Influence of Circadian Rhythm on the Surgical Stress Response in Bitches Undergoing Elective Ovariohysterectomy Pauline Silva dos Santos, Luísa Pereira Zacchi, Maria Helena Moreno, Márcio Oleszczyszyn, Heloísa Vieira Cordeiro, et al. Animals, 2026 Circadian rhythm regulates several physiological functions, and influences endocrine and metabolic responses in mammals, with cortisol acting as important modulator of this mechanism. Cortisol secretion is affected by both internal and external factors and is intensified under stress conditions. The response to surgical stress is consistently observed after surgical procedures, such as ovariohysterectomy (OVH). Therefore, this study aimed to evaluate the influence of the circadian rhythm on the surgical stress response following elective OVH in healthy bitches. Twenty patients weighing between 10 and 20 kg were hospitalized 48 h before surgery and remained hospitalized for 48 h postoperative. The animals were randomly allocated into two groups and underwent OVH either in the morning (6–8 h—a.m., GAM) or at night (18–20 h—p.m., GPM). Surgical procedures were standardized with respect to the surgical team, technique applied and duration; this was carried out in order to induce a comparable level of surgical stress. Physical parameters (systolic blood pressure, heart rate, respiratory rate and rectal temperature) and laboratorial analyses (cortisol, leukogram, protein thiols, no protein thiols, vitamin C, ferric reducing ability of plasma and thiobarbituric acid reactive substances) were assessed immediately before surgery and at 2, 4, 6, 12, 24 and 48 h, as well as 14 days postoperatively. No significant changes in cortisol profile were detected. However, significant alteration in the respiratory rate, rectal temperature, time to first urine, and lipid peroxidation were observed in the GPM group, suggesting that surgeries performed at night induce greater disturbances in homeostasis than those performed in the morning.
Chemical Restraint in Southern Tiger Cats (Leopardus guttulus) with Methadone or Morphine Associated with Xylazine-Ketamine Jean Carlos Boesing, Marina Marangoni, Ana Letícia Rodrigues Marques, Fernando Luis Cemenci Gnoatto, Zalmir Silvino Cubas, et al. Acta Veterinaria, 2025 The Southern Tiger Cat (Leopardus guttulus) is an endangered species, requiring effective anesthesia for clinical procedures, yet species-specific studies are lacking. This study aims to assess and compare the effectiveness of methadone or morphine combined with xylazine-ketamine for the immobilization of Southern Tiger Cats (Leopardus guttulus). The animals were randomly allocated to receive sedation with methadone (0.3 mg kg) or with morphine (0.5 mg kg) in association with xylazine-ketamine (1.0 mg kg and 10.0 mg kg, respectively) intramuscularly. Electrocardiography parameters and physiological variables were recorded every five minutes since the application. After 40 minutes of assessment, reversal protocol for opioids and α2-adrenergic agonist was applied using naloxone and yohimbine, and the quality of recuperation was evaluated. In this study, no significant differences were noted between groups or assessment times in the physiological variables monitored. One subject, presented idioventricular accelerated rhythm, attributed to morphine administration and confirmed by its reversal. Recovery evaluation demonstrated favorable outcomes, although some animals presented adverse effects, exacerbated by supplementary ketamine doses. The morphine-xylazineketamine and methadone-xylazine-ketamine protocols demonstrated similar efficacy in Southern Tiger Cats (Leopardus guttulus), exhibiting stable physiological parameters and smooth recovery. The use of antagonists facilitated uneventful recovery, contributing valuable insights into anesthetic protocols for endangered species. The applied protocols provided safe examination and valuable insights into anesthetic protocols for this endangered species.
Recurrent Megacolon and Fecaloma in a Cat Pauline Silva dos Santos, Juliana Schmitz Bascherotto, Agatha Costa Malisnki, Vitória Santos Guimarães, Emanuel Caon, et al. Acta Scientiae Veterinariae, 2025 Background: The Megacolon is characterized by dilation and hypomotility of the large intestine which results in fecal retention, being common a chronic cause of constipation in cats, and usually idiopathic. The affected shows progressive and recurrent signs of constipation throughout months to years. The initial treatment is clinical with laxatives, enemas, prokinetic medications and dietary adjustments. However, in cases of unsuccessful results of medical therapy, surgical intervention is necessary. The objective of this report is to describe the management of a male Persian cat with chronic constipation, obstipation and recurrent megacolon treated by clinical and surgical means. Case: A 1.2-year-old male Persian cat, weighing 4.35 kg , presented over 8 years, several episodes of constipation and megacolon confirmed by clinical, laboratory, simples and/or contrast radiographic and ultrasound exam. Despite the initial success of the clinical treatment, it recurred after 4 months and clinical exam and new radiographs indicated recurrence and the patient was treated with mineral oil and suppositories. After 12 months, the patient presented fecal retention, rectal protrusion and tenesmus, when clinical and alimentary adjustments were performed. After new crisis, the cat was hospitalized and underwent to several clinical procedures with no success, being referred to colotomy, and 30 days after, subtotal colectomy. During 2.5 years, the patient received clinical attention in another veterinary center. After this, a serious constipation recurred and colotomy was performed. Two years later, the patient suffered with frequent constipation and was submitted to total colectomy, after failure of clinical treatments. Despite surgery, the cat developed acute renal failure and died after the procedure. Discussion: The megacolon, characterized by increase in the diameter of the large intestine and hypomotility, is not a specific disease, but a condition with many causes such as neurological, endocrine, behavioral or congenital. Between others, the idiopathic is the most common, as observed in this patient. In this case, the diagnosis was achieved through history, laboratory and imaging exams, including radiographs which showed the colon distended and replete of feces, a typical find of patients with megacolon. The contrast radiography ruled out anatomical malformations, but did not provide a conclusive diagnosis regarding the etiology. The clinical treatment included a combination of pasty diet, mineral oil, suppositories, enemas and medications, in addition to fluid therapy, as complementary treatment. Although there was temporary improvement with lactulose and psyllium, which facilitate the intestinal transit, the alimentary management was not efficient at long term. It is recognized that over time the patients develop generalized colonic smooth muscle dysfunction, as identified in this patient by ultrasound, which indicates colonic inertia and need for surgical intervention. The subtotal colectomy was performed after several attempts at medical and surgical approaches over more than two years. Studies indicate that preserving ileocolic junction can minimize the recurrence of constipation, opposite to excision which can increase diarrhea in the long term. Usually, the post-surgery survival is long, with good quality of life, as long as an adequate diet maintenance, which was a challenge in this patient, since it refused the high-fiber diet. The medical treatment of constipation should be applied but may be unfeasible or ineffective, as observed several times in this case. This case illustrates the severity of idiopathic megacolon in cats and reinforces the need to consider early surgical intervention when the condition is not responsive to diet and medical therapy, to improving the patient quality of life and avoid complications which can cause increased morbidity and contribute to patient mortality. Keywords: constipation, colotomy, subtotal colectomy, total colectomy.
Anesthetic management in a free-ranging crab-eating fox (Cerdocyon thous) with splenic rupture – case report M. Marangoni, A.L.R. Marques, A.F.F. Meznerovvicz, H.V. Cordeiro, T. Champion, et al. Arquivo Brasileiro De Medicina Veterinaria E Zootecnia, 2025 The crab-eating fox (Cerdocyon thous) is a medium-sized mammal found throughout South America, known for its adaptability to diverse environments and a varied diet. Recently, habitat loss and increased encounters with roadways have led to a rise in road traffic accidents involving this species, resulting in significant trauma such as splenic rupture. This report details the anesthetic management of a free-ranging crab-eating fox with splenic rupture following a road traffic accident. The patient, an adult male weighing 6.6 kg, presented with hypotension and pale mucous membranes. Initial chemical restraint was administered using tiletamine-zolazepam and morphine. An abdominal ultrasound revealed splenic rupture with active hemorrhage and a systolic arterial pressure (SAP) of 60 mmHg. Immediate fluid resuscitation was initiated, but the patient remained hypotensive. A transversus abdominis plane (TAP) block was performed with bupivacaine and lidocaine, which significantly reduced the need for isoflurane. The splenorrhaphy was performed, and the patient's condition improved with fluid therapy, dobutamine infusion, and reduced isoflurane concentration. Postoperatively, SAP stabilized, and urinary output was within normal ranges, indicating no acute renal injury. This case highlights the TAP block's effectiveness in managing pain and stabilizing hemodynamics, underscoring the need for tailored anesthetic approaches in wildlife trauma.
Impact of Ovarian Suspensory Ligament Rupture on Surgical Stress in Elective Ovariohysterectomy in Bitches Pauline Silva dos Santos, Victor Mendes de Oliveira, Keli Cristina Corbellini Oltramari, Vitória Santos Guimarães, Sarah Fernandes, et al. Veterinary Sciences, 2024 Ovariohysterectomy (OVH) is a common procedure in bitches, where ovarian suspensory ligament (OSL) rupture facilitates hemostasis but may also have adverse effects. Given the importance of minimizing the surgical stress response, this study aimed to evaluate the impact of OSL rupture in 20 healthy bitches undergoing elective open OVH; a celiotomy via the ventral midline was performed, and hemostasis achieved using bipolar coagulation, either with OSL rupture (OSL-R) or without (OSL-NR). Pain was assessed over 24 h post-surgery using the Visual Analogue Scale and the Short Form of the Glasgow Composite Measure Pain Scale. The physical parameters, complete blood count, glucose levels, erythrocyte sedimentation rate, and neutrophil oxidative and phagocytic functions were evaluated pre-surgery and at 6, 12, 24, and 48 h, as well as 10 days after. Oxidative metabolism was assessed through vitamin C and protein thiols, reduced glutathione, and thiobarbituric acid reactive substances. No differences in trans- and postoperative pain were observed between techniques, except for analgesic rescue rates. Differences were noted in the heart rate, total leukocyte count, segmented neutrophils, eosinophils, and monocytes. Both techniques resulted in low oxidative and phagocytic changes. Overall, OSL rupture appears to elicit a slightly more intense surgical stress response than the non-rupture technique.
Changes in Biomarkers of Inflammation and Oxidative Status in Dogs Subjected to Celiotomy or Video-Assisted Ovariohysterectomy Fabíola Dalmolin, Camila Peres Rubio, Carla Sordi Furlanetto, Rafael Steffens, Najla Ibrahim Isa Abdel Hadi, et al. Veterinary Sciences, 2024 We evaluated the surgical stress response of dogs undergoing three ovariohysterectomy (OVH) techniques. Twenty-nine healthy females were allocated into groups: celiotomy and ligature (CelioSut), celiotomy and bipolar energy (CelioBip), and a video-assisted technique using two portals and bipolar energy (VidBip). Clinical evaluation was performed, and the following blood analyses were determined: acute phase proteins (C-reactive protein and haptoglobin), white blood cell counting (WBC), and biomarkers of oxidative status. The VidBip required more time despite a smaller incision, lower heart rate, and earlier feeding and urination. All groups had high white blood cells counts; the C-reactive protein (CRP) levels peaked at 6 and 12 h in all groups and was higher in the CelioBip and VidBip groups compared to CelioSut; haptoglobin concentrations peaked at 48 h in all groups and increased in dogs of the CelioSut group. Trolox equivalent antioxidant capacity, ferric reducing ability of plasma, cupric reducing antioxidant capacity, and advanced oxidation protein were not significantly different among the groups or time points. Total thiol concentrations were lower in CelioBip and CelioSut groups. All surgical techniques induced an inflammatory and oxidative stress response, but the video-assisted technique produced early clinical recovery. The bipolar device produces fewer disturbances than suspensory ligament rupture and ligature.
Mammary Cystadenoma: Diagnosis and Treatment in a Bitch Gabriela Corrêa de Almeida, Najla Ibrahim Isa Abdel Hadi, Izabelle Moutinho, Vinícius Cardoso de Oliveira, Victor Mendes de Oliveira, et al. Acta Scientiae Veterinariae, 2023 Background: Although malignant mammary alteration is highly studied in canine, data about benign lesions is sparse. A study reported 27.1% of benign alteration, being 5.9% cystadenomas. It is a unique or multiple lesion, characterized by lined and well differentiated epithelial cells. The alteration is well recognized in women, opposite to canines, which present cysts or not, and it is more frequent in ovary, kidney, salivary gland, thyroid, pancreas and mammary gland. Related to cysts, ultrasonography and cytological exams help the diagnosis and treatment. In this way, this report presents the diagnosis, the treatment and 4 years follow up canine mammary cystadenoma. Case: A 5-year-old non-spayed Mongrel bitch, weighing 5.9 kg, presented mammary enlargement identified by the owner since 8 months before. The patient had received exogenous contraceptives 3 times, being the last one 12 months before; after detection, the enlargement increased in volume along the time. It was a 9x2x1 cm nodular and fluctuant enlargement in the left inguinal mammary gland; the ultrasound exam confirmed many fluid collection delimited by a thin echogenic capsule and anechoic content. No alterations were detected at other glands and abdomen. Fine-needle aspiration promoted the liquid drainage, which presented no cells identified by cytology for 2 times. The patient was submitted to OVH and nodulectomy and discharged after anesthetic recovery, with prescription of meloxicam, dipyrone and topic chlorhexidine digluconate 1%. After 4 days the owner verified the color change of the skin at the nodulectomy site. We identified a purplish alteration 13 days after, as well as wound healing, being sutures removed and warm compresses prescribed; normal color was verified after 8 days. Posteriorly at 1 and 4 years the patient was evaluated and no clinical, mammary and ultrasonography alterations were detected. Discussion: The non-spayed bitches which receive exogenous contraceptive are more likely to mammary alteration development, as observed in this patient. According to the Brazilian Mammary Consensus, the malignant mammary alteration bigger than 3 cm must be treated by unilateral mastectomy and lymphadenectomy, an aggressive surgery which involves long anesthesia and hemodynamic disturbances due to the surgical stress response. Considering the absence of malignant signs, an encapsulated alteration, the absence of malignant signs and a relatively young patient, the patient was treated by nodulectomy, opposite to the recommended. The benign mammary neoplasms are more susceptible to hormonal influence compared to the malignant one after synthetic progesterone application, since the benign have more progesterone and estrogen receptors. In this way, the OVH was performed in order to reduce the hormonal influence. The OVH was performed firstly to avoid abdominal contamination by liquid or cells, according to the aseptic and atraumatic surgical principles. The histological tumor exam revealed cystadenoma with papillary formation, and mild uterine cystic endometrial hyperplasia not visible by ultrasonography image. Although it was a benign alteration, the authors considered the risk of malignant lesion after exogenous contraceptive. For this, the patient was assessed by clinical and ultrasonography exam 1 and 4 years after to verify recurrence or new lesions, which were not observed and indicated treatment effectiveness. It was recognized that surgical aggressiveness changes the immune response and it predisposes to neoplasm development. Although the authors believe in the positive effect of less aggressive surgery to patients with benign alterations, more studies are necessary to verify the benign neoplasm behavior in order to suggest the adequate treatment. Keywords: benign neoplasm, canine contraceptive, mammary cyst, mastectomy, surgical stress, mammary nodulectomy.
Unilateral uterine agenesis in a bitch: Reproductive consideration, surgical sterilization and histopathological description Archives of Veterinary Science, 2019
