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Measurement properties of pain scoring instruments in farm animals: A systematic review protocol using the COSMIN checklist

  • Rubia Mitalli Tomacheuski,

    Roles Investigation, Methodology, Validation, Writing – original draft

    Affiliation Department of Anesthesiology, Medical School (FMB) of São Paulo State University (UNESP), Botucatu, São Paulo, Brazil

    ⨯
  • Beatriz Paglerani Monteiro,

    Roles Investigation, Methodology, Project administration, Supervision, Validation, Writing – review & editing

    Affiliation Département de sciences cliniques, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada

    ⨯
  • Marina Cayetano Evangelista,

    Roles Investigation, Methodology, Resources, Validation, Writing – review & editing

    Affiliation Département de sciences cliniques, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada

    ⨯
  • Stelio Pacca Loureiro Luna,

    Roles Methodology, Resources, Writing – review & editing

    Affiliation Department Veterinary Surgery and Animal Reproduction, School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP), Botucatu, São Paulo, Brazil

    ⨯
  • Paulo Vinícius Steagall

    Roles Conceptualization, Investigation, Methodology, Project administration, Resources, Supervision, Writing – review & editing

    paulo.steagall@umontreal.ca

    Affiliations Department of Anesthesiology, Medical School (FMB) of São Paulo State University (UNESP), Botucatu, São Paulo, Brazil, Département de sciences cliniques, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada

    ⨯

Research Article

20 Jan 2023: Tomacheuski RM, Monteiro BP, Evangelista MC, Luna SPL, Steagall PV (2023) Measurement properties of pain scoring instruments in farm animals: A systematic review using the COSMIN checklist. PLOS ONE 18(1): e0280830. https://doi.org/10.1371/journal.pone.0280830 View research article

Abstract

Society has been increasingly concerned about the impact of pain on farm animal welfare. This systematic review aims to provide evidence relating to the measurement properties (i.e. reliability, validity, and sensitivity) of pain scoring instruments used for pain assessment in farm animals. A literature search will be performed using five databases (MEDLINE, EMBASE, Web of Science, CAB abstracts and Biological Abstracts) and search terms related to pain, pain scales and different species of farm animals. Eligibility criteria will include full-text studies on the development and/or validation of acute and chronic pain scoring instruments for farm animals including bovine (beef and dairy), ovine, caprine, camel, swine and poultry. Exclusion criteria will include studies that report the use of pain scales for the validation of another instrument, or those reporting ethograms/list of behaviors potentially indicating pain without a scoring system. Study titles and their abstracts will be screened for eligibility by one investigator. Full-text articles will be independently reviewed for eligibility and evaluated by two investigators. Relevant information will be recorded and evaluated systematically according to the Consensus‐based Standards for the Selection of Health Measurement Instruments (COSMIN) checklist using an adapted data collection sheet. The following measurement properties and characteristics of the instruments will be assessed: content validity (internal consistency, structural and cross-cultural validity), reliability, measurement error, criterion and construct validity, responsiveness, interpretability and feasibility. Following the assessment of methodological quality and quality of the findings, evidence for each measurement property will be summarized into high, moderate, low or very low. This systematic review will provide further insights into the evidence-based measurement properties of pain scoring instruments in farm animals. It may identify possible gaps of knowledge with these tools as a potential target for future studies in farm animals with a positive impact on animal welfare.

Citation: Tomacheuski RM, Monteiro BP, Evangelista MC, Luna SPL, Steagall PV (2021) Measurement properties of pain scoring instruments in farm animals: A systematic review protocol using the COSMIN checklist. PLoS ONE 16(5): e0251435. https://doi.org/10.1371/journal.pone.0251435

Editor: Arda Yildirim, Tokat Gaziosmanpasa Universitesi, TURKEY

Received: November 30, 2020; Accepted: April 26, 2021; Published: May 14, 2021

Copyright: © 2021 Tomacheuski et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data from this study will be made available upon study completion.

Funding: The work of RT was funded by a scholarship from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brazil (001) and a grant from The São Paulo Research Foundation (FAPESP) Thematic Projects (2017/12815-0).

Competing interests: The authors have declared that no competing interests exist.

Introduction

Society has been increasingly concerned about the impact of pain on farm animal welfare [1]. Farm animals are less frequently treated for pain when compared with companion animals [2] and horses [3]. Possible reasons for this include the misconception that farm animals do not feel as much pain as small animals, concerns related to withdrawal times of analgesics for human food safety, lack of knowledge about assessing pain in farm animal species [3, 4], and budget considerations for the cost of analgesic therapies combined with the low zootechnical and affective value of farm animals [5–8]. Pain causes suffering, fear and stress, negatively impacting animal welfare and sometimes decreasing productivity [5, 9, 10]. Pain recognition and measurement are important components of animal welfare [5].

Pain assessment in animals is commonly performed through evaluation of species-specific behaviors [11] and changes in facial expressions [12–14]. Other methods of pain assessment include the use of quantitative sensory testing for evaluation of the animals’ sensory profile [15] and the use of kinetics or kinematics for evaluation of levels of activity and lameness [16–18]. However, these outcome measures require specific equipment and training and are not readily available in practice. Surrogate measures of pain might also include animal production outcomes, physiological parameters, and biomarkers [19–21]; yet these are not necessarily specific to pain. For these reasons, in practice, pain assessment relies on the evaluation of behaviors that could be associated with pain (including facial expressions) using scoring instruments (i.e. scales, tools, metrology instruments, etc.). Pain scoring instruments are non-invasive, inexpensive, do not require any equipment or restraint and may be performed by remote observation [22]. They are used to identify and quantify pain, and to monitor response to analgesic treatments. These instruments focus on the behavioral expression of pain and generally include a systematic description of behaviors accompanied by their respective scores. When such behaviors only involve facial expressions, they are known by facial expression scales or grimace scales. Pain scoring instruments have been developed for farm animals and may include assessment of activity, body posture, response to interaction, attention to wound/painful area, and/or facial expressions [14, 22–26]. In ruminants, for example, the most frequently observed behaviors that are possibly associated with pain include changes in appearance, posture, gait, appetite, interaction with other animals and the environment, decreased or increased frequency of locomotion, weight bearing, vocalization, increased attention to the injured area, lip-licking, curved lips, teeth grinding, tremors and strong tail wagging [5, 26–29]. Similarly, behaviours that could be associated with pain and changes in facial expressions have been identified in swine [14, 22]. In poultry, there is a lack of studies regarding pain assessment; however, change or absence of normal behaviours have been described including decreased social interactions, increased aggression, showing guarding and/or grooming behaviour [30]. Unidimensional scales such as the numerical rating scale (NRS), simple descriptive scale (SDS) and visual analog scales (VAS) have been used in the past to measure postoperative pain in sheep [31, 32]. However, these tools are not considered adequate because they were developed and validated for humans who self-report their degree of pain; these scales are subjective, not species-specific and influenced by the level of familiarity/expertise of the observer [26, 33, 34]. Species-specific pain scales have been developed for use in farm animals, such as sheep, cattle and pigs, and different levels of validation have been reported for some of these instruments [14, 22, 23, 26, 35–37]. Nevertheless, there is lack of validated instruments for some species of farm animals, like goats, camels and poultry.

Pain scoring instruments need to undergo several steps of scientific validation to ensure they are valid and reliable before they can be used in practice with confidence. In order to evaluate whether an instrument is valid and reliable, one must assess the measurement (or psychometric) properties of such instrument. Measurement properties refer to the characteristics or attributes of an instrument which are a consequence of the methodology used in their respective studies. In other words, measurement properties refer to the quality of the methodology. The following are the most commonly reported measurement properties of pain scoring instruments: a) development/content validity (expert assessment of the items included in the scale, the calculation of a content validation index, development of ethograms and/or evidence from the literature [38, 39]); b) structural and/or cross-cultural validity [39–41]; c) internal consistency (degree of the interrelatedness among the items [39, 41]); d) measurement error (systematic and random error in a patient’s score that is not associated to real changes in the construct to be assessed including sensitivity, specificity and accuracy [41]); e) reliability (whether the scores are consistent between different observers and over time, known as inter- and intra-observer reliability, respectively [22, 39]); f) criterion validity (correlation of the proposed tool with other existent scales [39, 41]); g) construct validity (whether the tool measures what it is supposed to measure, in this case, pain, by comparing different known groups and if the scores decrease after rescue analgesia [39, 41]); h) responsiveness (ability to detect changes over time); and i) a definition of a cut off point for administration of rescue analgesia [22, 38, 42].

Systematic reviews of outcome measurement instruments (e.g. pain scoring instruments) are important for selecting the most suitable instrument to measure a construct of interest (i.e. pain) in the target study population [43]. To the authors’ knowledge, systematic reviews on the evidence of the measurement properties of different pain scoring systems in farm animals have not been published.

Objective

This systematic review aims to provide evidence relating to the measurement properties (i.e. reliability, validity and sensitivity) of pain scoring instruments used for pain assessment in farm animals using the Consensus Based Standards for the Selection of Health Measurement Instrument (COSMIN) methodology [41, 44, 45].

Materials and methods

Databases and search terms

Five bibliographic databases (MEDLINE via PubMed, EMBASE, Web of Science, and CAB abstracts and Biological Abstracts via Web of Science) will be searched to identify studies published in peer-review journals. There will be no publication period nor language restriction. The search terms were defined using MeSH (Medical Subject Headings), a controlled vocabulary thesaurus produced by the National Library of Medicine, which index articles for MEDLINE/PubMed and using DeCS (Health Science Descriptors), a structured and multilingual vocabulary used as a unique language in indexing articles from scientific literature via the Virtual Health Library, which includes databases such as LILACS, MEDLINE, PAHO IRIS Repository, BIGG International database GRADE guidelines, BRISA Regional Base of Health Technology Assessment Reports of the Americas, CARPHA EvIDeNCe Portal, Observatorio Regional de Humanos de Salud, and PIE Evidence-Informed Policies.

The chosen search terms have been refined and tested using PubMed. The following descriptor items will be included: ("pain scoring system*" OR "pain scale*" OR "pain indicator*" OR "grimace scale*" OR "facial expression*" OR "pain behavior*" OR "pain assessment*") AND ("farm animal*" OR ruminant* OR bovine OR beef OR cattle OR cow OR cows OR buffalo* OR camel* OR ovine OR sheep* OR lamb* OR goat* OR caprine* OR swine OR porcine OR pig OR pigs OR piglet* OR poultry* OR chicken* OR fowl* OR duck* OR geese).

Eligibility criteria

Original studies reporting the development and/or validation of pain scoring instruments for the assessment of pain in farm animals as well as manuscripts reporting the assessment of one or more measurement properties of these instruments, will be included. These studies may involve naturally-occurring or experimental acute and chronic painful conditions in bovine (beef and dairy, including buffalo), ovine (sheep and lamb), caprine (goat and kid), camel, swine (pig and piglets) and poultry (chicken, fowl, ducks, turkeys, and geese). These species were chosen since they are the most relevant species used for production of animal protein (meat, dairy products and eggs) according to the latest report from the Organisation for Economic Co-operation and Development (OECD) and the Food and Agriculture Organization (FAO) of the United Nations, the OECD-FAO Agricultural Outlook 2020–2029 [46].

Studies that only report the use of pain scales as an outcome measurement instrument (e.g. in randomized controlled trials comparing two different treatments), studies in which a pain scale is used in the validation of another instrument, studies reporting only ethograms/list of behaviors that could be indicators of pain without a scoring system, studies reporting non-ordinal pain assessment variables, or review and systematic reviews will not be included. Studies reporting the use of pain scoring instruments to measure constructs other than pain, for example studies assessing animal welfare, in which pain is considered within the overall evaluation, studies assessing nociceptive testing, and studies for which the full text is not available will be excluded.

Literature search

Study titles and their abstracts will be initially screened for eligibility by one investigator (RMT) using the search strategy described above. Full-text articles will be selected. The references will be exported into Endnote (version X9) and Covidence (a web-based software platform integrated with the Cochrane’s review production toolkit that streamlines the production of systematic reviews), and duplicates will be removed.

Full-text articles will be independently reviewed for eligibility criteria by two investigators (RMT and BPM) using Covidence. “Snowball” methods such as pursuing references of eligible articles and/or reviews and electronic citation tracking will be used to maximize the retrieval of relevant studies.

Data extraction

Data from included studies will be extracted by one reviewer (RMT) using a predefined data collection sheet (excel format). The following information will be extracted:

  1. characteristics of the study population (age; gender; breed/strain; where/how animals were housed; how animals were handled; duration and source of pain);
  2. characteristics of the scale (name/version; language/translation; scoring method; number and name of items/action units);
  3. setting and purpose for which the scale is intended (e.g. chronic or acute pain; adult or juvenile/pediatric animals; hospital, experimental or commercial setting), interpretability, and operational characteristics such as the feasibility of administration for users (i.e. time required for completion of the instrument; who are the end-users; whether training is required; whether evaluations can be done in real-time, or using image or video assessment).

Assessment of the measurement properties

The quality assessment and summary of evidence will be performed independently by two reviewers (RMT and BPM) using an excel file. All information will be recorded and evaluated systematically as adapted from the COSMIN (COnsensus‐based Standards for the selection of health Measurement INstruments) checklist [41]. The COSMIN is an initiative of an international multidisciplinary team of researchers with a background in epidemiology, psychometrics, qualitative research, and health care, who have expertise in the development and evaluation of outcome measurement instruments. It aims to improve the selection of outcome measurement instruments in research and clinical practice [41]. The COSMIN methodology was specifically developed and validated for use in reviews of patient-reported outcome measures [41, 44, 45, 47]. However, it can be adapted and used for other types of outcome measurement instruments such as those in which pain is not self-reported and is evaluated by proxy, which is the case in veterinary medicine [45]. For these reasons, an adapted COSMIN evaluation sheet will be used in which items such as comprehensibility (by the patient point of view) and methods of interviewing will not be assessed. The following measurement properties will be evaluated: content validity (including internal consistency, structural and cross-cultural validity), reliability, measurement error, criterion and construct validity, and responsiveness. Moreover, interpretability and feasibility will be evaluated. If the reviewers (RMT and BPM) are unable to reach a consensus on the assessment of measurement properties, a third reviewer will be consulted (PVS). Table 1 shows the general overview of the adapted COSMIN evaluation sheet.

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Table 1. General overview of the criteria used for assessment of methodological quality.

https://doi.org/10.1371/journal.pone.0251435.t001

First, each study will be assessed for methodological quality, rated as: very good, adequate, doubtful, inadequate or not applicable; and quality of the findings, rated as: sufficient or positive [+], when the majority of the summarized results meet the criteria for good measurement properties; insufficient or negative [–], when the majority of the summarized results do not meet the criteria for good measurement properties; conflicting findings [+/-] or indeterminate [?]. Thereafter, the evidence for each measurement property will be summarized into high, moderate, low or very low for each pain scoring system.

Reporting of the findings of this systematic review will be done according to the recommendations from PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and the 10-step guideline from COSMIN.

Impact

Pain assessment and management are fundamental parts of animal welfare. This systematic review will provide further insights into the evidence-based measurement properties of pain scoring instruments in farm animals. It may identify gaps in knowledge with these tools as a potential target for future studies in farm animals to improve in animal welfare.

Limitations

Evidence might be limited or unavailable for some measurement properties or some species. As previously described, the COSMIN checklist was developed for assessing patient-reported outcome measures. In the case of non-verbal animals, pain assessment relies on evaluation by proxy using direct observation of behaviors or facial expressions using pain scales and/or grimace scales. For this reason, some items (i.e. comprehensibility, methods of interviewing) will not be assessed.

Acknowledgments

Ms. Marie-Claude Poirier for the invaluable help with databases, search terms and literature search.

References

  1. 1. Rioja-Lang FC, Connor M, Bacon HJ, Lawrence AB, Dwyer CM. Prioritization of Farm Animal Welfare Issues Using Expert Consensus. Front Vet Sci. 2020;6: 495. pmid:31998770
  2. 2. Remnant JG, Tremlett A, Huxley JN, Hudson CD. Clinician attitudes to pain and use of analgesia in cattle: where are we 10 years on? Vet Rec. 2017;181: 400–400. pmid:28814534
  3. 3. Lorena SE, Luna SP, Lascelles BDX, Corrente JE. Current attitudes regarding the use of perioperative analgesics in dogs and cats by Brazilian veterinarians. Vet Anaesth Analg. 2014;41: 82–89. pmid:24344759
  4. 4. Hewson CJ, Dohoo IR, Lemke KA, Barkema HW. Factors affecting Canadian veterinarians’ use of analgesics when dehorning beef and dairy calves. Can Vet J. 2007;48: 1129–1136. pmid:18050793
  5. 5. Anil L, Anil SS, Deen J. Pain Detection and Amelioration in Animals on the Farm: Issues and Options. J Appl Anim Welf Sci. 2005;8: 261–278. pmid:16436030
  6. 6. Gleerup KB. Identifying Pain Behaviors in Dairy Cattle. WCDS Adv Dairy Technol. 2017;29: 231–239.
  7. 7. Raekallio M, Heinonen KM, Kuussaari J, Vainio O. Pain Alleviation in Animals: Attitudes and Practices of Finnish Veterinarians. Vet J. 2003;165: 131–135. pmid:12573601
  8. 8. Watts SA, Clarke KW. A survey of bovine practitioners attitudes to pain and analgesia in cattle. Cattle Pract. 2000;8: 361–362.
  9. 9. Green LE, Hedges VJ, Schukken YH, Blowey RW, Packington AJ. The impact of clinical lameness on the milk yield of dairy cows. J Dairy Sci. 2002;85: 2250–2256. pmid:12362457
  10. 10. Telles FG, Luna SPL, Teixeira G, Berto DA. Long-term weight gain and economic impact in pigs castrated under local anaesthesia. Vet Anim Sci. 2016;1: 36–39. pmid:32734022
  11. 11. Flecknell P. Analgesia from a veterinary perspective. Br J Anaesth. 2008;101: 121–124. pmid:18424804
  12. 12. Evangelista MC, Watanabe R, Leung VSY, Monteiro BP, O’Toole E, Pang DSJ, et al. Facial expressions of pain in cats: the development and validation of a Feline Grimace Scale. Sci Rep. 2019;9: 1–11.
  13. 13. McLennan KM, Rebelo CJB, Corke MJ, Holmes MA, Leach MC, Constantino-Casas F. Development of a facial expression scale using footrot and mastitis as models of pain in sheep. Appl Anim Behav Sci. 2016;176: 19–26.
  14. 14. Di Giminiani P, Brierley VLMH, Scollo A, Gottardo F, Malcolm EM, Edwards SA, et al. The Assessment of Facial Expressions in Piglets Undergoing Tail Docking and Castration: Toward the Development of the Piglet Grimace Scale. Front Vet Sci. 2016;3: 1–10.
  15. 15. Krug C, Devries TJ, Roy J-P, Dubuc J, Dufour S. Algometer Precision for Quantifying Mechanical Nociceptive Threshold When Applied to the Udder of Lactating Dairy Cows. Front Vet Sci. 2018;5: 215. pmid:30258846
  16. 16. Flower FC, Sedlbauer M, Carter E, Von Keyserlingk MAG, Sanderson DJ, Weary DM. Analgesics improve the gait of lame dairy cattle. J Dairy Sci. 2008;91: 3010–3014. pmid:18650277
  17. 17. O’Callaghan KA, Cripps PJ, Downham DY, Murray R D. Subjective and objective assessment of pain and discomfort due to lameness in dairy cattle. Anim Welf. 2003;12: 605–610.
  18. 18. Chapinal N, de Passillé AM, Rushen J, Wagner S. Automated methods for detecting lameness and measuring analgesia in dairy cattle. J Dairy Sci. 2010;93: 2007–2013. pmid:20412914
  19. 19. Mogil JS. Animal models of pain: Progress and challenges. Nat Rev Neurosci. 2009. pp. 283–294. pmid:19259101
  20. 20. Costa VGG, Vieira AD, Schneider A, Rovani MT, Gonçalves PBD, Gasperin BG, et al. Systemic inflammatory and stress markers in cattle and sheep submitted to different reproductive procedures. Cienc Rural. 2018;48.
  21. 21. Prunier A, Mounier L, Le Neindre P, Leterrier C, Mormède P, Paulmier V, et al. Identifying and monitoring pain in farm animals: a review. Animal. 2013;7: 998–1010. pmid:23254122
  22. 22. Luna SPL, de Araújo AL, da Nóbrega Neto PI, Brondani JT, de Oliveira FA, dos S Azerêdo LM, et al. Validation of the UNESP-Botucatu pig composite acute pain scale (UPAPS). Staffieri F, editor. PLoS One. 2020;15: e0233552. pmid:32480399
  23. 23. de Oliveira FA, Luna SPL, do Amaral JB, Rodrigues KA, Sant’Anna AC, Daolio M, et al. Validation of the UNESP-Botucatu unidimensional composite pain scale for assessing postoperative pain in cattle. BMC Vet Res. 2014;10: 200. pmid:25192598
  24. 24. Häger C, Biernot S, Buettner M, Glage S, Keubler LM, Held N, et al. The Sheep Grimace Scale as an indicator of post-operative distress and pain in laboratory sheep. Olsson IAS, editor. PLoS One. 2017;12: 1–15. pmid:28422994
  25. 25. Viñuela-Fernández I, Jones E, Welsh EM, Fleetwood-Walker SM. Pain mechanisms and their implication for the management of pain in farm and companion animals. Vet J. 2007;174: 227–239. pmid:17553712
  26. 26. Silva NEOF, Trindade PHE, Oliveira AR, Taffarel MO, Moreira MAP, Denadai R, et al. Validation of the Unesp-Botucatu composite scale to assess acute postoperative abdominal pain in sheep (USAPS). PLoS One. 2020;15: e0239622. pmid:33052903
  27. 27. Molony V, Kent JE. Assessment of acute pain in farm animals using behavioral and physiological measurements. J Anim Sci. 1997;75: 266. pmid:9027575
  28. 28. Lorena SERS, Luna SPL, LASCELLES BD, Corrente JE. Attitude of Brazilian veterinarians in the recognition and treatment of pain in horses and cattle. Vet Anaesth Analg. 2013;40: 410–418. pmid:23461405
  29. 29. Futro A, Masłowska K, Dwyer CM. Ewes direct most maternal attention towards lambs that show the greatest pain-related behavioural responses. PLoS One. 2015;10: 1–15. pmid:26217942
  30. 30. Gaynor JS, Muir WW. Handbook of Veterinary Pain Management: Third Edition. 3rd ed. Missouri: Mosby Elsevier; 2014.
    • 31. Welsh EM, Gettinby G, Nolan AM. Comparison of a visual analogue scale and a numerical rating scale for assessment of lameness, using sheep as a model. Am J Vet Res. 1993;54: 976–983. pmid:8323070
    • 32. Ley SJ, Livingston A, Waterman AE. The effect of chronic clinical pain on thermal and mechanical thresholds in sheep. Pain. 1989;39: 353–357. pmid:2616185
    • 33. Price DD, Bush FM, Long S, Harkins SW. A comparison of pain measurement characteristics of mechanical visual analogue and simple numerical rating scales. Pain. 1994;56: 217–226. pmid:8008411
    • 34. Holton LL, Scott EM, Nolan AM, Reid J, Welsh E, Flaherty D. Comparison of three methods used for assessment of pain in dogs. J Am Vet Med Assoc. 1998;212: 61–66. pmid:9426779
    • 35. Häger C, Biernot S, Buettner M, Glage S, Keubler LM, Held N, et al. The Sheep Grimace Scale as an indicator of post-operative distress and pain in laboratory sheep. PLoS One. 2017;12: 1–15. pmid:28422994
    • 36. Guesgen MJ, Beausoleil NJ, Leach M, Minot EO, Stewart M, Stafford KJ. Coding and quantification of a facial expression for pain in lambs. Behav Processes. 2016;132: 49–56. pmid:27693533
    • 37. Gleerup KB, Andersen PH, Munksgaard L, Forkman B. Pain evaluation in dairy cattle. Appl Anim Behav Sci. 2015;171: 25–32.
    • 38. Silva NEOF, Trindade PHE, Oliveira AR, Taffarel MOT, Moreira MAP, Denadai R, et al. Validation of the Unesp-Botucatu composite scale to assess acute postoperative abdominal pain in sheep (USAPS). PLoS One. 2020;15: e0239622. pmid:33052903
    • 39. Streiner DL., Norman GR. Health Measurement Scales: a practical guide to their development and use. 4th ed. New York: Oxford University Press; 2008.
      • 40. Della Rocca G, Catanzaro A, Conti MB, Bufalari A, De Monte V, Di Salvo A, et al. Validation of the Italian version of the UNESP-Botucatu multidimensional composite pain scale for the assessment of postoperative pain in cats. Vet Ital. 2018;54: 49–61. pmid:29631315
      • 41. Prinsen CAC, Mokkink LB, Bouter LM, Alonso J, Patrick DL, de Vet HCW, et al. COSMIN guideline for systematic reviews of patient-reported outcome measures. Qual Life Res. 2018;27: 1147–1157. pmid:29435801
      • 42. Streiner DL, Norman GR, Cairney J. Health Measurement Scales: a practical guide to their development and use. Oxford: Oxford University Press; 2015.
        • 43. Mokkink LB, Terwee CB, Patrick DL, Alonso J, Stratford PW, Knol DL, et al. The COSMIN checklist for assessing the methodological quality of studies on measurement properties of health status measurement instruments: An international Delphi study. Qual Life Res. 2010;19: 539–549. pmid:20169472
        • 44. Mokkink LB, de Vet HCW, Prinsen CAC, Patrick DL, Alonso J, Bouter LM, et al. COSMIN Risk of Bias checklist for systematic reviews of Patient-Reported Outcome Measures. Qual Life Res. 2018;27: 1171–1179. pmid:29260445
        • 45. Mokkink LB, Boers M, van der Vleuten CPM, Bouter LM, Alonso J, Patrick DL, et al. COSMIN Risk of Bias tool to assess the quality of studies on reliability or measurement error of outcome measurement instruments: a Delphi study. BMC Med Res Methodol. 2020;1–26. pmid:33267819
        • 46. OECD, FAO. OECD-FAO Agricultural Outlook 2020–2029. OECD; 2020.
          • 47. Terwee CB, Mokkink LB, Knol DL, Ostelo RWJG, Bouter LM, De Vet HCW. Rating the methodological quality in systematic reviews of studies on measurement properties: A scoring system for the COSMIN checklist. Quality of Life Research. Springer; 2012; 651–657. https://doi.org/10.1007/s11136-011-9960-1 pmid:21732199
            • 48. McLennan KM, Miller AL, Dalla Costa E, Stucke D, Corke MJ, Broom DM, et al. Conceptual and methodological issues relating to pain assessment in mammals: The development and utilisation of pain facial expression scales. Appl Anim Behav Sci. Elsevier B.V.; 2019; 1–15.