Although rabbits are widely used in experiments that lead to pain and are also companion animals, they mask pain which makes it difficult to recognize it. The RPBS (Rabbit Pain Behavior Scale), developed in partnership between the FMVZ-Unesp-Botucatu and the University of Newcastle (United Kingdom), has been robustly validated and presents a score indicating the need for analgesic intervention.
Behavioral Scale of Pain in Rabbits
(Rabbit Pain Behavior Scale – RPBS)
The RPBS presents six characteristics:
1) Posture
2) Activity
3) Interaction and appetite
4) Facial expression
5) Attention to the affected area
6) Diverse behaviors (miscellaneous)
Each characteristic has 3 levels scored from 0 to 2, where 0 represents normality or absence of pain and 2 indicates the greatest possible pain.
Please see below the description of the behaviors of the ethogram of rabbits in pain.
Behavior
Description
Videos
1. Activity
Active
Moves and/or moves around
Inactive
Remains stationary
2. Position in the cage
Front
Front of the cage
Back
Back of the cage
Change position
Moves around the cage: front to back or back to front
3. Posture
Normal
Flexes pelvic limbs under the hip, thoracic limbs under the body; abdomen and chest not supported on cage floor
Seated
Sits with vertically extended thoracic limbs
Lying down
Lies with the abdomen and chest in contact with the cage floor and horizontally extended thoracic limbs
Lying on one side
Lies on one side of the body with horizontally extended thoracic limbs
Quadrupedal
In the quadrupedal position with the four limbs extended vertically; abdomen not in contact with the cage floor
Bípede
Supported on both pelvic limbs; thoracic limbs not touching the floor
Change posture
Alternates between different postures
4. Position of the ears in relation to the body
Completely lowered
Parallel to the vertebral column
Semi-lowered
Semi-lowered (positioned between fully lowered and erect)
Erect
Erect, perpendicular to the spine
‘Scissors’ ears
Each ear moves to different positions
5. Eye opening
Open
Fully open
Semi-closed
Semi-closed
Closed
Closed
Not visible
Not possible to visualize the eyes
6. Typical rabbit behaviors
Jump
Jumps to move around with both pelvic limbs at the same time
Rotating jump
Jumps performing a 180º or 360º rotation with both pelvic limbs at the same time
React
Moves head and/or body sharply in response to environmental stimulus (e.g., sound stimulus)
Shake body
Shakes the whole body
Shake the head
Shakes only the head
Dig
Digs the floor
Explore
Sniffs the cage floor and/or walls and/or bars curiously
Gnaw
Gnaws the floor or bars of the cage
Press limbs
Presses limbs strongly against the cage floor
Stretch
Stretches the body
Scratch ear
Scratches the ears with the limbs
Punch
Extends the thoracic limbs horizontally, quickly alternating between right and left
7. Interaction with motivational items
Interact with pinecone
Interacts with the pinecone (chews, gnaws, pushes with the thoracic limbs)
Eat carrot
Eats the carrot
8. Physiological behaviors
Drink
Drinks water from the water trough
Eat feed
Eats feed from the feeder
Ingest cecotropes
Ingests anal cecotropes
9. Self-cleaning: by licking; possibly with assistance from the thoracic limbs
Head
Head and ears
Body
Body, including abdomen and limbs (except affected limb)
10. Pain-related behaviors
Lick affected area
Licks affected region
Twitch
Presents spasms in the skin of the back
Flinch
Moves body quickly dorsally and for no apparent reason
Wince
Shrinks back and closes eyes
Stagger
Partially loses balance
Fall
Totally loses balance; falls to the floor
Tremble
Presents tremors observed in head and ears
Suspend limb
Keeps the affected limb suspended
Put weight on and raise
Raises and puts weight on the affected limb repeatedly
Try to get up
Tries to get up, but remains in a normal posture or lying down
Writhe
Contracts the muscles of the abdomen
Before the evaluation, it is indicated to include in the rabbit’s cage/pen a new motivational item (toy, pine cone, etc.) and a palatable food (snacks, vegetables such as carrots or fresh leaves).
Behavioral pain scale in rabbits (RPBS)
1) Posture
Videos
A) Moves around normally and/or jumps
B) Presents bipedal or quadrupedal position
C) Walks at a very slow pace
D) Lies for most of the time
E) Does not move for most of the time
Score
Presence of state A and/or B only
0
Presence of one of states C, D, or E
1
Presence of two or more of states C, D, or E
2
2) Activity
Videos
A) The rabbit moves normally and/or when stationary performs normal activity *
B) The rabbit moves little and does not perform normal activity
C) The rabbit is immobile and does not perform normal activity
Score
Presence of state A
0
Presence of state B
1
Presence of state C
2
* Interacts with environmental enrichment objects (pine cone, toy and others), eats, drinks water, digs shavings, presents self-cleaning behavior, sniffs the environment
3) Interaction and Appetite
Videos
A) Interacts with environmental enrichment objects *
B) Eats **
C) Sniffs the environment
D) Presents self-cleaning behavior (grooming), except at the affected area
Score
The rabbit presents more than one of these behaviors
0
The rabbit presents one of these behaviors
1
The rabbit does not present any of these behaviors
2
* Pine cone, toy, pen substrate
** Food, vegetables, greens, or snacks
4) Facial Expression
Videos
A) Keeps eyes wide open and ears erect all the time
B) Keeps eyes semi-closed or closed at any moment*
C) Presents drooping ears at any moment
Score
The rabbit displays expression A
0
The rabbit displays expression B or C
1
The rabbit displays expressions B and C
2
*Do not consider blink of eyes as semi-closed or closed eyes
5) Attention to the affected area
Videos
A) Licks the affected area
B) Presses the abdomen against the floor
C) Keeps one limb suspended
Score
The rabbit does not present any of these behaviors
0
The rabbit presents one of these behaviors
1
The rabbit presents more than one of these behaviors
2
6) Miscellaneous behaviors
Videos
A) Attempts to stand up, but remains lying down
B) Rapid dorsal movement of the body (flinches)
C) Retracts and closes the eyes (winces)
D) Tremors *
Score
The rabbit does not present any of these behaviors
0
The rabbit presents one of these behaviors
1
The rabbit presents more than one of these behaviors
2
* More easily observed in the head and ears
After watching the videos corresponding to all sub-items of each item on the scale, watch the test videos, and analyze and score the behaviors. Then check the responses for each video. You are able to use the scale when your scores are up to 20% higher or lower than the template scores in at least three tests.
Decision to perform analgesia*
Score
Analgesic intervention score
(cut-off point)
RPBS
0 to 12
≥ 3
Diagnostic uncertainty zone: scores between 3 and 4
Numerical scale
0 to 10
≥ 4
Simple descriptive scale
1 to 4
≥ 2
Visual analogue scale
0 – 100 mm
≥ 23 mm
* Regardless of the score, it is up to the veterinarian to decide whether or not to use analgesics, according to the clinical evaluation.
After reading and training the previous items, click below to assess pain in your animal.