Transcript Pain and injury Adroaldo J. Zanella ANS 305

Pain and injury
Adroaldo J. Zanella
ANS 305
Introduction
 Freedom from physical
discomfort and pain
 Freedom from injury and disease
– Animal welfare codes/laws in many
parts of the world.
Introduction
 Animals are capable of an experience which
they avoid, given the opportunity, and
which can dominate their physiology and
behavior in a similar way to the experience
of pain in man (Flecknell & Molony, 1997)
Pain
 Pain is a sensation which, without involving
higher level brain processing such as that
associated with fear, is very aversive.
Pain
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Nociceptive neurons
Some degree of tissue injury
Protective motor reactions
Emotional responses
Learned avoidance behavior
Modify social or other behavior
Animal pain
 Comparative anatomy, physiology and
behavior indicates that animal pain is
similar to that in humans (National
Research Council, 1992, Short and van
Poznak, 1992)
Recognition of animal pain
 Anthropomorphism
– Help to recognize acute pain
– Fail to identify chronic pain
Chronic pain
 Animals may be hyperalgesic to certain
types of noxious stimuli !
Legislation
 Laboratory animals
– Extensive legislation in the USA and European
countries (LASA, 1990; NRC, 1992; FELASA,
1994)
 Farm animals
– Some laws in Europe; limited discussion in the
USA
• Humane slaughter
• Husbandry procedures
My work
 Responses of piglets to castration
– Stress hormones were higher for more
than 24 post surgery in animals
castrated with no anesthesia compared
to control pigs (e.g. anesthesia)
 Responses of foals to branding
– Foals that were branded showed higher
physiological responses to hoof
trimming than non-branded controls
Assessment of pain
 Behavior
– Vocalization
– Time budget
– Posture
– Food and water intake
 Physiology
– Glucocorticoids
– Opioids
Stress axis
Hypothalamus
CRF
Anterior Pituitary=
ACTH
ß-endorphin
Adrenal:
Cortex= Glucocorticoids
Medulla= Catecholamines
Occurrence of pain
 Wild animals:
– Some hunting techniques
– Pest control
Occurrence of pain
 Farm animals:
– Housing
– Transportation
– Slaughter techniques
– Genetic selection
– Injuries
– Husbandry procedures
– Training techniques (Tennessee Walker)
Occurrence of pain
 Leg injuries, lameness, impaired
locomotion:
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Pigs:
Cattle
Sheep
Horses
Poultry
Turkey
Occurrence of pain
 Husbandry procedures (without anesthesia):
– Castration
– De-horning
– Tail-docking
– De-beaking
– Branding
Occurrence of pain
 Companion animals
– Genetic selection (hip displasia)
– Injuries
– Surgical procedures
• Declawing
• Debarking
• Ears cropping
Occurrence of pain
 Laboratory animals:
– Experimental procedure
– Genetic selection
– Housing
– Deliberately induced painful conditions
Failure to Alleviate Pain
 Analgesic drugs are not used regularly by
veterinarians (Townsend, 1987: 30-50%;
Dohoo & Dohoo, 1996:49%).
Additional information
 Recent textbooks are more informative
 New compounds are available
 Growing food safety concerns
– Casualty slaughter
 Controlled substances (how to handle)
 Existence of legislation restricting the use
of analgesics in food animals
 Costs
The future
 New compounds (UK):
• Butorphanol, buprenorphine, flunixin,
carprofen, ketoprofen, meloxicam
 Work on laboratory animals may
help farm animals
 Public perception of farming
procedures may accelerate the
necessary changes
 We should play an active role