Environment and prednisone interactions in the treatment of recurrent airway obstruction (heaves).

The study investigates the effectiveness of environment management, specifically changing the bedding and diet of horses, and the use of oral prednisone to treat Recurrent Airway Obstruction (RAO) in horses. It found that altering the environment significantly improved lung function and reduced inflammation, while prednisone induced a quicker reduction in airway inflammation but did not further improve the airway function.

Research Methodology and Experiment

• The research involved twelve RAO-susceptible horses that were housed in stables, fed hay, and had their bedding made out of straw until they developed symptoms of airway obstruction.
• After this, the bedding was switched to wood shavings, and the horses were put on a pelleted diet for two weeks. During this period, the lung function of the horses was measured, and bronchoalveolar lavage (a procedure to obtain samples of lung cells) was carried out before and after the environmental modifications.
• In addition to this, the horses were also treated with prednisone tablets as part of the experiment. This part of the treatment was conducted in a ‘crossover design’, which means that horses were subjected to the treatment, then taken off it, and then put back on it.
• The airway obstruction, lung function, and inflammation levels were measured at regular intervals, before environmental modification, 3, 7, and 14 days after environmental modification, and after 30 days of being in the pasture.

Research Findings

• The study found that airway obstruction was significant before modifying the environment. However, lung function improved significantly within three days of changing the environment and continued to improve until Day 7.
• It was also observed that the improvement in lung function was best after the horses had spent 30 days at the pasture, indicating that reducing exposure to the allergens by changing the environment was a crucial aspect of treating RAO.
• The research findings also highlighted that the use of oral prednisone, while it led to a more rapid reduction in airway inflammation, did not result in a quicker improvement in airway function compared to the environmental modification alone.
• In terms of cellular changes, the total number of cells, as well as the number and proportion of neutrophils (a type of white blood cell), were all highest before the environmental changes were made. The numbers decreased over time when the horses were put on prednisone and continued to decrease when the horses were returned to the pasture.

Final Summary and Implications

• The research paper stresses the importance of allergen reduction as a significant part of the treatment protocol for Recurrent Airway Obstruction. This is because changes to the horses’ environment, such as the type of bedding and diet, showed marked improvement in lung function and reduction of inflammation.
• While prednisone resulted in the rapid reduction of airway inflammation, its effect on improving airway functionality was not significantly higher than that achieved through environment modification alone. This suggests that although prednisone can offer quick relief, it does not contribute significantly towards overall airway health improvement as compared to a good allergen management strategy.