Pulmonary haemorrhage in standardbred horses after racing.

This study investigates the occurrence of blood in the trachea and other related conditions in Standardbred horses after races. Through endoscopic examinations on a voluntary sample of 92 horses, the researchers found that around 32.4% showed traces to large amounts of blood in their trachea. No direct relationships with factors such as the horse’s age, sex, race distance or placement were found.

Research Methodology

• The researchers used endoscopic examinations to investigate the upper respiratory tract of the horses. This method of examination is usually employed to visualize interior parts of the body by inserting a special instrument called an endoscope.
• The study involved the examination of 92 Standardbred horses that participated in one or more races at four consecutive, weekly race meetings. It is important to note that these examinations were voluntary, meaning that not all horses that raced were examined.

Observations

• A significant percentage, 32.4%, of the examined horses exhibited evidence of blood in their trachea, ranging from trace amounts in mucus to larger quantities on the tracheal walls. It is worth noting no visible bleeding or epistaxis (nosebleeds) were observed.
• Varying degrees of pharyngeal lymphoid hyperplasia were seen in 44 horses. This condition is a reaction of the lymphoid tissue in the throat to foreign bodies or irritants and can cause respiratory discomfort in the animals.
• Two horses had an abnormal movement of the left arytenoid cartilage. This is a structure in the larynx that controls the opening of the windpipe and can cause breathing problems if it’s not functioning correctly.
• Fifteen of the horses had grains of sand in their respiratory tract, another potential cause of discomfort or complications.

Findings and Conclusions

• Despite the significant percentage of horses showing signs of pulmonary haemorrhage (bleeding in the lungs), there was no correlation found with the horse’s age, sex, the distance of the race, race placement or the date of the race. This suggests that other factors may be responsible for the haemorrhage.
• A trend was noted where horses appeared to have less mucus and mucopurulent material after longer races and on the last 3 race nights. Mucopurulent material refers to a thick discharge produced during inflammation.
• The presence of conditions such as pharyngeal lymphoid hyperplasia, asynchronous movement of the left arytenoid cartilage, and sand grains in the respiratory tract might also have implications for the horse’s respiratory health and performance, and should be further investigated in future studies.