Pain Management - Dr. Monique Pairis-Garcia, Iowa State University, Dr. Anna Johnson Butters, Iowa State University, from the 2014 World Pork Expo, June 4 - 6, 2014, Des Moines, IA, USA.
More presentations at http://www.swinecast.com/2014-world-pork-expo
Dr. Monique Pairis-Garcia, Dr. Anna Johnson Butters - Pain Management
1. Pain Management For
Piglets During
Castration and Tail
Docking
Monique Pairis-Garcia BS, DVM, PhD, mdpairis@iastate.edu
Anna Johnson BSc, MSc, PhD, johnsona@iastate.edu
Department of Animal Science,
Iowa State University
Ames, IA 1
2. Objectives
• Defining pain
• How to measure pain?
• Regulatory concerns for using pain
relieving drugs in the United States
• Case Study: Drug efficacy for pain
management during castration
2
3. Defining Pain
Pain: “Unpleasant sensory and emotional
experience associated with actual or potential
tissue damage”1
Pain and suffering are clinically important
conditions adversely affecting an animal’s
quality of life (short-term or long-term)
Prevention and alleviation of animal pain and
suffering (i.e., management) are important
goals
1IASP, 2004 3
6. Castration
• Removal of testicles or destruction of
testicular formation2
– Prevention of unwanted breeding
– Reduced fighting and aggression
– Meat quality improvement
• Pain associated with scrotal incision,
extraction of the testes and severing of the
spermatic cords
62Petherick , 2010
Mcglone, 2014
7. Tail Docking
• Portion of tail removed
– Prevent/Decrease tail biting
– Decrease economic loss associated with
reduction in growth performance and increased
incidence of infection
• Pain associated with
physical removal3
7
Liat Romme Thomsen, 2013
3Sutherland et al, 2011
9. Physiological Measures
• Hormones
– ACTH (Adrenocorticotropic hormone)4
– Cortisol
• Catecholamines
– Norepinephrine/Epinephrine5 effects on:
• Heart rate
• Glucose levels
• Lactate levels
**Physiological measures can also increase due to
general arousal and handling**
94Prunier et al, 2005; 5Hay et al 2003
10. Physiological Measures
• Immune function6
– Acute phase proteins
– Pro-inflammatory cytokines
– Antibody response
**May result in greater welfare
concerns if animal’s health is
compromised**
10
Wikipedia, 2014
6Moya et al, 2008
11. Behavioral Measures
• Behavioral changes
– Locomotion and Posture7
• Head turning toward hindquarters
• Hind leg lifting
• Slow twitching tail
– Maintenance behaviors8
• Reduced feeding
• Reduced drinking
• Reduced activity
117Wemelsfeder and van Putten, 1985; 8McGlone and Hellman, 1988
12. Vocalization
• Behavioral indicator of pain9
– Immediate vocal response
– High frequency calling
– Increased calling rate
129Xin et al, 1989
13. Performance Measures
• Average daily gain
• Feed intake
• Market weight
• Carcass quality
• Mortality
13
Iowa State University, 2011
15. Regulatory Concerns in the U.S.
• Animal drugs intended for use in the U.S are
regulated by Food and Drug Administration (FDA)
Center for Veterinary Medicine (CVM)10
• There are no pain relieving drugs specifically
approved by FDA for use in livestock in the U.S.11
• Extra-label drug use (ELDU) is regulated under the
Animal Medicinal Drug Use Clarification Act of 1994
(AMDUCA)
1510Smith and Modric, 2013 11Coetzee, 2011
16. AMDUCA requirements
• Valid Veterinary-Client-Patient Relationship (VCPR)
• Extra-label use limited to circumstances when a
threat is posed to the health of an animal, or when
failure to treat results in suffering or death
• FDA approved animal and human drugs
• There is no approved product to address the issue
• Product administered under the direction of a
licensed veterinarian and assigned an extended
withdrawal time to avoid residues.
16
19. Local anesthetics
Local
• Most commonly used pain relieving drug in
food animal medicine12
• Produces loss of sensation without loss of
consciousness by preventing and blocking
nerve impulses
– Lidocaine/Prilocaine
**Short Acting**
1912Muir et al, 1995
20. Lidocaine
• Lidocaine is commonly suggested as a drug
for pain relief during castration and tail
docking.
• Lidocaine is NOT APPROVED for veterinary
use
• Only Lidocaine approved for humans can
legally be prescribed under AMDUCA and
used in an extra-label manner
20
21. General Anesthetics
• Loss of feeling or sensation
• State of unconsciousness with absence of
pain sensation
• Suppresses cerebral activity
– Co2
– Isoflurane
– Sevoflurane
**Short Acting**
21
28. Production Measures
• Mean weight on castration day was not
different.
• No difference in weight gain
• 11% morbidity with no treatment effect
• 5% mortality with no treatment effect
28
29. Case Summary
• Lidocaine reduced pain during castration
• Meloxicam reduced pain after castration
• No treatment effects on:
– Skin temperature, weight gain, morbidity or
mortality
• Herdsmen effectively administered local
anesthesia
29
30. Take home points
• Pain associated with castration and tail
docking is a current welfare issue on farm
• Pain relief may be conducted using either
anesthetics, analgesics or a combination of
both
• Use of these drugs in an extra label manner is
approved under AMDUCA
• Multi-modal drug approach is most effective
for pain relief
30
IASP: International Association for the Study of Pain
Pain typically involves a noxious stimulus or event that activates nociceptors in the body’s tissues that convey signals to the central nervous system, where they are processed and generate multiple responses, including the “unpleasant sensory and emotional experience” central to the IASP definition
Procedures: defined as elective events performed on the animal by a veterinarian or caregiver specific to sows and boars that may result in the animal experiencing pain.
Management: Defined as facilities or environments that predispose or increase the likelihood of conditions that may cause pain
Disease: Defined as non-elective medical conditions that may cause the animal pain
Procedures: defined as elective events performed on the animal by a veterinarian or caregiver specific to sows and boars that may result in the animal experiencing pain.
Management: Defined as facilities or environments that predispose or increase the likelihood of conditions that may cause pain
Disease: Defined as non-elective medical conditions that may cause the animal pain
Petherick, J.Carol (2010). Castration. In Daniel S. Mills, Jeremy N. Marchant-Forde, Paul D. McGreevy, David B. Morton, Christine J. Nicol, Clive J. C. Phillips, Peter Sandoe and Ronald R. Swaisgood (Ed.), The Encyclopedia of Applied Animal Behaviour and Welfare (pp. 82-83) Wallingford, England: CAB Internarional.
In other parts of the world, for example the United States, no such legislation exists and pigs may be
castrated at any age without proviso other than non-legally
binding recommendation (e.g. AVMA, 2010 which recommends
castrating within the first 14 days of age).
The sympathetic nervous system is activated during
different kinds of stress (pain, anger and fear) and several
changes are noted in the body, for example: dilated
pupils, increased heart rate and blood pressure, redirected
blood from the skin, decreased digestion and
dilated bronchioles. During activation adrenocorticotropic
hormone is released and induces secretion of cortisol
[9]. These changes can be used as possible indicators
of pain and several of these changes have been shown in
piglets during and after castration [2,10,11].
Stress, trauma, infection or inflammation also triggers
the acute phase protein response, which is a part of the
body’s early defence. Serum amyloid A (SAA) is a major
acute phase protein in pigs that can increase quickly
and with large amplitude, and SAA level can therefore
be used for defining the health and welfare status of
pigs [12].
Stress, trauma, infection or inflammation also triggers
the acute phase protein response, which is a part of the
body’s early defence. Serum amyloid A (SAA) is a major
acute phase protein in pigs that can increase quickly
and with large amplitude, and SAA level can therefore
be used for defining the health and welfare status of
pigs [12].
The Food and Drug Administration’s Center for Veterinary Medicine (CVM) ensures that safe and effective approved animal drugs are available for use in the United States. Although no drugs are currently approved for analgesic use in swine, CVM supports the ethical treatment and management of swine and aims to improve the availability of safe and effective drugs for the control of pain. CVM encourages drug companies to use innovative approaches to demonstrate the effectiveness of drugs for analgesic use in swine. There is an obvious need for continued research into the development of adequate behavioral and physiologic measures that can be used to reliably demonstrate the effectiveness of new animal drugs for the control of pain in swine (Smith and Modric, 2013)
Treatment of pain falls into three major categories 1. Anesthetics 2. Sedative/tranquilizers and 3.analgesics. Among the analgesic categories includes: opioids, nonsteroidal antiinflammatory
drugs (NSAIDs) and α2-agonists.
Lidocaine withdrawal: 5 days
Epidural for rectal/vaginal prolapse or dystocia, hernia repair, surgery on prepuce, penis or rear legs
Anesthesia can be
defi ned as the loss of feeling or sensation (Blood and
Studdert, 1995), and general anesthetic agents achieve
this by causing a state of unconsciousness, which results
in an absence of pain sensation over the entire
body. Inhalation of CO2 causes anesthesia by suppressing
nerve cell function and cerebral electrical activity
(Martoft et al., 2003). The advantages of using CO2 as a
form of anesthesia include the speed at which CO2 can
be administered, the speed at which animals return to
consciousness, the fact that CO2 is not a restricted drug
requiring administration by a veterinarian, and lastly,
that there are no issues with drug residues (Gerritzen et
al., 2008).
http://secure.swissinfo.ch/eng/archive/Parliament_moves_to_improve_animal_rights.html?cid=4569378
Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most common categories of drugs used to manage pain in animals. NSAIDS have several action modes including anti-inflammatory, antipyretic and analgesic properties. The biochemical action of NSAID’s is the inhibition of cyclooxygenase enzymes (COX) which are responsible for the production of prostaglandins, thromboxane A2, and conversion of arachidonic acid via lipoxygenase catalase pathway.
Flunixin meglumine labeled in swine at 2.2 mg/kg IM for pyrexia associated with respiratory disease
Aspirin is commonly used for pyrexia control and analgesic but are not approved by the FDA for use in animals.
Collected vocalization, resistant movements, wounds, ear and skin temperature, acute phsae protein sickness treatment and mortality
A total of 63 piglets (11%) were treated for health problems
between the castration day and three weeks of
age. The piglets were equally distributed over the treatments
(C:17, M:11, L:17 and LM:18). During the same
period, 26 piglets (5%) died but no significant effect of
treatment on mortality was found (C:6, M:6, L:4 and
LM:10).
The mean weight on the castration day was 2.2 kg (SD
= 0.5 kg) for all treatments. There was no significant
difference between treatments in weight gain (kg)
between the castration day and three weeks of age.