L20: Euthanasia (Shearer)

Question 1

Sentience

Answer 1

Ability to feel or perceive pain, or experience some form of emotion whether positive or negative
-requires a nervous system that is functionally capable of cognition (ie. Thinking) and the ability to emotionally experience its status as bad or good

Question 2

Objective in humane euthanasia

Answer 2

“Good death” whereby life is ended without pain or distress to the animal
-requires techniques that induce immediate loss of consciousness followed by cardiac and resp. Arrest which results in loss of brain fx and death

Question 3

For an animal to experience something, it must be both ____ and _____; an unconscious animal experiences nothing

Answer 3

Sentient and conscious

Question 4

Disadvantages of using barbiturates (non-inhalant agents)

Answer 4

• cost
• requires restraint of the animal
• must be admin. By vet
• carcass disposal complicated by drug residue, and risk for wildlife

Question 5

Veterinary Medicine Mobility Act

Answer 5

Makes it legal for vets to transport, administer, or dispense controlled substances while providing care outside the locations where those substances are registered

Question 6

Most common method used for on-farm euthanasia of cattle

Answer 6

• gunshot (classified as physical method)
• effectiveness depends on selection of appropriate firearm, type of bullet, accuracy of aim
• can take 7-10 minutes for heart to stop
• causes less fear and anxiety and induces a more rapid, painless, and humane death

Question 7

Recommended firearms for euthanasia of cattle

Answer 7

Handguns: 0.32-0.45 caliber
Rifles: 0.22 magnum or higher
Shotgun: 0.410 to 28 gauge (calves), 12, 16, or 20 gauge for cows

*bullets should be solid point

Question 8

T/F: death is not assured with penetrating captive bolt alone**

Answer 8

TRUE: secondary step is required whenever penetrating captive bolt used (ie. Second shot, exsanguination, pithing, IV KCl)

DOES induce immediate unconsciousness

Question 9

KCl should never be used as the sole method of euthanasia

Answer 9

Only for use in unconscious animals for the purpose of ensuring death

Question 10

Main advantage of KCl

Answer 10

No risk to predators/scavengers

Question 11

Causes of captive bolt failure

Answer 11

• poor maintenance of cartridge
• damp cartridges
• low air pressure in pneumatic stunners

Question 12

Physical observable parameters of unconsciousness***

Answer 12

• animal collapses immediately
• animal makes no attempt to right itself
• body and muscles become rigid immediately after the shot followed by brief tetanic spasms –> uncoordinated hind limb movements
• immediate and sustained cessation of rhythmic breathing**
• absence of vocalization
• absence of eye reflexes
• eyelids remain open facing straight forward

Question 13

Optimum position for captive bolt or gunshot for cattle**

Answer 13

• At the intersection of 2 imaginary lines from the lateral canthi to the base of the opposite horns
• approximately 3 inches anterior to the poll in the mature Holstein cow
• halfway on a line drawn laterally from ear to ear

Question 14

Manually applied blunt force trauma is NOT acceptable method of euthanasia - why?

Answer 14

Skull too hard to achieve immediate unconsciousness and destruction of brain tissue

Question 15

Unacceptable methods of euthanasia in beef and dairy cattle

Answer 15

• manually applied blunt force trauma
• injection of chemical agents or substances
• injection of xylazine or other alpha-2 agonist followed by KCl or MgSO4
• air injection into vein
• electrocution
• drowning
• exsanguination of conscious animals

Question 16

How many cattle are slaughtered per day in the US?

Answer 16

100,000 per day

35 million annually

Question 17

Exceptionally immature animals (ie. Oppossums, marsupials) require several months before consciousness appear

Answer 17

:)

Question 18

Moderately immature animals (cats, dogs, rabbits, rats) require 4-14 days to reach a conscious state

Answer 18

:)

Question 19

Neurologically mature animals (cattle, sheep, horses) are sentient in utero but remain unconscious until birth

Answer 19

During the last 40% of gestation, 8 or more neuro-inhibitors actively maintain the fetus in a sleep-like unconscious state

Question 20

Onset of consciousness**

Answer 20

• effect of neuro-inhibition are reduced, and neuro-activation increases
• respiration relieves hypoxic inhibition of cerebrocortical activity
• loss of placental influence reduces availability of cortically directed neuro-inhibitors and their precursors

Question 21

3 mechanisms that protect fetus during delivery (physically stressful event)

Answer 21

1) O2 use by brain reduced due to sleep-like unconscious state
2) O2 sparing: fetal motor systems become quiescent during delivery
3) “The Emergency Response”: occlusion of umbilical cord leads to isoelectric EEG which reduces O2 requirements by 95%, which protects brain from hypoxia for 5-6 minutes, and after umbilical cord is cut when breathing starts