Chemical Immobilization

1. Chemical Immobilization

2. What is it? • Anesthesia of wild, free-ranging, feral animals, or those unaccustomed to human contact • Can be given with or without physical restraint of the animal

3. Objectives • Handle a wild animal in a manner that: • Inflicts least amount of stress and pain to animal • Has least risk of injury to both animal and handler • Requires: • Patience • Humaneness • Animal care • Personal safety

4. When should it be used? • Only as a last resort • When all other means of restraint are insufficient • “Does the need to capture or handle this animal justify risking this animal’s life?” • Commonly used for a variety of species • Carnivores • Ungulates • Small mammals

5. Pros • Research • Attaching radio collars, ear tags, etc. • Taking blood or other samples • Moving an animal from one location to another • Less trauma during handling • Risk of injury and stress decreased

6. Cons • Cost • Drugs • $15-$30 (per deer) • Equipment • Darts - $4 per dart • Rifle - $500-$700 • Transmitter - ~$200 • Receiver - ~$900

7. Cons • Can’t determine physiological health of animal prior to administering drugs • Risks to animal • Physical injury • Medical complications • Respiratory arrest • Cardiac arrest • Shock • Bloat • Hyper-hypothermia

8. Cons • Risks cont. • Fleeing animals have a higher chance of building up heat, and reacting poorly to the drug • Ungulates and small mammals in recovery are more susceptible to predation • Can cause social stress • Change dominance hierarchies • Neonates may be rejected

9. Cons • Risks to humans • Risk from animals before they are “knocked-out” • Risk from accidental exposure to the lethal drugs

10. Drug Administration • 4 basic types: • Hand injection with syringe • Pole syringe – “jabstick” • Blow gun • Dart gun

11. Ungulates • Since ungulates are difficult to approach, immobilization is used when: • They are confined to a corral or trap • They are moderately habituated to people • They can be stalked (‘hunted’) • Easiest method in some areas is to dart from a helicopter

12. Carnivores • Trapping is usually recommended before immobilization of large carnivores • Can be immobilized with: • Dart gun • Blowpipes • Syringe poles (jabstick)

13. Small Mammals • Usually trapped then immobilized • Raccoons usually immobilized with jab-stick, as they can carry rabies • Other small mammals immobilized with a hand-held syringe or a jabstick

14. Darting • When would we need to dart an animal? • How successful is this method? • Fast enough for accuracy • Slow enough as to minimize tissue damage

15. Darting Considerations • Will the dart function properly? • Discharge mechanism • Will the dart hit the targeted injection site? • Where on the animal should you aim?

16. Darting Considerations • Will the dart deliver complete drug injection? • Will the dart strike with excessive impact and cause injury? • Will the wound become infected?

17. Using a Dart Gun • 3 types of dart guns: • Powder charged • CO2 • Air • Must practice at known distances • Arcing trajectory • Very poor ballistics • Weight of dart • Drugs • Transmitter

18. Using a Dart Gun • Powder charged rifle • Modified 22 caliber rifle • 50 caliber barrel sits on top of conventional barrel • Blank 22 charges - provide air pressure that is transferred into top barrel projecting dart towards target

19. Using a Dart Gun • Different types of darts: • 1 – 3cc • Radio-tracking darts • Helpful for free-ranging wildlife

20. After the Shot • Approach slowly, quietly • Animal may need re-dose if not fully anesthetized • Assess depth of anesthesia • Blink reflex, ear reflex, heart and respiration rate

21. After the Shot • Proper positioning • Sternal position for ungulates • Protect eyes • Apply lubricant • Blindfold • Monitor vital signs

22. After the Shot • Dart Removal • Must be surgically removed (darts are barbed) • Fill wound with antibiotic cream • Observe animal until complete recovery • If animal does not recover properly, then euthanasia may be the only option

23. Drugs • Controlled substances • Must be obtained from licensed veterinarian • DEA prescription • Two Broad Categories • Neuromuscular Blocking Agents • Central Nervous System Agents

24. Neuromuscular Blocking Agents • Immobilize through paralysis • Extremely low safety margin • Mortality common with paralysis of respiratory muscles • These have been banned as use for immobilizing animals • High mortality rate, low safety margins

25. Central Nervous System Drugs • Act directly on brain/spinal cord • Alter perception of environment • Alleviate fear and anxiety • Depress motor activity • Three major types • Opioids • Cyclohexamines • Neuroleptics

26. Opioids • “Morphine-like” • Highly potent • Effective in small volumes • Wide margin of safety • Can be immediately reversed • Cause loss of consciousness, alleviates perception of pain • Commonly used for free-ranging wildlife and zoo species

27. Opioids • Common opioids used in animal immobilization: • Carfentanil, Etorphine, Sufentanil, Fentanyl, Butorphanol • Take care in handling – minute doses are extremely toxic to humans • Can be absorbed through mucous membrane

28. Cyclohexamines • Produce ‘altered consciousness’ • Dissociate mental state from environmental stimulation • Retain many vital reflexes • Cannot walk but can move tongue, blink, swallowing motion • Peripheral analgesia (lack of pain perception) • Sufficient to suture skin wounds

29. Cyclohexamines • Common Cyclohexamines: • Ketamine (‘Special K’) • Tiletamine -> Telazol • Phencyclidine (PCP) • Cyclohexamines are dangerous when used alone and are NOT reversible • Must be used in conjunction with other drugs (Neuroleptics)

30. Neuroleptics • Produce calmness and relaxation • Referred to as ‘tranquilizers’ • Does not cause loss of consciousness or alleviate pain perception • Will cause death before they cause loss of consciousness • Neuroleptics are used in conjunction with other drugs (Cyclohexamines and Opioids)

31. Neuroleptics • Commonly used neuroleptics: • Diazapam (Valium) • Very wide margin of safety • Calming effect and muscle relaxation • Xylazine (Rompun, Cervizine, Anased) • Fairly wide margin of safety • Drug of choice for carnivores and ungulates • Immediately, completely reversible ->Tolazine

32. Drug Mixtures • Three Tiers: • Tier 1: ketamine + neuroleptic (xylazine) • Weakest ‘knockdown power’, short duration • Tier 2: Telazol or Telazol + neuroleptic • Moderate ‘knockdown power’, long duration • Tier 3: Opioid + neuroleptic • Highest ‘knockdown power’, duration determinant on reversal

33. Drug Dosages • How much drugs do we deliver to an animal? • Based on 3 key pieces of information: • How much does the animal weigh (kg)? • What is the recommended drug dosage for the species we are working with? • What is the concentration of the medication we are using?

34. White-tailed deer • Separated into 3 categories, all with different drug recommendations • Tame • Mildly excited • Wild, free-ranging • Typically a xylazine/Telazol mixture • 1 cc per 100 lbs. • Reversal Drug – tolazoline (Tolazine) • Administered to “bring animal back”

35. Summary • Chemical immobilization can be beneficial, but there are many risks involved • Darting, although a popular method, requires practice and patience • Success rates are variable – usually something goes wrong • Prior to the shot you must know: • Approx. weight of animal you are shooting • Almost exact distance to target, within 1-3 yards

36. Summary • Drugs • Many various types used in wildlife immobilization • Xylazine (Rompun) • Tiletamine + zolazepam (Telazol) • Ketamine • Carfentanil

37. Summary • Drugs • Before administering you must know its: • Capabilities • Side-effects • Reversal Agents (if any) • Effective Concentrations • Species specific recommendations