Risk factors for race-day fatality in flat racing Thoroughbreds in Great Britain (2000 to 2013)

A key focus of the racing industry is to reduce the number of race-day events where horses die suddenly or are euthanased due to catastrophic injury. The objective of this study was therefore to determine risk factors for race-day fatalities in Thoroughbred racehorses, using a cohort of all horses participating in flat racing in Great Britain between 2000 and 2013. Horse-, race- and course-level data were collected and combined with all race-day fatalities, recorded by racecourse veterinarians in a central database. Associations between exposure variables and fatality were assessed using logistic regression analyses for (1) all starts in the dataset and (2) starts made on turf surfaces only. There were 806,764 starts in total, of which 548,571 were on turf surfaces. A total of 610 fatalities were recorded; 377 (61.8%) on turf. In both regression models, increased firmness of the going, increasing racing distance, increasing average horse performance, first year of racing and wearing eye cover for the first time all increased the odds of fatality. Generally, the odds of fatality also increased with increasing horse age whereas increasing number of previous starts reduced fatality odds. In the ‘all starts’ model, horses racing in an auction race were at 1.46 (95% confidence interval (CI) 1.06–2.01) times the odds of fatality compared with horses not racing in this race type. In the turf starts model, horses racing in Group 1 races were at 3.19 (95% CI 1.71–5.93) times the odds of fatality compared with horses not racing in this race type. Identification of novel risk factors including wearing eye cover and race type will help to inform strategies to further reduce the rate of fatality in flat racing horses, enhancing horse and jockey welfare and safety

Dynamic ventrorostral displacement of the dorsal laryngeal mucosa in horses.

The objectives of this report were to describe the occurrence and features of dynamic ventrorostral displacement of the dorsal laryngeal mucosa (VRDDLM) in a group of Thoroughbred horses presented for investigation of poor performance and/or abnormal respiratory noise. Records from 600, dynamic, endoscopic examinations of the upper respiratory tract of horses were reviewed. Horses with VRDDLM were identified as those in which the dorsal laryngeal mucosa progressively obscured the interarytenoid notch and dorsoaxial portion of the corniculate processes of the arytenoid cartilages during high-speed exercise. The condition was recognised in 12 horses. Concurrent abnormalities of the respiratory tract of eight horses were also identified and included, axial deviation of the aryepiglottic folds, vocal cord prolapse, unilateral and bilateral ventromedial luxation of the apex of the corniculate process of the arytenoid cartilage, and intermittent dorsal displacement of the soft palate. VRDDLM is a rare abnormality of the upper portion of the respiratory tract of horses that may be associated with abnormal respiratory noise and potentially poor performance. The significance of the condition is not known, but the presence of this condition in combination with other, obstructive diseases of the equine airway warrants further investigation

The application of exhaled breath analysis in racing Thoroughbreds and the influence of high intensity exercise and ambient temperature on the concentration of carbon monoxide and pH in exhaled breath

Analyses of exhaled breath (EB) and exhaled breath condensate (EBC) are non-invasive modalities for assessing the lower airways but these methods have not been applied to Thoroughbred racehorses in training. The aims of this study were to determine whether EB and EBC could be obtained from Thoroughbred racehorses in the field and to investigate the effects of exercise per se and during different ambient temperatures and humidity on exhaled concentrations of nitric oxide (eNO), carbon monoxide (eCO) and EBC pH. EB and EBC samples were obtained from 28 Thoroughbred racehorses pre- and post-exercise during warm (n = 23) and/or cold (n = 19) ambient temperatures. eNO was detected in 19/84 EB samples. eCO was measured in 39/42 EB samples pre-exercise (median 1.3 ppm) and concentrations decreased significantly post-exercise (median 0.8 ppm, P < 0.005) and were associated with ambient temperature. EBC pH was 4.51 ± 0.23 pre-exercise and increased significantly post-exercise (4.79 ± 0.59, P = 0.003). The study documented the collection of EB and EBC from Thoroughbred racehorses in a field setting. Alterations in concentrations of volatile gases and EBC pH occurred in response to exercise, and were likely to have been influenced by environmental factors