn0.05 mg/kg carfentanil plus 0.2 mg/kg xylazine 5 mg/kg naltrexone plus 2 mg/kg tolazoline
Recommended Dosages for Other Small Mammals SpeciesImmobilization dosages ____________________________________________________ Badger 4.4 mg/kg Telazol ® Beaver10 mg/kg ketamine plus 1 mg/kg xylazine Marmot 80 mg/kg ketamine plus 10 mg/kg xylazine Muskrat50 mg/kg ketamine plus 5 mg/kg xylazine Opossum 10 mg/kg ketamine plus 2 mg/kg xylazine Porcupine 5 mg/kg ketamine plus 2 mg/kg xylazine Rabbit 30 mg/kg ketamine plus 6 mg/kg xylazine Squirrel 10 mg/kg Telazol ®
SUMMARY ► Drugs and the equipment used to administer them have become more sophisticated, efficacious, and safe over the past half century. ► Today, capture drugs should be part of every wildlife management professional’s armamentarium. ► Although capture drugs should be used judiciously, they should always be considered as a primary solution to should always be considered as a primary solution to problems where animal and human safety is uppermost. problems where animal and human safety is uppermost.