¹Universiti Putra Malaysia, Faculty of Veterinary Medicine, Department of Companion Animal Medicine & Surgery, 43400, Serdang, MALAYSIA
²The Veterinary Referral Centre, Al Murooj Complex, Trade-Centre 2, DIFC, Dubai, UNITED ARAB EMIRATES
³Universiti Putra Malaysia, Faculty of Veterinary Medicine, Department of Veterinary Preclinical Sciences, 43400, Serdang, MALAYSIA
⁴The Ohio State University, College of Veterinary Medicine, Department of Veterinary Clinical Sciences, 43210, Columbus, This article is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0) Review Article Kafkas Universitesi Veteriner Fakultesi Dergisi Journal Home-Page: http://vetdergikafkas.org E-ISSN: 1309-2251 Pain functions as a natural alarm to an underlying disease, trauma or surgery. In disease, it prompts investigation of the cause(s), whereas in trauma or surgery, it acts as a protective warning to safeguard the injured site against further damage. Absence or inadequate perception of pain may result in undetected disease progression and insufficient protection of injured tissues, ultimately leading to adverse outcomes. Poorly managed acute pain can trigger stress hormone release and is associated with reduced activity, increased heart rate and blood pressure, behavioral alterations, shivering, hypersensitivity, aggression, vocalization, anorexia, weight loss, delayed wound healing, depression, transition to chronic pain, and prolonged hospitalization. Therefore, this review aims to discuss the pathophysiology, recognition, assessment, and management of acute pain in veterinary patients, with emphasis on improving animal welfare and clinical outcomes. Kafkas Univ Vet Fak Derg x (x): x-x, 2026 DOI: 10.9775/kvfd.2026.36363 UNITED STATE OF AMERICA DOI : 10.9775/kvfd.2026.36363 Effective perioperative pain management depends on a thorough understanding of pain mechanisms and reliable assessment methods. Pain serves as a vital protective mechanism, acting as an alarm for underlying disease, trauma, or surgical injury. In disease, it prompts investigation of causative factors, while in trauma or surgery, it encourages protection of injured tissues. Inadequate management of acute pain can lead to significant physiological and behavioral consequences, including stress hormone release, increased heart rate and blood pressure, behavioral alterations, delayed wound healing, chronic pain development, and prolonged hospitalization. Keywords included pain pathways, nociception, pain models, analgesics, multimodal analgesia, electroencephalography, algometry, ketamine, and lidocaine. The purpose of this review is to enhance clinicians" and researchers" understanding of acute pain and nociception in dogs and cats, with particular emphasis on perioperative settings. The physiological processes involved in pain transmission, modulation, perception, as well as peripheral and central sensitization are discussed. Additionally, commonly used subjective and objective pain assessment techniques, including behavioral scoring systems and physiological indicators, are reviewed to support accurate pain recognition. This review is presented in two complementary parts. Part I focuses on pain pathophysiology and assessment, forming the foundation for Part II, which evaluates pharmacological and multimodal analgesic strategies for perioperative pain management. Keywords : Cats, Dogs, Nociceptive pathways, Pain assessment, Perioperative pain, Sensitization