View
155
Download
0
Category
Tags:
Preview:
DESCRIPTION
Pain: Abolishing a Necessary Evil - Donald C. Lay Jr., PhD, Research Leader, Livestock Behavior Research Unit, USDA, from the 2014 NIAA Annual Conference titled 'The Precautionary Principle: How Agriculture Will Thrive', March 31 - April 2, 2014, Omaha, NE, USA. More presentations at http://www.trufflemedia.com/agmedia/conference/2014_niaa_how_animal_agriculture_will_thrive
Citation preview
Pain: Abolishing a Necessary Evil
Donald C. Lay Jr. Research Leader
Livestock Behavior Research UnitAgricultural Research Unit, USDA
West Lafayette IN, on Purdue University Campus
Livestock Behavior Research Unit Mission (Agricultural Research Service-USDA)• to develop scientific measures of animal
welfare that will allow an objective evaluation of animal agricultural practices
• to improve existing practices and invent new practices that can enhance animal welfare and increase animal productivity
Publications on “Farm Animal Welfare”(18,521, Science Direct)
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 20130
200
400
600
800
1000
1200
1400
1600
1800
Mounting Regulation, Policy, Standards and Assessments
• Tyson Announcement, Jan. 8th, 2014– Stop the use of Blunt Force Trauma
– Eliminate or reduce pain from tail docking and castration
• Producer Groups and External On-Farm Assessment Programs
Skin
Dorsal gray horn (Spinal cord)
Reticular formation (Brain stem)
Thalamus (Diencephalon)
Somatosensory (Cortex)
A, C -fibers
Injury
Skin
A-, C-fibers
Cheng, 2005; Modified from Neuroscience Exploring the brain, 2001
Pain in Humans
A-thickly myelinated = fastC – unmyelinated = slow, polymodal
Cheng, 2005
Pain Mediators
Function of Pain• Adaptive evolutionary strategy to protect the
body.– Early warning system.
– Allows animals to learn what not to do.
– The more intense the pain, the greater the threat.
• Non-adaptive pain.– Pain that persists after trauma is healed.
– Neuromas and other neuropathic pain
CIPA and HSANCongenital insensitivity to pain with anhidrosisHereditary Sensory and autonomic neuropathy
• Never feel the stick of a needle
• Never feel a cut or a burn
• Never feel hunger
• Never feel uncomfortable in a chair
Pain is Necessary!
• Babies gnaw their fingers bloody• Poke their eye so hard as to cause abrasions• Lean on hot surfaces to cause 3rd degree burns• Most die before 3 years of age• Cause of death
– Heat stroke– Dehydration– Fever– Blood poisoning
Pain is difficult to measure• Pain has both physiological and psychological components.
• Animals cannot communicate verbally regarding their sensory and emotional experience.
• Pain can be overridden with other feelings, such as fear, fighting, and feeding motivation ….
• Pain is also affected by multiple factors, such as genetic strain, age, production status; environments, and lesion and lesion size.
Neuroanatomy associated with pain in chickens
Sensory receptors
Lunam, 2005
In humans:
• Mechanical nociceptors
• Thermal nociceptors
• Chemical nociceptors
In chickens:
• Herbst corpuscles and • Grandry’s corpuscles• Free Nerve endings
• Behavioral and physiological studies
There are similar behavioral and physiological changes in response to injury between chickens and mammals (Cheng, 2005; Kuenzel, 2007).
• Pharmacological studies
Pain killers (analgesics) can reducepain in both chickens and humans. (Gentle, 1991; Glatz et al., 1992; Paul-Murphy & Ludders, 2001).
Conclusions
• Chickens can feel pain.• Chickens feel pain in a similar
manner to that in mammals.
Definition of pain in animals
In animals• Pain is an aversive sensory and emotional
experience by the animal in response to damage or a threat to the integrity of its tissues (Molony & Kent, 1997; Robertson, 2002; Vinuela-Fernandz et
al., 2007)
In humans• Pain is an unpleasant sensory and emotional
experience associated with actual or potential tissue damage (Merskey and Bogduk, 1994)
Pain can be recognized and assessed indirectly• Physical parameters
Body score (body injury) Growth rate
• Physiological parametersNeurotransmittersNeuropeptides
• Behavioral parametersGeneral behavior (eating, drinking)Guarding behavior (protect injured areas)
Neuroma Trigeminal ganglia Beak
Normal nerve fibers
Regrowth
Neuroma
Degenerating of neuroma
Neuromas may increase pain sensitivity --- chronic pain
Soma Fibers Terminals
Ending of beak stump (post-trimming)
Tissue Scar
Targets
Target
NeuromasHistological characteristics
A neuroma is a tangled mass of a damaged (cut) axon terminal inside the injured area.
Consists of unmyelinated fibers, and then becomes myelinated fibers (A-fibers)
Physiological characteristics
A source of substantial ectopic firing (spontaneous pain)
Increase pain sensitivity
Painful Situations in Agriculture
• Controllable– Beak Trimming– Castration– Tail docking– Branding
• Uncontrollable– Birth– Accidents– Injury
Analgesics are Beneficial
Coetzee et al., 2012
Bulls castrated without analgesic (meloxicam) show a greater incidence of Bovine Respiratory Disease
Why not just use analgesics?
They would need to be:1) readily available and registered for use2) easy to administer3) quick and long acting4) have short withdrawal periods5) show return on investmentOnly 1 approved anti-inflammatory in the U.S. for swine and cattle; a few for cattle and swine in E.U. and U.K.
Schwartzkopf-Genswein et al., 2012
Cannibalism will Increase in Prevalence with More Space
a
c
N. intramand.
N. ophthal. med.
C
Predicted Levels of Behavioral Expression+none or incomplete, ++low, +++moderate, and ++++full or high
1 Furnished Cage Non-cage (Barn) Outdoor
(Free-Range)
Behavioral Opportunities
Conventional Cage
Small
Large
Slats / Litter
Aviaries
Nesting + +++ +++ ++++ ++++ ++++ Brooding + + + + + + Perching + ++ ++ +++ +++ +++ Mating + + + + + + Stereotyped and sham behaviors
++++ ++ ++ + + +
Cannibalism and feather pecking
++ ++ +++ ++++ ++++ ++++
Social aggession
++ +++ ++++ ++ ++ ++
Smothering ++ ++ +++ ++++ ++++ +++ 2
Lay et al., 2010
Infrared trimmed
ControlHeated blade trimmed
Does Beak Trimming Cause Pain? Funded by AFRI
Control
Hot Blade trimmed
Infrared trimmed
Drinking Behavior During Warm Water Pain Test
Infrared Beak trimming has been adopted by the United Egg Producers, 2010
Five Weeks Later!
Hen Behavior is Positive but ……Keel Bone Fractures
• 46 % to 90 % have fractures
Nicol et al, 2010
Effect of Analgesic on Perching Behavior of Hens with Keel Bone Fractures
Late
ncy
to la
nd
First two bars are hens with and without analgesic that do not have fractures.The second two bars are hens with and without analgesic that do have fractures.
Nasr et al, 2012
Routine Piglet Processing
• Soon after birth, piglets undergo processing procedures, which are likely sources of stress:
- Teeth resection- Tail docking- Identification- Iron administration- Castration
• For each process, there is a choice of methods
Marchant-Forde et al., 2009 Funded by the National Pork Board
Objectives
• To evaluate stress responses evoked by two alternative methods performed singly: – Teeth (TR) – clip vs. grind – Tails (TD) – cold clip vs. hot clip – Identification (ID) – ear notch vs. ear tag – Iron (FE) – injection vs. oral paste – Castration (CA) – cords cut vs. cords torn
Results
• To evaluate stress responses evoked by two alternative methods performed singly: – Teeth (TR) – clip vs. grind – Tails (TD) – cold clip vs. hot clip – Identification (ID) – ear notch vs. ear tag – Iron (FE) – injection vs. oral paste – Castration (CA) – cords cut vs. cords torn
= worse
Conclusions
• Carried out singly, we can identify which method has least impact on piglet welfare
• Carried out together, it’s much less clear
• The key combination is accuracy and speed
Piglet Aversion to Euthanasia Gases
1
3 3
2
4
5
6
7
90% Carbon Dioxideor70:30 mixtures of:
Nitrogen:Carbon DioxideNitrous Oxide:Carbon DioxideNitrous Oxide:Oxygen
Rault et al., 2012, in pressFunded by the National Pork Board
Euthanasia: Stress and DeathTwo-Step Procedure
Gas treatment CO2 N2/CO2N2O/CO2 N2O/O2
p-value
Transfer from
treatment to CO2
chamber (seconds) 2.9 ± 0.3a 6.4 ± 0.6b 6.7 ± 1.0b 14.7 ± 2.1c
0.001
Time to death after transfer (seconds) 7.8 ± 1.3 7.6 ± 1.0 5.6 ± 0.3 9.3 ± 1.2 0.20
Total procedure duration (seconds) 10.8 ± 1.3a 13.9 ± 1.2a
11.3 ± 1.4a
24.0 ± 3.0b 0.005
Rault et al., 2012
EEG and Euthanasia
Carbon Dioxide
Nitrous Oxide
Lameness in SowsExercised sows will have:
– An increase in bone density and an increase in muscular weight compared to control sows
– An increase in osteoblastic activity and a decrease in osteoclastic activity compared to control sows
– Improved condition of joints and hooves compared to control sows
Lameness in Sows will Likely Increase with Increase Movement
Loose housing of Sows will likely acerbate this problem as the increase in movement will provide opportunity for torn cartilage to worsen.
Tail Docking Practice in Dairy Cows
Introduced in 1990s in New Zealand to combat Leptospirosis
DOCKED INTACT
Behaviors Recorded:
Tail Swing, Weight Shift, Foot Stomp, Tail CurveEicher et al., 2000
Are Docked Tails more Sensitive to Heat and Cold?
Bottom Line:
Docking causes pain, but less pain in adult cows.
Docked cows have more flies and avoidance behaviors.
Docked tails show signs of neuromas (possibly painful).
Docking doesn’t decrease somatic cell counts.
Conclusions
• Life without pain doesn’t exist.• We recognize that animals feel pain.• Our responsibility is to alleviate or minimize
pain.
• We support future efforts to develop management tools to minimize pain and create alternative practices that alleviate pain.
Thank You
ARS-USDA Meeting Tomorrow’s Challenges Today
Recommended