Exploration of the Fecal Microbiota and Biomarker Discovery in Equine Grass Sickness.

Equine grass sickness (EGS) is a frequently fatal disease of horses, responsible for the death of 1 to 2% of the U.K. horse population annually. The etiology of this disease is currently uncharacterized, although there is evidence it is associated with Clostridium botulinum neurotoxin in the gut. Prevention is currently not possible, and ileal biopsy diagnosis is invasive. The aim of this study was to characterize the fecal microbiota and biofluid metabolic profiles of EGS horses, to further understand the mechanisms underlying this disease, and to identify metabolic biomarkers to aid in diagnosis. Urine, plasma, and feces were collected from horses with EGS, matched controls, and hospital controls. Sequencing the16S rRNA gene of the fecal bacterial population of the study horses found a severe dysbiosis in EGS horses, with an increase in Bacteroidetes and a decrease in Firmicutes bacteria. Metabolic profiling by 1H nuclear magnetic resonance spectroscopy found EGS to be associated with the lower urinary excretion of hippurate and 4-cresyl sulfate and higher excretion of O-acetyl carnitine and trimethylamine-N-oxide. The predictive ability of the complete urinary metabolic signature and using the four discriminatory urinary metabolites to classify horses by disease status was assessed using a second (test) set of horses. The urinary metabolome and a combination of the four candidate biomarkers showed promise in aiding the identification of horses with EGS. Characterization of the metabolic shifts associated with EGS offers the potential of a noninvasive test to aid premortem diagnosis.

Dental Disease in Aged Horses and Its Management.

Improved recognition of equine geriatric conditions has resulted in a surge in our aged population with a concurrent escalation of many age-related dental pathologies. Prevention of these disorder is the ultimate aim but early identification and appropriate management can increase an animal's oral comfort and maximise its masticatory ability. There is only a finite amount of tooth available for eruption in the horse and therefore as the teeth become worn and less efficient as a grinding unit, dietary modification becomes a paramount consideration to accommodate this. Geriatric animals have differing requirements for restraint and sedation with treatment of coexisting disorders also an important requirement.

Management of paracondylar process fracture in three horses.

BACKGROUND: Fractures of the paracondylar process of the occipital bone may cause headshaking, neck pain and neurologic deficits. The condition is being recognised more frequently with increasing availability of computed tomography. However, to date only limited information is available as to presentation, treatment, surgical approach and outcome. OBJECTIVES: To describe the clinical signs, imaging findings, treatment, surgical approach and outcome in three horses diagnosed with paracondylar process fracture. STUDY DESIGN: Retrospective case series. METHODS: Clinical records and diagnostic images of affected cases were reviewed. RESULTS: Two cases had ventral nonunion fractures-one of these presented with neck pain, headshaking and behavioural changes, while in the other the fracture was a suspected incidental finding in a case of poor performance. A third case with a more dorsal fracture presented with acute facial nerve paralysis. Diagnosis was by computed tomography in all cases, although imaging of ventral fractures by radiography was found to be feasible. Where clinical signs could be associated confidently with the fracture, conservative management resulted in improvement but not complete resolution. Repeated recurrence of clinical signs after prolonged periods of remission necessitated surgical removal in one case, which was readily accomplished with the aid of ultrasound guidance, and led to rapid resolution of clinical signs without significant post-operative complications. The surgical approach is described. MAIN LIMITATIONS: Limited follow-up was available. CONCLUSIONS: Paracondylar process fracture should be considered as a differential diagnosis for headshaking, neck pain, poor performance and facial paresis, and is a justification for performing computed tomography in such cases. A multi-disciplinary approach is beneficial due to the potential for orthopaedic, neurologic, ophthalmologic and behavioural clinical signs, with additional need for expertise in diagnostic imaging and pain management. Surgical fragment removal should be considered for ventral fractures.

A computed tomographic study of endodontic and apical changes in 81 equine cheek teeth with sagittal fractures.

BACKGROUND: Sagittal fractures of equine cheek teeth are commonly observed during oral examination. There are few reports on the apical and endodontic pathology associated with such fractures seen during computed tomographic (CT) examination. OBJECTIVES: This study aimed to document the prevalence of CT changes indicative of apical disease in equine cheek teeth, which have suffered a sagittal fracture involving the clinical ± reserve crown. STUDY DESIGN: This study is a retrospective case series. METHODS: CT examinations of equine heads with sagittal fractures of cheek teeth present were reviewed: 81 teeth from 49 horses were identified to have a sagittal cheek tooth fracture. The images were evaluated for apical pathology including gas (in the endodontic system and periapically), widened periodontal space, periapical sclerosis, apical clubbing, cementoma/hypercementosis, lamina dura loss, associated sinusitis and sinus mucosal swelling. An apical infection grading system was created to give each tooth a score. Hounsfield units were used to measure the density of the endodontic, apical and periapical regions. The fracture length ratio was recorded. Statistical analysis was performed using a generalised estimating equation to evaluate predictors of apical infection and associations between clinical signs and CT abnormalities. RESULTS: Eighty-seven sagittal fractures (56 buccal, 17 palatal/lingual and 14 midline) from 81 teeth were recorded (74 maxillary and 7 mandibular). Apical infection was diagnosed in 73% (37/51, P = .05) of buccal, 55% (6/11, P = .07) of palatal/lingual, 100% (13/13) of midline, 100% (6/6) of multiple fractures and 96% (23/24, P = .008) of fractures involving infundibula. There was no significant relationship between apical infection and the presence of clinical signs associated with dental pathology (P = .4). There was no significant association between fracture length ratio and apical infection (P = 1.0). Midline sagittal fractures were significantly associated with sinusitis when compared with all other maxillary fractures (odds ratio [OR] 5.92, 95% confidence interval [CI] 1.67-20.83, P = .006). Loss of the lamina dura was not significantly associated with apical infection (P = .5). MAIN LIMITATIONS: There is a maxillary cheek tooth bias in the data set and the subjective grading system. CONCLUSIONS: A large proportion of fractured cheek teeth have evidence of apical infection on CT examination and therefore warrant treatment.

Equine Suture Exostosis: A Review of Cases from a Multicenter Retrospective Study.

Suture exostosis is an intriguing and not uncommon pathology that has to be included in the differential diagnosis for horses with swelling of the head. Although several singular case reports have been published, no large case series is available. The aim of this study is to report a multicentric retrospective collection of suture exostosis cases. Data concerning horses with suture exostosis in the facial region were collected retrospectively. Information regarding breed, age, gender, history, imaging findings, initiated treatment, response to treatment and follow up was recorded. One hundred and five cases of various breeds were reported. Analysis revealed the cases could be grouped into four entities: 45 developed following sino-nasal surgery, 23 following trauma, seven with underlying sinus pathology and 25 idiopathic. Treatment consisted of sequestra removal, plate fixation, antimicrobial and anti-inflammatory drugs or no treatment. Whereas initial localized pain fades within few days or weeks, resolution or reduction of the swelling was obtained in most cases after 3 months to 1.5 years. The etiopathogenesis of suture exostosis seems to consist of different entities. Identification of an underlying cause, particularly the presence of a bone sequester and infection is important to speed up resolution and before concluding an idiopathic case. When performing sinusotomies, it is important to provide as little trauma as possible to the surgical site in order to prevent suture exostosis as a complication.

Partial ostectomy of the dens to correct atlantoaxial subluxation in a pony.

OBJECTIVE: To report a surgical technique that allows decompression and anatomic re-alignment for management of subluxation of the atlantoaxial articulation. STUDY DESIGN: Clinical report. ANIMALS: Four-year-old Welsh Section B pony gelding. METHODS: Attempts at closed reduction of subluxation of the atlantoaxial articulation under general anesthesia were unsuccessful, so a ventral surgical approach allowing partial ostectomy of the dens of the axis was used to facilitate reduction. RESULT: Recovery from surgery was uneventful and the pony remained comfortable without neurologic deficits. Both neck stiffness and ataxia resolved. Radiographic examination at 5 days and 6 months postoperatively showed normal anatomic position of the dens of the axis and stabilization of the atlantoaxial joint. CONCLUSION: Partial ostectomy of the dens using a ventral approach can be used to facilitate reduction of atlantoaxial subluxation.

2011 Census Field design: getting the numbers right.

A labour force of over 30,000 temporary field staff has been employed to carry out the Census. This article summarises the role of the field staff in collecting census questionnaires from households and communal establishments for the March 2011 enumeration. Building on the lessons learned from the 2001 Census, and taking account of changes in society and technology since 2001, the article provides a summary of the planned field staff structures and processes intended to deal with returned questionnaires and non-responders.

Evaluation of the 2009 rehearsal and lessons learned for the 2011 Census.

A rehearsal for the 2011 Census was held in October 2009. This article provides a detailed summary and evaluation of this rehearsal, highlighting the successes, areas requiring improvement, and improvements planned for 2011 as a result of key lessons learned.

A tangential radiographic projection for investigation of the equine temporomandibular joint.

OBJECTIVE: To (1) describe a tangential radiographic projection of the equine temporomandibular joint (TMJ) and (2) optimize the radiographic angle and determine its use in standing sedated horses. STUDY DESIGN: Descriptive study. ANIMALS: Cadaveric equine skulls (n=11); 8 horses with a history of quidding or headshaking. METHODS: Tangential radiographic projections were taken of a TMJ of a cadaveric skull before and after intra-articular injection of radiographic contrast. Additional tangential radiographic projections were taken after TMJ dissection and placement of a wire along the articular surface of the mandibular condyle. Subsequently, 3 tangential radiographs were taken of both TMJs of 10 skulls at 75 degrees , 70 degrees , and 65 degrees to the dorsal plane (Rt/Le15Cd70D-Le/RtRVO). Each of the 3 images for each TMJ was ranked by 4 observers who were unaware of the projection angle. Interobserver variation was calculated using a Friedman analysis of variance and significance of the most prevalent angle with a 1-sample repeated measures test. Tangential radiographic projections of both TMJs were then taken of 8 standing sedated horses. RESULTS: Tangential radiographic projections allowed the lateral half of the TMJ to be viewed without superimposition of other structures and the anatomic orientation was determined. A 70 degrees projection to the dorsal plane was ranked as significantly better than other views (P<.001). There was no significant interobserver variation and the technique was safely performed in standing sedated horses with excellent image quality obtained. CLINICAL RELEVANCE: Tangential radiography of the TMJ may complement and add to information obtained from clinical examination and ultrasonography before referral for more advanced imaging techniques.

Evaluation of the long-term oral consequences of equine exodontia in 50 horses.

The aims of this study were to objectively evaluate and quantify the process of post-extraction cheek teeth (CT) dental drift in horses, and to report on associated disorders of CT wear and long-term periodontal health. Fifty horses that had CT oral extraction because of apical infection were prospectively re-examined and a full oral examination, including measurements of some dental parameters, was performed. Narrowing of the extraction space was noted in all cases with complete closure occurring in 18% of horses. The rate of dental drift was calculated as 15.7% of extraction space/year (range 4-50%) and was not associated with the age at extraction (P=0.78) or frequency of dental care since extraction (P=0.48). There was a significant negative relationship between the rate of dental drift and the duration of time since extraction (P=0.008). Overgrowths were present on the opposite CT row in 98% of horses, including opposite the extracted CT and on the Triadan 06s and 11s. No significant difference was noted in either the number of diastemata (P=0.9) or periodontal disease score (P=0.8) between the extraction and the contralateral cheek tooth rows.

Trephination of the equine rostral maxillary sinus: efficacy and safety of two trephine sites.

OBJECTIVE: To examine 2 rostral maxillary sinus (RMS) trephine sites for safety and efficacy using skulls of horses of varying age. STUDY DESIGN: Descriptive study. ANIMALS: Cadaveric equine skulls (n=40). METHODS: Two RMS trephination sites (rostral, caudal) were made in each skull. Radiographic projections using markers at each site were used to determine if sites were within the RMS and directly overlying a cheek tooth. Sinusotomy in 14 skulls was used to determine correlation between radiographic and anatomic location of trephine sites, and of the rostrolateral aspect of the maxillary septum. Age-related risk of trephine site being directly over a cheek tooth was determined using logistic regression. RESULTS: Trephine site was within the RMS in 98% of skulls using the rostral portal and 68% using the caudal portal. The rostral site was over a cheek tooth in 18% of skulls compared with 10% using the caudal site. There was a significant negative relationship between the trephine site overlying a tooth and horse age for rostral (P=.02) and caudal (P=.03) sites. The radiographic appearance of the maxillary septum correlated to the rostrolateral portion of the septum in 12 of 14 skulls that had sinusotomy. CLINICAL RELEVANCE: The rostral RMS trephine portal is more reliable than the caudal site for entering the RMS. Horses

Complications of equine oral surgery.

The vast majority of equine oral procedures are dental-related and, unless great care is taken, almost all such procedures have the potential to cause marked short- or long-term damage to other oral structures. This review of the more common complications of oral surgery begins at the rostral oral cavity with procedures of the incisors, and then moves caudally to deal with complications related to procedures of wolf teeth and cheek teeth, including salivary duct disruption and dental sinusitis. Finally, complications associated with maxillary and mandibular fractures are discussed.