Respiratory disease is common in the horse population and is often associated with poor performance in equine athletes. Despite their outstanding strength and aerobic capacity, little regard is given to draft horses and the respiratory disorders they may encounter when performing athletic activity. For this reason, the objectives of this study were: (1) to determine the prevalence of exercise-induced pulmonary hemorrhage (EIPH), tracheal mucus (TM) and recurrent laryngeal hemiplegia (RLH) in a population of competitive draft pulling horses, and (2) to determine if there was an association between horse weight, height, age, amount pulled, or competition placing with EIPH, TM or RLH in draft pullers. Results of this study identified EIPH in 26% of the study population, RLH in 32% and TM in 82% of participating horses; however, no risk factors were identified for the development of these problems in draft pulling horses.

Atrial fibrillation (AF) is the most clinically relevant cardiac arrhythmia identified in the Standardbred racehorse. However, there is limited literature regarding athletic ability in Standardbred racehorses following AF conversion. To investigate this issue, the objectives of this review were to: i) determine the success rate in using quinidine sulphate to treat AF in a population of hospitalized equine patients in Atlantic Canada between January 2008 and December 2019; and ii) measure return to athletic ability (using racetrack earnings and top-3 finishes) following cardioversion with quinidine sulphate in a population of Standardbred racehorses. Overall, 73% (16/22) of AF instances in this study were successfully treated with enteral quinidine sulphate. No significant difference was detected in racetrack earnings or number of top-3 finishes for each horse that raced at least 5 times pre- and post-conversion. Key clinical message: To the authors' knowledge, this is the first published review to assess the athletic ability of Standardbred racehorses following cardioversion with enteral quinidine sulphate. Based on the current information, it does not appear that treatment of AF with quinidine sulphate affects future athletic performance in horses that achieved cardioversion.

Summary A 3‐year‐old Standardbred trotting gelding presented to the Atlantic Veterinary College for diagnostic work‐up of poor performance and abnormal respiratory noise during exercise. Physical examination was unremarkable, and no significant findings were identified on standing endoscopic examination of the upper respiratory tract. Treadmill endoscopy was utilised for dynamic evaluation of the upper respiratory tract; a diagnosis of epiglottic retroversion was confirmed. The owner requested euthanasia of the gelding, and a post‐mortem evaluation was completed. Despite thorough gross and histological examination of the head and neck on post‐mortem examination, no evidence was identified to support the postulated aetiologies for epiglottic retroversion currently found in the literature. This case represents the first reported findings from a post‐mortem examination of a horse with epiglottic retroversion.

A study of musculoskeletal injuries in Standardbred racehorses on Prince Edward Island was conducted to determine the incidence and risk factors for injury. Monthly information was collected from 10 trainers and 153 Standardbred horses over a 12-month period. Seventeen new injuries were identified in pacers, representing a horse level incidence risk of 23% and an incidence rate of injury of 2.19 per horse-month at risk. Forty-one percent of the injuries occurred during a race, 53% during training and 6% during jogging. Fourteen horses had experienced a previous injury and 3 of these horses experienced a new injury during the study period. Potential risk factors for injury were the speed at which the horse was trained, previous injury, and the conformational fault of offset knees.

The objective of this study was to determine the proportion of horse farms on Prince Edward Island, Canada that comply with the requirements of the Code of Practice for the Care and Handling of Equines (Code). An investigator performed on-farm assessments while administering a questionnaire to owners of 50 horse farms. The percentage of farms in compliance with specific requirements in the Code ranged from 20% to 100% per requirement. The largest areas of non-compliance regarding facilities and housing were the lack of the ability to segregate sick or injured animals and the lack of an emergency action plan. It was determined that 72% of farms were in compliance with body condition scores and 54% reported to have taken corrective action when required. Farm owners who were aware of the Code were more likely to have good quality air in their barns as well as an emergency action plan in place.

SummaryA 6‐month‐old Standardbred weanling presented with acute non‐ambulatory tetraparesis. Cranial nerve examination was normal and neuroanatomic localisation suggested there was a focal C1‐C5 spinal cord lesion. Post‐mortem examination identified a cervical vertebral epidural haematoma at the level of C2‐C3 causing spinal cord compression and neurological deficits. Histological examination determined the haematoma was several weeks old making the lesion chronic. Since the clinical progression was acute, this suggests an acute on chronic pathophysiology. Even with no history of trauma, an epidural haematoma should be on the differential list in young horses with acute tetraparesis.

Mesothelioma is a rare malignancy in horses. This report describes a case in which marked hemoperitoneum, moderate anemia, and moderate dependent edema were the presenting clinical signs in a 2-year-old Standardbred stallion with mesothelioma of the vaginal tunic. On necropsy, approximately 40 L of dark red fluid distended the abdomen. A dark red mass infiltrated and effaced the right pampiniform plexus, and red nodular masses were present multifocally on the parietal and visceral peritoneal surfaces. Histopathologically, the masses were composed of malignant spindle cells with a sarcomatoid appearance. Using immunohistochemistry, tumor cells were cytokeratin and vimentin positive and factor VIII-related antigen negative: compatible with a diagnosis of mesothelioma. This is the first report of mesothelioma arising from the vaginal tunic of a horse with subsequent spread to the peritoneum. This case adds additional information regarding the clinical presentation and behavior of mesothelioma originating from the vaginal tunic in horses. (C) 2019 Elsevier Inc. All rights reserved.

A stallion presenting for surgical correction of an acquired inguinal hernia was also diagnosed with a nephrosplenic entrapment (NSE) intraoperatively. Surgical intervention resulted in a successful outcome. To date, these conditions have not been reported to occur simultaneously.