Towards a better assessment of acute pain in equines

A special issue of Animals (ISSN 2076-2615). This special issue belongs to the section "Equids".

Deadline for manuscript submissions: closed (1 January 2021) | Viewed by 120717

Special Issue Editors


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Guest Editor
Department of Veterinary Medicine, University of Milan, Via dell'Università 6, Lodi, Italy
Interests: animal welfare; pain assessment; facial expression; animal cognition
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Guest Editor
Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584CM Utrecht, The Netherlands
Interests: donkey medicine; pain assessment, local anaesthetic techniques, anaesthesiology, intensive care
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Horses and donkeys can suffer from different health issues such as colic, acute laminitis, dental and other problems, fractures, or injuries that cause acute pain, thus compromising their health and welfare. In the last 10 years, considerable progress has been made in recognition and treatment of pain in animals; however, a reliable, feasible, and effective method for the assessment and monitoring of equine acute pain is still a challenge. We invite original research papers related to the improvement of acute pain assessment in horses and donkeys, including new methods (e.g., pain scales,) and/or pain indicators (e.g., biomarkers). Additional topics may include the validation of automatic systems for recognition of pain indicators or the effects of training of assessors with the aim to improve the reliability of pain assessment.

Dr. Emanuela Dalla Costa
Dr. Thijs van Loon
Guest Editors

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Keywords

  • horse
  • donkey
  • acute pain
  • pain scale
  • pain indicator
  • biomarkers
  • reliability

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Published Papers (11 papers)

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Research

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11 pages, 1336 KiB  
Article
Objective Assessment of Chronic Pain in Horses Using the Horse Chronic Pain Scale (HCPS): A Scale-Construction Study
by Johannes P. A. M. van Loon and Lucia Macri
Animals 2021, 11(6), 1826; https://doi.org/10.3390/ani11061826 - 18 Jun 2021
Cited by 22 | Viewed by 6288
Abstract
The objective assessment of chronic pain is of utmost importance for improving welfare and quality of life in horses. Freedom from disease and pain is one of the ‘five freedoms’ that are necessary for animal welfare. The aim of this study was to [...] Read more.
The objective assessment of chronic pain is of utmost importance for improving welfare and quality of life in horses. Freedom from disease and pain is one of the ‘five freedoms’ that are necessary for animal welfare. The aim of this study was to develop a pain scale for the assessment of chronic pain in horses (Horse Chronic Pain Scale; HCPS), which is based on behavioural and facial expressions. The scale was used to assess 53 horses (26 horses diagnosed with chronic painful conditions by means of clinical examination and additional diagnostic procedures (consisting of osteoarthritis, chronic laminitis, chronic back and neck problems, chronic dental disorders) and 27 healthy control animals). Animals were assessed once daily for three consecutive days by two observers that were blinded to the condition of the animals and were unaware of any analgesic treatment regimens. The HCPS consists of two parts, the Horse Chronic Pain Composite Pain Scale (HCP CPS, with behavioural parameters) and the EQUUS-FAP (Equine Utrecht University Scale for Facial Assessment of Pain). The HCP CPS had good inter-observer reliability (intraclass correlation coefficient (ICC) = 0.84, p < 0.001), while the EQUUS-FAP component (with facial expression-based parameters) had poor inter-observer reliability (ICC = 0.45, p < 0.05). The inter-observer reliability of the combined HCPS was good (ICC = 0.78, p < 0.001). The HCPS revealed significant differences between horses with chronic painful conditions and control horses on 2 out of 3 days (p < 0.05). In conclusion, we tested a composite pain scale for the assessment of chronic pain in horses based on behavioural and facial expression-based parameters. Further studies are needed to validate this pain scale before it can be used in practice. Full article
(This article belongs to the Special Issue Towards a better assessment of acute pain in equines)
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12 pages, 12052 KiB  
Article
Development and Validation of an Automated Video Tracking Model for Stabled Horses
by Nuray Kil, Katrin Ertelt and Ulrike Auer
Animals 2020, 10(12), 2258; https://doi.org/10.3390/ani10122258 - 30 Nov 2020
Cited by 9 | Viewed by 3924
Abstract
Changes in behaviour are often caused by painful conditions. Therefore, the assessment of behaviour is important for the recognition of pain, but also for the assessment of quality of life. Automated detection of movement and the behaviour of a horse in the box [...] Read more.
Changes in behaviour are often caused by painful conditions. Therefore, the assessment of behaviour is important for the recognition of pain, but also for the assessment of quality of life. Automated detection of movement and the behaviour of a horse in the box stall should represent a significant advancement. In this study, videos of horses in an animal hospital were recorded using an action camera and a time-lapse mode. These videos were processed using the convolutional neural network Loopy for automated prediction of body parts. Development of the model was carried out in several steps, including annotation of the key points, training of the network to generate the model and checking the model for its accuracy. The key points nose, withers and tail are detected with a sensitivity of more than 80% and an error rate between 2 and 7%, depending on the key point. By means of a case study, the possibility of further analysis with the acquired data was investigated. The results will significantly improve the pain recognition of horses and will help to develop algorithms for the automated recognition of behaviour using machine learning. Full article
(This article belongs to the Special Issue Towards a better assessment of acute pain in equines)
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14 pages, 284 KiB  
Article
Prospective Feasibility and Revalidation of the Equine Acute Abdominal Pain Scale (EAAPS) in Clinical Cases of Colic in Horses
by Yamit Maskato, Alexandra H. A. Dugdale, Ellen R. Singer, Gal Kelmer and Gila A. Sutton
Animals 2020, 10(12), 2242; https://doi.org/10.3390/ani10122242 - 29 Nov 2020
Cited by 15 | Viewed by 4411 | Correction
Abstract
Assessment of the severity of pain in colic cases is subjective. The Equine Acute Abdominal Pain Scale (EAAPS), previously validated using film clips of horses with colic, was tested for feasibility and revalidated in both medical and surgical colic cases in Israel and [...] Read more.
Assessment of the severity of pain in colic cases is subjective. The Equine Acute Abdominal Pain Scale (EAAPS), previously validated using film clips of horses with colic, was tested for feasibility and revalidated in both medical and surgical colic cases in Israel and the UK. Feasibility qualities evaluated were quickness and ease-of-use. Pain in 231 horses, presented for colic, was assessed by 35 participants; 26 in the UK and 9 in Israel. Without prior training, participants assessed the severity of pain using two scales; the EAAPS and a visual analogue scale (VAS). Convergent validity comparing the EAAPS to the VAS was substantial, discriminant validity was good, and predictive validity for surgical treatment was similar to the VAS, but for mortality, the VAS was significantly better. No participants reported the EAAPS to be “very slow” or “very difficult” to use. The mode reported was “quick”/“very quick” and “easy”/“very easy” to use, though in less than 10% of cases, it was reported to be a little less quick or easy. More experienced first-time users found it significantly quicker to use than less experienced participants. In conclusion, the EAAPS is the only equine pain assessment scale that has been tested and found to demonstrate good feasibility for use in the referral hospital setting. Full article
(This article belongs to the Special Issue Towards a better assessment of acute pain in equines)
16 pages, 2410 KiB  
Article
Identification of Body Behaviors and Facial Expressions Associated with Induced Orthopedic Pain in Four Equine Pain Scales
by Katrina Ask, Marie Rhodin, Lena-Mari Tamminen, Elin Hernlund and Pia Haubro Andersen
Animals 2020, 10(11), 2155; https://doi.org/10.3390/ani10112155 - 19 Nov 2020
Cited by 22 | Viewed by 8504
Abstract
Equine orthopedic pain scales are targeted towards horses with moderate to severe orthopedic pain. Improved assessment of pain behavior and pain-related facial expressions at rest may refine orthopedic pain detection for mild lameness grades. Therefore, this study explored pain-related behaviors and facial expressions [...] Read more.
Equine orthopedic pain scales are targeted towards horses with moderate to severe orthopedic pain. Improved assessment of pain behavior and pain-related facial expressions at rest may refine orthopedic pain detection for mild lameness grades. Therefore, this study explored pain-related behaviors and facial expressions and sought to identify frequently occurring combinations. Orthopedic pain was induced by intra-articular LPS in eight horses, and objective movement asymmetry analyses were performed before and after induction together with pain assessments at rest. Three observers independently assessed horses in their box stalls, using four equine pain scales simultaneously. Increase in movement asymmetry after induction was used as a proxy for pain. Behaviors and facial expressions commonly co-occurred and were strongly associated with movement asymmetry. Posture-related scale items were the strongest predictors of movement asymmetry. Display of facial expressions at rest varied between horses but, when present, were strongly associated with movement asymmetry. Reliability of facial expression items was lower than reliability of behavioral items. These findings suggest that five body behaviors (posture, head position, location in the box stall, focus, and interactive behavior) should be included in a scale for live assessment of mild orthopedic pain. We also recommend inclusion of facial expressions in pain assessment. Full article
(This article belongs to the Special Issue Towards a better assessment of acute pain in equines)
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10 pages, 993 KiB  
Article
Objective Assessment of Acute Pain in Foals Using a Facial Expression-Based Pain Scale
by Johannes van Loon, Nicole Verhaar, Els van den Berg, Sarah Ross and Janny de Grauw
Animals 2020, 10(9), 1610; https://doi.org/10.3390/ani10091610 - 10 Sep 2020
Cited by 5 | Viewed by 4967
Abstract
Pain assessment is very important for monitoring welfare and quality of life in horses. To date, no studies have described pain scales for objective assessment of pain in foals. Studies in other species have shown that facial expression can be used in neonatal [...] Read more.
Pain assessment is very important for monitoring welfare and quality of life in horses. To date, no studies have described pain scales for objective assessment of pain in foals. Studies in other species have shown that facial expression can be used in neonatal animals for objective assessment of acute pain. The aim of the current study was to adapt a facial expression-based pain scale for assessment of acute pain in mature horses for valid pain assessment in foals. The scale was applied to fifty-nine foals (20 patients and 39 healthy controls); animals were assessed from video recordings (30–60 s) by 3 observers, who were blinded for the condition of the animals. Patients were diagnosed with acute health problems by means of clinical examination and additional diagnostic procedures. EQUUS-FAP FOAL (Equine Utrecht University Scale for Facial Assessment of Pain in Foals) showed good inter- and intra-observer reliability (Cronbach’s alpha = 0.95 and 0.98, p < 0.001). Patients had significantly higher pain scores compared to controls (p < 0.001) and the pain scores decreased after treatment with NSAIDs (meloxicam or flunixin meglumine IV) (p < 0.05). Our results indicate that a facial expression-based pain scale could be useful for the assessment of acute pain in foals. Further studies are needed to validate this pain scale. Full article
(This article belongs to the Special Issue Towards a better assessment of acute pain in equines)
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16 pages, 1089 KiB  
Article
Application of a Ridden Horse Pain Ethogram and Its Relationship with Gait in a Convenience Sample of 60 Riding Horses
by Sue Dyson and Danica Pollard
Animals 2020, 10(6), 1044; https://doi.org/10.3390/ani10061044 - 17 Jun 2020
Cited by 30 | Viewed by 22600
Abstract
A Ridden Horse Pain Ethogram (RHpE) comprising 24 behaviours has been developed to facilitate the identification of musculoskeletal pain. The aim was to further test the RHpE by its application to a convenience sample (n = 60) of sports horses and riding [...] Read more.
A Ridden Horse Pain Ethogram (RHpE) comprising 24 behaviours has been developed to facilitate the identification of musculoskeletal pain. The aim was to further test the RHpE by its application to a convenience sample (n = 60) of sports horses and riding school horses in regular work and assumed by their owners to be working comfortably. All horses performed a purpose-designed dressage-type test of 8.5 min duration in walk, trot and canter, with their normal rider. The RHpE was applied retrospectively to video recordings acquired in a standardised fashion. Seventy-three percent of horses were lame (≤ grade 2/8) on one or more limbs; 47% had gait abnormalities in canter. Ridden Horse Pain Ethogram scores ranged from 3 to 16/24 (median 9); rider skill score ranged from 2.5 to 8/10 (median 4.75). The effect of horse age, breed, sex, work-discipline, epaxial muscle hypertonicity or pain, an ill-fitting saddle, rider skill score, the presence of lameness or gait abnormalities in canter on the RHpE score was assessed using Poisson regression. Two variables were retained in the final multivariable analysis, rider skill score as a continuous variable (p < 0.001), and lameness (p = 0.008). A RHpE score ≥8 was a good indicator of the presence of musculoskeletal pain. Full article
(This article belongs to the Special Issue Towards a better assessment of acute pain in equines)
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7 pages, 626 KiB  
Article
Does Thirty-Minute Standardised Training Improve the Inter-Observer Reliability of the Horse Grimace Scale (HGS)? A Case Study
by Francesca Dai, Matthew Leach, Amelia Mari MacRae, Michela Minero and Emanuela Dalla Costa
Animals 2020, 10(5), 781; https://doi.org/10.3390/ani10050781 - 30 Apr 2020
Cited by 22 | Viewed by 4311
Abstract
The Horse Grimace Scale (HGS) is a facial-expression-based pain coding system that enables a range of acute painful conditions in horses to be effectively identified. Using valid assessment methods to identify pain in horses is of a clear importance; however, the reliability of [...] Read more.
The Horse Grimace Scale (HGS) is a facial-expression-based pain coding system that enables a range of acute painful conditions in horses to be effectively identified. Using valid assessment methods to identify pain in horses is of a clear importance; however, the reliability of the assessment is highly dependent on the assessors’ ability to use it. Training of new assessors plays a critical role in underpinning reliability. The aim of the study was to evaluate whether a 30-minute standardised training program on HGS is effective at improving the agreement between observers with no horse experience and when compared to an HGS expert. Two hundred and six undergraduate students with no horse experience were recruited. Prior to any training, observers were asked to score 10 pictures of horse faces using the six Facial Action Units (FAUs) of the HGS. Then, an HGS expert provided a 30-minute face-to-face training session, including detailed descriptions and example pictures of each FAU. After training, observers scored 10 different pictures. Cohen’s k coefficient was used to determine inter-observer reliability between each observer and the expert; a paired-sample t-test was conducted to determine differences in agreement pre- and post-training. Pre-training, Cohen’s k ranged from 0.20 for tension above the eye area to 0.68 for stiffly backwards ears. Post-training, the reliability for stiffly backwards ears and orbital tightening significantly increased, reaching Cohen’s k values of 0.90 and 0.91 respectively (paired-sample t-test; p < 0.001). The results suggest that this 30-minute face-to-face training session was not sufficient to allow observers without horse experience to effectively apply HGS. However, this standardised training program could represent a starting point for a more comprehensive training program for those without horse experience in order to increase their reliably in applying HGS. Full article
(This article belongs to the Special Issue Towards a better assessment of acute pain in equines)
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17 pages, 2796 KiB  
Article
Monitoring Acute Pain in Donkeys with the Equine Utrecht University Scale for Donkeys Composite Pain Assessment (EQUUS-DONKEY-COMPASS) and the Equine Utrecht University Scale for Donkey Facial Assessment of Pain (EQUUS-DONKEY-FAP)
by Machteld C. van Dierendonck, Faith A. Burden, Karen Rickards and Johannes P.A.M. van Loon
Animals 2020, 10(2), 354; https://doi.org/10.3390/ani10020354 - 22 Feb 2020
Cited by 33 | Viewed by 8149
Abstract
Objective pain assessment in donkeys is of vital importance for improving welfare in a species that is considered stoic. This study presents the construction and testing of two pain scales, the Equine Utrecht University Scale for Donkey Composite Pain Assessment (EQUUS-DONKEY-COMPASS) and the [...] Read more.
Objective pain assessment in donkeys is of vital importance for improving welfare in a species that is considered stoic. This study presents the construction and testing of two pain scales, the Equine Utrecht University Scale for Donkey Composite Pain Assessment (EQUUS-DONKEY-COMPASS) and the Equine Utrecht University Scale for Donkey Facial Assessment of Pain (EQUUS-DONKEY-FAP), in donkeys with acute pain. A cohort follow-up study using 264 adult donkeys (n = 12 acute colic, n = 25 acute orthopaedic pain, n = 18 acute head-related pain, n = 24 postoperative pain, and n = 185 controls) was performed. Both pain scales showed differences between donkeys with different types of pain and their control animals (p < 0.001). The EQUUS-DONKEY-COMPASS and EQUUS-DONKEY-FAP showed high inter-observer reliability (Cronbach’s alpha = 0.97 and 0.94, respectively, both p < 0.001). Sensitivity of the EQUUS-DONKEY-COMPASS was good for colic and orthopaedic pain (83% and 88%, respectively), but poor for head-related and postoperative pain (17% and 21%, respectively). Sensitivity of the EQUUS-DONKEY-FAP was good for colic and head-related pain (75% and 78%, respectively), but moderate for orthopaedic and postoperative pain (40% and 50%, respectively). Specificity was good for all types of pain with both scales (91%–99%). Different types of acute pain in donkeys can be validly assessed by either a composite or a facial expression-based pain scale. Full article
(This article belongs to the Special Issue Towards a better assessment of acute pain in equines)
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Review

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22 pages, 501 KiB  
Review
Pressure Algometry for the Detection of Mechanical Nociceptive Thresholds in Horses
by Kevin K. Haussler
Animals 2020, 10(12), 2195; https://doi.org/10.3390/ani10122195 - 24 Nov 2020
Cited by 21 | Viewed by 3574
Abstract
The clinical assessment of pain is subjective; therefore, variations exist between practitioners in their ability to identify and localize pain. Due to differing interpretations of the signs or severity of pain equine practitioners may assign varying levels of clinical significance and treatment options. [...] Read more.
The clinical assessment of pain is subjective; therefore, variations exist between practitioners in their ability to identify and localize pain. Due to differing interpretations of the signs or severity of pain equine practitioners may assign varying levels of clinical significance and treatment options. There is a critical need to develop better tools to qualify and quantify pain in horses. Palpation is the most common method to detect local tenderness or sensitivity. To quantify this applied pressure, pressure algometry has been used to gradually apply pressure over specified landmarks until an avoidance response is noted, which is defined as the mechanical nociceptive threshold (MNT). Numerous studies have used pressure algometry in different applications to measure MNTs in horses. There is an acute need to establish normative values within different body regions and to develop standardized methods of testing MNTs to better guide practitioners in the diagnosis and treatment of pain. The aim of this systematic review was to summarize the evidence for the use of pressure algometry in horses. There is good evidence that pressure algometry is a repeatable, semi-objective method that can be used in a wide array of clinical and research applications to assess MNTs in horses. Full article
(This article belongs to the Special Issue Towards a better assessment of acute pain in equines)
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Other

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1 pages, 154 KiB  
Correction
Correction: Maskato et al. Prospective Feasibility and Revalidation of the Equine Acute Abdominal Pain Scale (EAAPS) in Clinical Cases of Colic in Horses. Animals 2020, 10, 2242
by Yamit Maskato, Alexandra H. A. Dugdale, Ellen R. Singer, Gal Kelmer and Gila A. Sutton
Animals 2022, 12(8), 1001; https://doi.org/10.3390/ani12081001 - 13 Apr 2022
Viewed by 1117
Abstract
The authors wish to make the following corrections to this paper [...] Full article
(This article belongs to the Special Issue Towards a better assessment of acute pain in equines)
21 pages, 12117 KiB  
Commentary
Equine Discomfort Ethogram
by Catherine Torcivia and Sue McDonnell
Animals 2021, 11(2), 580; https://doi.org/10.3390/ani11020580 - 23 Feb 2021
Cited by 37 | Viewed by 51313
Abstract
In recent years, there has been a growing interest in and need for a comprehensive ethogram of discomfort behavior of horses, particularly for use in recognizing physical discomfort in domestically managed horses. A clear understanding of the physical discomfort behavior of horses among [...] Read more.
In recent years, there has been a growing interest in and need for a comprehensive ethogram of discomfort behavior of horses, particularly for use in recognizing physical discomfort in domestically managed horses. A clear understanding of the physical discomfort behavior of horses among caretakers, trainers, and professional health care personnel is important to animal welfare and caretaker safety. This is particularly relevant to pain management for hospitalized equine patients. Various pain scale rubrics have been published, typically incorporating only a few classically cited pain behaviors that, in many cases, are specific to a particular body system, anatomic location, or disease condition. A consistent challenge in using these rubrics in practice, and especially in research, is difficulty interpreting behaviors listed in various rubrics. The objective of this equine discomfort ethogram is to describe a relatively comprehensive catalog of behaviors associated with discomfort of various degrees and sources, with the goal of improving understanding and clarity of communication regarding equine discomfort and pain. An inventory of discomfort-related behaviors observed in horses has been compiled over 35 years of equine behavior research and clinical consulting to medical and surgical services at the University of Pennsylvania School of Veterinary Medicine’s equine hospital. This research and clinical work included systematic evaluation of thousands of hours of video-recordings, including many hundreds of normal, healthy horses, as well as hospitalized patients with various complaints and/or known medical, neurologic, or orthopedic conditions. Each of 73 ethogram entries is named, defined, and accompanied by a line drawing illustration. Links to online video recorded examples are provided, illustrating each behavior in one or more hospitalized equine patients. This ethogram, unambiguously describing equine discomfort behaviors, should advance welfare of horses by improving recognition of physical discomfort, whether for pain management of hospitalized horses or in routine husbandry. Full article
(This article belongs to the Special Issue Towards a better assessment of acute pain in equines)
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