Efficacy of three corticosteroids for the treatment of heaves.

The research study investigates the effectiveness of three corticosteroids to treat a respiratory condition known as heaves in horses. The results showed that dexamethasone was the most effective in relieving airway obstruction, while oral prednisone showed varying results among the horses.

Study Design and Procedure

• The research used a cross-over design to assess the efficacy of the corticosteroids in relieving airway obstruction and inflammation in horses suffering from heaves.
• Airway obstruction was induced by keeping the horses stabled throughout the 10-day treatment period.
• The severity of the obstruction and inflammation was quantified by measuring lung function and bronchoalveolar lavage fluid (BALF) cytology, respectively.
• All the nine horses involved in the study underwent the same procedures, receiving the four treatments in random order. These were no treatment, daily oral prednisone tablets, daily intravenous dexamethasone solution, and intramuscular dexamethasone-21-isonicotinate every three days.

Findings and Results

• When the horses received no treatment, their lung function did not show significant changes while stabled but improved when they were in pasture.
• The study revealed that daily intravenous administration of dexamethasone solution caused a rapid improvement in lung function within three days. This improvement reached or even exceeded values obtained when horses were left at pasture.
• Dexamethasone-21-isonicotinate was also quick to show results, with eight out of nine horses demonstrating improved lung function. One horse did not respond to this particular treatment.
• On the other hand, oral prednisone tablets showed inconsistent results with no effect noticeable on the third and seventh days of treatment. However, by the tenth day, five out of nine horses showed some improvement in lung function.
• The research concluded that dexamethasone used intravenously rapidly relieves airway obstruction in horses affected by heaves.
• Oral prednisone, despite having erratic effects, might prove beneficial for some horses after more than a week of treatment.
• With regards to the effect of the treatments on BALF cytology, only dexamethasone intravenous solution resulted in a decrease in the percentage of neutrophils at Day 10 of treatment; the other treatments showed no significant effect on BALF cytology.