Objective Assessment of Acute Pain in Foals Using a Facial Expression-Based Pain Scale.

Johannes Van Loon,Janny De Grauw,Nicole Verhaar,Els Van Den Berg,Sarah Ross

doi:10.3390/ani10091610

Abstract

Simple SummaryResearch has shown that objective assessment of pain in horses can be performed by subjectively scoring facial expressions. So far, no studies have been conducted to develop a pain measuring tool for the assessment of pain in foals. In other species like pigs and sheep, facial expressions have been shown to be good indicators of pain in neonatal animals. In this study, a pain scale that is already available for mature horses (EQUUS-FAP: Equine Utrecht University Scale for Facial Assessment of Pain) was adapted to measure different types of acute pain in neonatal and older foals with acute pain based on facial expressions. The scale was based on a pain scale that has been shown to be useful in mature horses with various types of acute pain (colic, orthopaedic, and head-related pain). This pain scale was tested in 20 patients with different types of acute pain (colic, laminitis, postoperative pain) and 39 healthy control animals. The authors found that the EQUUS-FAP FOAL (Equine Utrecht University Scale for Facial Assessment of Pain in Foals) is a reproducible pain scale that can be used to assess pain in neonatal and older foals.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.

Highlights

Objective pain assessment in horses has received much attention in the last decades [1,2] and facial-expression-based pain scales have been described for horses [3,4], mice [5], and cats [6].The EQUUS-FAP (Equine Utrecht University Scale for Facial Assessment of Pain) is a facial expression-based pain scale that has been described in horses with acute colic pain [7], acute head-related pain [8], and acute and postoperative orthopaedic pain [9]
Further studies are needed to validate the Piglet Grimace Scale for other potentially painful procedures, but this study showed that facial expressions could potentially be used in neonatal mammals to assess pain
The current study shows that the EQUUS-FAP FOAL pain scale that is based on facial expressions position of the eyelids cannot be completely evaluated due to the direction of the camera

Summary

Introduction

Objective pain assessment in horses has received much attention in the last decades [1,2] and facial-expression-based pain scales have been described for horses [3,4], mice [5], and cats [6].The EQUUS-FAP (Equine Utrecht University Scale for Facial Assessment of Pain) is a facial expression-based pain scale that has been described in horses with acute colic pain [7], acute head-related pain [8], and acute and postoperative orthopaedic pain [9]. Objective pain assessment in horses has received much attention in the last decades [1,2] and facial-expression-based pain scales have been described for horses [3,4], mice [5], and cats [6]. Robertson [10] described the changes in physiological parameters from birth to adulthood in horses and the importance of behavioural expressions in recognizing pain in neonatal foals. O’Neill et al [11] examined the developmental trajectories of infant facial expressions of pain during the first year of life. They described changes in distress regulation influencing pain expression. Infants showed decreasing signs of intense distress and sensory overload (shown by tightly shutting the eyes with a cry mouth) when aging from 2 months of age to 6 months of age

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