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BACKGROUND: The pleiotropic effects of the melanocortin system show promise in overcoming limitations associated with large variations in opioid analgesic effectiveness observed in equine practice. Of particular interest is variation in the melanocortin-1-receptor (MC1R) gene, which dictates pigment type expression through its epistatic interaction with the agouti signalling protein (ASIP) gene. MC1R has previously been implicated in opioid efficacy in other species; however, this relationship is yet to be explored in horses. In this study, analgesic effectiveness was scored (1-3) based on noted response to dura penetration during the performance of cerebrospinal fluid centisis after sedation and tested for association with known genetic regions responsible for pigmentation variation in horses. RESULTS: The chestnut phenotype was statistically significant (P < 0.05) in lowering analgesic effectiveness when compared to the bay base coat colour. The 11bp indel in ASIP known to cause the black base coat colour was not significant (P>0.05); however, six single nucleotide polymorphisms (SNPs) within the genomic region encoding the ASIP gene and one within MC1R were identified as being nominally significant (P

Equine assisted services (EAS) consist of a complex system of horse, human, and environmental factors which ultimately impact program effectiveness. Despite recognition in the literature that organizational affiliation with spirituality or religion impacts values, practices, and culture, connection between faith, spirituality, and specific religious belief, when combined with EAS is a nascent field of inquiry. Despite preliminary observations that suggest many organizations offering EAS are affiliated with religious institutions or claim their practices are informed by a particular faith, the extent of these non-secular affiliations is unknown in current literature. To explore this, we surveyed 113 EAS organizations to determine the extent and type of non-secular (i.e., faith-based) affiliations and whether these affiliations were professed publicly, to all internal staff and participants, to staff only, or not at all (i.e., level of “transparency”). We collected data on a range of horse characteristics and program practices. We used chi-square analyses to assess associations between secular/non-secular status and characteristics of practices. Of 93 organizations, 71% claimed a non-secular affiliation. Of non-secular organizations, 61% were fully transparent, and 36% were open about their belief system only internally with staff and participants. More non-secular organizations emphasized horses that were sensitive to humans and the environment (p = 0.0063). Non-secular organizations placed more importance on partnering with horses with a history of abuse or neglect (p = 0.0461). Transparency of faith or religious affiliation was associated with selection of horses based on girth, bone, and sturdiness (p = 0.0004). This is the first study to explore how a proxy for organizational-level values is associated with EAS practice differences. Further research is needed to determine if program-level differences in faith affiliation impact outcomes for participants in EAS.

Horses and cattle have shown low susceptibility to SARS-CoV-2, and there is no evidence of experimental intraspecies transmission. Nonetheless, seropositive horses in the US and seropositive cattle in Germany and Italy have been reported. The current study investigated the prevalence of antibodies against SARS-CoV-2 in horses and cattle in Switzerland. In total, 1940 serum and plasma samples from 1110 horses and 830 cattle were screened with a species-specific ELISA based on the SARS-CoV-2 receptor-binding domain (RBD) and, in the case of suspect positive results, a surrogate virus neutralization test (sVNT) was used to demonstrate the neutralizing activity of the antibodies. Further confirmation of suspect positive samples was performed using either a pseudotype-based virus neutralization assay (PVNA; horses) or an indirect immunofluorescence test (IFA; cattle). The animals were sampled between February 2020 and December 2022. Additionally, in total, 486 bronchoalveolar lavage (BAL), oropharyngeal, nasal and rectal swab samples from horses and cattle were analyzed for the presence of SARS-CoV-2 RNA via reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). Six horses (0.5%; 95% CI: 0.2-1.2%) were suspect positive via RBD-ELISA, and neutralizing antibodies were detected in two of them via confirmatory sVNT and PVNA tests. In the PVNA, the highest titers were measured against the Alpha and Delta SARS-CoV-2 variants. Fifteen cattle (1.8%; 95% CI: 1.0-3.0%) were suspect positive in RBD-ELISA; 3 of them had SARS-CoV-2-specific neutralizing antibodies in sVNT and 4 of the 15 were confirmed to be positive via IFA. All tested samples were RT-qPCR-negative. The results support the hypotheses that the prevalence of SARS-CoV-2 infections in horses and cattle in Switzerland was low up to the end of 2022.

Steroid-associated laminitis remains a major concern with use of corticosteroids in horses. Individual case factors such as joint pathology, pre-existing endocrinopathies, or corticosteroid type, dose, and timing influencing steroid-induced laminitis risk have not been investigated. This study aimed to determine if systemic absorption of triamcinolone acetonide (TA) varies between intrasynovial (antebrachiocarpal) and extrasynovial (sacroiliac) injection sites, and to determine the effects of TA absorption on glucose, insulin, cortisol, and adrenocorticotropic hormone (ACTH). Twenty adult horses were randomized into antebrachiocarpal or sacroiliac joint injection groups, and each horse received bilateral injections with a total dose of 18 mg triamcinolone. Blood was collected prior to injection and at 1, 2, 4, 6, 8, 10, 12, 16, 20, 24, 36, 48, 60, and 72 h post-injection. Peak TA absorption occurred at 8 h in both groups, and was significantly higher in the intrasynovial group compared to the extrasynovial group (1.397 ng/mL, 0.672 ng/mL, p 20 μU/mL) from both groups experienced a more marked hyperinsulinemia, reaching a mean peak insulin of 197.5 μU/mL as compared to 90.06 μU/mL in those with normal baseline insulin. Cortisol and ACTH were significantly decreased from baseline at timepoints from 4-72 h post-injection in both groups. This study is the first to evaluate drug absorption from the sacroiliac site and demonstrates that drug absorption varies between intrasynovial and extrasynovial injection sites. TA absorption causes metabolic derangements, most notably a marked hyperinsulinemia that is more severe in horses with elevated baseline insulin values. The influence of baseline endocrinopathies on response to corticosteroid administration as well as the effect of corticosteroid-induced metabolic derangements warrant further investigation as risk factors for corticosteroid-associated laminitis.

INTRODUCTION: Understanding the pharmacokinetics and pharmacodynamics of fentanyl in horses is crucial for optimizing pain management strategies in veterinary medicine. METHODS: Six adult horses were enrolled in a randomized crossover design. Treatments included: placebo, two 100 mcg/h patches (LDF), four 100 mcg/h patches (MDF), and six 100 mcg/h patches (HDF). Patches were in place for 72 h. Blood was obtained for fentanyl plasma concentration determination, thermal threshold, mechanical threshold, heart rate, respiratory rate, and rectal temperature were obtained prior patch placement and at multiple time points following patch placement for the following 96 h. Fentanyl plasma concentration was determined using LC-MS/MS. Data were analyzed using a generalized mixed effects model. RESULTS: Mean (range) maximum plasma concentration (Cmax), time to Cmax, and area under the curve extrapolated to infinity were 1.39 (0.82-1.82), 2.64 (1.21-4.42), 4.11 (2.78-7.12) ng/ml, 12.7 (8.0-16.0), 12.7 (8.0-16.0), 12 (8.0-16.0) h, 42.37 (27.59-55.56), 77.24 (45.62-115.06), 120.34 (100.66-150.55) h ng/ml for LDF, MDF, and HDF, respectively. There was no significant effect of treatment or time on thermal threshold, mechanical threshold, respiratory rate, or temperature (p > 0.063). There was no significant effect of treatment on heart rate (p = 0.364). There was a significant effect of time (p = 0.003) on heart rate with overall heart rates being less than baseline at 64 h. CONCLUSIONS: Fentanyl administered via transdermal patch is well absorbed and well tolerated but does not result in an anti-nociceptive effect as measured by thermal and mechanical threshold at the doses studied.

BACKGROUND: Dexamethasone is routinely administered to horses but its effect on the antibody response to a commercial EIV/EHV vaccine is unclear. HYPOTHESIS: Horses receiving dexamethasone will have lower postvaccination antibody levels against EIV and EHV-1 than vaccinated controls. ANIMALS: Fifty-five healthy adult research horses. METHODS: Randomized cohort study. Control (no vaccine, group 1), vaccination only (EIV/EHV-1/EHV-4, Prestige 2, Merck Animal Health, group 2), vaccination and concurrent single intravenous dose of dexamethasone (approximately .05 mg/kg, group 3), vaccination and 3 intravenous doses of dexamethasone at 24 hours intervals (group 4). Serum SAA levels were measured on day 1 and day 3. Antibody levels against EIV (hemagglutination inhibition assay, Kentucky 2014 antigen) and EHV-1 (multiplex ELISA targeting total IgG and IgG 4/7) were measured on day 1 and day 30. RESULTS: Significantly increased mean antibody titers after vaccination were only noted against EIV and only after the vaccination alone (n = 14, prevaccine mean [prvm] 166.9, SD 259.6, 95% CI 16.95-316.8; postvaccine mean [povm] 249.1, SD 257.2, 95% confidence interval [CI] 100.6-397.6, P = .02) and the single dose dexamethasone (n = 14, prvm 93.14, SD 72.2, CI 51.45-134.8; povm 185.1, SD 118, CI 116.7-253.6, P = .01), but not after multiple doses of dexamethasone (n = 14, prvm 194.3, SD 258.3, CI 45.16-343.4; povm 240.0, SD 235.7, CI 103.9-376.1, P > .05). CONCLUSION: The effect of dexamethasone on the postvaccine antibody response varies depending on the dosing frequency and the antigen-specific antibody type.

Fetal age in Quarter Horses can be predicted within 2 weeks from 100- to 200- days of gestation using femur length, biparietal diameter (cranium diameter) and eye approximated volume. However, as pregnancy advances, the femur and cranium become too large to be imaged in their entirety using ultrasound and the corresponding biometric parameters can no longer be measured. In this longitudinal study, the proximal phalanx (P1) was evaluated as a novel biometric parameter for late gestation to predict fetal age and bone maturation. Transrectal ultrasound was performed in ten pregnant mares with known ovulation dates, every two weeks from 240- days of gestation until parturition. P1 was imaged in 69 % of the examinations. Inability to image P1 was due to obstructive positioning such as carpal or fetlock flexion, or posterior presentation of the fetus. Advancing fetal age did not affect visibility of P1. P1 length correlated significantly with days of gestation and a correlation equation was established: y = 0.3837x -69.55 where y is the predicted value of P1 length and x is the day of gestation (with day 0 being the day of ovulation). When P1 length was equal to or larger than the width of the ultrasound image (52.5 mm), 90 % of mares (9/10) were above 300- days of gestation. Ossification of the proximal and distal epiphysis of P1 typically appeared between 277- and 303 -days of gestation (mean: 288 days). The proximal epiphysis did not close before parturition whereas the distal one closed between 306- and 333-days of gestation (mean: 320 days). P1 epiphyseal appearance and closure occurred chronologically reflecting bone maturation. Radiographic findings at birth and prenatal ultrasound findings were in agreement, apart from timing of P1 distal epiphyseal closure. In conclusion, P1 length can be used as a new fetal biometric parameter to assess fetal age and growth after 240- days of gestation. The knowledge of P1 bone maturation process in utero as a marker for fetal bone development, may also be valuable in clinical decision-making when considering inducing parturition in the mare. [ABSTRACT FROM AUTHOR]

Summary This case report describes a novel fixation technique of scapular neck fracture in a 2‐week‐old Arabian foal using two 3.5 mm tibial‐plateau‐levelling‐osteotomy (TPLO) locking plates originally designed for small animal orthopaedic surgery. The foal presented with a traumatic short oblique scapular neck fracture. Fracture fixation was performed under general anaesthesia using two anatomically pre‐shaped 3.5 mm TPLO locking plates; one on each side of the spine of the scapula. Fracture fixation was successful using two TPLO locking plates. Minimal soft tissue manipulation and identification of the suprascapular nerve allowed for relatively atraumatic application of the implants. The implants were left in place. Follow‐up evaluation 2 years after surgical intervention confirmed the horse to be sound with no clinical or gait abnormalities. Stabilisation of a short oblique scapular neck fracture in a 2‐week‐old foal with an anatomically pre‐shaped implant led to a good outcome in this case report. No complications were encountered during the recovery period. The use of an anatomically pre‐shaped locking plate intended for use on dogs, which is widely available in the veterinary industry, has proven to be a viable alternative for a scapular neck fracture fixation in this foal. [ABSTRACT FROM AUTHOR]

Objective Design Setting Animals Interventions Measurements and Main Results Conclusions To compare the ability of bioreactance noninvasive cardiac output (BR‐NICO) with thermodilution cardiac output (TDCO) for the measurement of cardiac output (CO) in healthy adult horses receiving 2 different IV volume replacement solutions.Prospective randomized crossover study from September to November 2021.University teaching hospital.Six university‐owned adult horses.Horses were randomly assigned to receive 7.2% hypertonic saline solution (HSS) or 6% hydroxyethyl starch (130/0.4) solution (HETA). BR‐NICO and TDCO were measured simultaneously at baseline, 10, 20, 30, 40, 50, 60, 90, and 120 minutes before fluid administration and again at the same times after starting a bolus infusion of IV volume replacers. All solutions were administered within 10 minutes.BR‐NICO and TDCO were strongly correlated (Pearson r2 = 0.93; P < 0.01). Regression analysis showed the relationship between TDCO and BR‐NICO was BR‐NICO = 0.48 × TDCO + 0.6. For the corrected BR‐NICO values, the Bland–Altman agreement mean bias and lower/upper limits of agreement were −0.62 and −5.3 to 3.9 L/min, respectively. Lin's concordance (95% confidence interval) between methods was 0.894 (0.825–1.097). Compared with baseline, HSS increased the CO at 10 and 20 minutes (TDCO and BR‐NICO). Compared with baseline, HETA decreased the CO at 10 and 20 minutes (TDCO and BR‐NICO) and increased the CO at 90 (TDCO only) and 120 minutes (TDCO and BR‐NICO).BR‐NICO strongly agreed with TDCO in the measurement of CO in healthy unsedated adult horses. HSS administration significantly increased CO in the first 30 minutes, while HETA initially decreased CO at 10 minutes but increased CO to above baseline values by 90 minutes. [ABSTRACT FROM AUTHOR]

Summary A 22‐year‐old donkey (Equus asinus) mare was presented for investigation of a 3‐day history of lethargy and anorexia. Serum biochemistry profile revealed severe increased liver‐derived enzymes. Abdominal ultrasound demonstrated several large round cysts in the liver. Broad‐spectrum antimicrobials and anti‐inflammatory therapy were started. However, exacerbation of the clinical signs occurred, and the donkey was euthanised. Necropsy and histopathological evaluation showed multiple hydatid cysts with protoscoleces from Echinocococcus spp. in the liver with replacement of parenchyma by fibrosis accompanied by liver atrophy, severe ascites and thorax effusion. The present report describes the first case of a molecularly confirmed Echinococcus equinus infection in a donkey in northern Switzerland. [ABSTRACT FROM AUTHOR]

Summary Lameness in the horse is one of the most common reasons a horse is seen by a veterinarian. As the foot is frequently the source of lameness, research utilising reversible methods of foot lameness induction is vital to improving knowledge in this area. This literature review aims to describe published methods of reversible foot lameness induction, identify any limitations and summarise research findings where these methods have been utilised. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance is a global threat, and pet-associated strains may pose a risk to human health. Equine veterinarians are at high risk of carrying methicillin-resistant staphylococci (MRS), but specific risk factors remain elusive, and few data are available for other personnel involved in the horse industry. The prevalence, characteristics, and risk factors for nasal carriage of MRS in horses and their caregivers were studied in northwestern Italy. Nasal swabs from 110 asymptomatic horses housed at 21 barns and 34 human caregivers were collected. Data on barns, horses, and personnel were acquired through questionnaires. The samples were incubated in selective media, and the bacterial isolates were identified by mass spectrometry. Risk factors were investigated by Poisson regression. MRS were isolated from 33 horses (30%), 11 humans (32.4%) and 3 environmental samples (14.2%). Most isolates were multidrug resistant (MDRS). The prevalence of MRS and MDRS was greater in racehorses and their personnel than in pleasurable and jumping/dressing horses. MRS carriage in caregivers was associated with an increased prevalence of MRS carriage in horses. The frequency of antimicrobial treatments administered in the barn during the last 12 months was a risk factor for MRS carriage in horses [prevalence ratio (PR) 3.97, 95% CI 1.11, 14.13] and caregivers (PR 2.00, 95% CI 1.05, 3.82), whereas a good ventilation index of the horse tabling environment was a protective factor (PR 0.43, 95% CI 0.20, 0.92). Our data reveal relevant interactions occurring between bacterial communities of horses and humans that share the same environment, suggesting that One Health surveillance programs should be implemented. [ABSTRACT FROM AUTHOR]

Summary Complications associated with nasogastric tube placement are infrequent and usually not severe. This article details a case of a pharyngo‐oesophageal fistula in a 6‐year‐old Arabian racing gelding initially presenting with recurrent oesophageal obstruction and dysphagia 5 months after recovering from a medically treated colic. Initially, a suspected diverticulum was diagnosed using a combination of endoscopic examinations and barium‐contrast radiography. Its occurrence was believed to be secondary to a pharyngeal abscess occurring as a consequence of repeated or long‐term nasogastric tube placement during the previous treatment for colic. Continuing, and unresolvable, oesophageal obstruction and dysphagia resulted in the gelding being euthanised. Post‐mortem examination revealed the presence of a pharyngo‐oesophageal fistula. [ABSTRACT FROM AUTHOR]

Ruminant milk has been the main source of milk produced and consumed worldwide. But with the promotion of functional foods, people began to shift their attention to niche dairy products. The composition of mare's milk is similar to that of human milk and has unique healthcare effects and is hypoallergenic, so it has received widespread attention. The increase in demand for mare milk has also made dairy horses a research hotspot. This paper systematically summarized the contents from tissues and organs to molecular breeding, including the structure of horse udders, lactation rules, mare milk components and characteristics, factors affecting milk production and the molecular regulatory mechanism of lactation. It was hoped to provide a reference for theoretical and practical research ondairy horses. [ABSTRACT FROM AUTHOR]

OBJECTIVE To optimize and evaluate methods for the detection of the inflammatory biomarkers myeloperoxidase (MPO) and calprotectin (CP) in equine feces by ELISA. ANIMALS Healthy horses (n = 28) and horses with intestinal inflammation (n = 10). METHODS Feces were suspended in buffer to create fecal supernatant. Serum and fecal supernatant were analyzed using ELISA kits validated for the detection of MPO and CP in equine serum. Assay validation steps included intra- and interassay variability (coefficient of variation [CV]), dilution linearity, spike recovery, and sample type correlation. Variations in sample handling protocols (centrifugation speed, extraction buffer, and filtration) were evaluated. RESULTS 17 paired fecal and serum samples were used for initial analysis (10 healthy horses, 7 colitis). Previously reported sample handling protocols resulted in detectable MPO and CP but poor CV, linearity, and spike recovery. There was a linear correlation between serum and fecal samples for CP but not MPO. There was a significant difference between the concentration and CV of alternative sample handling protocols for CP and MPO, with improved CV for CP (2.1% to 18.6%) but not MPO (14.4% to 53.4%). Processing fresh feces with a fecal extraction buffer and filtration of supernatant resulted in the best CV (0.5% to 3.8%) and recovery (45% to 64%) for CP. Detection of MPO was inconsistent regardless of method. CLINICAL RELEVANCE There are few reliable diagnostic modalities for inflammation of the equine large colon. Findings support quantification of CP in equine feces using the described ELISA kit and protocol. With additional study to establish reference interval and clinical utility, the fecal inflammatory biomarker CP may allow for noninvasive quantification of intestinal inflammation in horses. [ABSTRACT FROM AUTHOR]

Summary: A 17‐year‐old Quarter Horse broodmare was taken to surgery for signs of colic unresponsive to medical management. The small colon was strangulated by a pendulous ovarian pedicle. The strangulation was freed, and the affected ovary was removed. The mare developed signs of a small colon obstruction 4 days after surgery. The mare was euthanised 6 days after surgery because of a GI rupture. A post‐mortem examination revealed necrosis of the previously strangulated portion of small colon. [ABSTRACT FROM AUTHOR]

Summary: 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 were 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 were 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. [ABSTRACT FROM AUTHOR]

Summary: 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‐related 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 1‐min 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‐related compression of the base of the epiglottis is a 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. [ABSTRACT FROM AUTHOR]

Summary: A 15‐year‐old Warmblood gelding was presented with macroscopic haematuria and stranguria for 2 months. Cystoscopy revealed a pedunculated cauliflower‐like mass, exiting from the right ureteral orifice into the bladder. Ureteroscopy showed a right dilated ureter (2.3 mm). The ureteral lumenal mucosa was smooth, and the mass had its origin approximately 10 cm cranial from the orifice. The right kidney appeared macroscopically normal on ultrasonography. The mass was removed transendoscopically by means of a cautery snare leaving a small part at the base. Histopathological analysis identified it as a mucosal polyp. Recovery was uncomplicated and the gelding was discharged 3 days after surgery. During cystoscopic examination 5 months later, there was no sign of right ureteral inflammation, but a small stalk of the polyp was seen within the ureter. [ABSTRACT FROM AUTHOR]

Summary: Four cases of flexor retinaculum desmopathy following an accident during the landing phase of jumping and their outcomes are discussed, and an overview of the subjects is provided. The four horses presented with a sudden onset of severe lameness during landing after jumping, which markedly decreased in the first few days. In all cases, the painful area was not localisable on the first day; however, marked swelling was observed on the second day and in all cases, the injury to the carpal flexor retinaculum was visible on ultrasound. The horses were sound in a straight line at 9 (Case 1), 4 (Case 2) and 2 (Case 3) weeks after the injury. Case 4 was not presented until 8 weeks after the incident. During subsequent examination, Case 4 was found to be sound, although it had not returned to training. The owner reported the lameness ended 4 weeks after the incident. All the horses successfully returned to their former competition levels and did not show any problems related to the carpal flexor retinaculum. However, there were significant differences in the regeneration times among the cases, ranging from 5 to 21 months. [ABSTRACT FROM AUTHOR]

Summary: This case report describes the successful conservative management of a comminuted fracture of the atlas and occiput involving the atlanto‐occipital joint. To the authors' knowledge, treatment of fractures involving the atlanto‐occipital joint in the horse and intrathecal subarachnoid space corticosteroid injection in the standing sedated patient has not been previously reported. Clinical signs following atlanto‐occipital (AO) fracture included acute onset ataxia, proprioceptive deficits and neck stiffness; which developed immediately post‐trauma during head and tail rope‐assisted recovery from general anaesthesia. Radiographic examination was not diagnostic immediately post‐trauma and computed tomography (CT) imaging subsequently identified articular fractures of the atlas and occiput. Treatment included ultrasound‐guided intrathecal medication of the subarachnoid space and intra‐articular medication of the left AO joint under standing sedation. Medication resulted in a marked improvement in clinical signs (grade 4 ataxia to grade 1 ataxia) and a return to ridden exercise 12 months post‐injury. [ABSTRACT FROM AUTHOR]

Summary: This report describes the successful treatment of a cutaneous haemangiosarcoma in a 12‐year‐old horse presented for evaluation of a cutaneous mass on the left gluteal region. The horse was treated by complete large surgical excision of the neoplastic tissue. A good cosmetic outcome as well as a short recovery time was achieved with an autologous skin grafting split thickness modified Meek technique. A long‐term follow‐up of the patient showed no reoccurrence of the haemangiosarcoma and a successful return to athletic performance. To the authors' knowledge, this is the first equine primary cutaneous haemangiosarcoma treated with complete excision and subsequently autologous skin grafting with a long‐term follow‐up and good outcome despite the poor prognosis. [ABSTRACT FROM AUTHOR]

Summary: 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 postoperative 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 risk 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. [ABSTRACT FROM AUTHOR]

Summary: This case series describes three cases of osseous cyst‐like lesions of the proximal phalanx (P1), which were associated with a complete fracture. The fractures and osseous cyst‐like lesions were analysed through radiographic and computed tomographic (CT) images for fracture configuration and prodromal factors, such as subchondral sclerosis and periosteal new bone formation. Internal stabilisation was performed in all cases through placing transcortical bone screws under CT guidance. In conclusion, the presence of osseous cyst‐like lesions in the proximal P1 as well as the addition of prodromal markers, such as localised periosteal new bone formation and subchondral bone sclerosis, suggest pathological subchondral bone with the potential to fracture and stabilisation should be prioritised. [ABSTRACT FROM AUTHOR]

Summary: Skin grafting is a simple technique that can be performed by equine practitioners to improve cosmetic outcomes in wounds with large skin defects that would not heal functionally or cosmetically with standard wound therapy interventions. Successful skin grafting is not difficult but relies upon appropriate preparation of the wound bed and effective immobilisation of the grafted area after skin graft placement. Prior to grafting, the wound bed should be treated with a moist wound healing dressing to prepare the granulation tissue bed to receive the graft. For best results, skin grafts should be placed in wounds free of infection with healthy granulation tissue, and motion should be reduced in the graft region in the early postoperative period. When successful, skin grafts cover granulation tissue and encourage wound contraction and epithelialisation while decreasing exuberant granulation tissue resulting in a more cosmetic result. This review will advance practitioners' understanding of skin grafting in horses, including graft classification and techniques, donor site selection, recipient site preparation and postoperative management strategies to optimise graft retention and ongoing research in this field. [ABSTRACT FROM AUTHOR]

To study the changes in dynamic compliance (C dyn), ventilation/perfusion (V ˙ / Q ˙) mismatch and haemodynamic variables in hypoxaemic anaesthetized horses whose PaO 2 increased following salbutamol inhalation. Retrospective, clinical, cohort study. A group of 73 client-owned horses treated with salbutamol when PaO 2 <100 mmHg (13.3 kPa) during anaesthesia. Horses were divided into two groups: responders (R), where PaO 2 after salbutamol ≥1.2 PaO 2 before treatment (i.e. ≥20% increase), and non-responders (NR), where PaO 2 after salbutamol <1.2 PaO 2 before treatment. Demographic data and intraoperative variables before treatment were compared between R and NR. C dyn , arterial to end-tidal carbon dioxide difference [P(a-E´)CO 2 ], estimated ratio of dead space to tidal volume (est.V D /V T), estimated shunt fraction (F-shunt), heart rate, systolic, mean and diastolic arterial pressure and dobutamine requirements were compared before and after treatment within R and NR. For each variable, the difference (Δ) between values pre- and posttreatment was calculated and compared between groups R and NR. Numerical data were compared using univariate or bivariate analysis and categorical data were compared using chi-square test; p < 0.05. Of the 73 horses 50 were classified as R while 23 horses were classified as NR. There was no statistical difference between R and NR for demographic data or initial intraoperative variables except for body weight [R: 531 (170–715) kg, NR: 540 (420–914) kg]. While salbutamol did not alter C dyn in either group, it significantly decreased P(a-E´)CO 2 , est.V D /V T and F-shunt in R only. ΔP(a-E´)CO 2 , Δest.V D /V T and ΔF-shunt were significantly greater in R (−17.8%, −19.0% and −24.1%, respectively) than in NR (11.5%, 6.6% and −0.3%, respectively). In hypoxaemic anaesthetized horses responding to inhaled salbutamol by a ≥1.2 increase in PaO 2 no change in C dyn was detected, but indicators of V ˙ / Q ˙ mismatch improved. [ABSTRACT FROM AUTHOR]

To compare the efficacy of inhaled salbutamol with salmeterol for the treatment of arterial hypoxaemia in anaesthetized horses. Prospective, randomized, clinical study. A total of 108 client-owned horses (American Society of Anesthesiologists status I–V) anaesthetized for elective and emergency procedures. Horses were premedicated with acepromazine [intramuscularly 0.1 mg kg–1 or intravenously (IV) 0.05 mg kg–1] and xylazine (0.6 mg kg–1 IV). Midazolam (0.06 mg kg–1 IV) and ketamine (2.2 mg kg–1 IV) were combined to induce anaesthesia, and isoflurane in oxygen/air mixture (inspired oxygen fraction 0.7) was used for maintenance of anaesthesia. Mechanical ventilation was initiated without delay using the following ventilator settings: tidal volume 10 mL kg–1, respiratory rate 8 breaths minute–1, inspiratory-to-expiratory time ratio 1:2, no positive end-expiratory pressure. If arterial blood gas analysis revealed PaO 2 < 100 mmHg (13.3 kPa), the administration of either inhaled salbutamol (2 μg kg–1) or salmeterol (0.5 μg kg–1) was randomly assigned Blood gas analysis was repeated 15 and 30 minutes after treatment. The intervention was considered successful when PaO 2 after treatment ≥ 1.2 × PaO 2 before treatment (i.e. ≥20% increase). PaO 2 at 15 and 30 minutes was compared between groups using Mann–Whitney U test; p < 0.05 was considered significant. Of the 108 horses, 60 were administered salbutamol, 65% and 60% responded successfully at 15 and 30 minutes, increasing their initial PaO 2 by 38% and 44%, respectively. The other 48 horses were administered salmeterol, 35% responded successfully at 15 and 30 minutes, increasing their initial PaO 2 by 3% and 4%, respectively. PaO 2 was significantly higher after salbutamol than after salmeterol at 15 and 30 minutes. Using the described protocol, inhaled salbutamol was more effective than salmeterol in improving PaO 2 in anaesthetized horses with value < 100 mmHg (13.3 kPa). [ABSTRACT FROM AUTHOR]

This study describes the pharmacokinetics and pharmacodynamics, including antinociceptive effects, of a transdermal buprenorphine solution in horses. It was hypothesized that transdermal application would lead to sustained blood concentrations and antinociceptive effects with fewer adverse effects compared with intravenous (IV) injection. Prospective nonrandomized four-part parallel experimental study. A group of eight horses (three mares and five geldings) aged 6–12 years. Horses were administered incremental doses of 15, 30 and 45 μg kg–1 of buprenorphine transdermal solution and a single IV dose of 5 μg kg–1 of buprenorphine with a 2 week washout period between treatments. Concentrations of buprenorphine were determined in plasma using liquid chromatography–tandem mass spectrometry and modeled using a nonlinear mixed effects population pharmacokinetic model to determine pharmacokinetic parameters. Pharmacodynamic effects, including changes in locomotor activity, heart rate, body temperature, gastrointestinal borborygmi, thermal and mechanical nociceptive thresholds were recorded. Mixed effects analysis of variance and post hoc comparisons were performed using a Bonferroni multiple comparison adjustment to assess differences in pharmacodynamic parameters between baseline and each time point within each dose group and between dose groups at the same time point. Transdermal application of buprenorphine resulted in low systemic concentrations relative to IV injection. Bioavailability after transdermal application was 11%. Thermal nociceptive thresholds were significantly (p < 0.05) increased (4.3–10.7% relative to baseline) for up to 72 hours in the IV dose group, but only sporadically in the transdermal dose groups (2.5–9.9% relative to baseline). Changes in locomotor activity, heart rate and borborygmi varied over time and with dose. Limited thermal antinociceptive effects were observed at the transdermal doses studied likely owing to limited absorption relative to IV dosing. Future studies may be directed toward investigating antinociceptive effects of higher transdermal doses and different application sites. [ABSTRACT FROM AUTHOR]

The use of immersive methodologies is a trend in the educational environment, but their outcomes in the teaching–learning process need to be better understood. This study aimed to assess the impact of the educational environment on learning equine distal limb ultrasonography, comparing immersive classroom, traditional classroom, and virtual classroom. A total of 153 veterinary medicine students from the first to the third semester participated in this study. The students were divided into four groups: traditional (n = 22), immersive (n = 100), online (n = 31), and traditional‐immersive (n = 15). The students completed a questionnaire before and immediately after the class. The online group had a lower average gain in correct answers compared to the others (p < 0.01). Regarding student perception, it was observed that the virtual group had the lowest satisfaction score (p < 0.001), and students in the immersive and online environments were more satisfied with the resources used compared to the traditional classroom (p = 0.01). Concluding, in the present study students showed a greater interest in environments associated with technology, and that in‐person modalities resulted in significantly superior learning outcomes compared to online ones. [ABSTRACT FROM AUTHOR]

Background: Equine joint disease including septic arthritis (SA) and osteoarthritis (OA) is a critical cause of equine lameness. Platelet‐rich plasma (PRP) is one of the most popular regenerative therapies to treat equine OA, even SA, but the evidence in support of the treatment is conflicting. Objectives: The aim of the study was to systematically review the current evidence on PRP products used for SA and OA, as well as the efficacy of PRP products as treatment for OA on the basis of a meta‐analysis of the available literature. Study design: Systematic review and meta‐analysis. Methods: A systematic search of relevant databases (PubMed, Web of Science, Scopus) was performed to identify studies published from 2013 to 2023, in accordance with the PRISMA guidelines. Randomised controlled trials, non‐randomised trials and controlled laboratory studies that used at least one type of PRP products were included. Dichotomous outcomes were presented using odds ratios (ORs) and 95% confidence intervals (95% CIs). Results: A total of 21 publications were identified in the systematic review and 5 of them in the meta‐analysis. These publications involved various types of PRP products and reported different outcomes. Although most of the studies were associated with a high risk of bias, the overall estimated effect was consistent with a significant improvement in the PRP products treatment group compared with the control group (OR: 15.32; 95% CI: 3.00–78.15; p < 0.05). There was a significant improvement in clinical performance outcomes between the groups (OR: 36.64; 95% CI: 3.69–364.30; p < 0.05). Conclusion: PRP products as intra‐articular treatment are likely efficacious for treatment of equine OA and have potential for treating SA. These conclusions might be affected by the limited number of randomised controlled studies and high variability of different types of PRP products. To better evaluate the efficacy of PRP, a widely recognised classification system and the utilisation of randomised, blinded, equivalency or non‐inferiority trials are required. [ABSTRACT FROM AUTHOR]

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Copyright of Equine Veterinary Journal is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Congenital heart defects (CHDs) can have profound and potentially life‐threatening consequences on horses' health and performance capability. While CHDs are rare in the general horse population, the Arabian breed is disproportionately overrepresented and thus is widely suspected to be genetically predisposed. This review discusses the most common CHDs in Arabian horses, including ventricular septal defect (VSD), tetralogy of Fallot (TOF), patent duct arteriosus (PDA), tricuspid valve atresia (TVA) and atrial septal defect (ASD). This review also explores how future research into the genetic factors that likely underpin many CHDs can revolutionise the way these disorders are managed in Arabian horses. [ABSTRACT FROM AUTHOR]

Background: 18F‐sodium fluoride (18F‐NaF) positron emission tomography (PET) has been validated as a useful imaging technique in the racehorse fetlock. The use of 18F‐NaF PET in the nonracehorse fetlock has not been reported. Objectives: To describe 18F‐NaF PET findings in nonracehorse fetlocks, to compare with computed tomography (CT) findings and to compare PET findings between horses with and without fetlock pain. Study design: Retrospective observational study. Methods: All horses undergoing 18F‐NaF PET and CT imaging of the fetlock between October 2016 and March 2021 were included in the study. Medical records were reviewed for associated lameness information. Results: Thirty‐six fetlocks (33 front and 3 hind) from 25 horses were included. The interobserver agreement for PET [0.62 (95% confidence interval [CI] 0.59–0.65)] was higher than for CT [0.47 (95% CI 0.43–0.51)]. Increased 18F‐NaF uptake was most common in the medial subchondral bone of the proximal phalanx (23/36), the dorsomedial (20/36) and dorsosagittal (16/36) metacarpal/metatarsal distal subchondral bone, whereas sclerosis was identified on CT in these areas in 22 of 36 (p > 0.9), 33 of 36 (p = 0.001) and 23 of 36 (p = 0.15), respectively. Significant correlations were found between PET grades and both subchondral sclerosis and resorption CT grades (p < 0.001, Spearman r = 0.19 and 0.21, respectively). Abnormal 18F‐NaF uptake in the proximal sesamoid bones (PSBs) was identified in 12 of 36 of the fetlocks, which was more common than CT abnormalities (3/36, p = 0.02). Periarticular increased uptake was seen in 7 of 36 fetlocks, whereas osteophytosis was recognised on CT in 20 of 36 (p = 0.1). Maximal standardised uptake values (SUVmax) were significantly higher in painful than in nonpainful fetlocks (22.0 and 11.9, respectively, p = 0.038). Main limitations: Retrospective study and limited sample size. Conclusions: Overall PET and CT findings follow a similar distribution in their location. PET identified more abnormalities in the PSBs than CT. SUVmax is a pertinent factor to take into consideration for the assessment of the clinical significance of findings. [ABSTRACT FROM AUTHOR]

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Background: Early‐life locomotor activity during turn out may alter susceptibility to musculoskeletal disease and injury via modulation of behaviours and tissue development during growth. Objectives: Investigate associations between turn out practices and rates of musculoskeletal disease and injury in young Thoroughbreds on stud farms in the United Kingdom. Study design: Prospective cohort. Methods: Daily records were kept on location and duration of turn out for 134 Thoroughbred foals on six stud farms, from birth until leaving the farm or study exit. Data on veterinary‐attended episodes of musculoskeletal disease or injury were collated concurrently. Average daily turn out times (hours), areas (acres) and group size (n foals) were calculated for rolling 7‐ and 30‐day periods of age. Multivariable Cox regression, including farm as a random effect, was used to investigate associations between turn out practices and musculoskeletal disease and injury. Results: The overall incidence of musculoskeletal disease or injury was 5.3 cases/100 foal‐months at risk (95% confidence interval [CI]: 4.2–6.6). Compared with 24/7 turn out, average daily turn out times of between 9 and 23 hours over a 7‐day period were associated with a 4.6‐fold increase in musculoskeletal injury rate (95% CI: 1.7–12.3; P < 0.001), adjusting for farm and paddock area. Each 1‐acre increase in the average daily turn out area during the 4th month of life, reduced the rate of musculoskeletal disease and injury between 6 and 18 months of age by 24% (hazard ratio 0.76, 95% CI: 0.58–0.99; P < 0.001), adjusting for farm and turn out time. Main limitations: Non‐random sample of participants may affect generalisability. Use of veterinary‐attended events likely underestimates disease/injury rates. Conclusions: Results suggest that disruptions or alterations to turn out time routines increase injury risk and should be avoided where possible. Turn out in larger paddocks, particularly before weaning, may confer protection against subsequent musculoskeletal disease and injury. [ABSTRACT FROM AUTHOR]

Background: Data on equine lumbar pathology hardly exist in breeds other than Thoroughbreds. Objectives: To describe pathological changes of the osseous lumbar vertebral column in Warmblood horses, Shetland ponies and Konik horses. Study design: Descriptive post‐mortem study. Methods: The lumbar vertebral columns of 34 Warmblood horses, 28 Shetland ponies, and 18 Konik horses were examined by computed tomography (CT). Osteoarthritis (OA) of articular processes (APJs), OA of intertransverse joints (ITJs), intervertebral disc (IVD) mineralisation, impingement of spinous (SPs) and transverse (TPs) processes and spondylosis were scored. Breed differences in prevalence and severity of pathologies were analysed by linear regression analysis and by calculating Spearman's rank correlation coefficients (rs). Results: In Warmblood horses, the prevalence of OA of APJs, impingement of SPs and TPs was respectively 90%, 36%, and 35%, significantly higher than in the other breeds (p < 0.001). In Konik horses, IVD mineralisation (40%) and spondylosis (10%) were more frequent than in Warmbloods and Shetland ponies (p = 0.03). Severity score for OA of ITJs was highest in Shetland ponies (p < 0.001). For impingement of SPs, severity score was highest in Warmbloods (p = 0.03), and of TPs lowest in Shetland ponies (p = 0.003). For all parameters, except for spondylosis in Shetland ponies, there was a positive correlation between percentage of vertebrae affected and age, with IVD mineralisation scores increasing faster in Konik horses (p < 0.001). In all breeds, there was also a positive relation between scores of severity and age for OA of APJs and ITJs and for IVD mineralisation, with severity scores increasing faster in Shetland ponies (p = 0.04). Strong left/right correlations of the severity scores were seen for OA of the APJ, ITJ, impingement of TPs, and paramedian spondylosis (rs = 0.74–0.86, all p < 0.001). Main limitations: Clinical histories were not available. Conclusions: There are distinct breed differences between prevalence and severity of osseous pathologies of the lumbar spine. Warmblood horses have higher scores for most pathologies with IVD mineralisation being more important in Konik horses and OA of ITJs in Shetland ponies. [ABSTRACT FROM AUTHOR]

Background: Recently, treatment of equine atrial tachycardia by three‐dimensional electro‐anatomical mapping (3D EAM) and radiofrequency catheter ablation (RFCA) has been described. Myocardial sleeves in the caudal vena cava and pulmonary veins are a potential trigger for initiation and perpetuation of atrial tachycardia and atrial fibrillation in the horse. Isolation of these myocardial sleeves by RFCA may be an effective treatment for these arrhythmias. Objectives: To describe the feasibility of 3D EAM and RFCA to isolate caudal vena cava and pulmonary veins in adult horses using 3D mapping and a contact force (CF)‐guided ablation system. Study design: In vivo experiments. Methods: 3D EAM and RFCA was performed in five horses without cardiovascular disease under general anaesthesia, using the CF‐guided system CARTO®3. Point‐by‐point RFCA aimed for isolation of caudal vena cava and pulmonary veins. Radiofrequency energy was delivered in power‐controlled mode with a target power of 45 W, CF between 10 and 15 g and 30 mL/min irrigation rate, until an ablation‐index of 450–500 was reached. Results: In the right atrium, myocardial sleeves of the caudal vena cava were isolated (n = 5). In the left atrium, isolation of ostium II (n = 3), ostium III (n = 1) and ostium I, II and III en bloc (n = 1) was performed. Successful isolation was confirmed by entrance and exit block. Main limitations: Horses were euthanised at the end of the procedure, so long term effects such as potential reconnection of isolated veins could not be studied. Conclusions: This is the first description of 3D EAM and RFCA with CARTO®3 in horses, thereby showing the technical feasibility and successful caudal vena cava and pulmonary vein isolation. CF measurement allowed monitoring of catheter‐tissue contact, resulting in efficient acute lesion creation as confirmed by entrance and exit block. This is a promising treatment for cardiac arrhythmias in horses. [ABSTRACT FROM AUTHOR]

Background: Transrectal ultrasonography is the best technique for evaluating the ventral aspect of the lumbosacral and sacroiliac regions yet this diagnostic technique does not always lead to a final diagnosis of back pain in horses. Objectives: To describe anatomical variations and acquired pathological bony changes (APBCs) in the lumbosacral and sacroiliac regions detected by ultrasonography (US) and computed tomography (CT) examinations on specimens. We hypothesised that age, body mass, previous use and anatomical variations may be correlated with the presence and/or severity of APBCs. Study design: Descriptive cadaver study. Methods: Lumbosacroiliac specimens were obtained from 51 horses that died or were euthanised for reasons other than the study and underwent US and CT examinations post‐mortem. Results: Forty‐two specimens were analysed. The most prevalent lumbosacral disc morphology was type 2 (21/42), and protrusions were found in 15/42 specimens. Abnormal echogenicity of the L5‐L6 and lumbosacral discs was detected in 11/42 and 30/42 specimens, respectively. Abnormalities in the size of the L5‐L6 disc were found in 10/42 specimens and correlated with promontorium localisation (Cramér's V coefficient [V] = 0.42) and lumbosacral disc morphology (type 1: V = 0.41; type 5: V = 0.69). The most prevalent orientation of the L6 spinous process (SP) was convergent (24/42). The promontoria were mostly located between L6 and S1 (36/42). Lumbosacral spondylosis was detected in 24/42 specimens and spondylolisthesis in one. Age was associated with the severity of APBCs in the sacroiliac joints, lumbosacral intertransverse joints, articular process joints, spondylosis and L6 or S1 bone plate irregularities. Lumbosacral spondylosis or L6 extremitas caudalis irregularity was associated with lumbosacral angulation, variability in the size of the L5‐L6 disc and localisation of the promontorium, L6 SP orientation and L6 extremitas caudalis irregularity with abnormal echogenicity of the LS disc. Main limitations: Lack of information on clinical signs. Conclusions: High variability and prevalence of the anatomical variations and APBCs in the lumbosacroiliac region were observed, and correlations between some anatomical variations and APBCs and between APBCs and age were reported. [ABSTRACT FROM AUTHOR]

Copyright of Equine Veterinary Journal is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Desmitis of the accessory ligament of the deep digital flexor tendon (ALDDFT) is a commonly reported injury. Despite the commonality of this injury, the literature is limited to small case series, with the reported success following treatment varying from 18% to 75%. Objectives: To identify the prognosis and factors associated with a return to work following ALDDFT injury. Study design: Retrospective case series. Methods: Medical records of horses from four equine hospitals (January 2000 and December 2018) with a diagnosis of desmitis of ALDDFT were reviewed. Data retrieved included case detail, use, history, lameness treatment and follow‐up. Success was defined as returning to work. Backward stepwise logistic regression was used to identify variables significantly associated with return to work. Results: Ninety‐one horses were included. The mean age was 13.5 years (standard deviation 4.9 years). Thirty‐four percent (28/91) of horses were sound at the initial presentation. Sixty‐eight percent (62/91) of horses were managed using controlled exercise alone, 28% (29/91) were treated with intra‐lesional injection, therapeutic ultrasound, extracorporeal shockwave therapy or desmectomy of the ALDDFT and 3% (3/91) were euthanased without treatment. Sixty‐four percent (54/85) of horses returned to work. Horses that were lame at follow‐up were less likely to return to work (odds ratio [OR] 107.93, 95% confidence interval [CI] 20.06–580.61, p < 0.001) than those that returned to soundness. Identification of adhesions on ultrasonography was also associated with having reduced odds for return to work when compared to horses without adhesions (OR 0.10, 95% CI 0.01–0.76, p = 0.03). Main limitations: Retrospective nature of the study, the potential of selection bias with regards to follow‐up. Conclusion: Sixty‐four percent (54/85) of horses returned to work following injury of the ALDDFT. Persistence of lameness and adhesion formation were significantly associated with a poor outcome. [ABSTRACT FROM AUTHOR]

Background: Mesenchymal stem cells are an innovative therapeutic for various equine orthopaedic diseases, including soft tissue injuries. Objectives: To evaluate the safety and efficacy of tenogenic primed equine allogeneic peripheral blood‐derived mesenchymal stem cells (tpMSCs) in horses with naturally occurring superficial digital flexor tendon (SDFT) and suspensory ligament (SL) injuries. Study design: Multicentre, blinded, randomised, placebo‐controlled clinical trial. Methods: One hundred client‐owned horses with SDFT and SL injuries were randomised to receive an intralesional tpMSC (66) or saline (34) injection. Clinical and ultrasonographic evaluation was performed before treatment and on Days 56 ± 3 and 112 ± 3 after treatment. Long‐term data on re‐injury was collected up to 2 years after treatment. Results: Significantly more tpMSC‐treated horses achieved improvement in fibre alignment score (FAS) (100% vs. 54.5%, p < 0.001) and echogenicity (97.0% vs. 57.6%, p < 0.001) on Day 112 ± 3, and their lesion size decreased significantly (−27.6 ± 25.91 vs. −4.6 ± 26.64 mm2, p < 0.001) compared to the placebo group. A FAS = 0 was achieved in 65% of tpMSC‐treated horses, as compared to 9% of placebo‐treated horses at Day 112 ± 3. The attending veterinarians reported no re‐injury in 41 of 53 tpMSC and in 2 of 26 saline‐treated horses available for long‐term follow‐up (p < 0.001). Main limitations: As this study consisted of client‐owned horses, no samples for histology were collected. Long‐term follow‐up was only available for a subset of enrolled horses. Conclusions: The intralesional administration of tpMSCs was safe and improved the quality of healing and long‐term outcomes in sports horses with naturally occurring SDFT and suspensory injuries. [ABSTRACT FROM AUTHOR]

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Equine practitioners frequently inject local anaesthetics (LA) intra‐articularly in both diagnosis of lameness and for pain management intra‐ or post‐operatively with synovial endoscopy. Recent reviews of the human and veterinary literature support the concept that chondrotoxicity of LA on joint tissues depends on the type of drug, dose administered, and duration of exposure. The purpose of this review is to summarise the current literature describing intra‐articular local anaesthetic use, including both in vitro and in vivo studies, and to draw some comparisons to literature from other species where potential toxicity and duration of effect have been evaluated with the goal of advancing the field's understanding of intra‐articular local anaesthetic use in horses, and indicating future directions for the field. The aggregate data available from all species, while generally sparse for horses, indicate that LA are rapidly cleared from the synovial fluid after injection, often within 30 min. In vitro data strongly suggest that lidocaine and bupivacaine are likely more chondrotoxic than other LA, although to what extent is still unknown, and cytotoxicity of LA may be mitigated through concurrent injection with HA, PRP, and drug combinations including nonsteroidal anti‐inflammatories and opioids. The current body of in vitro research is not reflective of the in vivo environment, and further in vitro work, if performed, should focus on mimicking the native joint environment, utilising PK data and joint/injection volumes to replicate the native environment more accurately within the joint and the expected exposures to LA. [ABSTRACT FROM AUTHOR]

Background: Complications are a practical consideration for elective magnetic resonance imaging (MRI) studies performed under general anaesthesia but relatively little is known about their distribution and risk factors. Objectives: To describe the incidence of complications associated with MRI performed under general anaesthesia at a large referral facility and evaluate potential risk factors for these complications. Study design: Retrospective case–control study. Methods: Patient information and details of the MRI procedure were collected retrospectively from medical records of all horses that had undergone an MRI under general anaesthesia at the University of Pennsylvania, New Bolton Center, between September 2005 and April 2012. Complications and categorical variables were examined by chi‐squared or Fisher's exact tests as appropriate. A mixed‐effects logistic regression approach was used to evaluate associations between explanatory variables and the outcome variable (complications or pyrexia). A univariable screen was used to select variables (likelihood ratio test p < 0.2) for inclusion in the multivariable analysis. Statistical significance was inferred when p ≤ 0.05. Results: Complications were noted after MRI in 51 (17.4%) of 293 events eligible for inclusion. Complications included pyrexia (n = 35), pneumonia (n = 14), colic (n = 10), facial/nerve paralysis (n = 6), diarrhoea (n = 4), and other (n = 3). The odds of developing a post‐anaesthetic complication were significantly decreased in horses that received peri‐anaesthetic antimicrobials (OR 0.29, 95% CI 0.14–0.63, p = 0.002). Increased age (OR 0.87, 95% CI, 0.76–0.99, p = 0.03) and peri‐anaesthetic antimicrobial administration (OR 0.23, 95% CI 0.08–0.65, p = 0.005) were associated with a decreased odds of developing pyrexia. Main limitations: Single centre retrospective design. Conclusions: Potential complications including pyrexia, pneumonia and colic should be recognised when pursuing MRI under general anaesthesia. The administration of peri‐anaesthetic antimicrobials decreased the odds of a complication and warrants consideration, particularly in horses that might be classified as high risk. [ABSTRACT FROM AUTHOR]

Copyright of Equine Veterinary Journal is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Background: Repair of sagittal proximal phalanx (P1) and parasagittal metacarpal/metatarsal III (MC/MTIII) fractures has evolved over recent decades from a procedure carried out solely under general anaesthesia, to one commonly performed under standing sedation. To date, standing fracture repair has not been evaluated for large cohorts. Objective s : To determine short‐term (survival to discharge) and long‐term (return to racing) outcomes of horses undergoing standing repair of MC/MTIII and P1 fractures, and to compare pre‐surgical and post‐surgical racing performance. Study design: Single‐centre retrospective cohort study. Methods: Retrospective clinical record review of 245 cases undergoing standing repair of MC/MTIII or P1 fractures, 1 January 2007–30 June 2021. Data on signalment, fracture configuration and complications were collected and full race records were retrieved from the Racing Post Database (www..racingpost.com). Chi‐squared and Mann–Whitney U tests were used to determine any difference in variables between horses that raced after surgery compared to those that did not. McNemar change and Wilcoxon signed‐rank tests were used to compare pre‐ and post‐surgical racing performance, p ≤ 0.05. Results: Ninety‐eight percent [95% confidence interval (CI): 96.2%–99.7%] of horses survived hospital discharge, and 75.1% (95% CI: 68.9%–81.4%) raced after surgery, a median of 241 days later. Horses that raced post‐surgery were significantly less likely to have suffered from complications during hospitalisation than those that did not race again [17.3% (95% CI: 11%–24%) vs. 36.5% (95% CI: 23%–50%), p = 0.005]. Comparing pre‐ and post‐operative racing performance, there was no significant difference in earnings per start [median £628.00, interquartile range (IQR) 115.90–1934.80 vs. £653.20, 51.00–1886.40, p = 0.7] or proportion of horses winning [51% (95% CI: 41%–61%) vs. 54% (95% CI: 44%–64%), p = 0.8] or being placed first–third [77% (95% CI: 68%–85%) vs. 71% (95% CI: 62%–80%, p = 0.5] in at least one race. Main limitations: Retrospective nature of study with reliance on clinical records and public databases, limiting data available for analysis. Conclusions: Standing fracture repair is a viable treatment option for MC/MTIII or P1 fractures that returns horses to the racetrack within an acceptable time frame and is capable of restoring pre‐surgical athletic ability. [ABSTRACT FROM AUTHOR]

Background: Equestrian eventing involves competing in three phases: dressage, jumping, and cross‐country. Competitors are ranked by number of penalties accrued—with those who have fewer penalties ranked higher. Completing the cross‐country phase with zero obstacle penalties is commonly referred to as 'running clear'. Understanding factors associated with running clear can help athletes plan strategically for success, while also helping governing bodies to refine qualification criteria for elite levels. Objectives: This study was carried out to identify factors associated with running clear in the cross‐country phase of Fédération Equestre Internationale (FEI) eventing. Study design: Retrospective cohort study of 107 348 horse starts worldwide in all FEI competitions between January 2008 and December 2018. Methods: Multivariable logistic regression models constructed stepwise using a bi‐directional process. Two study cohorts were assessed: a complete cohort that met all inclusion requirements and separately, a cohort that included only horses starting at the level above their previous start. Results: Sixteen factors were associated with running clear. Factors associated with increased likelihood of doing so included lower event level, lower dressage score earlier in the event, fewer recent FEI event starts, and more clear runs in their previous three FEI events. For horses that had stepped up an event level, 14 of these factors were still associated with running clear. Main limitations: Data available covered only FEI events, no national federation competitions were available for inclusion in horse histories. No prior veterinary information or data on training were available. Conclusions: This study provides a framework that allows stakeholders to potentially better understand the appropriate level of competition for any particular horse/rider combination, given the combination's recent history. This could provide an additional direct benefit in terms of safety by reducing the likelihood of a combination falling during cross‐country. [ABSTRACT FROM AUTHOR]