Perineural anaesthesia is a useful technique in equine surgery, providing pre-emptive targeted anaesthesia of the surgical site, reducing volatile anaesthetic requirements, improving recovery quality and providing post-operative pain relief. Surgery under standing sedation in horses has increased in popularity, mandating the need for effective locoregional anaesthesia and analgesic techniques. Nerve location techniques offer greater accuracy than blind techniques when placing injectate. These methods can help to avoid structures such as blood vessels and minimise direct nerve damage during needle placement, reducing the chance of procedure-related complications. This review will discuss the most pertinent research in the veterinary literature where objective methods of nerve location have been used to perform peripheral nerve blocks in horses. The efficacy of using objective methods to perform nerve blocks in equine anaesthesia is discussed by the authors, providing useful information to equine anaesthetists, and potentially improve the quality of anaesthesia and analgesia in horses.

EVE Clinical CommentaryThe case report by describes an interesting case of rib fracture in a race horse with an attributable hindlimb lameness. This case is the first to suggest that caudal rib fractures are a cause of hindlimb lameness and peri regional diagnostic analgesia of a rib fracture can be used to alleviate hindlimb lameness.A recent retrospective study reported 73 horses diagnosed with a rib fracture of which 56% (41/73) presented due to poor performance with a fewer number of horses presenting with lameness as a primary complaint (21/73). Undoubtedly rib fractures are painful in the acute stages of injury, with the most common site for rib fracture in a horse being dorsally (5-15cm from the costovertebral junction) on the 18th rib (Hall et. al. 2022). In this study, not all horses with caudal rib fractures were found to have lameness those that were lame had a variable pattern of lameness. All of the horses which underwent diagnostic analgesia were found to have lameness independent to the rib fracture. However only a small percentage of horses underwent diagnostic analgesia, a limitation of a retrospective study.An alternative retrospective case series of 50 rib fractures reported 5 fractures of the first rib which all occurred in racing thoroughbreds (age 2-7 years with a median age of 3), all of which had ipsilateral forelimb lameness. In the absence of a traumatic incident the authors suggested that fractures of the 1st rib may represent fatigue fracture pathology associated with training. A similar aetiology is possible for caudal rib fractures but is considered unlikely as this injury is not over represented in racing Thoroughbreds compared with a general population of horses and trauma remains the most likely cause.Ribs can be imaged in detail with nuclear scintigraphy given the relatively small amount of overlying soft tissue. Orthogonal images (lateral, dorsal and oblique) should be used to localise region, extent, pattern and origin of increased radiopharmaceutical uptake. Nuclear scintigraphy is highly sensitive in identifying osteoblastic activity but has low specificity for identifying the nature of the pathological process. Fractures show increased radiopharmaceutical uptake within 24-72 hours post injury, making nuclear scintigraphy highly sensitive in the acute stage of disease verses radiographic signs which may not be seen for around 7-10 days unless the fracture is displaced. The appearance of a fracture on nuclear scintigraphy includes 5-7 days of diffuse intense uptake, 1-4 weeks of focal intense uptake (figure 1.) and then a gradual decrease of radiopharmaceutical uptake over the next 6-12 months. This prolonged visibility on scintigraphy means that is difficult to age a fracture based on scintigraphy alone. Ultrasonography is potentially more suitable to monitor fracture healing and identify those cases which are non-healing and requiring intervention. Costochondral junctions normally have a moderate increased radiopharmaceutical uptake on nuclear scintigraphy and should not be mistaken for a rib fracture (figure 1.). The caudal ribs overly the kidney (figure 1.) but in most instances have a mild to moderate diffuse region of increased radiopharmaceutical uptake. The use of furosemide one hour before imaging has been advocated to improve soft tissue clearance and improve image count to background ratio. This was evaluated in a recent study where 1mg/kg furosemides was administered intravenously 1 h post 99m Tc-HDP administration and the image quality was assessed subjectively and semi-quantitively. There was no significant difference in image quality or radiation dose rate to handler, with a minimum distance of 30cm distance having the most effect on reducing handler dose rate by 65% .Ultrasonographic examination is highly sensitive and specific in identifying rib fractures (Hall et. al. 2022). If a rib fracture is suspected in the initial stages of examination, then survey ultrasonographic examination of the ribs is recommended, especially the caudal ribs. However, rib fractures rarely result in focal localising pain on palpation and so even a detailed clinical examination may be unrewarding. Ultrasonography of the ribs is a simple technique; clipping isn’t required and discontinuity and callus within the lateral cortex of the ribs is easy to identify (Figure 2) but should not be confused with the costochondral junction (figures 3 and 4). The costochondral junction is identified by the presence of hypoechoic cartilage and it should be noted that the margins of adjacent ribs are normally irregular at this site. In contrast, a rib fracture does not contain hypoechoic cartilage, though the rib margins are likely to be irregular and commonly periosteal new bone may be seen.In this case of hindlimb lameness due to fracture of the 18th rib , the horse took 12 months to recover and resume ridden exercise with conservative therapy. Ultrasonographic examination can monitor fracture healing and is useful in identifying non-healing fractures which may represent surgical candidates. Hall and colleagues (2022) reported six horses which underwent surgery due to failed initial conservative management which resulted in continued fracture instability, callus at the fracture site or fracture displacement causing impingement on adjacent ribs. One horse which underwent wedge ostectomy and internal fixation with a locking compression plate returned to its previous level of exercise. All other surgically managed cases (5/73) underwent partial rib resection. Most horses in this study were managed conservatively (67/73). Given the very small number of surgically managed cases it is not possible to determine if fracture healing or outcome would have been improved if surgical intervention had been performed in more cases.Peri-regional analgesia of a rib fracture is commonly used in human medicine as a therapeutic aid and is easy to perform in the horse. In this instance the ipsilateral hindlimb lameness was partially alleviated by this technique in the acute stage of lameness and completely abolished in the chronic stage of lameness. Perineural analgesia can result in increased radiopharmaceutical uptake within the soft tissues on bone phase scintigraphy, up to 7 days post blocking , with 50% of horses having uptake at the site of a tibial perineural injection one day post injection, 25% of horses at the block site 3 days post injection and 1 horse with increased radiopharmaceutical uptake 7 days post injection. An appropriate washout period is recommended prior to scintigraphy if perineural analgesia has been performed to prevent false positive results.Although rib fractures are largely under reported in adult horses this case report and recent retrospective studies confirm they should be considered a differential diagnosis for cases of poor performance and both fore and hind limb lameness. Diagnostic analgesia could be used to determine significance of the rib fracture in cases of hind limb lameness.

Background: Ocular diseases, especially corneal diseases, are common in horses and their occurrence is associated with trauma. It is not known if management practices promote or prevent the development of ocular diseases, such as corneal ulcers. Objectives: This study aimed to evaluate how stable management practices, such as environment, feeding, or use of fly masks, are related to the development of eye diseases, primarily corneal ulceration, in horses. Study design: A survey of horse owners in the state of North Carolina was conducted which asked owners how they managed their horses and their responses were correlated to the types of eye diseases the horses experienced. Methods: Data collected from the survey included the primary environment of the horse (stable or pasture), type and method of feeding of hay, use of fly masks, and eye diseases that the horses have developed. Correlations between management practices and eye disease were then performed. Results: Of 446 horses, 161 (36% of total) had been diagnosed with a corneal ulcer, 44 (10%) had multiple corneal ulcers, 65 [15%] horses had uveitis, and 15 (3%) had immune-mediated keratitis. Horses that were kept in pasture exclusively were significantly less likely to have had a corneal ulcer than horses kept in a combination of pasture and stalls (p=0.0348). There were no significant correlations between types of hay or how hay was fed with the occurrence of corneal ulceration or other ocular diseases. Main limitations: Results, such as disease diagnoses, are solely based on horse owner responses and not medical professionals. Conclusions: Horses kept primarily in pasture have fewer ocular diseases, likely because they sustain less ocular trauma compared to horses kept in stables. How hay is fed does not correlate with the incidence of corneal or other ocular disease.

A six-week-old male Shetland pony is presented with pollakiuria and a scrotal mass. The diagnostic procedures conducted included a thorough clinical examination, external palpation, a scrotal ultrasonographic exam and urinary catheterization. These revealed an indirect herniation of the urinary bladder into the tunica vaginalis. Subsequently, the case was managed surgically by performing a partial cystectomy through an inguinal approach. Bilateral castration was performed with the affected side an additional closure of the superficial inguinal ring. Five months post-surgery, a routine telephone questionnaire highlighted no post-operative concerns. Gross examination of the inguinal region revealed no abnormalities and the foal was maturing as expected.

Difficulty to extubate any patient is not a problem commonly thought of during general anaesthesia. This case report describes some of the factors that lead to this predicament and the successful surgical removal of the endotracheal tube via a tracheostomy. This case report also highlights some of the deficiencies in the clinical practice of veterinary anaesthesia. Further research is required for the selection size criteria of endotracheal tubes in all species and the monitoring of cuff pressures during general anaesthesia.

The use of intracytoplasmic sperm injection (ICSI) for the production of equine embryos has significantly increased over the past decade, leading to the creation of labs specific for ICSI and related in vitro fertilization techniques. However, the commitment, resources and skills necessary for developing a viable IVF lab can be underestimated or under-appreciated. The purpose of this paper is to share the difficulties our clinic encountered when developing an IVF lab.

Simple dilution of semen is the oldest method to process semen for artificial insemination with either fresh or cooled. This was developed prior to the optimization centrifugation techniques for semen through a combination of trial and error and research. Simple dilution and is a faster method to process semen, is easy to use and works in many circumstances. For on farm semen use a 1:1 (v/v) semen to extender ratio is used. A variety of other techniques have been developed, such as cushion centrifugation, density gradient centrifugation and sperm filtration. Cushion centrifugation is used to concentrate the sperm and allows higher centrifugation speeds than centrifugation alone. This allows for improved recovery rates of sperm. Density gradient centrifugation has been used to select for morphologically normal sperm but suffers from low recovery rates. Processing sperm with this technique can result in improved motility and improved DNA integrity of sperm. Sperm filtration is another method to concentrate sperm without the use of centrifugation; however, this technique has lower recovery rates compared to cushion centrifugation. This review will discuss these techniques in the application of processing equine semen for either fresh or cooled-shipped use.

Enteroliths, faecaliths, ingested foreign bodies, and bezoars are examples of focal intraluminal obstructions that can lodge in inaccessible parts of the gastrointestinal tract. Pneumatic lithotripsy, as described in the accompanying article, is an option to manage obstructions caused by mineralized concretions. However, pneumatic lithotripsy may not be safe or effective for all intraluminal obstructions. Awareness of other strategies or secondary abdominal approaches to address these challenging presentations can help improve the surgeon's ability to problem solve in these situations and achieve successful resolution of the obstruction.

Recognition of the role that biofilms play in the persistence of chronic wounds and lack of response to therapy in horses is increasing. Prevention of biofilm development in early stages of wound care involves three primary strategies: wound debridement and cleansing to reduce bacterial counts in the wound bed, appropriate use of advanced wound dressings, and implementation of topical antimicrobial agents. Once formed, eradication of biofilms requires elimination to improve the wound environment for contraction and epithelialization while not further harming the native cells integral to the healing process, which is achieved predominantly through repeated lavage and debridement combined with topical antimicrobial therapy. This review will establish why and how biofilms form, how to recognize clinical indications that biofilms have formed in equine wounds, and to review current diagnostic options and biofilm-based wound care (BBWC) strategies to eradicate biofilms. Clinical scenarios for cases in which biofilms developed and were successfully treated will be presented. This review will advance practitioners’ understanding of the presence and role of biofilms in chronic wounds and provide an updated summary of recommended treatment strategies.

Background: Horses exercised “onto the bit” with periods of induced poll flexion can demonstrate a unique array of upper respiratory tract (URT) disorders. Objectives: To describe a previously unreported exercise-induced disorder of the epiglottis associated with poll flexion in harness racehorses. Study design: Retrospective observational study. Methods: Medical records of all harness racehorses that presented for exercising URT endoscopy between 2005 and 2022 were reviewed. These horses were exercised on a high-speed treadmill using a previously standardised protocol with alternating one-minute phases of free head carriage (no rein tension on the bit) and poll flexion (driven onto the bit with long reins) until they could no longer maintain the trotting gait. Results: Seven Standardbreds and 11 Norwegian-Swedish Coldblooded trotters were diagnosed with unilateral or bilateral compression of the epiglottis during exercise in poll flexion. These horses demonstrated progression of this disorder during the phases of induced poll flexion and showed no signs of epiglottic compression during phases exercised with free head carriage. Main limitations: Retrospective nature of study and limited sample size due to low prevalence. Conclusions: Exercise-induced compression of the base of the epiglottis is an URT disorder only evident videoendoscopically when horses are driven onto the bit leading to poll flexion. It is most often seen in association with dynamic laryngeal collapse but can also be witnessed as a solitary disorder. Videoendoscopically, it appears that the compression is initiated by the rostral advancement of the larynx and hyoid apparatus within a progressively narrowing intermandibular space during poll flexion. Visually this leads to local inward compression of the lateral nasopharyngeal walls and base of the epiglottis. Further studies are ongoing to confirm this hypothesis and to objectively quantify the degree of URT obstruction caused by this conformational narrowing of the epiglottis during poll flexion.

Caudal cervical spine pathologic lesions are a common cause of pain, lameness, ataxia, poor performance, or any mixture of these clinical signs. Combined radiographic and computed tomography myelography imaging of the caudal cervical spine is imperative when spinal cord compression, nerve root compression, and/or intervertebral disc disease is suspected. Surgical arthrodesis (ventral interbody fusion) of the C7-T1 articulation can be performed successfully and it is important for veterinarians to be aware that treatment at this level is possible.

Objective: To report clinical characteristics, surgical management, and medium-term outcomes of 3 Arabian neonatal foals with meniscal disruption associated with septic arthritis of the lateral femorotibial joint. Methods: Three neonatal Arabian foals with septic arthritis of the lateral femorotibial joint (LFTJ), were diagnosed with lateral meniscal (LM) tears, based on persistent lameness despite improving synovial parameters, ultrasound (US) findings (protrusion of meniscal tissue beyond the level of the condyles, with hypoechoic regions), contrast Computed Tomography findings, and confirmed on arthroscopy. Treatment included arthroscopic debridement and lavage of the joint with debridement of the meniscal tear. Postoperative care included systemic and intra-articular antimicrobials, based on culture and sensitivity results. Two of the foals received intra-articular injections of autologous mesenchymal stem cells. Results: Grade III meniscal tears were observed in the LFTJ of the affected joints of all foals, involving the meniscal body (n=3) and caudal horn (n=1). Purulent material within the torn tissue, was debrided with a synovial resector. Foal 1 was lame-free as a yearling. Foal 2 was lame at walk at 7.5 months and euthanatized due to poor prognosis. Foal 3 showed mild lameness at trot in a straight line at 6 months. Disruption of the LM continued to be visible on US in both foals at these time-points. Conclusion: Meniscal disruption and infection should be considered a differential in neonatal foals with persistent femorotibial septic arthritis. In such cases, the LM could be the primary nidus of infection.

Background Podcasts have become a popular digital forum for discussing scientific information with peers, as well as with the non-scientific community, often referred to as ‘edutainment’. It is unclear how science-based podcasts can support the veterinary industry through, for example, supporting good husbandry practices. Objectives To understand the influence of ‘edutainment’ on equine owners’ husbandry decisions Study Design The sample population was listeners of the Conversations in Equine Science (CES) podcast recruited to complete an online survey via a link promoted by the CES hosts. The survey contained Likert-like questions assessing how listeners rated the importance of different forms of evidence when making husbandry decisions and questions relating to husbandry changes made. Methods A mixed methods approach was used to analyse the data. The Likert package for R was used to explore importance ratings. Free text questions were analysed via a content analysis with a constructionist epistemological position. Results The experience of veterinarians and scientific evidence was considered the most important forms of evidence that owners used when making decisions about their horse’s management (93% agreed and 91% agreed they were important respectively). Additionally, 74% of respondents had made a change to the management or training principles prompted by an episode of CES, suggesting edutainment can be a prompt to management change. Of these, the majority (55%) had done so based on a joint discussion of the podcast and their own reading of the evidence. Main Limitations This was an opportunistic sample of those already invested in the edutainment format, and may not represent those owners with no interest in scientific evidence. Conclusions Podcasts are an easy-access, low-cost medium to convey research and current trends in the equine/equitation science genre. They may be a valuable tool for the veterinary industry to employ to support horse welfare.

Adipose tissue is not only required for energy storage but is an essential endocrine organ with a central role in the pathology of obesity. The understanding of its role, both in human and equine medicine, is continually evolving. With obesity being an ever-growing problem in the equine population, gaining owner compliance is critical when implementing management plans. The aim of this review is to encourage the inclusion of the concept of adiposity in discussions with horse owners on obesity and metabolic syndrome. In doing this, we hope to improve clients understanding and therefore maximise the impact of diagnostic tests, monitoring tools and management.

The case report by Navarro-Lopez et al., (2023) in this issue describes a thorough differential diagnosis in an equine with acute neurological disease. Rabies was confirmed by direct fluorescent antibody test (DFA). Rabies virus (RABV) was isolated from brain tissue of the ill mare by intracerebral inoculation in sucking mice. Sequencing and phylogenetic inference allowed the identification of the rabies virus variant (RVV) associated with this case. Thus, Navarro-Lopez et al., reported that the rabid mare got infected with a rabies virus variant associated with skunks. This clinical commentary elaborates on the seemingly rare skunk rabies across North America (NA) highlighting its relevance in human and animal health that have remained somehow neglected

Ticks pose a significant threat to horses, as they can cause harm and transmit diseases. This study aimed to assess the experiences, knowledge, and practices of equine veterinarians regarding ticks and tick-borne diseases (TBDs) in the United States. A survey was conducted, covering topics such as tick biology, identification, prevention, and veterinary education. The results revealed variations in veterinarians’ knowledge on ticks and TBDs, highlighting the need for improved tick control options, enhanced education, and comprehensive resources for tick and TBD prevention. The study emphasizes the importance of accurate tick identification for effective diagnosis and treatment of TBDs in horses. The limitations of the study include potential response bias and a limited sample size. To address these issues, collaborations between academia, industry, and the human medicine community are recommended to strengthen veterinarian training and education on ticks and TBDs. This research provides valuable insights for developing continuing education programs that focus on tick-borne illness prevention in horses.

Treatment of guttural pouch mycosis with salpingopharyngostomyAmanda R Watkins1 and Eric J Parente11University of Pennsylvania New Bolton Center, Kennett Square PAThe case report by Rowe et al (2023) published in this issue describes a case of bilateral guttural pouch mycosis in a 9-month-old thoroughbred colt that was diagnosed due to unusual severe neurologic abnormalities including neck pain and abnormal head carriage. There was no evidence of hemorrhage in this case and therefore the colt was treated with debridement of the mycotic plaques, topical enilconazole, and ultimately a salpingopharyngeal fistula in the dorsal pharyngeal recess to inhibit the growth of the mycosis. The treatments were successful, and the colt went on to race.The guttural pouch is an diverticulum of the auditory tube that is found in ungulates possessing an odd number of toes, including the horse.1 The guttural pouches are susceptible to fungal and bacterial infections and the intimate association of the pouches with major arteries and nerves makes such infections potentially life-threatening. While the purpose of the guttural pouch is an area of speculation among equine researchers it is thought that cooling the blood before it reaches the brain especially during exercise is an important function.1 The cooling of the blood is achieved by a large air filled space separated from the internal carotid artery by only a thin membrane. Therefore, any locally invasive disease within the guttural pouches can have dire consequences.Fungal infection of the guttural pouch occurs rarely but, due to its anatomical position in relation to many neurovascular structures of the head, even mild disease can result in fatal hemorrhage and neurological sequelae.2 Obtaining a positive culture from these cases can be difficult however the most commonly isolated fungal species is Aspergillus fumigatus.2 The warm, dark, and humid environment of the guttural pouch may predispose it as a site of fungal infection. Jukic et al showed that the oxygen and carbon dioxide partial pressures within the guttural pouch vary significantly between horses and that they remain relatively static throughout the respiratory cycle in a normal guttural pouch.3 This inter-horse variation may explain the seemingly random distribution of horses that are affected by guttural pouch mycosis. Additionally the individual differences may contribute to the less aggressive phenotype that resolves without treatment in 15-28 days that is seen in the experimentally induced Aspergillus guttural pouch mycosis model.4 The case described in this report may have been complicated by the mixed infection cultured from the guttural pouch of both Aspergillus fumigatus and Streptococcus equi subsp. zooepidemicus .Salpingopharyngostomy is the creation of a fistula between the pharynx and the guttural pouch and has been described as a treatment for guttural pouch mycosis.3,5–7 The theory behind this procedure is that it opens the guttural pouch to the fluctuating change of respiratory gases and temperatures of the respiratory tract. Jukicet al demonstrated that following salpingopharyngostomy there was no difference in the mean partial pressures of oxygen and carbon dioxide within the guttural pouch however, the variability of the pressures was significantly increased with the partial pressures oscillating with the respiratory pattern.3 This introduction of varying gas levels may change the environment within the guttural pouches making them less hospitable to fungal growth and allowing for faster resolution of the infection. In this case, due to the bilateral nature of the disease the authors created a single salpingopharyngostomy in the dorsal pharyngeal recess to gain access to both guttural pouches simultaneously. Creating a bilateral opening is easily created and can even be made larger and more likely to remain patent by ablating part of the septum between the two pouches.Aspergillus species are highly aerobic and can grow in most oxygen environments. However, they are also capable of growing at low oxygen tension and growth under these conditions may affect their pathogenicity by allowing secretion of virulence factors.8Hyperbaric oxygen treatment of A. fumigatus biofilms in vitro resulted in decreased biofilm proliferation by over 50%, though the effect was transient with growth re-establishing at 6 hours post treatment.9 In human medicine, individuals with invasive fungal infections caused by Aspergillus spp . are routinely treated with hyperbaric oxygen therapy in addition to surgical debridement and anti-fungal medications.10 Though there is a lack of controlled evidence to support this therapeutic in fungal infection, the complications are minimal and it is thought to improve the efficacy of neutrophils and macrophages by meeting their increased oxygen demands when clearing infections.11Additionally increased oxygen may improve the quality of the collagen matrix being created during the healing process.11An additional therapeutic that might have been helpful in this case prior to salpingopharyngeal fistulation is topical oxygen therapy (TOT) which has been recently published by Lepage et al for use as an adjunct treatment in epistaxis cases following transarterial coil embolization (TACE) or as a primary treatment in non-bleeding cases.12 Part of the rationale behind pursuing additional treatment options by this group is the percentage of horses that fail to completely resolve the neurologic sequelae of the disease which has been reported at 50%.13 When examining the issue of recurrent epistaxis following TACE the survival rate is 84% which places this high level of persistent neurological abnormalities into sharp relief. Dysphagia particularly can be severe enough to necessitate euthanasia even in the face of successful hemorrhage management. Certainly, dysphagia can be reversible as in the case published by Whitehead et al that was managed successfully with topical anti-fungals, carotid occlusion and esophagostomy but it can be a lengthy process that not all owners or patients will tolerate.14Guttural pouch mycosis does not lend itself to aggressive surgical debridement given the closely associated vessels and nerves to the mycotic plaques, however the somewhat enclosed environment of the guttural pouch may be an advantage for TOT. Lepage et al treated cases with TOT 4 times per day at 15 L/min for 1-2 weeks by placing an indwelling catheter into the affected guttural pouch and leaving it in place as much as possible for the duration of hospitalization. During treatments the horses were restrained with their heads at the height of the withers to decrease the opening of the guttural pouch orifice to maintain a closed high oxygen environment, though swallowing would still result in transient openings of the orifices.12Following a minimum of two treatments the fungal plaques were seen to begin regressing. Additionally the reported resolution or significant improvement of 10/12 neurologic disorders is encouraging compared to the 9/18 cases of resolution reported in a larger retrospective study on TACE.13It is unlikely TOT and salpingopharyngostomy would have any additive effect if done concurrently since it is unlikely the higher oxygen tension could be achieved with the fistula. The two procedures could be considered in series with the salpingopharyngostomy created after initial TOT. The advantage of the salpingopharyngostomy alone is that it is a single treatment without the need for further treatments or hospitalization. Furthermore, while Jukic et al showed some variations in partial pressures of gas in horses with salpingopharyngostomies there was not significant variation in temperature or humidity. The horses were housed in a controlled environment during short sampling periods in that study and variations may be greater if horses with salpingopharyngostomies are not housed in an environmentally controlled condition.Some of the clinical signs of this case report are difficult to attribute directly to the mycosis infection and there was confounding evidence of bacterial infection and other treatments. Regardless, guttural pouch mycosis can result in severe and possibly fatal disease as it almost did in this case report. Salpingopharyngostomy is an alternative treatment strategy to traditional medical treatment that should be considered in horses with guttural pouch mycosis.References1. Baptiste KE, Naylor JM, Bailey J, Barber EM, Post K, Thornhill J. A function for guttural pouches in the horse. Nature . 2000;403:382-383.2. Ludwig A, Gatineau S, Reynaud MC, Cadoré JL, Bourdoiseau G. Fungal isolation and identification in 21 cases of guttural pouch mycosis in horses (1998–2002). Vet J . 2005;169(3):457-461. doi:10.1016/j.tvjl.2004.06.0053. Jukic CC, Cowling NR, Perkins NR, Eps AW, Ahern BJ. Evaluation of the effect of laser salpingopharyngostomy on the guttural pouch environment in horses. Equine Vet J . 2020;52(5):752-759. doi:10.1111/evj.132214. Greppi MC, Guillot J, Melloul E, Bourdoiseau G, Lepage O, Cadoré JL. Experimental induction of mycotic plaques in the guttural pouches of horses. Med Mycol . Published online October 4, 2016:myw073. doi:10.1093/mmy/myw0735. Koch DW, Ericksen KA, Easley JT, Hackett ES. Clinical outcome of horses with guttural pouch infection following transpharyngeal fenestration. J Am Vet Med Assoc . Published online May 5, 2022:1-5. doi:10.2460/javma.22.01.00416. Koch DW, Easley JT, Nelson BB, Delcambre JJ, McCready EG, Hackett ES. Comparison of two techniques for transpharyngeal endoscopic auditory tube diverticulotomy in the horse. J Vet Sci . 2018;19(6):835. doi:10.4142/jvs.2018.19.6.8357. Watkins AR, Parente EJ. Salpingopharyngeal fistula as a treatment for guttural pouch mycosis in seven horses. Equine Vet J . 2018;50(6):781-786. doi:10.1111/evj.128308. Hall LA, Denning DW. Oxygen requirements of Aspergillus species.J Med Microbiol . 1994;41(5):311-315. doi:10.1099/00222615-41-5-3119. Dhingra S, Buckey JC, Cramer RA. Hyperbaric Oxygen Reduces Aspergillus fumigatus Proliferation In Vitro and InfluencesIn Vivo Disease Outcomes. Antimicrob Agents Chemother . 2018;62(3):e01953-17. doi:10.1128/AAC.01953-1710. Segal E. Hyperbaric Oxygen in the Treatment of Invasive Fungal Infections: A Single-Center Experience. 2007;9.11. Kaufman H, Gurevich M, Tamir E, Keren E, Alexander L, Hayes P. Topical oxygen therapy stimulates healing in difficult, chronic wounds: a tertiary centre experience. J Wound Care . 2018;27(7):426-433. doi:10.12968/jowc.2018.27.7.42612. Lepage OM, Di Francesco P, Moulin N, et al. The Effect of Topical Oxygen Therapy in Horses Affected with Mycosis of the Guttural Pouch: An Experimental Pilot Study and a Case Series. Anim Open Access J MDPI . 2021;11(11):3329. doi:10.3390/ani1111332913. Lepage OM, Piccot-Crézollet C. Transarterial coil embolisation in 31 horses (1999-2002) with guttural pouch mycosis: a 2-year follow-up.Equine Vet J . 2010;37(5):430-434. doi:10.2746/04251640577447996014.Whitehead AE, Whitty J, Scott M, Léguillette R. Reversible dysphagia secondary to guttural pouch mycosis in a gelding treated medically with voriconazole and surgically with carotid occlusion and esophagostomy.Can Vet J . 2018;59(2):165-170.

Internal bleeding and mucosal bleeding in hollow organs are uncommon conditions in equine medicine and endoscopy. Most of the times, they respond to treatment of the underlying primary condition. However, there are cases in which a rapid and effective control of blood loss is required and the animal is not suited for surgery or general anaesthesia. We report two cases referred to our Veterinary Teaching Hospital with signs of urinary disease and bladder haemorrhage identified by cystoscopy which were successfully managed with topical application of a haemostatic carboxymethyl-starch powder. The product was applied directly on the bleeding mucosa after bladder emptying either under endoscopic guidance or blindly, through a urinary catheter. The application of the haemostatic powder appears to be easy to perform, safe, and helpful in controlling mucosal bleeding in hollow organs in the short time, with no adverse reactions noticed. This approach should be considered in cases where mucosal bleeding can be identified by endoscopy and a prompt control of blood loss is required, also in the field.