. "Appendix: Tools to Monitor and Assess Health Status and Well-Being in Stress and Distress." Recognition and Alleviation of Distress in Laboratory Animals. Washington, DC: The National Academies Press, 2008.
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Recognition and Alleviation of Distress in Laboratory Animals
Appendix
Tools to Monitor and Assess Health Status and Well-Being in Stress and Distress
The following pages contain ethograms, various types of scoring sheets, clinical assessments, and behavioral observations applicable to laboratory animals. As stated in the report, the interpretation of physiologic measurements as indicators of stress, distress, or welfare status is relative and does not always point to direct or straightforward links. Because little is known about behavioral changes directly attributed to stress and even less about distress, recognizing stress and distress in laboratory animals based on behavioral changes remains a significant challenge to investigators and animal care staff. Recognition of distress should be derived from intimate knowledge of the species’ or strain’s normal behavior and may be based on (1) clinical signs and/or (2) significant deviation from the expected behavioral repertoire. As a rule, when the expected repertoire of physiologic behaviors is absent or modified, an investigation into the reasons for the change is necessary.
Some clinical signs (e.g., changes in temperature, respiration, feeding behavior) indicate an abrupt onset of distress while others (e.g., weight loss) develop over a longer period of time and may serve as warnings. A thorough clinical examination with references to baseline effects of age, gender, genotype, etc., is necessary to establish the presence of distress, while an abrupt and marked change in behavior lasting more than a few days may also indicate a disease state. Although normal behaviors may sometimes be characterized simply by a lack of atypical behavior, such as stereotypic (i.e., repetitive) or self-injurious behavior, some species and strain differences are not always easy to discern, and further complications
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Appendix
Tools to Monitor and Assess Health Status and Well-Being in Stress and Distress
The following pages contain ethograms, various types of scoring sheets, clinical assessments, and behavioral observations applicable to laboratory animals. As stated in the report, the interpretation of physiologic measurements as indicators of stress, distress, or welfare status is relative and does not always point to direct or straightforward links. Because little is known about behavioral changes directly attributed to stress and even less about distress, recognizing stress and distress in laboratory animals based on behavioral changes remains a significant challenge to investigators and animal care staff. Recognition of distress should be derived from intimate knowledge of the species’ or strain’s normal behavior and may be based on (1) clinical signs and/or (2) significant deviation from the expected behavioral repertoire. As a rule, when the expected repertoire of physiologic behaviors is absent or modified, an investigation into the reasons for the change is necessary.
Some clinical signs (e.g., changes in temperature, respiration, feeding behavior) indicate an abrupt onset of distress while others (e.g., weight loss) develop over a longer period of time and may serve as warnings. A thorough clinical examination with references to baseline effects of age, gender, genotype, etc., is necessary to establish the presence of distress, while an abrupt and marked change in behavior lasting more than a few days may also indicate a disease state. Although normal behaviors may sometimes be characterized simply by a lack of atypical behavior, such as stereotypic (i.e., repetitive) or self-injurious behavior, some species and strain differences are not always easy to discern, and further complications
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are introduced by gender, age, physiological state, genetics, and genetic modification of the animals.
The first three tables below contain behavioral categories and descriptions of physiologic activities in which rhesus macaques, common marmosets, and rabbits engage. In order to determine what kind of behavior it is that an animal exhibits, one needs to be knowledgeable in the ethology and husbandry of the species in question. For example, aggression may be a signal for fear or pain, but may also be observed in lactating mothers protecting their nest. Determining the variation of the behavior from normalcy is a matter of training, studying, and observation.
TABLE A-1 An ethogram for Macaca mulatta (rhesus macaque)
Behavioral Categories
Recorded Behavior
Definitions
Aggressive behaviors
Facial threat displays
Open mouth face ± bared teeth or vocalization
Aggressive approach
Stiff approach, attacking run
Physical aggression
Slap, grab, biting, or wrestling
Submissive behaviors
Facial submissive display
Bared teeth grin ± vocalization
Avoidance
Avoid, flee, leave, displaced
Active appeasement
Groom present, lip smacking
Affiliative behaviors
Affiliative contact
Contact sit (within arms reach), embrace, touch
Passive grooming
Being groomed
Active grooming
Grooming other animal
Sexual behaviors
Sexual contact
Genital present/inspection, mounting
Appetitive behaviors
Foraging
Food search, eating, drinking
Other activities
Active
Locomotion, enrichment use, self-grooming
Abnormal behaviors
Abnormal behaviors
Stereotypies, autoaggression
Inactive
Inactive
Lying, huddling, sitting, sleeping
Vigilance
Monitoring others
Visually following other individuals
Reprinted from Augustsson, A. and J. Hau. 1999. A simple ethological monitoring system to assess social stress in group-housed laboratory rhesus macaques. J Med Primatol 28:84-90.
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TABLE A-2 An ethogram for Callithrix jacchus (common marmoset)
Behavior
Code
Definition
Agonism
Tufts-flick
TF
Rapid back-and-forth movement of ear tufts
Frown
FR
Lower eyebrows, furl brow, and turn down corners of mouth while staring
Cuff
CU
Swift, superficial blow or scratch performed aggressively
Chase
CH
Pursue partner, with one or both animals exhibiting aggression and/or submission (not play)
Fight
FI
Grapple aggressively with partner(s), involving biting, clawing, and wrestling
Attack
AT
Lunge at or pounce on partner aggressively; may or may not result in fight
Snap bite
SB
Direct a single short, sharp bite at partner
Submit
SU
Flatten ear tufts and/or facial grimace (partially open mouth with corners of mouth retracted, exposing lower and sometimes upper teeth) and/or slit eyes (eyelids half closed)
Continuous submit
CS
Continuous submit; start scoring after 5 sec
Retreat
RE
Starting from a stationary position, move at least one body length away from another animal within 1 sec of the other animal establishing proximity (within 10 cm)
Play
Play
PL
Two or more animals lunge, grapple, wrestle, or chase for at least 1 sec in absence of aggression or intense submission; play face may or may not be present
Solicit play
SP
Direct play face toward, pounce on, or initiate grapple with partner, in absence of ongoing play with partner
Play face
PF
Open mouth without retraction of the lips
Join play
JP
Join ongoing play bout between two or more partners
End play
EP
Discontinue all social play for ≥ 3 sec
Social play
SO
Social interactions involving non-aggressive physical contact with other individuals; high activity
Infant-associated behaviors
Climb on
ON
Climb onto any part of partner’s body so that all four limbs are on partner
Solicit climb on
SC
Position body directly above infant and/or pull infant onto body; may or may not result in infant climbing onto partner’s body
Climb off
OF
Voluntary climb off partner’s body after having all four limbs on partner
Push off/reject
PO
Prevent juvenile from climbing onto body, or rub or otherwise force juvenile off body
Nurse
NU
Have mouth on female’s nipple for ≥ 1 sec
End nursing
EN
Discontinue nursing posture
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Behavior
Code
Definition
Other social behaviors
Sniff/nuzzle
SN
Orient face against or toward partner, excluding anogenital region
Anogenital inspect
AI
Orient face against or toward anogenital region of partner, or use hands or mouth to investigate anogenital region of partner; includes anogenital groom
Groom
GR
Use hands and/or mouth to pick through fur and/or mouth of partner, excluding anogenital region
Sexual solicit
SS
Stare at partner with ear tufts flattened and eyes slit
Mount
MO
Climb on partner’s back from behind and grip partner around waist and legs; may be accompanied by pelvic thrusting
Initiate huddle
IH
Establish passive, torso-torso body contact with partner, with both animals remaining stationary and in passive contact for at least 3 sec
Leave huddle
LH
Terminate huddle after at least 3 sec of passive, torso-torso body contact during which both partners remained stationary
Object steal
OS
Take any nonfood object from hands or mouth of partner
Attempt object steal
AO
Attempt but fail to take nonfood object from hands or mouth of partner
Food-associated behaviors
Food steal
ST
Take any food from hands or mouth of partner
Attempt food steal
AF
Attempt but fail to take food from hands or mouth of partner
Share food
SH
Eat from a food source from which partner is simultaneously eating or that partner is occupying without removing any food from partner’s mouth or hands
New food
NF
Eat from a food source that no other animal is currently holding, eating from, or occupying
Individual behaviors
Bristle strut
BS
Arching posture and/or strut locomotion and/or general piloerection
Scent mark
SM
Rub or drag anogenital, suprapubic, or sternal region along substrate, object, or partner
Genital present
GP
Raise tail to expose genitals
Object manipulation
OM
Sniff, bite, chew, gouge, handle, pounce on, grapple with, or otherwise manipulate inanimate object, excluding food items and water bottle, for at least 1 sec
Written by Lissa Pabst. From Primate Info Net, Library and Information Service, National Primate Research Center, University of Wisconsin-Madison. Available at: http://pin.primate.wisc.edu/callicam/ethogram.html.
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TABLE A-3 An ethogram for rabbits
Common rabbit postures, behaviors, and vocalizations
Purring or teeth purring—A sound made by lightly and quickly grinding/vibrating the teeth as the whiskers quiver; a sign of contentment
Oinking or honking—A sound made to gain food or attention or during courtship
Clicking—A happy sound often made after a welcomed treat is given
Wheezing or sniffing—Nasal sounds made by ‘talkative’ rabbits; can be distinguished from abnormal respiratory sounds because they are intermittent and stimulated by interaction with the rabbit
Whimpering or low squealing—A fretting noise that is made when one picks up a rabbit that is reluctant to be handled; made often by pregnant and pseudopregnant does
Chinning—Rubbing the secretions from the scent glands under the chin on inanimate objects and people to mark possession. Glands are more developed in males than females
Nudging or nuzzling—The nose is used to nudge a person’s hand or foot, or the rabbit may pull on a pant leg to signal a desire for attention. When enough petting has been done the rabbit may push the hand away
Head shaking, ear shaking, body shudder—A shake of the head or body in response to an annoying smell or unwanted handling; often occurs as the rabbit settles down and becomes relaxed enough to begin eating and grooming
Courting or circling—A sexual or social behavior whereby a rabbit circles another rabbit or the feet of a human while softly honking
Scratching at the floor—A rabbit may scratch at the floor with its forepaws in order to get a person’s attention or to be picked up
Nipping—Not always done in anger, this can mean ‘move over’ or ‘put me down’
Presentation—The head is extended forward with the feet tucked under the body and the chin placed on the floor in order for the rabbit to present itself as subordinate for petting from humans or to be groomed by another rabbit
Flattening—A fear response wherein the rabbit flattens its abdomen onto the floor with ears laid back against the head; the eyes may be bulging
Thumping—A sharp drumming of the hind feet as a warning or an alert to other rabbits of danger; often accompanied by dilation of the pupils and seeking refuge
Teeth grinding—A slower, louder teeth crunching, sometimes seen with bulging of the eyes and usually indicating discomfort, pain, or illness
Snorting or growling—A warning sound, either hissing or a short barking growl, that occurs with aggression or fear and is often seen with the ears flattened against the head and the tail up and in the grunt-lunge-bite sequence
Isolation—When a rabbit that normally seeks attention from its mates and human companions isolates itself and is less active. Such a rabbit should be checked for illness
Kicking—If a rabbit feels insecure when being picked up it will kick violently in an effort to escape. The hindquarters must be supported to prevent trauma to the spine or legs. A rabbit should be placed hind-end first into a cage in order to help prevent injuries caused by kicking
Aggression—Strained, upright stance with tail stretched out and ears laid back in defensive posture; the rabbit may also kick high and backwards
Loud, piercing scream—Similar to a human baby crying; signaling pain and fear, as when the rabbit is caught by a predator
Scanning—A rabbit with impaired vision may move its head from side to side to scan the area around it
Reprinted with permission from Macmillan Publishers Ltd: [Lab Animal] (Mayer 2007), copyright (2007). Mayer J. Use of behavioral analysis to recognize pain in small mammals. Lab Anim 36(6):43-48.
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Other useful references for common normal behaviors of various laboratory animals include:
Whishaw, I. Q. and B. Kolb, eds. 2005. The Behavior of the Laboratory Rat: A Handbook with Tests. New York: Oxford University Press.
Pellis, S. M. and V. C. Pellis. 1987. Play-fighting differs from serious fighting in both target of attack and tactics of fighting in the laboratory rat Rattus norvegicus. Aggressive Behav 13:227-242.
Bassett, L., H. M. Buchanan-Smith, and J. McKinley. 2003. Effects of training on stress-related behavior of the common marmoset (Callithrix jacchus) in relation to coping with routine husbandry procedures. J Appl Anim Welf Sci 6(3):221-233.
Stevenson, M. F. and T. B. Poole. 1976. An ethogram of the common marmoset (Callithrix jacchus jacchus): General behavioural repertoire. Anim Behav 24:428-451.
Stone-Sade, D. 1973. An ethogram for rhesus monkeys. I. Antithetical contrasts in posture and movement. Am J Phys Anthropol 38(2):537-542.
Universities Federation for Animal Welfare. 1995. An ethogram for behavioural studies of the domestic cat (Felis silvestris catus L.) of the UK. Cat Behaviour Working Group. Hertfordshire, England: Universities Federation for Animal Welfare.
Morton, D. B. 2002. Behaviour of rabbits and rodents. In The Ethology of Domestic Animals—An Introductory Text, P. Jensen, ed. Oxford: CABI Wallingford Oxford. 193-209 pp.
Bayne, K. A. L., J. A. Mench, B. V. Beaver, and D. B. Morton. 2002. Laboratory Animal Behavior. In Laboratory Animal Science, ACLAM series, 2nd ed. New York: Academic Press. 1240-1264 pp.
Latham, N. and G. Mason. 2004. From house mouse to mouse house: The behavioural biology of free-living Mus musculus and its implications in the laboratory. Appl Anim Behav Sci 86:261-289.
Bothe, G. M. W., V. J. Bolivar, M. J. Vedder, and J. G. Geistfeld. 2004. Genetic and behavioral differences among five inbred mouse strains commonly used in the production of transgenic and knockout mice. Genes Brain Behav 3:149-157.
Fox, M. 1971. Behaviour of Wolves, Dogs, and Related Canids. New York: Harper & Row.
Leyhausen, P. 1979. Cat Behavior: The Predatory and Social Behavior of Domestic and Wild Cats. Barbara A. Tonkin translation. New York: Garland STMP Press.
Foster, H. L., J. D. Small, and J. G. Fox, eds. 1981. The Mouse in Biomedical Research, vol. 1-4. New York: Academic Press.
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Dixon, A. K. and H. U. Fisch. 1998. Animal models and ethological strategies for early drug testing in humans. Neurosci Biobehav Rev 23(2):345-358.
As stated in various places in the report, an effective assessment of distress is predicated upon solid knowledge of physiologic behaviors for each species and careful observation. In this respect, clinical and behavioral analysis of distress follows the investigative guidelines to determine the cause of any clinical symptomatology or pathology. Similarly, the goal of this exercise would be to remove, alleviate, or minimize the cause of distress (if doing so does not conflict with the research protocol) and support the animal in order to help it recover (see decision-making algorithm at the end of Chapter 4). The approach should integrate information from multiple behavioral and physiological parameters and should involve a team approach that includes researchers, veterinarians, and animal caretakers/ technicians, as distress levels will vary in relation to the species, husbandry conditions, and experimental protocol as well as with each individual animal. The Committee points out that differential diagnosis of signs (clinical and behavioral) attributed to pain, sickness, or distress is quite difficult and requires careful observation and clinical skills. The following tables showcase the overlapping clinical signs and abnormal behaviors associated both with distress and/or pain in various animal species.
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TABLE A-4 Species-specific clinical signs indicating pain, distress, or discomfort in experimental animals
Species
Cardiovascular
Respiratory
Other
Rat*
Dark claws and feet; eyes bulge and pale
Shallow rapid breathing; grunting on expiration
Red starring around eyes and nose; cyanosis, congestion and jaundice in mucous membranes or non-pigmented and non-hairy areas; square fast (dehydration)
Rabbit
As rat
White discharge from eyes, nose, and on inside of fore paws; cyanosis, congestion and jaundice in mucus membranes, or non-pigmented and non-hairy areas
Guinea pig
As rat
Cyanosis, congestion, and jaundice in mucus membranes or non-pigmented and non-hairy areas
Dog
As rat
Salivation and panting. As guinea pig. Raised body temperature; increase in specific gravity of urine and decrease in volume; sweaty paws, pupils dilate, eyes glazed
Cat
As dog
As dog. Circumanal gland discharge: third eyelid may protrude
Monkey
As dog
As dog
* Many signs in rats may also be seen in mice.
Reprinted from Morton, D. B. and P. H. M. Griffiths. 1985. Guidelines on the recognition of pain, distress and discomfort in experimental animals and an hypothesis for assessment. Vet Record 116:431-436.
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TABLE A-5 Species-specific signs of behavior indicating pain, distress, or discomfort in experimental animals
Species
Posture
Vocalising
Temperament
Locomotion
Other
Rat*
Persistent dormouse posture
Squeals on handling or pressure on affected area
May become more docile or aggressive
Abdominal writhing in mice.
Eats bedding; eats neonates
Rabbit
Looks anxious, faces back of cage (hiding posture)
Piercing squeal
Kicks and scratches or dozey
No spillage of food or water; eats neonates
Guinea pig
Urgent repetitive squealing
Rarely vicious; usually quiet; terrified, agitated
Drags legs back
No spillage of food or water
Dog
Anxious glances: seeks cold surfaces; tail between legs; hangdog look
Howls, distinctive bark
Aggression or cringing and extreme submissiveness, runs away
As guinea pig. Raised body temperature; increase in specific gravity of urine and decrease in volume; sweaty paws, pupils dilate, eyes glazed
Penile protrusion; frequent urination
Cat
Tucked-in limbs, hunched head and neck
Distinctive cry or hissing and spitting
Ears flattened; fear of being handled; may cringe
Monkey
Head Arms across body
Screams
Facial grimace
* Many signs in rats may also be seen in mice.
Reprinted from Morton, D. B. and P. H. M. Griffiths. 1985. Guidelines on the recognition of pain, distress and discomfort in experimental animals and an hypothesis for assessment. Vet Record 116:431-436.
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TABLE A-6 Common clinical signs associated with pain in small mammals
Production of fewer, smaller, or no fecal pellets
Reluctance to curl when sleeping (ferrets)
Tucked into abdomen
Anorexia
Strained facial expression, bulging eyes
Half-closed, unfocused eyes
Increased frequency and depth of respiration or shallow breathing
Aggression
Pushing abdomen on the floor
Lameness/ataxia
Stiff movements
Polyuria/polydipsia (especially with GI pain)
Immobility/lethargy/isolation
Head extended and elevated
Overgrooming/lack of grooming
Piloerection
Vocalization (squeal usually fear in rabbits)
Porphyrin secretion
Stretching with back arched
Self-mutilation
Stinting on palpation
Squinting (especially ferrets)
Hunched posture
Absence of normal behavior
Teeth grinding (bruxism)
Reprinted with permission from Macmillan Publishers Ltd: [Lab Animal] (Mayer 2007), copyright (2007). Mayer J. Use of behavioral analysis to recognize pain in small mammals. Lab Anim 36(6):43-48.
On the following page is a score sheet that may be used for behavioral phenotyping in mutant mice. As stated in the report, genetically modified mice may exhibit abnormal behaviors, but those behaviors may be characteristic of the background strain or environmental factors rather than a result of genetic modification. Background strain effects are particularly important where new genetic lines are not completely inbred. In those cases, variation should be expected as a result of different proportions of the progenitor background strains in each animal. Careful review of the characteristics of the background strains is necessary to avoid erroneously attributing differences in test results to the genetic modification. The score sheet was developed by Julie Watson, MA, VetMB, DACLAM, Johns Hopkins University Department of Molecular and Comparative Biology, adapted from Crawley and Paylor (1997).
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SHEET A-1
Investigational screen for behavioral phenotyping
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The following score sheets have been developed to assess animals in toxicology studies. This assessment is based on a detailed and systematic observation scheme that identifies and scores abnormalities according to a predetermined scale. The recorded symptomatology will determine the diagnosis and subsequent alleviatory actions. They can be adapted to any protocol or animal care facility system as long as the behavioral definitions are uniform across the same facility.
SHEET A-2
Investigational screen for toxicology studies
Step 1.
Daily Cageside Observations
This examination is typically performed with the animals in their cages and is designed to detect significant clinical abnormalities that are clearly visible upon a limited examination and to monitor the general health of the animals. The animals are not hand-held for these observations unless deemed necessary. Significant abnormalities that could be observed include but are not limited to: decreased/increased activity, repetitive behavior, vocalization, incoordination/limping, injury, neuromuscular function (convulsion, fasciculation, tremor, twitches), altered respiration, blue/pale skin and mucous membranes, severe eye injury (rupture), alterations in fecal consistency and fecal/urinary quantity.
Clinical Observations
Study personnel will conduct careful, hand-held, clinical examinations during the live phase of the study. The categorical observations made during this examination use a description to record the severity. These observations can be made at any time during the study.
Abnormal behavior: Description of unusual behaviors (e.g., circling, stereotypy) and changes in posture (e.g., arched back, splayed stance) not noted during the cageside portion of examination.
Abnormalities of the eye: Any additional descriptive observations concerning the eye, including, but not limited to, cloudiness, opaqueness, overall size, ruptures, etc.
Abnormal urine or feces: Description of animal excreta used to assess general health of animal, includes changes in color or quantity.
Abnormalities of the gastrointestinal (GI) tract: Description of atypical visual finding related to the gastrointestinal tract (e.g., prolapsed rectum, decreased water or food intake, reflux of test material).
Injury: Description of injury the animal has sustained.
Missing extremity: Description of missing body part, includes tail, ears, limbs, etc.
Abnormal muscle movements: Description of unusual movements (e.g., tremors or convulsion).
Palpable mass/swellings: Description of unusual growths or swellings. Includes the location, onset, appearance, and progression of any finding.
Abnormal posture: Description of unusual posture or stance.
Abnormalities of the reproductive system: Description of atypical visual findings in the reproductive organs, including but not limited to: prolapsed vagina, unretracted penis, scrotum bluish, enlarged testicles.
Abnormal respiration: Description of changes in respiration including shallow, slow, rapid, or mouth breathing.
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Abnormal skin or hair-coat/mucous membranes: Description of atypical skin or mucous membrane color, changes in hair coat, loss of fur, etc.
Excessive soiling: Description and location of increased body soiling.
General abnormalities: Description of any other atypical finding not fitting any of the previous observation categories.
Step 2. Detailed Clinical Observations (DCO)
The purpose of the DCO examination is to provide information on the physical health of the animals for the duration of a study, as well as to document any changes in health status that may have occurred in response to chemical treatment of the animals. This examination, scheduled periodically during a study, is conducted in a careful and systematic manner. The examination begins at the head of the animal and works toward the rear of the animal. The observations are ranked according to severity.
Cage-side observations.
Abnormal movements or behaviors: Unusual body movements (e.g., tremors, convulsions), abnormal behaviors (e.g., circling, stereotypy) and changes in posture (e.g., arched back, splayed stance).
Resistance to removal: The degree to which the animal attempts to escape capture is scored. The observer will slowly present a gloved hand into the cage and will grasp the animal over the shoulder area or by the tail.
1 = Decrease—clearly less resistance to capture than typical
2 = Typical—minimally to actively avoids capture and may be mildly aggressive
3 = Increase—clearly more resistance to capture than typical and is very aggressive (attempts to bite)
Hand-held observations recorded while handling an animal.
Ranked observations—the following use a defined scale to rank the degree of severity:
Eye observations: Eyes are bilaterally examined; however, if a unilateral observation is made, a concurrent observation is not made for the other eye if it is within typical limits.
Palpebral closure
1 = Closed (50% to completely closed)
2 = Open
3 = Protruding eyes
Pupil size (aided by penlight): Under typical examination conditions (white light), the typical appearance of the pupils in albino animals is complete constriction. Therefore a decrease in pupil size cannot be observed.
0 = Unable to evaluate
1 = Decrease—clearly decreased pupil size compared to typical
2 = Typical—completely constricted pupils
3 = Increase—clearly increased pupil size compared to typical
Lacrimation (noncolored periocular wetness)
1 = Decrease—extremely dry appearance of cornea
2 = Typical—glistening cornea (moderate dryness or wetness)
3 = Increase—extensive wetness around the eyes
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Degree of salivation:
1 = Decrease—oral dryness
2 = Typical—limited to moderate perioral wetness, but lips and chin are dry
3 = Increase—extensive wetness around the mouth and lips
Muscle tone: An assessment of muscle tone at the time of the hand-held observations.
1 = Decrease—clearly less muscle tone than typical
2 = Typical—animal is neither very relaxed nor very tense
3 = Increase—clearly more muscle tone than typical
Extensor-thrust response: Extent of reflex response to brisk pushes (by finger) on the plantar surface of the hind feet.
1 = Decrease—clearly less response than typical
2 = Typical—clearly detectable extensor-thrust response
3 = Increase—clearly more response than typical
Reactivity to stimuli: The degree to which an animal struggles to get free from hand-held restraint is ranked.
1 = Decrease—very slight or no struggling
2 = Typical—mild to moderate struggling, animal may vocalize
3 = Increase—aggressive escape behavior, may try to bite observer and usually vocalizes
Categorical observations—these are described in step 1
Open-Field Observations—Ranked observations made by placing the animal on a level surface.
Responsiveness to touch: The ventral aspect of the tail is lightly stroked using a finger. Typically, the animal will lift its tail and wrap it around the finger when lightly touched.
1 = Decrease—does not lift tail, but may briefly hold tail in the air when manually lifted; no response to touch
2 = Typical—lifts tail when touched
3 = Increase—lifts tail and acts startled, may turn toward finger in an attack response
Gait evaluation: Open-field observations are used for gait evaluation. If the animal remains motionless in the open field, it may be forced to walk on its forelegs while the hindlegs are held off the floor.
1 = Unable to walk
2 = Clear knuckling, stumbling and poor coordination, may include falling and/or dragging of one or more limbs
3 = Typical—smooth and coordinated gait
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An alternative example is the following score sheet developed at the University of Birmingham Biomedical Sciences Unit, courtesy of David B. Morton, BVSc, PhD.
SHEET A-3
General screening and applicability
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As stated in Chapter 4, establishing surrogate or humane endpoints as part of the experimental protocol and before experiments commence is one of the ways to minimize and alleviate distress in laboratory animals. The following is an example of a tiered scoring system of defined humane endpoints specifically developed for an arthritis mouse model. In this system the levels range from 0-5. When the arthritic wound is judged to be between levels 0-3, the animals are evaluated weekly by the investigator/veterinarian/ animal care team. When the wound advances to level 4, the animals are evaluated daily. All animals whose wounds reach level 5 on any day or that remain at level 4 for ten consecutive days are euthanized. Because more than one person evaluates the animals, some variation among the animal care staff does exist, a fact that should be taken under consideration.
SHEET A-4
Establishing humane or surrogate humane endpoints
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Finally, the Committee acknowledges that to date there is lack of consensus on the best way to achieve “normal species-specific behavior” within the conditions most commonly provided for laboratory animals. To this effect, a pair testing record from the Wisconsin National Primate Research Center is included (courtesy of Joseph Kemnitz, PhD), which is used to document the process of social acclimation and housing of nonhuman primates. The animals are paired and their interactions are observed. Primates with undesirable behaviors are identified and appropriate measures are taken.
SHEET A-5
Nonhuman primate pair testing record
