Pain and injury

1
Pain and injury

• Adroaldo J. Zanella
• ANS 305

2
Introduction

• Freedom from physical discomfort and pain
• Freedom from injury and disease
• Animal welfare codes/laws in many parts of the
  world.

3
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)

4
Pain

• Pain is a sensation which, without involving
  higher level brain processing such as that
  associated with fear, is very aversive.

5
Pain

• Nociceptive neurons
• Some degree of tissue injury
• Protective motor reactions
• Emotional responses
• Learned avoidance behavior
• Modify social or other behavior

6
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)

7
Recognition of animal pain

• Anthropomorphism
• Help to recognize acute pain
• Fail to identify chronic pain

8
Chronic pain

• Animals may be hyperalgesic to certain types of
  noxious stimuli !

9
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

10
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

11
Assessment of pain

• Behavior
• Vocalization
• Time budget
• Posture
• Food and water intake
• Physiology
• Glucocorticoids
• Opioids

12
Stress axis
Hypothalamus CRF
Anterior Pituitary ACTH ß-endorphin
Adrenal Cortex Glucocorticoids Medulla
Catecholamines
13
Occurrence of pain

• Wild animals
• Some hunting techniques
• Pest control

14
Occurrence of pain

• Farm animals
• Housing
• Transportation
• Slaughter techniques
• Genetic selection
• Injuries
• Husbandry procedures
• Training techniques (Tennessee Walker)

15
Occurrence of pain

• Leg injuries, lameness, impaired locomotion
• Pigs
• Cattle
• Sheep
• Horses
• Poultry
• Turkey

16
Occurrence of pain

• Husbandry procedures (without anesthesia)
• Castration
• De-horning
• Tail-docking
• De-beaking
• Branding

17
Occurrence of pain

• Companion animals
• Genetic selection (hip displasia)
• Injuries
• Surgical procedures
• Declawing
• Debarking
• Ears cropping

18
Occurrence of pain

• Laboratory animals
• Experimental procedure
• Genetic selection
• Housing
• Deliberately induced painful conditions

19
Failure to Alleviate Pain

• Analgesic drugs are not used regularly by
  veterinarians (Townsend, 1987 30-50 Dohoo
  Dohoo, 199649).

20
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

21
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