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for 6 h, where it is possible to see facial movements such as asymmetric/low and accompanied by angled eyes, a tense withdrawn gaze and note the clinical evolution in the position of the ears in comparison with a. (c) 24 h post-treatment.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.