The anesthetic-surgical stress response consists of metabolic, neuroendocrine, hemodynamic, immunological, and behavioral adaptations through chemical mediators such as the adrenocorticotropic hormone, growth hormone, antidiuretic hormone, cortisol, aldosterone, angiotensin II, thyroid-stimulating hormone, thyroxine, triiodothyronine, follicle-stimulating hormone, luteinizing hormone, catecholamines, insulin, interleukin (IL)-1, IL-6, tumor necrosis factor-alpha, and prostaglandin E-2. Behavioral changes include adopting the so-called prayer posture, altered facial expressions, hyporexia or anorexia, drowsiness, sleep disorders, restriction of movement, licking or biting the injured area, and vocalizations. Overall, these changes are essential mechanisms to counteract harmful stimuli. However, if uncontrolled surgical stress persists, recovery time may be prolonged, along with increased susceptibility to infections in the post-operative period. This review discusses the neurobiology and most relevant organic responses to pain and anesthetic-surgical stress in dogs and cats. It highlights the role of stress biomarkers and their influence on autonomous and demeanor aspects and emphasizes the importance of understanding and correlating all factors to provide a more accurate assessment of pain and animal welfare in dogs and cats throughout the surgical process.

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, the parasympathetic 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.

Caffeine is widely used to improve neonatal health in animals with low vitality. Due to its pharmacokinetics and pharmacodynamics, caffeine stimulates the cardiorespiratory system by antagonism of adenosine receptors and alteration in Ca⁺² ion channel activity. Moreover, the availability of intracellular Ca⁺² also has positive inotropic effects by increasing heart contractibility and by having a possible positive effect on neonate vitality. Nonetheless, since neonatal enzymatic and tissular systems are immature at birth, there is a controversy about whether caffeine is an effective therapy for newborns. This review aims to analyze the basic concepts of caffeine in neonatal animal models (rat and mouse pups, goat kids, lambs, and piglets), and it will discuss the neuroprotective effect and its physiological actions in reducing apnea in newborns.

The present study aimed to systematically review the anxiolytic and analgesic effects of gabapentin and pregabalin in domestic cats to assess the quality of using these medications for stress, fear, and anxiety management, and the treatment of both acute and chronic pain. The search was carried out between March and May 2025 using four databases: PubMed, Scopus, ScienceDirect, and Google Scholar. The keywords used were the combination of “pregabalin,” “gabapentin,” “analgesia,” “anxiety,” “stress”, and “cats”. Narrative reviews, as well as experimental and observational studies, were included. Experimental studies were classified as randomized controlled trials, controlled clinical trials, and prospective clinical trials, using the GRADE Pro GDP software (FP7-HEALTH.2010.3.1-1-two stage) to assess the certainty and confidence of the evidence. The initial search identified 57 manuscripts, of which 40 met the inclusion criteria. These studies focused on the management of stress, fear, and anxiety, as well as the control of acute and chronic pain in cats. Of these, 21 mention the use of gabapentin as an anxiolytic, while five report similar therapeutic effects of pregabalin. Regarding pain treatment, 12 papers and 2 papers support the use of gabapentin and pregabalin, respectively. This study confirms the validity of both drugs as therapeutic options for the management of stress, fear, and anxiety that impact the emotional welfare of cats. Furthermore, these drugs have been included in therapeutic guidelines for the control and treatment of acute and chronic pain in domestic cats. In conclusion, this systematic review supports the use of both drugs. Still, it highlights the need for more in-depth research and additional clinical trials to complement the existing evidence on the use of gabapentin and pregabalin.

Pain management requires the identification of certain indicators to recognize pain. Various tools have been suggested to achieve an objective evaluation, including infrared thermography (IRT). The objective of this study was to assess the facial thermal nociceptive response produced by the use of cannabidiol (CBD) alone and in combination with meloxicam in female dogs undergoing elective ovariohysterectomy anesthetized with isoflurane. Sixty-four female dogs of different breeds were randomly distributed into four study groups according to the treatment received. G1: Placebo group (n = 16); G2: Group receiving intravenous meloxicam as premedication (0.2 mg Kg⁻¹) and every 24 h postoperatively 0.1 mg Kg⁻¹ (n = 16); G3: Group treated with CBD (n = 16) at a dose of 2 mg kg⁻¹ orally every 12 h; and G4: Group medicated with the combination of both treatments (n = 16). All treatments were administered for 48 h postoperatively. After the anesthetic surgical procedure, radiometric images were captured using IRT and physiological parameters during the events E_Basal, E_30min, E_1h, E_2h, E_3h, E_4h, E_8h, E_12h, E_24h and E_48h. Overall, it was found that the high, medium and low temperatures of the thermal windows of the eye, upper eyelid and lower eyelid, as well as the average temperature of the lacrimal gland in G1 between events, were significantly lower at E_30min, E_1h and E_2h compared to E_Basal (p = 0.01). Among treatments, a significantly higher temperature was observed in groups G2, G3 and G4 compared to G1 (p = 0.001) in the thermal windows of the upper eyelid, lower eyelid, lacrimal gland and ocular areas. Regarding physiological parameters, heart rate (HR) was higher in G1 compared to the animals in G2, G3 and G4 (p = 0.03). The respiratory rate (RR) was significantly lower in all four study groups during the postoperative events compared to their respective E_Basal (p < 0.05), while among treatments, G2, G3 and G4 had a lower RR compared to G1 (p = 0.03). Mild hypothermia was observed in all study groups at E_30min and E_1h compared to E_Basal (p = 0.001). No significant correlation was found between the temperatures of the assessed thermal regions and the physiological traits. In conclusion, CBD, whether administered alone or in combination with meloxicam, demonstrated comparable analgesic efficacy, which could control nociceptive cardiorespiratory and hemodynamic autonomic responses, as there were no significant changes in the facial thermal response between treatments G2, G3 and G4.

Cardiovascular function monitoring has been suggested as a key parameter to determine patient stability during the anesthetic process. However, the use of pulse co-oximetry has been suggested as a technology to complement the monitoring of this system as a direct way to assess hemoglobin (Hb) blood concentration. Therefore, this study aimed to correlate and determine the measurement bias between Hb blood levels with continuously determined blood hemoglobin concentration (SpHb) and arterial oxygen content values (SpOC), both obtained by noninvasive co-oximetry in dogs undergoing elective ovariohysterectomy (OVH). A total of 85 clinically healthy bitches of different breeds that were admitted for elective OVH surgery were evaluated. These animals underwent SpHb and SpOC capture after the in vivo setting for the duration of the surgical procedure. Likewise, five minutes before the end of the surgical procedure, a blood sample was obtained directly from the jugular vein to determine the blood concentration of Hb (Hb_LAB). The Bland–Altman analysis showed 95% limits of agreement from −4.22 to 4.99 g/dL with a BIAS (mean difference) of 0.384 ± 2.35 g/dL (r = 0.401). SpHb recordings were correlated with oxygen saturation (SpO₂) (r = 0.995), SpOC (r = 0.992) and with perfusion index (PI) (r = 0.418). Therefore, SpHb presents a moderate positive correlation with direct blood concentration of Hb. This possibly shows that continuous measurement of SpHb by noninvasive co-oximetry is a reliable and advanced alternative for monitoring Hb concentration in dogs under anesthesia.