INTRODUCTIONThe treatment of equine patients with angular limb and/or rotational deformities combined with closed physes presents a clinical challenge to equine practitioners. The report by Gaida et al in this issue outlines the management of one such case by utilizing a radial osteotomy for a deformity of the distal metacarpus. Although the authors had some challenges with the post-operative management, they did have an acceptable outcome with this technique.Osteotomies and ostectomies are uncommon surgical procedures used to treat angular and rotational limb deformities in patients beyond the time frame of growth retardation or in older patients that have acquired an angular limb deformity secondary to another pathology (healed fracture, osteoarthritis, or previous infection). The procedure involves transecting and possibly removing a portion of bone and stabilizing the resulting construct with implants to achieve a more anatomically appropriate limb. The most common anatomical location treated is the metacarpophalangeal/metatarsophalangeal joint or the diaphysis of MC3/MT3, followed by deformities of the carpal region, with the traumatic deformation of the carpal bones or the distal radius being the focus. Reports also exist of surgical correction of deformities involving the radial diaphysis (Auer, 2019).A thorough examination of the limb in question is necessary for surgical planning, including static and dynamic examination of the patient. Angular limb deformities can be complex with deformities in more than one plane and so a detailed understanding of the abnormality is fundamental for surgical success. Radiographs and computed tomographic examination of the affected area should be performed on all candidates. Three-dimensional printing combined with planning software can be valuable in assessing complicated deformities (Auer 2019, Auer 2022). When the abnormality involves only a simple deviation, the pivot point should be established based on pre-operative imaging, which is accomplished by drawing lines perpendicular to the joint surfaces proximal and distal to the deformity of the involved long bones and identifying the bisection point. The degree of deviation can then be calculated based on this point. In more complex cases, multiple pivot points may exist in different planes. These bisecting pivot points are used to determine the correction angle to be utilized intra-operatively. Identifying the complexity of the deformity as well as the planes involved will influence the surgical technique to be utilized. (Auer, 2019)

The case report by Vandecandelaere et al. (2025) describing two fatalities following administration of extended-release injectable omeprazole (ERIO) provides an important opportunity to reflect on the inherent risks associated with parenteral drug administration in horses. While these deaths are undoubtedly tragic, it is essential to contextualise this risk within the broader landscape of equine injectable therapeutics to provide balanced clinical guidance.

Summary: Listeria monocytogenes is a ubiquitous, small, rod shaped, gram-positive, facultatively anaerobic, saprophytic bacterium living in the plant-soil environment. Equine listeriosis is rarely reported and literature-based evidence is scarce. Horse presented at Equine Clinic of University of Veterinary Medicine and Pharmacy in Kosice, Slovakia, showed only limited neurological signs, but the illness was terminal. The duration of the disease was short and development of clinical signs after presentation to the clinic was fast. Patient succumbed to the infection within 12 hrs. after presentation; bacteria was diagnosed in the brain tissue using bacteriological culture method. Our brief paper describes the clinical signs on presentation, biochemistry and urine analysis findings, development of the clinical symptomatology and necropsy findings.

Background Operating theatres are major generators of waste and greenhouse gases. Methods The weights / types of waste from equine orthopaedic, colic, soft tissue and arthroscopic surgeries (convenience sampling) were audited during three six months periods: period 1, prior to intervention; period 2, following training / education of teams about waste segregation; period 3, following introduction of reusable surgical textiles (drapes, gowns, instrument packaging). Results In all surgery types, the mean total waste mass in period 3 was lower than the other two time periods. For all surgery types, the mean percentage of the waste that was offensive reduced from period 1 to period 2, followed by a further reduction in period 3. In all surgery types, the mean percentage of domestic waste was higher in period 3 than in period 1. The mean percentage of recyclable waste was lower during period 3 than during period 2. Main limitations Low numbers of surgeries. Conclusions Education and training of surgical teams on appropriate waste segregation and introduction of reusable surgical textiles resulted in reduced total waste and offensive waste, and increased domestic waste generated in equine surgery. These changes have reduced the carbon footprint of equine surgery in this theatre.

Are you looking at lymphoma or perhaps listening to it? The diagnosis of lymphoma can be challenging, reflecting the often-insidious effects of either the primary mass or secondary spread. The case report in this issue by Talbot et al. (2025) describes an unusual location for a primary lymphoma tumour, in the interventricular septum extending around the aortic valve. Significant cardiac findings were noted on auscultation; qualities of cardiac murmurs were consistent with findings attributable to an uncommonly encountered differential diagnosis of effective aortic stenosis. Though presumably not acute in onset at this location, clinical presentation was only prompted when overt signs of periocular swelling were observed by the owner. Lymphoma accounts for 1.3 to 2.8% of equine neoplasms (Taintor and Schleis 2011) and T-cell rich, large B-cell lymphoma (TCRBCL) is the most common subtype (40-45% of cases) (Durham et al. 2012, Valli et al. 2016). Lymphoma associated with peri-ocular swelling (Murphy et al. 1989, Rendle et al. 2012) has also been reported, in this case the peri-ocular swelling was an early sentinel, preceding detection of the primary cardiac infiltration. The accompanying case report also highlights pertinent nuances when interpreting cardiac findings and provides an important aide-mémoire for presentations and manifestations of TCRBCL.

Helminth infections remain highly prevalent among grazing equids worldwide, with cyathostomins and the tapeworm Anoplocephala perfoliata representing the most widespread parasites. While most horses tolerate low helminth burdens without overt clinical signs, a minority develop higher burdens that can result in substantial intestinal pathology. Infection with A. perfoliata burdens exceeding 20 worms has been strongly associated with mucosal ulceration, ileocaecal valve dysfunction and various forms of colic. Consequently, mounting evidence of reduced anthelmintic efficacy against A. perfoliata represents a growing concern, particularly in light of the apparent absence of a drug development pipeline for equine anthelmintics. This situation highlights the need for sustainable, evidence-based control strategies that favour diagnostic-led treatments over routine blanket deworming. Traditional coprological methods, although integral to nematode control, lack sensitivity for detecting A. perfoliata due to the parasite’s intermittent egg shedding and typically low faecal egg output. In contrast, serological and salivary immunoassays targeting parasite-specific IgG(T) have been developed, providing a more sensitive means of assessing infection status, with antibody levels shown to correlate with tapeworm infection levels. Incorporation of these tests into helminth control programmes enables targeted treatment of infected horses while minimising unnecessary anthelmintic use in individuals with little or no infection. When combined with robust pasture management practices, including regular faecal removal, maintenance of low stocking densities, rotational grazing with non-equine species and adequate paddock rest periods, diagnostic-led approaches can substantially reduce reliance on anthelmintics. This not only helps preserve drug efficacy through the maintenance of refugia but also supports sustainable long-term control of equine tapeworm infections. However, there remains an urgent need to develop validated methods for assessing anthelmintic efficacy against A. perfoliata, which should be a key priority for future research.

A neonatal foal presenting with surgical site infection following internal fixation of a transverse, displaced fracture of the distal third left metatarsus was successfully managed using negative pressure wound therapy (NPWT). Negative pressure wound therapy promoted rapid formation of healthy granulation tissue, resolution of infection and stability of the implant until bone healing was achieved while minimizing hospital personal exposure to multiple-drug-resistant pathogens.

Background: Antimicrobials essential for human health must be used judiciously. Objectives: Quantify current use and indications for critically important antibiotics (“protected antibiotics”) in general equine practice. Study Design: Prospective descriptive. Methods: Systemic use of 3 rd generation cephalosporins (ceftiofur), fluroquinolones (enrofloxacin and marbofloxacin), macrolides (clarithromycin), ansamycins (rifampin) and polymyxins (polymyxin B) (classified as “protected antibiotics”) were prospectively recorded in 19 equine practices over a six-month period (April - September 2023). Results: Protected antibiotics were prescribed to 200 horses with 10 horses prescribed two protected antibiotics concurrently. These included ceftiofur (48.2%), enrofloxacin (34.3%%), marbofloxacin (7.1%), polymyxin B (6.2%), rifampin (2.8%) and clarithromycin (1.4%). The mean number of protected antibiotics prescribed per practice was 10.5 (SD 12.4, range 0-41). The commonest clinical indications were respiratory disease (18.0%), foal septic diseases (16.5%), gastrointestinal diseases (15.0%), complicated wounds (13.5%), “dummy”/premature foals (7.5%) and cellulitis/lymphangitis (6.5%). Of 190 horses prescribed protected antibiotics, 76 (40.0%) were foals (less than 12 months of age). Horse age (foal or adult) was associated with specific antibiotic use (p < 0.001), with 73.7% of ceftiofur prescriptions for foals, and 97.0% and 100% of enrofloxacin and marbofloxacin prescriptions respectively for adults. Horses less than one year of age were less likely to have culture and antibiotic susceptibility testing (AST) compared to adults (P < 0.001). Commonest justifications for protected antibiotic use were lack of alternative preparations suitable for foals (27.5%), AST results (24.9%) and failure to respond to previous antibiotic treatment (17.1%). Main Limitations: Convenience sampling with small number of cases. Aminoglycoside use not evaluated. Conclusions: Respiratory and gastrointestinal diseases, complicated wounds and foal infections were the commonest reasons for protected antibiotic use. Lack of alternative drugs (for foals) and C&S results or failed previous treatments were commonest justifications.

Gastric outflow obstruction (GFO) occasionally requires surgical intervention in foals when medical management fails. Current literature lacks consensus on several surgical decisions, with most comprehensive reports dating back over a decade. Critical aspects—including jejunal loop orientation and necessity of jejunojejunostomy—remain debated among surgeons. Long-term data regarding complications, growth, and athletic performance are scarce. This case series documents the long-term outcomes of two Lusitano dressage foals that underwent bypass surgery for GFO, providing contemporary outcome data for specific surgical decisions where evidence remains limited. Two Lusitano foals underwent bypass procedures for GFO. Case 1: A 15-day-old orphan foal with pyloric stenosis underwent side-to-side gastrojejunostomy without jejunojejunostomy, with jejunal loop oriented left-to-right. Six years post-operatively, the horse performs dressage at a competitive level with normal growth and conformation. Case 2: A 12-hour-old foal underwent gastroduodenostomy; nearly three years later, it continues without complications. This series contributes recent outcome data for specific surgical decisions in bypass procedures. Both foals achieved favourable results. Left-to-right orientation gastrojejunostomy and without jejunojejunostomy worked perfectly. Importantly, extended follow-up documents the absence of long-term complications, normal growth, and athletic performance—critically needed information for surgical decision-making and owner communication regarding these uncommon, costly procedures.

Renal Tubular Acidosis: A ‘Basic’ DisorderHannah J. Mason, Luis G. Arroyo*Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada N1G 2W1* Corresponding author: Dr. Luis Arroyo; Email: larroyo@uoguelph.caRenal tubular acidosis (RTA) occurs when impaired acid excretion by the kidneys due to varied tubular disorders results in hyperchloremic metabolic acidosis with a normal anion gap. Within human literature, the disease can be classified into types I, II, III or IV, with differences in electrolyte imbalances and cited causes. The disease can be primary (inherited or idiopathic) or secondary to other disease or toxins (Bagga and Sinha 2020). Drugs that have been associated with RTA include amphotericin B, trimethoprim-sulfamethoxazole, tetracyclines, gentamicin, cephalosporins, carbonic anhydrase inhibitors and lithium carbonate (Arroyo et al. 2020). RTA has limited documentation within horses and has not been reported in donkeys. This case report by Kummer et al. (2025) is the first documentation of occurrence within mules.Type I, or distal, RTA occurs due to failure of hydrogen ion secretion in the intercalated cells of the distal tubules and collecting duct. This results in failure of urine acidification, reduced ammonium excretion, increased calcium and potassium excretion. The occurrence of hypokalemia is not fully understood but is a hall mark for early recognition of type I RTA (Kuncher et al. 2020). Increased urine calcium that occurs in type I RTA often causes urolithiasis or nephrolithiasis to occur in humans (Alexander et al. 2016), however to the authors knowledge this has not been recorded in horses. The presence of urinary calcium is higher in horses than people, which could explain this pathophysiological difference (Aleman et al. 2001).Type II, or proximal, RTA results from decreased bicarbonate resorption in the proximal tubules. This, with other proximal tubular absorption deficits, comprises Fanconi syndrome. Fanconi syndrome can be inherited or can occur secondary to other disease or toxins. A deletion mutation of the Fanconi anemia-associated nuclease 1 (FAN1) gene has been implicated in the development of Fanconi syndrome in Basenji dogs, resulting in mitochondrial damage in the kidneys (Farias et al. 2012). Transient Fanconi syndrome has been reported in two Quarter Horses, for which an inciting cause was unknown (Ohmes et al. 2014). It has been suggested that Quarter Horses are over-represented in Type II RTA but there have been no genetic links proven (Aleman et al. 2001; Arroyo et al. 2020).Neither type III nor IV RTA have been reported in horses. Type III RTA in humans is characterized by carbonic anhydrase II deficiency due to an inherited disorder. This produces a mixed RTA which is challenging for practitioners to diagnose and treat. Type IV RTA is caused by aldosterone deficiency or resistance which leads to hyperkalemia and ultimately impaired ammonium excretion (Kuncher et al. 2022).The mule in this case report presented with lethargy, anorexia, mild signs of colic and decreased fecal output (Kummer et al. 2025). These clinical signs are amongst those reported previously, which also include lethargy, poor performance and weight loss (Aleman et al. 2001). Limited history was known for this mule, so an inciting cause of RTA cannot be ruled out, though there is little known of RTA causes in equids (Aleman et al. 2001).RTA was suspected in this case following the detection of severe hyperchloremic metabolic acidosis, hypokalemia, hyponatremia and hypercalcemia with a normal anion gap. Kummer et al. (2025) recognise that urine sample collection before initiating fluid therapy may have provided additional information, however this appears to be a more helpful diagnostic tool in human RTA, whereby distinguishing acid from alkaline urine helps classify the type of RTA and therefore guides treatment approach. Alkaline urine indicates type I RTA in people, whereas acidic urine indicates type II RTA (Bagga and Sinha 2020).Kummer et al. (2025) report increased fractional excretion of sodium and decreased fractional excretion of potassium in this mule case report, but they recognise that prior initiation of fluid therapy could have influenced results. In a previous case report fractional excretion of sodium was increased but fractional excretion of potassium was normal (Ohmes et al. 2014). Another case series showed varied fractional excretions to all electrolytes tested (Aleman et al. 2001).Ammonium chloride load test showed inability to acidify urine, consistent with type I RTA. In a healthy patient, the induced metabolic acidosis would result in excretion of hydrogen ions and formation of ammonium within the collecting duct, leading to acidic urine. However, in this case report the Blood-pH only decreased very mildly during the ammonium chloride loading, which therefore may not have yielded sufficient change to cause urine acidification. The presence of metabolic acidosis should ideally be confirmed during the ammonium chloride loading using total carbon dioxide. In humans, the ammonium chloride loading is performed over a 3-day period (Santos et al. 2015), but this extended test has not been utilised in equids. Other functional tests utilised in other species include administering sodium bicarbonate, acetazolamide and furosemide, both with and without fludrocortisone (Santos et al. 2015).Renal ultrasound appears to have limited diagnostic value; one study showed 50% of horses showed abnormalities (Aleman et al. 2001), whereas other case reports did not support any renal ultrasonographic abnormalities (Ohmes et al. 2014). This mule was reported to have normal renal ultrasound findings (Kummer et al. 2025). The author would be interested to know if a urinalysis would have provided evidence of granular casts, indicative of tubular damage (MacLeay and Wilson 1998).The ammonium level in the urine was not reported, which is unsurprising as many laboratories will not measure it. An alternative option could have been measuring the urinary anion gap; a positive urinary anion gap in people with hyperchloremic metabolic acidosis represents inappropriate ammonium excretion, thus confirming RTA (Santos et al. 2015). However, to the authors knowledge this test has not been validated in horses.Treatment of RTA involves supplementation of sodium bicarbonate and potassium chloride, typically intravenously initially and then orally. Additional glucose or dextrose supplementation may stimulate intracellular uptake of potassium (Bayly 2018). Intravenous glucose was utilised in this case report due to the increased triglyceride reported. This might have had beneficial effects treating the RTA as well as reducing risk of hyperlipemia in the mule. Half of the estimated bicarbonate deficit should be addressed within the first 12 hours (Arroyo et al. 2020). An improvement in clinical demeanour is expected within the first 12- 24 hours. Horses may require long term sodium bicarbonate administration (Bayly 2018). However, both reported cases of Fanconi syndrome in Quarter Horses were transient; they did not require ongoing sodium bicarbonate supplementation (Ohmes et al. 2014).RTA, if identified and treated rapidly, has a reasonable prognosis, though little is known of the long-term prognosis (Bayly 2018). In one case report with a poor short-term outcome, ventricular tachycardia was reported as a potential side-effect of RTA (MacLeay and Wilson 1998). Within the human literature, close monitoring after RTA is recommended (Bagga and Sinha 2020). Kummer et al. (2025) should be congratulated on the short-term outcome achieved in this case. The author hopes that the long-term outcome will be positive, even if sodium bicarbonate and potassium chloride supplementation is always required. In any case, even if supplementation is discontinued, some equids have relapsed after cessation of treatment (Arroyo et al. 2020).ReferencesAleman, M. R., Kuesis, B., Schott, H. C., and Carlson, G. P. (2001). Renal Tubular Acidosis in Horses (1980–1999). Journal of Veterinary Internal Medicine , 15 (2), 136–143.Alexander, R. T., Cordat, E., Chambrey, R., Dimke, H., and Eladari, D. (2016). Acidosis and Urinary Calcium Excretion: Insights from Genetic Disorders. Journal of the American Society of Nephrology ,27 (12), 3511–3520.Arroyo, L. G., Estell, K. E., and Aleman, M. (2020). Renal Tubular Acidosis. In Large Animal Internal Medicine (Sixth, pp. 979–980). Elsevier.Bagga, A., and Sinha, A. (2020). Renal Tubular Acidosis. The Indian Journal of Pediatrics , 87 (9), 733–744.Bayly, W. M. (2018). Renal Tubular Acidosis. In Equine Internal Medicine (4th edn, pp. 966–969). Elsevier.Farias, F. H. G., Mhlanga-Mutangadura, T., Guo, J., Hansen, L., Johnson, G. S., and Katz, M. L. (2024). FAN1 Deletion Variant in Basenji Dogs with Fanconi Syndrome. Genes , 15 (11), 1469.Kummer, L., Lohmann, K., and Arnold, C. (2025). Renal tubular acidosis in a mule mare. Equine Veterinary Education , eve.14178.Kunchur, M. G., Mauch, T. J., Parkanzky, M., and Rahilly, L. J. (2024). A review of renal tubular acidosis. Journal of Veterinary Emergency and Critical Care , 34 (4), 325–355.Ohmes, C. M., Davis, E. G., Beard, L. A., Werf, K. A. V., Bianco, A. W., and Giger, U. (2014). Transient Fanconi Syndrome in Quarter Horses.Canadian Veterinary Journal , 55 , 147–151.Santos, F., Ordóñez, F. A., Claramunt-Taberner, D., and Gil-Peña, H. (2015). Clinical and laboratory approaches in the diagnosis of renal tubular acidosis. Pediatric Nephrology , 30 (12), 2099–2107.

Carpal valgus deformities remain a common challenge in foals, yet their aetiology is often multifactorial and rarely attributable to a single anatomical anomaly. Recent case reports by Müller et al. (2025) suggest that rudimentary ulnas may play a causative role in these deformities, but such claims warrant closer scrutiny. Since the early 1980s, when Auer reported partial ossification of rudimentary ulnas in about 20% of foals with a valgus deformity, these structures have been documented radiographically without consistent evidence of causation. Only in specific small breeds, such as Shetland Ponies and Miniature Horses, has the presence of complete ulnas or fibulas been clearly linked to severe developmental changes requiring early surgical correction. Outside such breed-specific forms of atavisms, the argument for causality is weak. A closer look at the three cases reported by Müller et al. illustrates this point. The first case reflected poor neonatal management, with abnormal (most likely incomplete at the time of birth) ossification of the cuboidal carpal bones far more relevant than any ulnar remnant. The second case showed an acceptable surgical response. The third case barely demonstrated a rudimentary ulna radiographically, making the supposed benefit of surgery questionable. In all three cases, the presence of an ossified ulna appears incidental rather than determinative. The real challenge remains proper diagnosis and timing of intervention. Radiographic assessment must be performed orthogonally to the carpal frontal plane, and clinicians should remain aware of methodological differences between bisecting line and parallel line measurements. In terms of treatment, transphyseal screw placement is effective at the distal metacarpus and metatarsus, but far less reliable at the distal radius, where prolonged growth increases the risks of overcorrection, and physeal injury. In light of the available evidence, the conclusions by Müller et al. overstate the role of rudimentary ulnas in carpal valgus deformities.

Manufacturer´s address:Titanium plug: Pferd Dental, 65329 Hohenstein, Germany, (info@pferdefit.de)

Temporohyoid osteoarthropathy: The challenge of modifying physiologic forcesSebastian Larriva MVZ, MS. Anne Brien DVM. Nicholas P. Hall DVM, MS, DACVS-LA.

CLINICAL COMMENTARYManagement of parotid gland trauma in horsesJ. F. HawkinsDepartment of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC.Correspondence: J.F. HawkinsEmail: jfhawkin@ncsu.eduKEYWORDSHorse, parotid gland, surgery, trauma, fluid accumulation, botulinum toxinThe parotid gland is the largest salivary gland in the horse and is located subcutaneously ventrally from the base of the ear and the wing of the atlas and extending dorsal and ventral to the jugular vein, maxillary vein and linguofacial vein. Rostrally the parotid gland is adjacent to the vertical ramus of the mandible. The parotid gland consists of multiple lobules of yellow to white, glandular tissue. The parotid gland secretes fluid into the oral cavity through the parotid salivary duct. The parotid salivary duct empties into the oral cavity at the level of teeth 308 and 309 or 408 and 409 (Dyce et al, 1987). Because of its subcutaneous location and limited fascial coverage the parotid gland is prone to external trauma. Lacerations in this area can involve the gland and manifest by saliva drainage from the wound. The drainage of saliva increases when the horse eats. In addition, lacerations involving the parotid duct from the angle of the mandible and adjacent to the facial artery and vein can result in fistula formation between the skin and the lacerated duct (Newton et al, 1997).One cause of parotid gland fistulation/drainage is iatrogenic surgical trauma. For example, during surgical removal of melanomas embedded in the parotid gland and during surgical approaches to the guttural pouch or mandible. A previously unreported complication of prosthetic laryngoplasty was detailed in the case report by Sanclemente et al (Sanclemente et al, 2025). Although anatomically close to the linguofacial vein it would be unusual to iatrogenically damage the parotid gland during prosthetic laryngoplasty (Rossignol and Ducharme, 2021). However, it should be straightforward to determine that lobes of the parotid gland were disrupted during the surgical approach to the larynx. The lobes of the parotid gland are characteristically dull white to yellow in appearance and are soft and friable (Dyce et al, 1987). Based on the author’s experience disruption of the parotid gland will lead to wound drainage or accumulation of fluid postoperatively (sialocele). When known surgical trauma to the parotid gland is recognized the author has left a portion of the incision open for drainage or placed a passive drain (Penrose) to encourage fluid drainage. Cases managed in this fashion have all been resolved without additional treatment.For the case reported here inadvertent disruption of the parotid gland during the laryngoplasty procedure resulted in severe, postoperative fluid accumulation. The sialocele formation contributed to a follow-up surgical procedure to explore the previous incision and to assess abduction of the arytenoid cartilage. Unfortunately, the laryngoplasty had failed necessitating a repeat laryngoplasty. Following repeat laryngoplasty the surgeons were faced with three treatment options including primary wound closure, leaving a portion of the incision open for drainage or placement of an active or passive drain. To minimize the risk for surgical site infection following repeat laryngoplasty the authors elected to perform a primary wound closure without establishing any form of drainage. Even without saliva leakage from the parotid gland the risk for a surgical site infection or seroma formation following a repeat laryngoplasty is high in the author’s experience. This case was complicated by an already high risk for postoperative seroma formation because of the repeat laryngoplasty and the iatrogenic damage to the parotid gland.A better option would have been open incisional drainage or placement of a Penrose drain. The primary reason being the high risk for ongoing drainage associated with the parotid gland and surgical trauma associated with repeat laryngoplasty. Another option would have been to place an indwelling suction drain. This decision is solely surgeon preference (Bischofberger, 2019). Both types of drainage solutions have their pros and cons and the advantages of preventing ongoing saliva accumulation outweigh the risk for a surgical site infection. Traumatic and iatrogenic parotid gland disruption can be managed successfully with open drainage and secondary wound healing and has been reported in humans and horses. In horses’ persistent drainage of saliva post parotid gland or duct injury has been managed with chemical involution of the parotid gland (Schmotzer et al, 1991).Sanclemente et al reported a novel method to decrease postoperative sialocele formation. Following repeat laryngoplasty, saliva drainage from the damaged parotid salivary gland was eliminated following intraglandular injection of botulinum toxin A. They reported that saliva accumulation ceased 5 days after the injection. The horse recovered successfully and was able to return to exercise without recurrence of exercise intolerance.The injection of botulinum toxin A and B in horses has been performed clinically and experimentally (Adam-Castrillo et al, 2004; DePuy et al., 2007; Gutierrez-Nibeyro et al., 2014; Jimenez et al., 2024). The reported dosages of botulinum toxin type A have ranged from 50 to 200 units and for type B have ranged from 50 to 2500 Units. In one study evaluating the injection of botulinum toxin type B into the external anal sphincter of horses no systemic effects were observed with dosages of 500, 1000, and 1500 units but a dosage of 2500 units resulted in lethargy, weakness and dysphagia for 14 days. This indicates an increased risk for clinical botulism following high dose administration of botulinum toxin B (Adam-Castrillo et al., 2004). To the authors’ knowledge no ideal dosage of botulinum toxin has been determined for the horse.In humans with parotid fistulas, drainage secondary to surgical procedures or trauma, the primary means of treatment has been establishment of drainage, second intention healing, bandaging, packing of the wound with gauze and intraglandular parotid injection of botulinum toxin (Chettyvattum et al., 2025; Hao et al., 2023; Jeong et al., 2024; Marks et al., 2024; O’Keefe et al., 2022; Santos et al., 2025; Send et al., 2018; Tighe et al., 2015). Type A botulinum toxin is the preferred agent to stop secretion of saliva from the parotid gland. The primary mechanism of action for botulinum toxin is the blocking of acetylcholine release and other neurotransmitters. The blockage of acetylcholine release decreases or eliminates saliva secretion and production from the parotid salivary gland. The botulinum toxin is injected percutaneously under ultrasonographic guidance (Marks et al., 2024). Dosages of botulinum toxin used in humans range from 5 to 100 units. Currently, in humans intraglandular injection of botulinum toxin A is the preferred method of resolving saliva fistulation secondary to an injured parotid gland.The authors of this case report used an empirical dose of 100 units of botulinum toxin A to manage persistent drainage from the surgically damaged lobe of the parotid gland. The author is not familiar with any experimental evidence of the effect of botulinum toxin A on secretion of saliva from the equine parotid gland. However, there has been an additional report of two horses with parotid trauma successfully managed with the intraglandular injection of 200 units of botulinum toxin A (Jimenez et al., 2024). Therefore, based on these three cases dosages of 100 to 200 units of botulinum toxin A could be used to manage persistent parotid salivary gland drainage of saliva (Jimenez et al., 2024; Sanclemente et al., 2025) without complications.Fortunately, parotid gland disruption secondary to a surgical approach to the equine larynx for laryngoplasty is rare. If lobes of the parotid gland are identified during a surgical approach to the larynx damage to the gland could be minimized by using blunt dissection to separate the gland from the linguofacial vein. In addition, the use of the LigasureTM device has been recommended to cauterize damaged portions of the parotid gland and minimize the risk for postoperative secretion of saliva in humans (Prokopakis et al., 2005). In general, the implantation of drains associated with equine laryngoplasty has been discouraged because of the presumptive risk of increased incidence of a surgical site infection. However, if this complication is encountered in additional cases leaving a portion of the incision open to allow drainage rather than completely close the surgical incision should be considered. The author has managed laryngoplasty seroma formation with targeted incisional suture removal to allow passive drainage of seroma from the surgical site and has not experienced an increased risk for a surgical site infection (Rossignol and Ducharme, 2021).In conclusion, damage to the parotid salivary gland can lead to fistulation, chronic drainage of saliva or sialocele formation and these complications can be managed with a variety of options. Based on the collective experience in humans, the intraglandular injection of botulinum toxin A should be considered to resolve this unusual complication in horses.

Background: Strangles, caused by Streptococcus equi, is an endemic disease of horses throughout the world. A vaccine against strangles, Strangvac, is available in Europe, but there are no published serological data following the revaccination of Sport horses. Objectives: To measure the antibody response of Sport horses to the components of Strangvac before and after third vaccination. Study Design: Longitudinal cohort study. Methods: Adult Sport horses were administered their third vaccination with Strangvac at 5 months (group 1, n=20) or 12 months (group 2, n=15) after second vaccination. Horses were monitored closely for adverse signs. Blood samples were collected from both groups immediately before and 14 days after third vaccination to quantify antibody responses by ELISA. Results: Transient signs of mild injection site swelling in 8.5 % horses for 2 days, and a temperature rise of ~0.8 oC in most horses for 1 day, occurred post-vaccination. Health status returned to normal within 48 hours. The antibody titres to the vaccine components were 3.34±0.31 and 3.14±0.29 before third vaccination and increased significantly to 3.90±0.29 and 3.90±0.17 after third vaccination in groups 1 and 2, respectively (P<0.0001 for both groups). Main limitations: Data and samples from a matched unvaccinated control group were unavailable. Conclusions: Strangvac was safe and a revaccination program after 5 or 12 months was equally efficient for the vaccination of Sport horses.

“Carpal Sheath Hernia in a Cob: Unusual Case, Unorthodox Fix”The case report presented by Neild et al. (2025) describes a rare and unusually complex case of carpal sheath synovial herniation in a cob-cross mare following tenoscopic treatment of a radial physeal exostosis and intra-thecal deep digital flexor tendon (DDFT) tear - an injury more commonly seen in racehorses due to carpal hyperextension (Southwood et al., 1998). The use of a synthetic polypropylene mesh to support the compromised carpal sheath wall represents a novel adaptation of herniorrhaphy techniques to equine synovial pathology and adds a valuable perspective to the growing body of surgical solutions for complex synovial outpouchings. Beyond its technical innovation, the case report also invites thoughtful discussion on several broader clinical themes, including the underlying aetiopathogenesis in an atypical breed, the localisation and assessment of pain in such cases, the interpretation of intrathecal tissue recovery, and the contextualisation of this case within the existing literature.Unusual presentation in a Cob-Cross: Synovial herniation of the carpal sheath is rarely seen in cob-type horses, whose upright limb conformation limits carpal hyperextension. While there is no published evidence specifically linking this condition to Thoroughbreds or other high-motion sport horses, it is thought to be more likely in these types due to the greater frequency of carpal overextension in such populations (Nixon et al., 2004; Southwood et al., 1998). In this case, however, the mare was diagnosed with a radial physeal exostosis where a concurrent deep dorsolaterally located DDFT tear would suggest significant bony pathology given that it matched the location of the exostosis. However, it is also possible that the tear could have been created or exacerbated by dynamic carpal over-extension although, notably, the report does not document this. An injury to the accessory ligament of the DDFT (ALDDFT) injury has also been associated with carpal over-extension and could have been responsible for chronic effusion, requiring repeat sheath injections, but was not reported by the authors.Definition of synovial herniation: ”Synovial Hernia” vs. ”Synoviocoele”: The terminology used to describe fluid-filled swellings associated with synovial structures, particularly the digital flexor tendon sheath (DFTS) and tarsal sheath, has long been inconsistent in the veterinary literature (Hawkins et al., 2021; Minshall et al., 2015; Crawford et al., 2011; Laverty 2009). Terms such as synovial hernia, synoviocoele, synovial ganglion cyst, and adventitious bursa have been applied somewhat interchangeably, though each has specific pathological and anatomical implications. In this case report, Neild et al. (2025) have elected to use the term “synovial hernia”, which traditionally refers to a protrusion of the synovial membrane through a defect in the joint capsule or tendon sheath, often still maintaining continuity with the synovial cavity. This implies that the stratum synoviale has remained intact but has extended abnormally through a fascial or capsular defect. However, given that histopathology was not performed in this case, there is no definitive evidence as to whether the herniated sac retained its synovial lining or was instead the result of rupture and subsequent extra-synovial fluid accumulation. As shown in Crawford et al. (2011), similar fluid-filled structures in the DFTS often lack a synovial lining when examined histologically and instead demonstrate myxomatous inflammation consistent with a synovial ganglion cyst. Minshall & Wright (2012) initially proposed the termsynoviocoele as the most neutral and anatomically descriptive term, simply denoting a cavity of synovial origin without implying a specific pathogenesis or histological profile. Thus, in the absence of histological confirmation in this case, ”synoviocoele” would have been the more conservative and technically accurate descriptor. It acknowledges the synovial origin of the lesion while avoiding assumptions about the integrity or composition of the synovial membrane. In future publications regarding these structures, it would be helpful for authors to clarify the rationale behind terminology choice, particularly when the underlying lesion’s nature - whether herniation, rupture, or cystic degeneration remains speculative in the absence of a biopsy (table 1).Pathogenesis of Synovial Herniation Post-Tenoscopy; The authors attribute the formation of the synovial hernia primarily to post-operative effusion and increased intrasynovial pressure, which may have forced synovial fluid and potentially the synovial membrane through a fascial defect at the site of tenoscopic portal creation. They propose that repeated intra-thecal corticosteroid injections may have further compromised local tissue integrity by suppressing fibroblast activity, contributing to fascial weakening (Stankler & Ewen 1972). Additionally, they acknowledge that multiple instrument passages during the initial tenoscopy could have enlarged the fascial rent, particularly between the ulnaris lateralis and lateral digital extensor muscles, an area that naturally experiences dynamic loading.While these are plausible contributors, the authors do not explore several other likely mechanisms. The cumulative biomechanical strain from exercise during the post-operative period may have exacerbated tension at the weakened portal site. Moreover, the potential for incomplete fascial healing, especially in a site of high motion and pressure fluctuation, could have predisposed the area to delayed herniation. The role of local ischaemia or microvascular disruption during surgery, particularly if compounded by corticosteroid use, was also not discussed but could have further impaired normal healing processes.Taken together, it is likely that the hernia developed as a multifactorial sequela of focal surgical trauma, prolonged synovial effusion, pharmacological tissue suppression, and mechanical stress over time. This case serves as a valuable reminder of the importance of portal site management, controlled rehabilitation, and consideration of long-term tissue resilience following tenoscopy, particularly in horses with conformational or workload factors that may place additional strain on surgical sites.Potential Sources of Pain in Synovial Herniation; Minshall and Wright (2012) proposed a “one-way valve” hypothesis for the pain caused by synoviocoeles, where pressure-related pain is central to their significance. In the discussion of the case report, the authors suggest that the clinical significance was likely a consequence of increased intrasynovial pressure secondary to post-operative effusion, with synovial fluid and possibly synovial membrane, being forced through a fascial defect at the tenoscopic portal site. While these are reasonable explanations, they are not explicitly linked to the clinical signs of pain observed in this case. The authors stop short of discussing how these structural changes might have resulted in significant lameness - up to grade 4/5 (AAEP scale) at walk, which is unusual for many synovial outpouchings unless they are large, tense, or associated with deeper pathology. The presence of visibly thinned, compromised skin overlying the hernia was well described in the report but not directly discussed as a pain source. In clinical practice, excessive tension on thinning dermis, particularly in a mobile region like the proximolateral antebrachium, is highly likely to cause nociceptive discomfort and may have been a significant contributor to the horse’s lameness (Muir 2010). Furthermore, the anatomical location of the hernia - situated between the ulnaris lateralis (UL) and lateral digital extensor fasciae places it within a region of considerable muscular activity. The anatomical location of the hernia - between the ulnaris lateralis and lateral digital extensor fasciae places it in an area of substantial muscular activity. This is reminiscent of the biomechanical interplay proposed in accessory carpal bone fracture pathogenesis, where asynchronous contraction of ulnaris lateralis and flexor carpi ulnaris occurs due to their differing embryological origins from dorsal versus ventral limb musculature (Diogo & Abdala 2010; Radue 1981). Despite UL’s developmental classification as an extensor, its functional role as a flexor, combined with flexor carpi ulnaris’s distinct insertion on the accessory carpal bone, creates opposing mechanical forces on the bone.Repetitive mechanical irritation, friction, or stretching of tissues during movement may have further sensitised the area. Although the authors do mention persistent effusion and synovitis, they do not explore whether this inflammatory environment might have sustained or amplified the horse’s pain. Furthermore, given the proximity of superficial nerves in this area, nerve stretch or entrapment cannot be ruled out, especially in a large, space-occupying lesion (Hawkins et al., 2021). In these authors’ opinion, the pain observed in this case is most likely to have arisen from a combination of dermal tension, mechanical irritation, persistent low-grade synovitis, and possibly neuropathic mechanisms. A more comprehensive assessment of pain pathways in similar cases, including diagnostic blocks and dynamic palpation would enhance our understanding of when such hernias are clinically significant and warrant surgical correction.Diagnostic Challenges : While the pathology is self-evident, synovial herniation is not always associated with pain and lameness, which creates a diagnostic challenge to the clinician. A lack of pain on palpation along with ability to deflate the hernia on non-weight bearing examination, has been proposed previously to be useful clinical indicators of significance (Hawkins et al., 2021), but the authors provide no mention of any pain on digital palpation or compression; and would argue against the hernia as the cause of the lameness. The authors acknowledge that diagnostic anaesthesia of the carpal sheath was not performed during the recurrent lameness episodes. This omission leaves uncertainty regarding the actual source of pain and whether the hernia was causative or coincidental.In this report, the authors note diffuse sheath inflammation at repeat tenoscopy of the carpal sheath, but without correlating that finding directly with lameness. Furthermore, the authors state that the tendon injury demonstrated good healing at the repeat tenoscopy therefore unlikely to be contributing to the ongoing lameness. Tendon pain can exist in the absence of surface defects and during healing. Unfortunately, however, intra-synovial diagnostic analgesia is not always able to differentiate these sites of pain.Surgical Insight and Considerations; The pressure-related pain is central to the previously proposed surgical indication of tenoscopic decompression (Minshall & Wright (2012); Hawkins et al. (2021). In this case, it would appear that the communicating defect was large and therefore could not be associated with a ‘one-way valve’ phenomenon. Thus, an alternative approach was necessary and their choice to use a synthetic mesh was an important innovation. The authors describe clear surgical rationale: the fascial defect was too large for simple closure, and resection of the hernial sac would have created a large defect in the synovial membrane with attendant risks of synovial sepsis (Hawthorn et al., 2016). The mesh provided tensile support and allowed for imbrication of synovium without excess tension - a sound approach, especially given the persistent effusion that may have otherwise predisposed to recurrence. However, the post-operative superficial necrosis, likely due to horizontal mattress sutures, suggests the need for alternative skin-closure techniques in future applications. Importantly, the mesh-induced fibrosis likely played a role in preventing re-herniation, as seen in other species (Fitzgerald & Kumar 2014), but long-term consequences of mesh use in equine synovial structures remain unknown and warrant further study. It should be noted, however, that these authors have observed a large synovial herniation resolving in time although the mechanism why this can occur in some cases but not others is unknown (figure 1).Conclusion: This case report offers a creative and successful solution for treating a carpal sheath synovial hernia in a cob-cross horse following tenoscopy - an infrequent but frustrating complication. The authors are commended for introducing mesh herniorrhaphy into equine orthopaedic practice in a synovial context. That said, clarification of the origin of the pain would help limit this approach to those herniations which can be linked definitively with pain and help differentiate the need for a conservative approach or other surgical approaches, such as tenoscopic decompression (Minshall and Wright 2012; Hawkins et al. 2021). Future directions could include better defining the origin and antalgic effects of synovial herniation, the indications for mesh repair, and exploring long-term effects of mesh-induced fibrosis in the synovial environment.

\received DD MMMM YYYY \acceptedDD MMMM YYYY Background : The diagnosis and management of pituitary pars intermedia dysfunction (PPID) in horses is based on evaluating abnormal plasma concentrations of adrenocorticotrophic hormone (ACTH). Treatment commonly includes the oral dopamine agonist pergolide mesylate, which suppresses the pathologic overproduction of ACTH. Cabergoline is a commercially available long-acting injectable dopamine agonist that may provide an alternative means of treating horses with PPID by producing similar effects on plasma ACTH concentrations. Objectives: To evaluate the effects of IM cabergoline administration on plasma ACTH concentrations in horses with PPID Study Design: Experimental study with multiple repeated measures Methods: Twelve adult horses with PPID were randomly divided into treatment and control groups. The treatment group was administered a 0.01 mg/kg dose of intramuscular cabergoline at two time points, two weeks apart. Control horses received an intramuscular injection of sterile saline at the same time points. Horses were monitored for adverse effects. Blood samples were collected for endogenous ACTH concentration monitoring at serial time points. Results: Horses in the treatment group had a reduction in plasma ACTH concentration from a mean of 153.35 pg/mL to 24.117pg/mL following the initial administration of cabergoline. Their ACTH levels remained within the seasonally appropriate range until twelve days after the second cabergoline injection. Horses in the control group never achieved appropriate ACTH concentrations. The treated horses showed appetite suppression immediately following cabergoline administration, but no significant weight loss when compared to control horses. Main Limitations: The study group was small, and data collection overlapped with the natural fall rise in ACTH, which complicated interpretation of the results. Conclusions: Injectable cabergoline appeared effective in reducing plasma ACTH concentrations in the PPID horses to seasonally appropriate ranges. There appeared to be a transient reduction in appetite following cabergoline injection, but not a significant loss of weight in comparison to control horses.

Abstract Background Horses are used in various countries for multiple purposes and often play a crucial role in the livelihood of many communities. However, parasitic infections represent a significant threat to their health and productivity. Objectives:  This study aimed to identify gastrointestinal parasite species affecting horses using coprological methods and to assess the influence of certain factors (age, sex, and bioclimatic zone) on these infections. Study design: These samples were analyzed using flotation techniques to detect fecal parasitic forms (eggs, oocysts) and larvae. Methods: Between January and May 2024, fresh fecal samples were collected from 121 horses in Setif region (Northeastern Algeria). Prevalences were calculated for each gastrointestinal parasite and the influence of certain intrinsic (age, sex) and extrinsic (region) parameters on these prevalences was analyzed. We have found, namely Strongylus vulgaris (38.84%), Oxyrus equi (7. 44%), Parascaris equorum (24.62%), Anoplocephala spp. 6.61% and 5.79 were carriers of Eimeria leuckarti and 4.96% had Giardia duodenalis cysts Conclusions This study demonstrates that horses in the Setif region are commonly affected by gastrointestinal parasites, with a predominance of mixed infestations. Both helminths and protozoa were identified, with Strongylus vulgaris and Parascaris equorum being the most prevalent species. The variations in infestation rates across age groups, sex, and geographical zones highlight the influence of environmental and management factors.   Keywords : Horse, parasite, gastrointestinal, Algeria