Lecture 4- Large Animal Euthanasia Flashcards
What are the musts of euthanasia
Must relieve fear and apprehension, must induce unconsciousness as rapidly as possible, ensuring minimum pain and suffering
What is the order of events in euthanasia
- Sedation/tranquilization
- Unconsciousness
- Cardiorespiratory arrest
What are the modes of action for euthanasia
Hypoxemia, depression of neurons vital for life, physical damage to brain tissue
What are reasons for large animal euthanasia
Food production, pain and suffering, intractable conditions/situations, chronic incurable conditions
How to determine when it is time
Chronic and incurable
Poor prognosis
Animal hazard to self or handler
Constant pain relieving medications for rest of life
What are approved methods of euthanasia
Injectable barbiturates
Captive bolt
Gunshot
Potassium chloride while anesthetized
How do injectable barbiturates work
Cause CNS depression
Death occurs from respiratory arrest and myocardial hypoxia
What are some examples of injectable barbiturates for euthanasia and what is the dose
Pentobarbital 100mL IV
Thiopental 20-30mg/kg
When is a captive bolt used
When tissues must be free of drug residues
How does captive bolt euthanasia work
Produces unconsciousness followed by exsanguination
What are the three types of captive bolts
Penetrating, non-penetrating, free bolt
How does a penetrating captive bolt work
Penetrates skull, catastrophically damages the cerebrum and part of cerebellum
Causes destruction of vital centers of brain, increase ICP and animal loses consciousness
What is the most effective captive bolt mechanism
Penetrating captive bolt- destroys brain matter while also leaving brain stem intact thus ensuring heart continues to pump during exsanguination
What is a disadvantage of penetrating captive bolt
Brain matter is allowed to enter the blood stream and possibly contaminating the other tissue
What causes unconsciousness in non-penetrating captive bolt
Bolt strikes forehead with great force causing concussion
What are the pro’s and con’s of the non-penetrating captive bolt
Pro- less likely to spread brain matter into blood stream, concerns about mad cow disease (BSE)
Con- less reliable at causing immediate and permanent unconsciousness
When is a free bolt used
Emergency, in the field euthanasia of large farm animals that can’t be restrained
Free bolt is only capable of firing when
Firmly pressed against a surface- typically animals forehead
Where should captive bolt be placed on head and what structures do we need to avoid
Placed on midline of forehead, 1/2 inch above eye level. Want to go through thinnest part of frontal sinus
What caliber is used in gunshot
32
Where should gunshot NOT be placed on horse
Between the eyes
How much potassium chloride is injected for euthanasia
50-100mL
What is the mechanism of death caused by potassium chloride
Cardiac arrest and tissue hypoxia
When is potassium chloride approved to be used
Unconscious or anesthetized
What are unapproved methods of euthanasia
Any method that does not induce unconsciousness before cardiorespiratory arrest
Ex: electrocution, exsanguination, air embolism, hydrogen cyanide, carbon dioxide, nitrogen inhalation, curariform drugs, potassium chloride
What are some hazards to be considered when euthanizing a large animal
Paddling of legs, poorly controlled kicking, muscle fasciculation
Prior to leaving death must be ensured by…
Absence of heart beat, respiration and corneal reflex
Create a pneumothorax
What are disposal options
Bury on property if legal and have correct equipment or haul away
Do not euthanize without ______ consent/notification
Insurance company
What are common restrictions for insurance policies on euthanasia
Will not permit euthanasia for loss of value or use, horse must be suffering d
Is a necropsy required for insurance companies
Yes, but be given the opportunity to examine horse or could compromise claim
