{"paper_id":"1da89f97-ac2e-483a-b6a0-e0e8984920c5","body_text":"Use of epidural anaesthesia as analgesic management in an Asiatic lion (Panthera leo persica) | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Use of epidural anaesthesia as analgesic management in an Asiatic lion (Panthera leo persica) Cristina Sánchez, Eva Martínez-Nevado, Mario Arenillas This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7519660/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 23 Dec, 2025 Read the published version in Veterinary Research Communications → Version 1 posted 16 You are reading this latest preprint version Abstract A 10-year-old lioness (Panthera leo persica), weighing 130 kg, was referred from Madrid Zoo to the Veterinary Teaching Hospital of the Complutense University of Madrid for evaluation of a lumbar soft tissue mass, previously diagnosed by biopsy as a chondrosarcoma, with potential surgical excision planned. A coordinated safety protocol was established between zoo and hospital staff, including predefined emergency routes and continuous supervision by experienced personnel and animal keepers. Anaesthetic premedication included intramuscular medetomidine (0.05 mg kg⁻¹) and ketamine (3 mg kg⁻¹), followed by propofol induction (1.2 mg kg⁻¹ IV) and maintenance with isoflurane in oxygen. Mechanical ventilation and comprehensive monitoring (ECG, non-invasive blood pressure, pulse oximetry, capnography, oesophageal temperature) were used. After computed tomography evaluation, the lion was elected for the chondrosarcoma surgical excision. Perioperative analgesia included intravenous methadone (0.1 mg kg⁻¹) and a sacrococcygeal epidural block with bupivacaine (0.3 mg kg⁻¹) and morphine (0.1 mg kg⁻¹). The epidural provided effective intraoperative analgesia, as evidenced by the absence of nociceptive responses and transient postoperative neurological deficits. The lion recovered uneventfully. This case underscores the feasibility and efficacy of epidural analgesia as part of a multimodal anaesthetic protocol in large felids undergoing major surgery. Asiatic lion epidural ketamine wildlife anaesthesia Background The use of anaesthesia in wild animals, particularly large carnivores like lions ( Panthera leo ), presents unique challenges due to the inherent risks of handling, the physiological stress of captivity, and the potential for unpredictable responses to anaesthetic agents. While general anaesthesia is commonly employed, the incorporation of locoregional techniques offers significant advantages, including enhanced perioperative pain control and reduced reliance on systemic analgesics, which may produce adverse side effects. However, the application of locoregional techniques in wild animals is less common and requires careful consideration of the species-specific anatomy, the pharmacodynamics of the selected agents, and the difficulties in monitoring and management during the postoperative period. In this case report, we describe the use of epidural anaesthesia as part of a multimodal analgesic approach, highlighting its benefits and challenges in the context of wildlife anaesthesia. Case Presentation An entire lioness ( Panthera leo persica ), aged 10 years, weighing 130 kg was referred from a zoological park (Madrid Zoo) to the Veterinary Teaching Hospital (Complutense University of Madrid) for a computed tomography scan to evaluate a chondrosarcoma in the lumbar region and, if indicated, to proceed with surgical excision. A prior veterinary visual examination of the lion at the zoo revealed no other abnormalities. Following sedation, a physical examination and as well as haematological and biochemical blood analysis were performed; all of which were within the physiological limits for the species (Maas 2013). A comprehensive safety protocol was collaboratively established by the zoo and hospital teams. The zoo veterinarian, designated as safety officer, conducted a thorough assessment of the reception area, CT suite, and operating theatre, and defined emergency exit routes in case of unexpected arousal. Two experienced zookeepers remained positioned at the rostral end of the patient throughout the procedures, to oversee and assist with all manipulations. Recovery and transport back to the zoo were also prearranged in accordance with established safety guidelines (Caulkett 2014). Anaesthetic premedication consisted of an intramuscular (IM) combination of medetomidine (0.05 mg kg - 1 ; Sedator; Dechra) and ketamine (3 mg kg - 1 ; Anesketin; Dechra) at the zoo. Once an adequate level of sedation had been achieved, the lion was transported to the Veterinary Hospital. Upon arrival, approximately 75 minutes after premedication, an additional IM dose of ketamine (1 mg kg - 1 ) was administered for safety, assuming that the initial sedation might have partially worn off, and an 18-gauge catheter was placed in the saphenous vein. Anaesthesia was then induced intravenously (IV) with propofol (1.2 mg kg - 1 ; Propofol Lipuro 1%; Braun). The trachea was intubated with a 14-mm cuffed endotracheal tube, and anaesthesia was maintained with isoflurane (Isovet; BBraun) vaporized in oxygen and delivered via a circle breathing system. Physiological parameters were monitored throughout the procedure using a multiparameter monitor (uMec12Vet; Mindray, Guangdong), including continuous electrocardiography, non-invasive blood pressure (oscillometry), pulse oximetry, capnography, and oesophageal temperature. The patient was positioned in sternal recumbency and pressure-controlled ventilation was initiated (Peak pressure 19 cmH 2 O; PEEP 5 cmH 2 O). Approximately 35 minutes after the onset of inhalational anaesthesia, hypercapnia (76 mmHg) was detected, accompanied by a decrease in tidal volume and airway pressure, findings consistent with a circuit leak. As a precaution, propofol (0.25 mg/kg, IV) was administered, and the endotracheal tube was removed, revealing a ruptured cuff. Reintubation was successfully performed, and no further complications were observed during the imaging procedure. Computed tomography revealed a contrast-enhancing soft tissue mass in the lumbar region, with no evidence of pulmonary metastases. Thereafter, the patient was transferred, under spontaneous ventilation, to a large-species operating room, where it was prepared for surgical chondrosarcoma removal 85 minutes after the induction of anaesthesia. Fluid therapy was initiated with lactated Ringer's solution (10 mL kg - 1 h - 1 ), and IV methadone (0.1 mg kg - 1 ; Semfortan; Dechra) was administered for perioperative analgesia, which resulted in marked ventilatory depression. Therefore, mechanical ventilation was reinitiated. In addition, a sacrococcygeal epidural block was performed using a loss-of-resistance technique, with bupivacaine (0.3 mg kg - 1 ; Bupivacaína 0.5%; BBraun) and morphine (0.1 mg kg - 1 ; Morfina; BBraun). The epidural technique was deemed successful, as evidenced by the absence of nociceptive response during the procedure and by the transient neurological deficits observed during early recovery. To enhance monitoring, an arterial catheter was placed in the lingual artery, which revealed lower blood pressure values compared with those obtained using the oscillometric method. However, since the patient did not exhibit clinical signs of hypotension, no intervention was required. The surgery lasted 88 minutes, with a total anaesthesia time of 205 minutes. Prior to extubation and complete recovery, IV dexmedetomidine (0.002 mg kg - 1 ; Sedadex; Dechra) was administered to facilitate the safe transport of the patient back to the zoo. For postoperative analgesia, meloxicam (0.1 mg kg - 1 ; Metacam; Boehringer) was administered subcutaneously at the end of the surgical procedure and was subsequently prescribed at half the dose every 24 hours. Additionally, tramadol was administered orally (2 mg kg - 1 every 12 hours; Tramadol EFG; Cinfa). The lioness regained the standing position 3 hours and 30 minutes after extubation, exhibiting mild paraparesis. By the next day, the animal demonstrated normal feeding behaviour, accepted postoperative analgesia, and showed no abnormal behavioural signs. Discussion and Conclusion Epidural administration of a combination of bupivacaine and morphine via the sacrococcygeal approach appears to be a safe and effective analgesic technique in lions. Bupivacaine provides a longer duration of analgesia compared to other local anaesthetics, making it a suitable choice for managing anticipated postoperative pain associated to tissue tension at the surgical site (Monteiro 2023). However, bupivacaine is also associated with prolonged motor blockade, which can be detrimental in fractious or wild animals due to the risk of a panicked and ataxic recovery (Morimoto 2001; Yun 2014). To mitigate these effects, sedation was extended with the administration of dexmedetomidine during recovery, resulting in a calm awakening with minimal ataxia. As an alternative, lidocaine-with or without morphine- offers a shorter duration of action while still providing effective analgesia when administered epidurally. Lidocaine has been shown to provide good analgesic effects, particularly in procedures such as tail amputation in lions (Singh 1992). Morphine, a hydrophilic opioid, has a relatively slow onset of action (up to 60 minutes). However, it can provide nociceptive inhibition for up to 24 hours without significantly affecting motor function and with minimal systemic uptake (Monteiro 2023). The efficacy of opioid drugs is further enhanced when combined with local anaesthetics, due to increased affinity for spinal cord receptors, making the combination of opioids with local anaesthetics particularly beneficial (Grubb 2020). The recommended doses of bupivacaine and morphine in wild felids are 0.3 mg/kg (not exceeding 6–9 mL) and 0.1–0.3 mg/kg, respectively. The analgesic effect usually lasts 8 to 12 hours while the anaesthetic effects persist for 1 to 4 hours (Gunkel 2007). In the present case, due to the sedation protocol used, the lioness was able to stand 3 hours after extubation, which allowed sufficient time for the motor effects to subside while maintaining effective analgesia. As a result, oral analgesics were not required until the next morning, when tramadol was administered approximately 15 hours after the epidural, and meloxicam was initiated 24 hours after its parenteral administration. As in other felids, the vertebral formula in lions follows the pattern C7 T13 L7 S3 Cd20–21 (Onwuama 2021). Regarding spinal anatomy, the conus medullaris in felids tends to extend more caudally than in canids, although data in large felids are scarce. In one study on wild felids, the apex was reported to reach as far as Cd2, making a lumbosacral epidural approach potentially unsafe (Mengue 2020). While there are no published descriptions of spinal cord length in Panthera leo persica, it is suspected that, as in other felids, the dural sac may extend caudally to the level of the S1 vertebra, increasing the risk of spinal blockade or injury with a lumbosacral epidural approach (Portela 2018; Richter 2024). For this reason, a sacrococcygeal approach was selected, together with a relatively high volume of injectate (0.3 mg/kg of 0.5% bupivacaine and 0.1 mg/kg of morphine). The effectiveness of the epidural analgesia administered was assessed intraoperatively by monitoring variability in standard haemodynamic parameters, namely heart rate, respiratory rate, and arterial blood pressure. These parameters were continuously recorded, and haemodynamic stability or the absence of significant responses to surgical stimulation was interpreted as indicative of adequate nociceptive blockade (Dourado 2022; Salla 2023). In the postoperative period, pain assessment relied primarily on behavioural observations by the veterinary team at the zoo, given the absence of validated pain scoring systems for this species (Gunkel 2007; Riley 2016; Monteiro 2023). Clinical indicators such as the onset of voluntary movements, time to first food intake, and the presence of calm, relaxed behaviour were used as surrogate markers of comfort and analgesic efficacy (Gunkel 2007; Serres-Corral 2011; Stanton 2015). Although these indicators are inherently subjective, they currently represent the most reliable means of assessing postoperative pain in this context. In terms of procedural organization and safety, the measures adopted in this case align with previous reports of free-ranging lion immobilizations, which highlight of thorough environmental assessment, the presence of trained personnel, clear delineation of high-risk areas (such as “red zones” around the head and limbs), and the implementation of intraoperative contingency plans (Tumbelaka 2012; Chinnadurai 2016, Sontakke 2017). An additional challenge in the present case was the need to transfer the animal between different facilities. This was accomplished under general anaesthesia using a dedicated stretcher, with two zoo veterinarians and several keepers providing continuous supervision throughout all transfers. In conclusion, this case illustrates the feasibility and effectiveness of combining bupivacaine and morphine via a sacrococcygeal epidural approach to provide perioperative analgesia in a lion undergoing major surgery. The technique offered adequate nociceptive control while minimizing systemic drug use, although careful consideration of potential motor blockade remains essential in wild felids. The incorporation of strict safety protocols coordinated teamwork between the zoological and hospital staff, and close intra- and postoperative monitoring were fundamental to ensuring a successful outcome. This is particularly relevant given that Asiatic lions are classified as Endangered by the International Union for Conservation of Nature (Breitenmoser 2024). Overall, this report highlights the importance of adapting established anaesthetic and analgesic strategies to the specific anatomical, behavioural, and logistical challenges of large carnivores in a clinical setting. Declarations Acknowledgements: The authors wish to thank the anaesthesia and surgery teams at the Complutense University of Madrid Teaching Hospital for their collaboration in managing this case. Special thanks are also extended to the zoo veterinarian Juncal García García, along with the rest of the veterinary staff and team of Madrid Zoo for travelling to the hospital, assisting during the procedures, and entrusting our centre with the care of this patient. Ethics declaration: not applicable. Funding: The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Competing Interests: The authors have no relevant financial or non-financial interests to disclose. Authors Contributions C.S. drafted the initial case report and incorporated feedback from all authors in subsequent versions. M.A. and E.MN. oversaw various aspects of clinical management and the revision process. All authors have read and agreed to the published version of the manuscript. Informed Consent Statement: Written informed consent has been obtained from the owner of the animals involved in this study. References Caulkett N, Shury T. (2014) Human safety during wildlife capture. In: West G, Heard D, Caulkett N (eds) Zoo Animal and Wildlife Immobilization and Anesthesia. 2nd edn. Wiley-Blackwell, Ames, pp 181–190. Chinnadurai SK, Strahl-Heldreth D, Fiorello CV, Harms CA. (2016) Best-practice guidelines for field-based surgery and anesthesia of free-ranging wildlife. I. Anesthesia and analgesia. J Wildl Dis. 52(2 Suppl):S14–27. https://doi.org/10.7589/52.2S.S14. Dourado A, Gomes A, Teixeira P, Lobo L, Azevedo JT, Dias IR, Pinelas R (2022) Antinociceptive effect of a sacro-coccygeal epidural of morphine and lidocaine in cats undergoing ovariohysterectomy. Vet Sci 9(11):623. https://doi.org/10.3390/vetsci9110623 Grubb T, Lobprise H (2020) Local and regional anaesthesia in dogs and cats: descriptions of specific local and regional techniques (part 2). Vet Med Sci 6(2):218–234. https://doi.org/10.1002/vms3.218 Gunkel C, Lafortune M (2007) Felids. In: West G, Heard D, Caulkett N (eds) Zoo and Wildlife Immobilization and Anesthesia. 1st edn. Blackwell Publishing, Ames, pp 443–459. Maas M, Keet DF, Nielen M (2013) Hematologic and serum chemistry reference intervals for free-ranging lions (Panthera leo). Res Vet Sci 95(1):266–268. https://doi.org/10.1016/j.rvsc.2013.01.023 Mengue PHS, Souza EC, Bernardes FCS, Montana MM, Thiesen R, Souza Junior P (2020) Skeletopy of the intumescentia lumbalis and conus medullaris applied to epidural anaesthesia in Leopardus geoffroyi. Folia Morphol (Warsz) 79(1):65–70. https://doi.org/10.5603/FM.a2019.0061 Monteiro BP, Lascelles BDX, Murrell J, Robertson S, Steagall PVM, Wright B (2023) WSAVA guidelines for the recognition, assessment and treatment of pain. J Small Anim Pract 64(4):177–254. https://doi.org/10.1111/jsap.13566 Morimoto K, Nishimura R, Matsunaga S, Mochizuki M, Sasaki N (2001) Epidural analgesia with a combination of bupivacaine and buprenorphine in rats. J Vet Med A Physiol Pathol Clin Med 48(5):303–312. https://doi.org/ 10.1046/j.1439-0442.2001.00360.x Onwuama K, Zubair A, Salami S, Kigir E, Jaji Z (2021) Morphological studies on the axial skeleton of the African lion (Panthera leo). Int J Vet Sci Anim Husbandry 6(2):9–14. http://doi.org/ 10.22271/veterinary.2021.v6.i2a.328 Portela DA, Verdier N, Otero PE (2018) Regional anesthetic techniques for the pelvic limb and abdominal wall in small animals: a review of the literature and technique description. Vet J 238:27–40. https://doi.org/10.1016/j.tvjl.2018.07.003 Richter J, Mülling CKW, Röhrmann N (2024) A morphometric study on the dimensions of the vertebral canal and intervertebral discs from Th1 to S1 in cats and their relevance for spinal diseases. Vet Sci 11(9):429. https://doir.org/10.3390/vetsci11090429 Riley J, Barron H (2016) Wildlife emergency and critical care. Vet Clin North Am Exot Anim Pract 19(2):613–626. https://doi.org/10.1016/j.cvex.2016.01.004 Salla K, Åhlberg T, Lepajoe J, Kallio-Kujala I, Mölsä S, Casoni D (2023) Efficacy of lumbosacral and sacrococcygeal epidural ropivacaine in dogs undergoing surgery for perineal hernia. Front Vet Sci 10:1163025. https://doi.org/10.3389/fvets.2023.1163025 Serres-Corral P, Fernández-Bellon H, Padilla-Solé P, Carbajal A, López-Béjar M (2021) Evaluation of fecal glucocorticoid metabolite levels in response to a change in social and handling conditions in African lions (Panthera leo bleyenberghi). Animals 11(7):1877. https://doi.org/10.3390/ani11071877 Singh M, Kanwar MS, Sharma SK, Vashiht NK (1992) Amputation of the tail in a lion (Panthera leo) under epidural analgesia. Indian Vet J 69:543. Sontakke S, Umapathy G, Kumar D, Singh DN. (2017) A manual on chemical immobilization of wild animals. In: Central Zoo Authority; Laboratory for the Conservation of Endangered Species (LaCONES), CSIR–Centre for Cellular and Molecular Biology (eds). Hyderabad, India. https://cza.nic.in/uploads/documents/publications/hindi/Final%20Mannual%20Chemical%20Immobilization%20of%20Wild%20Animals%20(1).pdf . Acceded 24 August 2025 Stanton LA, Sullivan MS, Fazio JM (2015) A standardized ethogram for the Felidae: a tool for behavioral researchers. Appl Anim Behav Sci 173:3–16. https://doi.org/10.1016/j.applanim.2015.04.001 Tumbelaka L, Sudarwati R, Mulia BH, Hastuti Y, Widianti A, Lewis J, Strike T. (2012) Veterinary Guidelines for the Handling of Sumatran Tigers in Conflict Situations. Wild Tiger Health Centre; 2012. Directorate of Forest Protection and Nature Conservation, Ministry of Forestry, Republic of Indonesia. https://wildtigerhealthcentre.org/wp-content/uploads/2020/04/Vet_guidelines_for_handling_of_Sumatran_tigers_in_conflict_2012_ENG.pdf . Accessed 24 August 2025 Yun MJ, Kwon MY, Kim DH, Lee JW (2014) Combined spinal-epidural anesthesia using a reduced dose of spinal bupivacaine and epidural top up leads to faster motor recovery after lower extremity surgeries. Korean J Anesthesiol 66(1):28–33. https://doi.org/10.4097/kjae.2014.66.1.28 Breitenmoser, U., Mallon, D.P., Ahmad Khan, J. & Driscoll, C. 2024. Panthera leo (Asiatic subpopulation) (amended version of 2023 assessment). The IUCN Red List of Threatened Species 2024: e.T247279613A259031465. https://dx.doi.org/10.2305/IUCN.UK.2024-1.RLTS.T247279613A259031465.en. Accessed on 02 September 2025. Additional Declarations No competing interests reported. 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While general anaesthesia is commonly employed, the incorporation of locoregional techniques offers significant advantages, including enhanced perioperative pain control and reduced reliance on systemic analgesics, which may produce adverse side effects. However, the application of locoregional techniques in wild animals is less common and requires careful consideration of the species-specific anatomy, the pharmacodynamics of the selected agents, and the difficulties in monitoring and management during the postoperative period. In this case report, we describe the use of epidural anaesthesia as part of a multimodal analgesic approach, highlighting its benefits and challenges in the context of wildlife anaesthesia.\\u003c/p\\u003e\"},{\"header\":\"Case Presentation\",\"content\":\"\\u003cp\\u003eAn entire lioness (\\u003cem\\u003ePanthera leo persica\\u003c/em\\u003e), aged 10 years, weighing 130 kg was referred from a zoological park (Madrid Zoo) to the Veterinary Teaching Hospital (Complutense University of Madrid) for a computed tomography scan to evaluate a chondrosarcoma in the lumbar region and, if indicated, to proceed with surgical excision. A prior veterinary visual examination of the lion at the zoo revealed no other abnormalities. Following sedation, a physical examination and as well as haematological and biochemical blood analysis were performed; all of which were within the physiological limits for the species (Maas 2013).\\u003c/p\\u003e\\u003cp\\u003eA comprehensive safety protocol was collaboratively established by the zoo and hospital teams. The zoo veterinarian, designated as safety officer, conducted a thorough assessment of the reception area, CT suite, and operating theatre, and defined emergency exit routes in case of unexpected arousal. Two experienced zookeepers remained positioned at the rostral end of the patient throughout the procedures, to oversee and assist with all manipulations. Recovery and transport back to the zoo were also prearranged in accordance with established safety guidelines (Caulkett 2014).\\u003c/p\\u003e\\u003cp\\u003eAnaesthetic premedication consisted of an intramuscular (IM) combination of medetomidine (0.05 mg kg\\u003csup\\u003e-\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e\\u003c/sup\\u003e; Sedator; Dechra) and ketamine (3 mg kg\\u003csup\\u003e-\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e\\u003c/sup\\u003e; Anesketin; Dechra) at the zoo. Once an adequate level of sedation had been achieved, the lion was transported to the Veterinary Hospital. Upon arrival, approximately 75 minutes after premedication, an additional IM dose of ketamine (1 mg kg \\u003csup\\u003e-\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e\\u003c/sup\\u003e) was administered for safety, assuming that the initial sedation might have partially worn off, and an 18-gauge catheter was placed in the saphenous vein. Anaesthesia was then induced intravenously (IV) with propofol (1.2 mg kg\\u003csup\\u003e-\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e\\u003c/sup\\u003e; Propofol Lipuro 1%; Braun). The trachea was intubated with a 14-mm cuffed endotracheal tube, and anaesthesia was maintained with isoflurane (Isovet; BBraun) vaporized in oxygen and delivered via a circle breathing system.\\u003c/p\\u003e\\u003cp\\u003ePhysiological parameters were monitored throughout the procedure using a multiparameter monitor (uMec12Vet; Mindray, Guangdong), including continuous electrocardiography, non-invasive blood pressure (oscillometry), pulse oximetry, capnography, and oesophageal temperature.\\u003c/p\\u003e\\u003cp\\u003eThe patient was positioned in sternal recumbency and pressure-controlled ventilation was initiated (Peak pressure 19 cmH\\u003csub\\u003e2\\u003c/sub\\u003eO; PEEP 5 cmH\\u003csub\\u003e2\\u003c/sub\\u003eO). Approximately 35 minutes after the onset of inhalational anaesthesia, hypercapnia (76 mmHg) was detected, accompanied by a decrease in tidal volume and airway pressure, findings consistent with a circuit leak. As a precaution, propofol (0.25 mg/kg, IV) was administered, and the endotracheal tube was removed, revealing a ruptured cuff. Reintubation was successfully performed, and no further complications were observed during the imaging procedure. Computed tomography revealed a contrast-enhancing soft tissue mass in the lumbar region, with no evidence of pulmonary metastases.\\u003c/p\\u003e\\u003cp\\u003eThereafter, the patient was transferred, under spontaneous ventilation, to a large-species operating room, where it was prepared for surgical chondrosarcoma removal 85 minutes after the induction of anaesthesia. Fluid therapy was initiated with lactated Ringer's solution (10 mL kg\\u003csup\\u003e-\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e\\u003c/sup\\u003e h\\u003csup\\u003e-\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e\\u003c/sup\\u003e), and IV methadone (0.1 mg kg\\u003csup\\u003e-\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e\\u003c/sup\\u003e; Semfortan; Dechra) was administered for perioperative analgesia, which resulted in marked ventilatory depression. Therefore, mechanical ventilation was reinitiated. In addition, a sacrococcygeal epidural block was performed using a loss-of-resistance technique, with bupivacaine (0.3 mg kg\\u003csup\\u003e-\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e\\u003c/sup\\u003e; Bupivacaína 0.5%; BBraun) and morphine (0.1 mg kg\\u003csup\\u003e-\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e\\u003c/sup\\u003e; Morfina; BBraun). The epidural technique was deemed successful, as evidenced by the absence of nociceptive response during the procedure and by the transient neurological deficits observed during early recovery.\\u003c/p\\u003e\\u003cp\\u003eTo enhance monitoring, an arterial catheter was placed in the lingual artery, which revealed lower blood pressure values compared with those obtained using the oscillometric method. However, since the patient did not exhibit clinical signs of hypotension, no intervention was required. The surgery lasted 88 minutes, with a total anaesthesia time of 205 minutes. Prior to extubation and complete recovery, IV dexmedetomidine (0.002 mg kg\\u003csup\\u003e-\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e\\u003c/sup\\u003e; Sedadex; Dechra) was administered to facilitate the safe transport of the patient back to the zoo.\\u003c/p\\u003e\\u003cp\\u003eFor postoperative analgesia, meloxicam (0.1 mg kg\\u003csup\\u003e-\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e\\u003c/sup\\u003e; Metacam; Boehringer) was administered subcutaneously at the end of the surgical procedure and was subsequently prescribed at half the dose every 24 hours. Additionally, tramadol was administered orally (2 mg kg\\u003csup\\u003e-\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e\\u003c/sup\\u003e every 12 hours; Tramadol EFG; Cinfa). The lioness regained the standing position 3 hours and 30 minutes after extubation, exhibiting mild paraparesis. By the next day, the animal demonstrated normal feeding behaviour, accepted postoperative analgesia, and showed no abnormal behavioural signs.\\u003c/p\\u003e\"},{\"header\":\"Discussion and Conclusion\",\"content\":\"\\u003cp\\u003eEpidural administration of a combination of bupivacaine and morphine via the sacrococcygeal approach appears to be a safe and effective analgesic technique in lions. Bupivacaine provides a longer duration of analgesia compared to other local anaesthetics, making it a suitable choice for managing anticipated postoperative pain associated to tissue tension at the surgical site (Monteiro 2023). However, bupivacaine is also associated with prolonged motor blockade, which can be detrimental in fractious or wild animals due to the risk of a panicked and ataxic recovery (Morimoto 2001; Yun 2014). To mitigate these effects, sedation was extended with the administration of dexmedetomidine during recovery, resulting in a calm awakening with minimal ataxia.\\u003c/p\\u003e\\u003cp\\u003eAs an alternative, lidocaine-with or without morphine- offers a shorter duration of action while still providing effective analgesia when administered epidurally. Lidocaine has been shown to provide good analgesic effects, particularly in procedures such as tail amputation in lions (Singh 1992).\\u003c/p\\u003e\\u003cp\\u003eMorphine, a hydrophilic opioid, has a relatively slow onset of action (up to 60 minutes). However, it can provide nociceptive inhibition for up to 24 hours without significantly affecting motor function and with minimal systemic uptake (Monteiro 2023). The efficacy of opioid drugs is further enhanced when combined with local anaesthetics, due to increased affinity for spinal cord receptors, making the combination of opioids with local anaesthetics particularly beneficial (Grubb 2020).\\u003c/p\\u003e\\u003cp\\u003eThe recommended doses of bupivacaine and morphine in wild felids are 0.3 mg/kg (not exceeding 6–9 mL) and 0.1–0.3 mg/kg, respectively. The analgesic effect usually lasts 8 to 12 hours while the anaesthetic effects persist for 1 to 4 hours (Gunkel 2007). In the present case, due to the sedation protocol used, the lioness was able to stand 3 hours after extubation, which allowed sufficient time for the motor effects to subside while maintaining effective analgesia. As a result, oral analgesics were not required until the next morning, when tramadol was administered approximately 15 hours after the epidural, and meloxicam was initiated 24 hours after its parenteral administration.\\u003c/p\\u003e\\u003cp\\u003eAs in other felids, the vertebral formula in lions follows the pattern C7 T13 L7 S3 Cd20–21 (Onwuama 2021). Regarding spinal anatomy, the conus medullaris in felids tends to extend more caudally than in canids, although data in large felids are scarce. In one study on wild felids, the apex was reported to reach as far as Cd2, making a lumbosacral epidural approach potentially unsafe (Mengue 2020). While there are no published descriptions of spinal cord length in Panthera leo persica, it is suspected that, as in other felids, the dural sac may extend caudally to the level of the S1 vertebra, increasing the risk of spinal blockade or injury with a lumbosacral epidural approach (Portela 2018; Richter 2024). For this reason, a sacrococcygeal approach was selected, together with a relatively high volume of injectate (0.3 mg/kg of 0.5% bupivacaine and 0.1 mg/kg of morphine).\\u003c/p\\u003e\\u003cp\\u003eThe effectiveness of the epidural analgesia administered was assessed intraoperatively by monitoring variability in standard haemodynamic parameters, namely heart rate, respiratory rate, and arterial blood pressure. These parameters were continuously recorded, and haemodynamic stability or the absence of significant responses to surgical stimulation was interpreted as indicative of adequate nociceptive blockade (Dourado 2022; Salla 2023).\\u003c/p\\u003e\\u003cp\\u003eIn the postoperative period, pain assessment relied primarily on behavioural observations by the veterinary team at the zoo, given the absence of validated pain scoring systems for this species (Gunkel 2007; Riley 2016; Monteiro 2023). Clinical indicators such as the onset of voluntary movements, time to first food intake, and the presence of calm, relaxed behaviour were used as surrogate markers of comfort and analgesic efficacy (Gunkel 2007; Serres-Corral 2011; Stanton 2015). Although these indicators are inherently subjective, they currently represent the most reliable means of assessing postoperative pain in this context.\\u003c/p\\u003e\\u003cp\\u003eIn terms of procedural organization and safety, the measures adopted in this case align with previous reports of free-ranging lion immobilizations, which highlight of thorough environmental assessment, the presence of trained personnel, clear delineation of high-risk areas (such as “red zones” around the head and limbs), and the implementation of intraoperative contingency plans (Tumbelaka 2012; Chinnadurai 2016, Sontakke 2017). An additional challenge in the present case was the need to transfer the animal between different facilities. This was accomplished under general anaesthesia using a dedicated stretcher, with two zoo veterinarians and several keepers providing continuous supervision throughout all transfers.\\u003c/p\\u003e\\u003cp\\u003eIn conclusion, this case illustrates the feasibility and effectiveness of combining bupivacaine and morphine via a sacrococcygeal epidural approach to provide perioperative analgesia in a lion undergoing major surgery. The technique offered adequate nociceptive control while minimizing systemic drug use, although careful consideration of potential motor blockade remains essential in wild felids. The incorporation of strict safety protocols coordinated teamwork between the zoological and hospital staff, and close intra- and postoperative monitoring were fundamental to ensuring a successful outcome. This is particularly relevant given that Asiatic lions are classified as \\u003cem\\u003eEndangered\\u003c/em\\u003e by the International Union for Conservation of Nature (Breitenmoser 2024). Overall, this report highlights the importance of adapting established anaesthetic and analgesic strategies to the specific anatomical, behavioural, and logistical challenges of large carnivores in a clinical setting.\\u003c/p\\u003e\"},{\"header\":\"Declarations\",\"content\":\"\\u003ch2\\u003eAcknowledgements:\\u0026nbsp;\\u003c/h2\\u003e\\n\\u003cp\\u003eThe authors wish to thank the anaesthesia and surgery teams at the Complutense University of Madrid Teaching Hospital for their collaboration in managing this case. Special thanks are also extended to the zoo veterinarian Juncal Garc\\u0026iacute;a Garc\\u0026iacute;a, along with the rest of the veterinary staff and team of Madrid Zoo for travelling to the hospital, assisting during the procedures, and entrusting our centre with the care of this patient.\\u003c/p\\u003e\\n\\u003ch2\\u003eEthics declaration:\\u0026nbsp;\\u003c/h2\\u003e\\n\\u003cp\\u003enot applicable.\\u003c/p\\u003e\\n\\u003ch2\\u003eFunding:\\u0026nbsp;\\u003c/h2\\u003e\\n\\u003cp\\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\\u0026nbsp;\\u003c/p\\u003e\\n\\u003ch2\\u003eCompeting Interests:\\u0026nbsp;\\u003c/h2\\u003e\\n\\u003cp\\u003eThe authors have no relevant financial or non-financial interests to disclose.\\u0026nbsp;\\u003c/p\\u003e\\n\\u003ch2\\u003eAuthors Contributions\\u003c/h2\\u003e\\n\\u003cp\\u003eC.S. drafted the initial case report and incorporated feedback from all authors in subsequent versions. M.A. and E.MN. oversaw various aspects of clinical management and the revision process. All authors have read and agreed to the published version of the manuscript.\\u0026nbsp;\\u003c/p\\u003e\\n\\u003ch2\\u003eInformed Consent Statement:\\u0026nbsp;\\u003c/h2\\u003e\\n\\u003cp\\u003eWritten informed consent has been obtained from the owner of the animals involved in this study.\\u003c/p\\u003e\"},{\"header\":\"References\",\"content\":\"\\u003col\\u003e\\n \\u003cli\\u003eCaulkett N, Shury T. (2014) Human safety during wildlife capture. In: West G, Heard D, Caulkett N (eds) Zoo Animal and Wildlife Immobilization and Anesthesia. 2nd edn. Wiley-Blackwell, Ames, pp 181\\u0026ndash;190.\\u003c/li\\u003e\\n \\u003cli\\u003eChinnadurai SK, Strahl-Heldreth D, Fiorello CV, Harms CA. (2016) Best-practice guidelines for field-based surgery and anesthesia of free-ranging wildlife. I. Anesthesia and analgesia. J Wildl Dis. 52(2 Suppl):S14\\u0026ndash;27. https://doi.org/10.7589/52.2S.S14.\\u003c/li\\u003e\\n \\u003cli\\u003eDourado A, Gomes A, Teixeira P, Lobo L, Azevedo JT, Dias IR, Pinelas R (2022) Antinociceptive effect of a sacro-coccygeal epidural of morphine and lidocaine in cats undergoing ovariohysterectomy. Vet Sci 9(11):623. https://doi.org/10.3390/vetsci9110623\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eGrubb T, Lobprise H (2020) Local and regional anaesthesia in dogs and cats: descriptions of specific local and regional techniques (part 2). Vet Med Sci 6(2):218\\u0026ndash;234. https://doi.org/10.1002/vms3.218\\u003c/li\\u003e\\n \\u003cli\\u003eGunkel C, Lafortune M (2007) Felids. In: West G, Heard D, Caulkett N (eds) Zoo and Wildlife Immobilization and Anesthesia. 1st edn. Blackwell Publishing, Ames, pp 443\\u0026ndash;459.\\u003c/li\\u003e\\n \\u003cli\\u003eMaas M, Keet DF, Nielen M (2013) Hematologic and serum chemistry reference intervals for free-ranging lions (Panthera leo). Res Vet Sci 95(1):266\\u0026ndash;268. https://doi.org/10.1016/j.rvsc.2013.01.023\\u003c/li\\u003e\\n \\u003cli\\u003eMengue PHS, Souza EC, Bernardes FCS, Montana MM, Thiesen R, Souza Junior P (2020) Skeletopy of the intumescentia lumbalis and conus medullaris applied to epidural anaesthesia in Leopardus geoffroyi. Folia Morphol (Warsz) 79(1):65\\u0026ndash;70. https://doi.org/10.5603/FM.a2019.0061\\u003c/li\\u003e\\n \\u003cli\\u003eMonteiro BP, Lascelles BDX, Murrell J, Robertson S, Steagall PVM, Wright B (2023) WSAVA guidelines for the recognition, assessment and treatment of pain. J Small Anim Pract 64(4):177\\u0026ndash;254. https://doi.org/10.1111/jsap.13566\\u003c/li\\u003e\\n \\u003cli\\u003eMorimoto K, Nishimura R, Matsunaga S, Mochizuki M, Sasaki N (2001) Epidural analgesia with a combination of bupivacaine and buprenorphine in rats. J Vet Med A Physiol Pathol Clin Med 48(5):303\\u0026ndash;312. https://doi.org/ 10.1046/j.1439-0442.2001.00360.x\\u003c/li\\u003e\\n \\u003cli\\u003eOnwuama K, Zubair A, Salami S, Kigir E, Jaji Z (2021) Morphological studies on the axial skeleton of the African lion (Panthera leo). Int J Vet Sci Anim Husbandry 6(2):9\\u0026ndash;14. http://doi.org/ 10.22271/veterinary.2021.v6.i2a.328\\u003c/li\\u003e\\n \\u003cli\\u003ePortela DA, Verdier N, Otero PE (2018) Regional anesthetic techniques for the pelvic limb and abdominal wall in small animals: a review of the literature and technique description. Vet J 238:27\\u0026ndash;40. https://doi.org/10.1016/j.tvjl.2018.07.003\\u003c/li\\u003e\\n \\u003cli\\u003eRichter J, M\\u0026uuml;lling CKW, R\\u0026ouml;hrmann N (2024) A morphometric study on the dimensions of the vertebral canal and intervertebral discs from Th1 to S1 in cats and their relevance for spinal diseases. Vet Sci 11(9):429. https://doir.org/10.3390/vetsci11090429\\u003c/li\\u003e\\n \\u003cli\\u003eRiley J, Barron H (2016) Wildlife emergency and critical care. Vet Clin North Am Exot Anim Pract 19(2):613\\u0026ndash;626. \\u0026nbsp;https://doi.org/10.1016/j.cvex.2016.01.004\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eSalla K, \\u0026Aring;hlberg T, Lepajoe J, Kallio-Kujala I, M\\u0026ouml;ls\\u0026auml; S, Casoni D (2023) Efficacy of lumbosacral and sacrococcygeal epidural ropivacaine in dogs undergoing surgery for perineal hernia. Front Vet Sci 10:1163025. https://doi.org/10.3389/fvets.2023.1163025\\u003c/li\\u003e\\n \\u003cli\\u003eSerres-Corral P, Fern\\u0026aacute;ndez-Bellon H, Padilla-Sol\\u0026eacute; P, Carbajal A, L\\u0026oacute;pez-B\\u0026eacute;jar M (2021) Evaluation of fecal glucocorticoid metabolite levels in response to a change in social and handling conditions in African lions (Panthera leo bleyenberghi). Animals 11(7):1877. https://doi.org/10.3390/ani11071877\\u003c/li\\u003e\\n \\u003cli\\u003eSingh M, Kanwar MS, Sharma SK, Vashiht NK (1992) Amputation of the tail in a lion (Panthera leo) under epidural analgesia. Indian Vet J 69:543.\\u003c/li\\u003e\\n \\u003cli\\u003eSontakke S, Umapathy G, Kumar D, Singh DN. (2017) A manual on chemical immobilization of wild animals. In: Central Zoo Authority; Laboratory for the Conservation of Endangered Species (LaCONES), CSIR\\u0026ndash;Centre for Cellular and Molecular Biology (eds). Hyderabad, India. https://cza.nic.in/uploads/documents/publications/hindi/Final%20Mannual%20Chemical%20Immobilization%20of%20Wild%20Animals%20(1).pdf\\u0026nbsp;. Acceded 24 August 2025\\u003c/li\\u003e\\n \\u003cli\\u003eStanton LA, Sullivan MS, Fazio JM (2015) A standardized ethogram for the Felidae: a tool for behavioral researchers. Appl Anim Behav Sci 173:3\\u0026ndash;16. https://doi.org/10.1016/j.applanim.2015.04.001\\u003c/li\\u003e\\n \\u003cli\\u003eTumbelaka L, Sudarwati R, Mulia BH, Hastuti Y, Widianti A, Lewis J, Strike T. (2012) Veterinary Guidelines for the Handling of Sumatran Tigers in Conflict Situations. Wild Tiger Health Centre; 2012. Directorate of Forest Protection and Nature Conservation, Ministry of Forestry, Republic of Indonesia. https://wildtigerhealthcentre.org/wp-content/uploads/2020/04/Vet_guidelines_for_handling_of_Sumatran_tigers_in_conflict_2012_ENG.pdf . Accessed 24 August 2025\\u003c/li\\u003e\\n \\u003cli\\u003eYun MJ, Kwon MY, Kim DH, Lee JW (2014) Combined spinal-epidural anesthesia using a reduced dose of spinal bupivacaine and epidural top up leads to faster motor recovery after lower extremity surgeries. Korean J Anesthesiol 66(1):28\\u0026ndash;33. https://doi.org/10.4097/kjae.2014.66.1.28\\u003c/li\\u003e\\n \\u003cli\\u003eBreitenmoser, U., Mallon, D.P., Ahmad Khan, J. \\u0026amp; Driscoll, C. 2024. \\u003cem\\u003ePanthera leo (Asiatic subpopulation)\\u003c/em\\u003e (amended version of 2023 assessment). \\u003cem\\u003eThe IUCN Red List of Threatened Species\\u003c/em\\u003e 2024: e.T247279613A259031465. https://dx.doi.org/10.2305/IUCN.UK.2024-1.RLTS.T247279613A259031465.en. Accessed on 02 September 2025.\\u003c/li\\u003e\\n\\u003c/ol\\u003e\"}],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":true,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"hideJournal\":false,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":true,\"isAuthorSuppliedPdf\":false,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":false,\"isPdf\":false,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"veterinary-research-communications\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":false,\"externalIdentity\":\"verc\",\"sideBox\":\"Learn more about [Veterinary Research Communications](https://www.springer.com/journal/11259)\",\"snPcode\":\"11259\",\"submissionUrl\":\"https://submission.nature.com/new-submission/11259/3\",\"title\":\"Veterinary Research Communications\",\"twitterHandle\":\"\",\"acdcEnabled\":true,\"dfaEnabled\":true,\"editorialSystem\":\"em\",\"reportingPortfolio\":\"Springer Hybrid\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":false},\"keywords\":\"Asiatic lion, epidural, ketamine, wildlife anaesthesia\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-7519660/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-7519660/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003eA 10-year-old lioness (Panthera leo persica), weighing 130 kg, was referred from Madrid Zoo to the Veterinary Teaching Hospital of the Complutense University of Madrid for evaluation of a lumbar soft tissue mass, previously diagnosed by biopsy as a chondrosarcoma, with potential surgical excision planned. A coordinated safety protocol was established between zoo and hospital staff, including predefined emergency routes and continuous supervision by experienced personnel and animal keepers. Anaesthetic premedication included intramuscular medetomidine (0.05 mg kg⁻\\u0026sup1;) and ketamine (3 mg kg⁻\\u0026sup1;), followed by propofol induction (1.2 mg kg⁻\\u0026sup1; IV) and maintenance with isoflurane in oxygen. Mechanical ventilation and comprehensive monitoring (ECG, non-invasive blood pressure, pulse oximetry, capnography, oesophageal temperature) were used. After computed tomography evaluation, the lion was elected for the chondrosarcoma surgical excision. Perioperative analgesia included intravenous methadone (0.1 mg kg⁻\\u0026sup1;) and a sacrococcygeal epidural block with bupivacaine (0.3 mg kg⁻\\u0026sup1;) and morphine (0.1 mg kg⁻\\u0026sup1;). The epidural provided effective intraoperative analgesia, as evidenced by the absence of nociceptive responses and transient postoperative neurological deficits. The lion recovered uneventfully. This case underscores the feasibility and efficacy of epidural analgesia as part of a multimodal anaesthetic protocol in large felids undergoing major surgery.\\u003c/p\\u003e\",\"manuscriptTitle\":\"Use of epidural anaesthesia as analgesic management in an Asiatic lion (Panthera leo persica)\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2025-09-22 13:50:15\",\"doi\":\"10.21203/rs.3.rs-7519660/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0},{\"type\":\"decision\",\"content\":\"Revision requested\",\"date\":\"2025-10-05T15:32:40+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2025-09-24T19:25:02+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2025-09-23T15:41:42+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2025-09-22T06:04:21+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2025-09-21T12:57:05+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2025-09-18T15:04:01+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"221438379166669931543002355277931263477\",\"date\":\"2025-09-16T17:02:07+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"322679060942780872130398319796553488963\",\"date\":\"2025-09-15T12:15:30+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"17494450477833553747487773209634554317\",\"date\":\"2025-09-15T11:38:32+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"139574820364098294573753434988364447852\",\"date\":\"2025-09-14T22:21:46+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"239856556227687340121169053014509408373\",\"date\":\"2025-09-13T05:10:02+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"123969141472378584338837853347941807070\",\"date\":\"2025-09-12T23:45:40+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewersInvited\",\"content\":\"\",\"date\":\"2025-09-12T23:24:50+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorAssigned\",\"content\":\"\",\"date\":\"2025-09-12T03:49:31+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"checksComplete\",\"content\":\"\",\"date\":\"2025-09-12T03:48:56+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"submitted\",\"content\":\"Veterinary Research Communications\",\"date\":\"2025-09-02T16:07:02+00:00\",\"index\":\"\",\"fulltext\":\"\"}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"veterinary-research-communications\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":false,\"externalIdentity\":\"verc\",\"sideBox\":\"Learn more about [Veterinary Research Communications](https://www.springer.com/journal/11259)\",\"snPcode\":\"11259\",\"submissionUrl\":\"https://submission.nature.com/new-submission/11259/3\",\"title\":\"Veterinary Research Communications\",\"twitterHandle\":\"\",\"acdcEnabled\":true,\"dfaEnabled\":true,\"editorialSystem\":\"em\",\"reportingPortfolio\":\"Springer Hybrid\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":false}}],\"origin\":\"\",\"ownerIdentity\":\"b983e705-b62e-4e75-8d94-0b1bb86eb35c\",\"owner\":[],\"postedDate\":\"September 22nd, 2025\",\"published\":true,\"recentEditorialEvents\":[],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"published-in-journal\",\"subjectAreas\":[],\"tags\":[],\"updatedAt\":\"2025-12-29T16:08:42+00:00\",\"versionOfRecord\":{\"articleIdentity\":\"rs-7519660\",\"link\":\"https://doi.org/10.1007/s11259-025-11032-z\",\"journal\":{\"identity\":\"veterinary-research-communications\",\"isVorOnly\":false,\"title\":\"Veterinary Research Communications\"},\"publishedOn\":\"2025-12-23 15:58:23\",\"publishedOnDateReadable\":\"December 23rd, 2025\"},\"versionCreatedAt\":\"2025-09-22 13:50:15\",\"video\":\"\",\"vorDoi\":\"10.1007/s11259-025-11032-z\",\"vorDoiUrl\":\"https://doi.org/10.1007/s11259-025-11032-z\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-7519660\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-7519660\",\"identity\":\"rs-7519660\",\"version\":[\"v1\"]},\"buildId\":\"8U1c8b4HqxoKbykW_rLl7\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}