Using the Facial Grimace Scale to Evaluate Rabbit Wellness in Post

clinical techniques Victoria Hampshire, VMD, Column Editor

Using the facial grimace scale to evaluate rabbit wellness in post-procedural monitoring Victoria Hampshire, VMD1 & Sheilah Robertson, BVMS (Hons), PhD, DACVAA, DECVAA, DACAW, DECAWBM (WSEL), Specialist in Welfare Science, Ethics and Law, MRCVS2

Rabbits are commonly used in biomedical research and might undergo potentially painful procedures during the course of a study. This column discusses the rabbit facial grimace scale as a tool for monitoring post- procedural pain and explains how it can be incorporated into a worksheet for evaluating rabbit wellness.

Among species whose use in research is regulated by the US Department of Agriculture (USDA), rabbits are the second most common, with more than 169,000 rabbits included in the USDA annual report of animal usage in research facili- ties for 2013 (ref. 1), the most recent report available. Some of these animals undergo procedures that have the potential to cause pain or distress. Therefore, post-procedural monitoring to detect pain or distress in rabbits is important to protect animal welfare. Most assessments of pain and distress

npg level of pain or distress that each reflects is ranked using a numerical scale on which low numbers represent low levels of pain or distress and high numbers represent FIGURE 1 | Rabbit FGS. Illustrations by Aleks Byrd. Normal (0). Ears are alert; eyes are wide. Whiskers high levels of pain or distress. Scores from have a gentle downward curve. Cheeks are puffy, not contracted or flattened. Nose appears relaxed, multiple attributes can be compiled into and nares form a U shape. Moderate (1). Ears are droopy in frontal view and oriented caudally at a 60º a composite score. Single or composite angle in profile view. Eyes are slightly narrowed (orbital tightening). Whiskers are flattened against scores may be used alone or combined the cheeks or oriented caudally. Cheeks are slightly flattened and there is less definition between the with quantitative or qualitative measure- cheeks and nose. Nares form a V shape. Severe (2). Ears are flattened in both frontal and profile views. Eyes are overtly tightened or closed. Whiskers and cheeks are markedly flat. Nose is drawn down toward ments to estimate the overall intensity of the chin; head is tucked against the chest. pain or distress that an animal is experienc- ing. Veterinarians or other observers can consider these estimates when prescribing facial expressions were believed to correlate towards observers or other external stimuli analgesic drugs2–6. with emotions. Driven by a desire to bet- within their primary or secondary enclo- Well-known animal pain experts have ter understand species-typical manifesta- sures during cage-side observations. This recently described a complex set of facial tions of pain or distress, animal researchers propensity to face an observer enables him expressions as attributes that may be use- have recently revisited this topic7–10. Facial or her to detect and document changes ful in augmenting existing pain-scoring expressions are relatively easy to observe in an animal’s status more frequently or tools. As early as Darwin’s era, animals’ because animals often orient themselves when first approaching the cage. Early and

1Capital Preclinical Scientific Research Consultants, LLC, Bethesda, MD. 2College of Veterinary Medicine, Michigan State University, East Lansing, MI. Correspondence should be addressed to V.H. ([email protected]).

LAB ANIMAL Volume 44, No. 7 | JULY 2015 259 clinical techniques

TABLE 1 | Daily rabbit wellness evaluation and date of last check) as well as notes on any incisions and on diet) should also be Attribute Observations Score* recorded, along with an overall veterinary FGS Normal, moderate, severe assessment and recommendation. Finally, Posture Reared, sitting, crouched, sprawled Ears Alert, neutral, droopy we recommend that a recheck interval be Exploration Playful, curious, ambulatory, shaking unambiguously stated at the end of the Vocalization Normal, moderate, severe worksheet. Tooth grinding Normal, moderate, severe Eating Normal, reduced, absent 1. US Department of Agriculture. Animals Used in Drinking Normal, reduced, absent Research 2013. http://www.aphis.usda.gov/ animal_welfare/downloads/7023/Animals%20 Defecation Normal, reduced, absent Used%20In%20Research%202013.pdf Urination Normal, reduced, absent 2. Weaver, L.A., Blaze, C.A., Linder, D.E., Grooming Normal, reduced, absent Andrutis, K.A. & Karas, A.Z. A model for clinical evaluation of perioperative analgesia in rabbits *0, normal; 1, moderate or reduced; 2, severe or absent. (Oryctolagus cuniculus). J. Am. Assoc. Lab. Anim. Sci. 49, 845–851 (2010). 3. Lipman, N.S., Marini, R.P. & Flecknell, P.A. frequent observation may enable detection pain-associated behaviors identified in any Anesthesia and analgesia in rabbits. in Anesthesia and Analgesia in Laboratory Animals of subtle changes that might indicate the treatment group. Serum corticosterone (eds. Kohn, D.F., Wixson, S.K., White, W.J. & need for analgesic intervention. concentrations (used as a marker of stress) Benson, G.J.) 205–232 (Academic, Boston, Various postural and behavioral attri- were no different between sham or tattoo 1997). 4. Lipman, N.S., Marini, R.P. & Flecknell, P.A. butes that may be useful for assessing treatments. Keating et al. concluded that Anesthesia and analgesia in rabbits. in 2,11 pain in rabbits have been described . the rabbit FGS was a reliable and accurate Anesthesia and Analgesia in Laboratory Keating et al. described facial expression tool for assessing pain in rabbits. We agree Animals 2nd edn. (eds. Fish, R.E., Brown, M.J., Danneman, P.J. & Karas, A.Z.) (Academic, responses to pain in rabbits, namely ear, and recommend that it be incorporated Boston, 2008). eye, whisker, cheek and nose positions, into post-procedural monitoring of well- 5. Parga, M.L. Assessment of the efficacy of and categorized them into a rabbit facial ness in laboratory rabbits. meloxicam and development of a pain scoring grimace scale (FGS)12 based largely on the We encourage technologists and oth- system based on behavior in rabbits undergoing elective surgery. BSAVA Congress 2003 Scientific coding methods used by Langford and col- ers tasked with routine pain assessment of Proceedings. (Birmingham, UK, 2003). leagues to characterize pain responses in rabbits to develop a protocol to guide their 6. Roughan, J.V., Flecknell, P.A. & Orr, H.E. mice10. Keating et al. utilized a prospec- evaluation and intervention approach. We Behavioral assessment of postoperative pain and analgesic effects of carprofen in the tive, blinded, crossover study in which the suggest that this protocol should include domestic rabbit. in Proceedings of the Eighth

Nature America, Inc. All rights reserved. America, Inc. © 201 5 Nature same investigator carried out ear tattoo- use of the FGS. We recommend that tech- World Congress of Veterinary Anaesthesia ing or a sham procedure on rabbits with nologists first become familiar with the (University of Tennessee, Knoxville, TN, 2003). 7. Gross, D.M. Defending the humanities with or without prior application of a topical facial gestures and expressions that charac- Charles Darwin’s The Expression of the Emotions

npg anesthetic cream containing lidocaine and terize each ranking on the FGS (Fig. 1). We in Man and Animals (1872). in The Secret History prilocaine. Treatment-blinded observ- find that illustrations are more helpful than of Emotion: from Aristotle’s Rhetoric to Modern Brain Science 34–59 (University of Chicago, ers watched video footage of each rabbit’s photographs both for training technologists Chicago, IL, 2007). facial expressions and assigned each rabbit and for regular use in assigning FGS scores 8. Gleerup, K.B., Forkman, B., Lindegaard, C. & a score on the FGS. Serum corticosterone because they can enhance the facial features Andersen, P.H. An equine pain face. Vet. concentrations were measured in blood to capture more detail. Anaesth. Analg. 42, 103–114 (2015). 9. Holden, E. et al. Evaluation of facial expression samples obtained from a catheter placed in When assessing a rabbit, technologists in acute pain in cats. J. Small Anim. Pract. 55, the contralateral ear vein, and blood pres- should use a worksheet to record their 615–621 (2014). sure, heart rate and behavioral responses findings. The date of the evaluation and 10. Langford, D.J. et al. Coding of facial expressions of pain in the laboratory mouse. Nat. Methods such as vocalization were all recorded. the number of days that have passed since 7, 447–449 (2010). Compared with other treatments, tattoo- the potentially painful procedure should 11. American College of Laboratory Animal ing without anesthetic cream resulted in be recorded. Next, each attribute of inter- Medicine. Guidelines for the Assessment and Management of Pain in Rodents and Rabbits higher FGS scores as well as more strug- est (Table 1), including the FGS, should be (American College of Laboratory Animal gling and vocalization, higher peak heart evaluated and scored. A table can be used Medicine, 2006). rate and higher blood pressure, which are to compile these scores (Table 1). Objective 12. Keating, S.C., Thomas, A.A., Flecknell, P.A. & Leach, M.C. Evaluation of EMLA cream for known physiologic and behavioral indi- findings (temperature, respiratory rate, preventing pain during tattooing of rabbits: cators of pain. Behavioral changes 1 hour heart rate and body weight (including changes in physiological, behavioral, and facial after treatment were minimal, with no change in body weight since last check expression responses. PLoS ONE 7, e44437 (2012).

260 Volume 44, No. 7 | JULY 2015 www.labanimal.com