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Review
. 2021 Nov;14(11):2984-2995.
doi: 10.14202/vetworld.2021.2984-2995. Epub 2021 Nov 26.

Nociceptive pain and anxiety in equines: Physiological and behavioral alterations

I Hernández-Avalos  1 , D Mota-Rojas  2 , J E Mendoza-Flores  3 , A Casas-Alvarado  2 , K Flores-Padilla  2 , A E Miranda-Cortes  1 , F Torres-Bernal  2 , J Gómez-Prado  2 , P Mora-Medina  4
Affiliations
Review

Nociceptive pain and anxiety in equines: Physiological and behavioral alterations

I Hernández-Avalos et al. Vet World. 2021 Nov.

Abstract

Pain and anxiety are two of the most important concerns in clinical veterinary medicine because they arise as consequences of multiple factors that can severely affect animal welfare. The aim of the present review was to provide a description and interpretation of the physiological and behavioral alterations associated with pain and anxiety in equines. To this end, we conducted an extensive review of diverse sources on the topic. The article begins by describing the neurophysiological pathway of pain, followed by a discussion of the importance of the limbic system in responses to pain and anxiety, since prolonged exposure to situations that cause stress and pain generates such physiological changes as tachycardia, tachypnea, hypertension, hyperthermia, and heart rate variability (HRV), often accompanied by altered emotional states, deficient rest, and even aggressiveness. In the long term, animals may show deficiencies in their ability to deal with changes in the environment due to alterations in the functioning of their immune, nervous, and endocrinologic systems. In conclusion, pain and anxiety directly impact the homeostasis of organisms, so it is necessary to conduct objective evaluations of both sensations using behavioral scales, like the horse grimace scale, complemented by assessments of blood biomarkers to analyze their correlation with physiological parameters: Heart rate, respiratory rate, HRV, theparasympathetic tone activity index, lactate and glucose levels, and temperature. Additional tools - infrared thermography, for example - can also be used in these efforts to improve the quality of life and welfare of horses.

Keywords: anxiety; equines; nociception; pain; welfare.

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Figures

Figure-1
Figure-1
Neurophysiological pathway of nociceptive pain [8,27-29].
Figure-2
Figure-2
The limbic system and its participation in sensations of pain and anxiety [51].
Figure-3
Figure-3
Clinical follow-up of pain based on the horse grimace scale in horses with different degrees of pain. (a) Acute pain severe; it is possible to observe dilation in nostrils, tension in the muzzle and chewing muscles, moreover, an asymmetric position in ears (flattener ears) in a male horse diagnostic with colic. (b) Acute pain moderate; it shows a horse male with colic with treatment for 6 h, where it is possible to see facial movements such as asymmetric/low and accompanied by angled eyes, a tense withdrawn gaze and note the clinical evolution in the position of the ears in comparison with a. (c) 24 h post-treatment. At first, they were, square flaring of the nostrils and tension in the muzzle and chewing muscles. At 24 h post-treatment, however, these scores had decreased. This evidence shows the utility of facial expressions for evaluating analgesic responses.
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References

    1. Taylor P.M, Pascoe P.J, Mama K.R. Diagnosing and treating pain in the horse. Vet. Clin. North Am. Equine Pract. 2002;18(1):1–19. - PubMed
    1. de Grauw J.C, van Loon J.P.A. Systematic pain assessment in horses. Vet. J. 2016;209(Mar):14–22. - PubMed
    1. Mota-Rojas D, Olmos-Hernández A, Verduzco-Mendoza A, Lecona-Butrón H, Martínez-Burnes J, Mora-Medina P, Whittaker A.L. Infrared thermal imaging associated with pain in laboratory animals. Exp. Anim. 2021a;70(1):1–12. - PMC - PubMed
    1. Maskato Y, Dugdale A.H.A, Singer E.R, Kelmer G, Sutton G.A. Prospective feasibility and revalidation of the equine acute abdominal pain scale (EAAPS) in clinical cases of colic in horses. Animals. 2020;10(12):2242. - PMC - PubMed
    1. Sneddon L.U, Elwood R.W, Adamo S.A, Leach M.C. Defining and assessing animal pain. Anim. Behav. 2014;97(11):201–212.

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