Equine Veterinary Journal最新文献

Background: Little information describing the biologic behaviour and therapies for corneal lymphoma exist.

Objectives: To characterise histologically confirmed equine corneal lymphoma considering breed, age or sex predisposition, histologic and immunologic features, therapies and outcomes.

Study design: Retrospective case series.

Methods: A multicentre retrospective medical record review was used to identify horses that presented with corneal disease confirmed morphologically as corneal lymphoma from 2012 to 2022.

Results: Mean age at diagnosis was 10.5 years. Males represented 18/26 cases. Warmblood (14) and Thoroughbred (6) breeds were most commonly represented. 25/26 had unilateral ocular involvement. No cases had evidence of multicentric lymphoma. Most eyes (77.7%) had a history of suspected immune-mediated keratitis (IMMK) or eosinophilic keratitis. Morphological diagnosis confirming lymphoma was available for all cases. B-cell lymphoma was diagnosed in 19/24 eyes for which immunohistochemistry was performed, with intermediate to large B-cell lymphoma being most common. Fifteen of 27 eyes received at least one form of adjunctive therapy following keratectomy. Four eyes, which did not receive adjunctive therapy following keratectomy, experienced recurrence. No horses treated with adjunctive therapy following keratectomy experienced recurrence. Malignant transformation of IMMK to lymphoma was morphologically documented in one eye and suspected in three others based on recurrence of clinical signs. All globes were retained and visualised at the last follow-up.

Main limitations: Incomplete medical records, owner subjectivity concerning onset of disease and cases being lost to follow-up.

Conclusions: Malignant transformation of IMMK to corneal lymphoma likely occurs in horses. Lymphoma should be a differential for nonulcerative keratitis in horses. Keratectomy and histopathology may be considered in progressive or refractory cases of IMMK to rule out neoplastic disease. Recurrence of corneal lymphoma is unlikely following excision and adjunctive therapy. Cases with large corneal surface area or deep stromal involvement may have a likelihood for recurrence.

The suspensory ligament (SL) is a key component of the elaborate and highly adapted suspensory apparatus in the horse. In addition to contributing to stabilisation of the metacarpophalangeal joint, the SL has a spring like function to reduce the energetic cost of locomotion. Although the SL is highly prone to injury in horses of all ages and competing in a wide range of disciplines, knowledge regarding fundamental structure-function relationships in the SL is lacking, particularly compared with other injury-prone tendinous structures such as the superficial digital flexor tendon. In this review, we discuss current knowledge of SL composition, structure and mechanical properties and describe the epidemiology, aetiology and pathophysiology of injuries. We evaluate different diagnostic approaches and treatment modalities and identify key areas for future research.

Background: In Great Britain, owners are keeping their horses into increasingly older age, reflecting societal changes in human-animal relationships. The uptake of routine veterinary services is reported to reduce as horses age. Horse owners seek information regarding their animal's health from alternative sources before and/or following veterinary involvement. Information regarding the experiences and behaviours of veterinarians toward older horse health care provision is limited.

Objective: This study sought to explore how veterinary care for the ageing horse is conceptualised and approached by veterinarians treating horses in Great Britain.

Study design: Exploratory qualitative.

Methods: A subset of qualitative data, collected as part of a larger study investigating how owners and veterinarians make decisions regarding the care of the older horses, was analysed using a constructivist grounded theory approach. Data included semi-structured in-depth interviews with nine veterinarians and veterinary clinical records pertaining to the horses of 13 participating owners.

Results: Veterinarians valued regular interactions with owners to optimise a horse's management, however, the timing and nature of veterinary involvement varied. The context of older age shaped decision-making and 'age-appropriate' interventions were negotiated within the context of each horse and owner. Where participants had concerns about a horse, they sought to achieve an owner's adherence to their advice while navigating the veterinarian-owner relationship. Interpersonal dimensions of veterinarian-owner interactions appeared to shape, and could challenge, veterinarians' delivery of health care services and their own sense of being a professional who cares for animals, and about people.

Main limitations: A sample of veterinarians were recruited for this study based on horse owners' involvement.

Conclusions: The provision of veterinary care for the older horse rests upon networks of relationships. Collaboration between the profession and owners in both the design and delivery of, veterinary health care services may better enable different types of knowledge and values to be brought together more effectively.

Hobbs, KJ, Johnson, PJ, Wiedmeyer, CE, Schultz, L, Foote, CA. Plasma syndecan-1 concentration as a biomarker for endothelial glycocalyx degradation in septic adult horses. Equine Vet J. 2023; 55(3): 456–462. https://doi.org/10.1111/evj.13862

The units used for syndecan in this paper were incorrect. The units have been updated to ng/ml throughout the article.

We apologize for this error.

Background: Traditional radiographic measurements of distal phalanx (Pd) displacement based on the outer hoof wall are not useful for diagnosis of acute laminitis.

Objectives: We hypothesised that the distance between the inner hoof wall and Pd ('lamellar lucent zone'; LLZ) measured on lateromedial digital radiographs would be increased in horses with acute and subacute laminitis compared with healthy horses.

Study design: Retrospective cohort study and in vivo experimental study.

Methods: Forelimb radiographs from 32 healthy and 18 laminitic mixed-breed horses were analysed retrospectively. Laminitis was defined by at least two clinical signs (acute multi-limb lameness, increased digital pulse amplitude and/or persistently warm hooves) for ≤3 days (acute), or >3 and ≤14 days (subacute) duration, without overt palmar rotation (≥3°), remodelling, or distal displacement of the Pd. Some laminitic limbs initially classified as acute were subsequently radiographed later in hospitalisation and also included as subacute. Twelve measurements including LLZ at proximal, middle, and distal locations were performed on 126 forelimb radiographs that met the criteria for acute laminitis (n = 39), subacute laminitis (n = 23) or healthy control (n = 64). A mixed effects linear regression model was used for comparisons and a receiver-operator characteristic (ROC) curve was created for select measurements. Three horses were serially radiographed to study the impact of magnification and obliquity.

Results: The mean [95% confidence interval] LLZ (mm) was increased in acute and subacute laminitis compared with control in the proximal (acute = 8.8 [8.4-9.2]; subacute = 9 [8-9.9]; control = 7.3 [7-7.7]), middle (acute = 8.9 [8.5-9.3]; subacute = 9.1 [8.2-10]; control = 6.9 [6.5-7.2]), and distal (acute = 9.1 [8.5-9.7]; subacute = 10.2 [9.1-11.3]; control = 7.5 [7.2-7.8]) dorsal lamellar regions (p < 0.001). At a cut-off of >7.5 mm for middle LLZ, sensitivity was 87% [73%-94%] and specificity 91% [81%-96%] for diagnosis of acute laminitis. Using the ratio of middle LLZ to distal phalanx cortical length, sensitivity was 95% [81%-99%] and specificity was 95% [87%-99%] (cut-off >0.11). Magnification and obliquity affected absolute LLZ measurements but did not alter LLZ ratios.

Main limitations: No histological confirmation of laminitis.

Conclusions: LLZ measurements are potentially useful for radiographic diagnosis of acute and subacute laminitis.

Background: MicroRNA (miRNA) has previously been used as a biomarker for cardiac disease in humans and dogs, however, studies in horses are not yet available.

Objectives: To determine if adult horses with moderate or severe mitral valve regurgitation have a different serum miRNA expression profile compared to healthy controls.

Study design: Retrospective cross-sectional.

Methods: Serum samples from 77 adult horses with moderate or severe mitral valve regurgitation and 77 healthy control horses were analysed using a commercial cardiac disease-specific miRNA panel previously used in dogs.

Results: The commercial canine cardiac miRNA panel had low discriminatory power as a biomarker for mitral valve regurgitation in adult horses. Sensitivity was 0.58 (95% Cl: 0.47-0.69) and specificity 0.57 (95% Cl: 0.46-0.68).

Main limitations: Clinical data were extracted retrospectively and currently there is no well-established criteria for grading mitral regurgitation in horses; there were few severe mitral regurgitation cases and the pathogenesis of mitral regurgitation was not considered. Controls were not matched by age, breed or sex. An assay developed for use in dogs was used.

Conclusion: Despite strong miRNA conservation across species, the commercially available canine cardiac miRNA panel failed as biomarker for mitral valve regurgitation in adult horses. Further research is needed to determine if an equine specific panel can be developed that performs better as biomarker for cardiac disease in horses.

Background: While previous reports come mostly from the southern Americas, several outbreaks of hypersalivation in horses were observed in Middle Europe from 2016 to 2018.

Objective: To describe feed-induced hypersalivation in European horses.

Study design: Analysis of feedstuffs.

Methods: Veterinarians and horse or stable owners were encouraged to submit feedstuffs from case outbreaks of hypersalivation in which, infectious diseases or other systemic causes of the syndrome were ruled out and intoxication was suspected. Feedstuff analysis was performed, including gross examination, microscopic analysis of fine particles, and for hay and forage mycological culturing and mycotoxin testing.

Results: Eleven case outbreaks were investigated. Typical clinical findings in the horses were either foamy saliva around the mouth or serous salivation with puddles forming on the ground. Some horses also showed lesions of the gingival mucosa and/or the tongue. Foamy hypersalivation, sometimes combined with lesions of tongue and/or gingiva, was associated with finding of ergot sclerotia and ergot alkaloids in hay or pasture plants (ergocornin and ergocorninin having the highest concentrations). Serous hypersalivation with massive loss of fluid was associated with the fungus Rhizoctonia spp. As indicated by the detection of traces of swainsonine, mycotoxin production on the forage was seen as likely cause. The cessation of clinical signs took days to weeks after diet change, probably depending on the duration, type and amount of toxin intake.

Main limitations: Small number of case outbreaks, records of clinical findings and horses' management were incomplete and were reported by horse owners.

Conclusion: Hypersalivation due to mycotoxins in the feed has become an emerging problem for horses in middle Europe.

Background: Fragile foal syndrome (FFS) or warmblood FFS Type 1 (WFFS) is a recessive, autosomal, hereditary, genetic defect causing late abortions, stillbirths and non-viable foals. Whether early pregnancy losses occur is unknown.

Objectives: To investigate how WFFS affects pregnancies and whether early pregnancy losses occur in WFFS matings and if there is a difference in pregnancy success between matings where both parents were allele carriers and those where only mare or stallion were WFFS carriers.

Study design: Retrospective cohort study.

Methods: Breeding records from a Warmblood stud farm were evaluated (2016-2019) and 2682 cycles of 177 mares analysed. Matings were assigned to four study groups, depending on the WFFS carrier status of the mare and stallion: N/WFFS × N/WFFS (n = 46), N/WFFS (mares) × N/N (n = 511), N/N × N/WFFS (stallions) (n = 191) and N/N × N/N (n = 2149).

Results: There were no differences in pregnancy rates between matings with only one WFFS carrier and those with non-carriers. When comparing N/WFFS × N/WFFS matings to those with only one or no WFFS-carrier, there were no increased pregnancy losses in the embryonic phase (day <42). By contrast, the N/WFFS × N/WFFS group had significantly more abortions (53.8%) than the other three study groups (7.9-9.2%; adjusted p < 0.0001). The higher losses were evenly distributed between the early (D42-150: 22.7% losses, n = 5) and late (D150-300: 29.4% losses, n = 5) foetal phase. The live foal rate per pregnancy for N/WFFS × N/WFFS matings was lowest (34.5%) and differed significantly (other groups 81%-84%; adjusted p < 0.0001); the peri- and postnatal mortality was higher (25%) compared with the other study groups (2.6%-3%).

Main limitations: Low sample size in N/WWFS × N/WFFS matings, unbalanced study design, outcomes are descriptive, all mares from one stud farm.

Conclusions: The mating of two WFFS carriers may lead to increased risks of pregnancy and foal loss.

Background: Warmblood horses are a popular breed around the world for equestrian sports. Previous studies have investigated ocular findings in other breeds of horses; however, no studies exist for the Warmblood breed.

Objectives: To determine the prevalence of ocular abnormalities in a convenience sample of Warmblood horses in South Africa and to determine if the prevalence of lens and chorioretinal lesions increase with age.

Study design: Descriptive, observational study.

Methods: Warmblood horses underwent a full ophthalmic examination which included a Schirmer tear test (STT), tonometry, fluorescein dye testing, slit lamp biomicroscopy and indirect ophthalmoscopy. Age was categorised into three groups namely <8 years old, 8-13 years old and 14+ years old for statistical analysis. Prevalence of lens and chorioretinal lesions were compared between age categories.

Results: One hundred and four horses (208 eyes) were examined. The age range was 5 months to 30 years (mean 11 years, standard deviation [SD] 6 years). Ocular pathology was noted in 125 eyes (60.1%) and 79 horses (76%). The highest number of lesions were noted in the choroid and retina, iris and lens. Chorioretinal lesions were seen in 100 eyes (48.1%) and in 65 horses (62.5%). Iridial lesions were seen in 19 eyes (9.1%) and 12 horses (11.5%). Cataracts were seen in 19 eyes (9.1%) and in 13 horses (12.5%). The presence of total chorioretinal lesions (eye level [p = 0.002]; horse level [p = 0.004]), focal chorioretinal lesions (eye level [p = 0.004]; horse level [p = 0.008]) and cataract (eye [p = 0.03]; horse level [p = 0.02]) were all shown to statistically increase with age.

Main limitations: A small sample size and limited geographic area.

Conclusions: There was a high prevalence of ocular pathology in this population of Warmblood horses in South Africa. This reiterates the importance of an ocular examination as a part of routine health checks, as well as during prepurchase examinations.

Background: Reliable lameness thresholds for vertical head displacement for trotting on a circular path and on different surfaces have yet to be defined. Withers movement in lame horses could help improve the diagnostic accuracy of sensor technology.

Objectives: To define head movement lameness threshold ranges and describe the relationship between head and withers movement during trotting under different circumstances in sound and forelimb lame horses.

Study design: Retrospective analysis of clinical data and comparison with control group.

Methods: Fifty-five sound and thirty-four naturally lame horses were trotted under field conditions on a hard surface on a straight line and on both directions on soft and hard surfaces. Movement asymmetry was analysed by measuring differences in displacement minima for head and withers using an inertial measurement unit sensor-based gait analysis system. Receiver operating characteristic (ROC) analysis was performed to define threshold ranges. Relationships between head and withers data were identified by calculating the correlation with linear regression analysis.

Results: Estimated lameness threshold values for vertical head movement asymmetry ranged from 11.5 to 12.5 mm. On both surfaces, a head movement asymmetry threshold range from 24.5 to 26.5 mm could be found for the circle. Lame horses showed significant correlations between head and withers movement on hard ground straight line (R² 0.714, p < 0.001) and inner leg lame horses on the lunge (R² 0.915, p < 0.001).

Main limitations: Different sources of lameness were not distinguished. Radius and speed during lungeing could not be perfectly controlled. Inclusion in the sound group was based on a subjective examination by one clinician and in the lame group two clinicians subjectively determined inner and outer leg lameness creating an extra amount of uncertainty.

Conclusions: Lameness thresholds for quantifying head movement asymmetry on the lunge were proposed. A significant correlation was observed between head and withers movement asymmetry under several conditions.