Characteristic of Inflammatory Airway Disease in Japanese Thoroughbred Racehorses

Abstract

Inflammatory airway disease (IAD) is a common cause of poor performance, interruption of training and premature retirement in racehorses. It is also reported that up to 80% of horses are affected at some point in the first years of training in UK and Australia. However, no studies with regard to the information on occurrence of IAD in Japanese Thoroughbred racehorses have been reported. To investigate the occurrence and the characteristics of IAD, epidemic research including endoscopic examination of the airway tract and trachea wash was conducted for Thoroughbred racehorses presenting coughs or poor performance which airway tract disease was suspected stalled in training facility managed by Japan Racing Association. Fifty-six out of 76 Thoroughbred racehorses (73.7%) presenting coughing or poor performance were diagnosed as IAD. Mean incidence rate of IAD was 0.3% and it has been confirmed that constant number of IAD exists in Japan. Up to 35.7% of IAD horses showed upper airway abnormalities in some extent. There was a trend for IAD horses to use wood shavings for bedding and fed hay from the ground compared with the control group. Therefore, improvement of stabling environment may aid in preventing IAD. This study demonstrated that Japanese Thoroughbred racehorses are affected by IAD likewise other countries as well as demonstrated the characteristics of IAD which may contribute to the clarification of the pathogenesis of IAD.

Association between exercise-induced pulmonary hemorrhage and inflammatory airway disease in polo ponies

“…In racehorses with a history of poor performance, IAD occurrence was higher [18]. Young horses in training often present posterior airways inflammation characterized by cytological evidence in tracheobronchial aspirates [32].…”

Plasma protein changes in horse after prolonged physical exercise: A proteomic study

“…Augmented levels of the protease inhibitors α1-AT and α1-AT-RP may contribute to suppress elastase activity and indirectly inhibit elastase-related complement activation [72]. This protease increases after intense exercise in horse [43,73] as well as during airway inflammation [74], which often develops during prolonged movement and training [75][76][77]. Moreover, high levels of α1-AT have been found after intensified training in equine muscle biopsy [38].…”

Infectious risk factors and clinical indicators for tracheal mucus inBritishNationalHunt racehorses

“…Most studies of respiratory disease in British racehorses have focused on inflammatory airway disease detected by tracheal wash sampling (trIAD) in young horses (≤4 years old) in training for Flat racing [1][2][3][4][5][6]. Commonly diagnosed and often subclinical, trIAD is a syndrome of lower airway inflammation frequently defined by a combination of increased endoscopically visible tracheal mucus and evidence of neutrophilic inflammation in tracheal wash samples [3][4][5][6][7][8][9][10][11]. Prevalence estimates vary according to case definition, but range from 33% in young racehorses [3] to 7.1% (95% confidence interval [CI] 5.7-8.7) in older (≥3 years old) National Hunt racehorses [12].…”